US20110077707A1 - Dual-use sensor for rate responsive pacing and heart sound monitoring - Google Patents

Dual-use sensor for rate responsive pacing and heart sound monitoring Download PDF

Info

Publication number
US20110077707A1
US20110077707A1 US12/955,065 US95506510A US2011077707A1 US 20110077707 A1 US20110077707 A1 US 20110077707A1 US 95506510 A US95506510 A US 95506510A US 2011077707 A1 US2011077707 A1 US 2011077707A1
Authority
US
United States
Prior art keywords
activity level
signal
heart sound
heart
processing circuit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12/955,065
Inventor
Keith R. Maile
Krzysztof Z. Siejko
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US12/955,065 priority Critical patent/US20110077707A1/en
Publication of US20110077707A1 publication Critical patent/US20110077707A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00Electrotherapy; Circuits therefor
    • A61N1/18Applying electric currents by contact electrodes
    • A61N1/32Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/362Heart stimulators
    • A61N1/365Heart stimulators controlled by a physiological parameter, e.g. heart potential
    • A61N1/36514Heart stimulators controlled by a physiological parameter, e.g. heart potential controlled by a physiological quantity other than heart potential, e.g. blood pressure
    • A61N1/36542Heart stimulators controlled by a physiological parameter, e.g. heart potential controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by body motion, e.g. acceleration
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00Electrotherapy; Circuits therefor
    • A61N1/18Applying electric currents by contact electrodes
    • A61N1/32Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/362Heart stimulators
    • A61N1/365Heart stimulators controlled by a physiological parameter, e.g. heart potential
    • A61N1/36585Heart stimulators controlled by a physiological parameter, e.g. heart potential controlled by two or more physical parameters

Definitions

  • This document relates generally to cardiac rhythm management systems and particularly, but not by way of limitation, to such a system sensing heart sounds and delivering rate responsive pacing.
  • a heart is the center of a person's circulatory system. It includes an electromechanical system performing two major pumping functions. The left portions of the heart draw oxygenated blood from the lungs and pump it to the organs of the body to provide the organs with their metabolic needs for oxygen. The right portions of the heart draw deoxygenated blood from the organs and pump it into the lungs where the blood gets oxygenated. The body's metabolic need for oxygen increases with the body's physical activity level. The pumping functions are accomplished by contractions of the myocardium (heart muscles). An increase in the body's metabolic need for oxygen is satisfied primarily by a higher frequency of the contractions, i.e., a higher heart rate.
  • the sinoatrial node In a normal heart, the sinoatrial node, the heart's natural pacemaker, generates electrical impulses, called action potentials, that propagate through an electrical conduction system to various regions of the heart to excite myocardial tissues in these regions. Coordinated delays in the propagations of the action potentials in a normal electrical conduction system cause the various regions of the heart to contract in synchrony such that the pumping functions are performed efficiently.
  • ECG electrocardiography
  • Pacing therapy treats cardiac arrhythmias by using an implantable pacemaker to deliver electrical pulses that substitute for the action potentials to excite the myocardium, thereby restoring the functions of the sinoatrial note and/or the natural electrical conduction system.
  • a pacing mode referred to as rate responsive pacing, or rate adaptive pacing, uses an indication of the body's physical activity level to dynamically adjust the pacing rate, which determines the frequency of the contractions.
  • amplitudes of the third heart sound (S3) and fourth heart sound (S4) are related to filing pressures of the left ventricle during diastole.
  • Fundamental frequencies of S3 and S4 are related to ventricular stiffness and dimension.
  • Chronic changes in S3 amplitude is correlated to left ventricular chamber stiffness and degree of restrictive filling.
  • Change in the interval between atrial contraction and S4 is correlated to the changes in left ventricular end of diastolic pressure.
  • Such parameters being correlated to the heart's mechanical properties and electromechanical association, quantitatively indicate abnormal cardiac conditions such as heart failure, including degrees of severity, and need of appropriate therapies.
  • Implantability requires that any circuit or functional module of the implantable pacemaker to be designed for the minimum size and energy consumption.
  • An implantable medical device includes a dual-use sensor such as a single accelerometer that senses an acceleration signal.
  • a sensor processing circuit processes the acceleration signal to produce an activity level signal and a heart sound signal.
  • the implantable medical device provides for rate responsive pacing in which at least one pacing parameter, such as the pacing interval, is dynamically adjusted based on the physical activity level.
  • the implantable medical device also uses the heart sounds for pacing control purposes or transmits a heart sound signal to an external system for pacing control and/or diagnostic purposes.
  • a cardiac rhythm management system includes a sensing circuit, a pacing circuit, a dual-use sensor, a sensor processing circuit, and a controller.
  • the sensing circuit senses at least one electrogram.
  • the pacing circuit delivers pacing pulses.
  • the dual-use sensor senses a signal indicative of activities and heart sounds.
  • the sensor processing circuit produces an activity level signal and a heart sound signal from the sensed signal.
  • the controller includes a rate responsive pacing algorithm execution module dynamically adjusting at least a pacing interval based on at least the activity level signal.
  • a cardiac rhythm management system includes an accelerometer, a processing circuit, and a controller.
  • the accelerometer senses an acceleration signal indicative of physical activities and heart sounds.
  • the processing circuit has an input to receive the acceleration signal, an amplifier, and a band-pass filter.
  • the amplifier has a programmable gain.
  • the band-pass filter has one or more cutoff frequencies programmable for producing an activity level signal during first time periods and producing a heart sound signal during second time periods.
  • the controller includes a processing circuit programming module adapted to program the gain and the cutoff frequencies.
  • a cardiac rhythm management system includes an accelerometer to sense an acceleration signal, a first processing circuit, and a second processing circuit.
  • the first processing circuit includes a first input to receive the acceleration signal, a first output indicative of a physical activity level, and a first gain-and-filter circuit to provide for a first gain and a first set of cutoff frequencies.
  • the second processing circuit includes a second input to receive the acceleration signal, a second output indicative of heart sounds, and a second gain-and-filter circuit to provide for a second gain and a second set of cutoff frequencies.
  • a signal indicative of activities and heart sounds is sensed using a single implantable sensor.
  • the sensed signal is processed to produce an activity level signal and a heart sound signal.
  • a rate responsive pacing algorithm dynamically adjusts at least one pacing parameter based on the activity level signal.
  • At least one type of heart sounds is detected from the heart sound signal.
  • an acceleration signal indicative of an activity level and heart sounds is sensed.
  • An amplifier is programmed with a first gain suitable for sensing the activity level for a first time period.
  • a band-pass filter is programmed with a first set of cutoff frequencies suitable for sensing the activity level for the first time period.
  • the sensed acceleration signal is amplified and filtered to produce an activity level signal.
  • the amplifier is programmed with a second gain suitable for sensing the heart sounds for a second time period.
  • the band-pass filter is programmed with a second set of cutoff frequencies suitable for sensing the heart sounds for the second time period.
  • the sensed acceleration signal is amplified and filtered to produce a heart sound signal.
  • an acceleration signal is sensed.
  • An activity level signal and a heart sound signal is produced concurrently from the acceleration signal by amplifying and filtering.
  • the acceleration signal is amplified with a first gain and filtered with a first set of cutoff frequencies suitable for producing the activity level signal, and is amplified with a second gain and filtered with a second set of cutoff frequencies suitable for producing the heart sound signal.
  • FIG. 1 is a block diagram illustrating an embodiment of a cardiac rhythm management system, including an implantable medical device, and portions of an environment in which it is used.
  • FIG. 2A is a block diagram illustrating an embodiment of a circuit of the implantable medical device.
  • FIG. 2B is a block diagram illustrating an embodiment of a controller being a part of the circuit of the implantable medical device.
  • FIG. 3 is a block diagram illustrating an embodiment of a circuit including a dual-use sensor and a sensor processing circuit for sensing a physical activity level and a heart sound signal.
  • FIG. 4 is a block diagram illustrating another embodiment of the circuit including the dual-use sensor and the sensor processing circuit for sensing the physical activity level and the heart sound signal.
  • FIG. 5A is a block diagram illustrating an embodiment of the circuit of FIG. 3 in which the sensor processing circuit includes an additional preconditioning circuit.
  • FIG. 5B is a block diagram illustrating an embodiment of the circuit of FIG. 4 in which the sensor processing circuit includes an additional preconditioning circuit.
  • FIG. 5C is a block diagram illustrating an embodiment of a circuit of the additional preconditioning circuit.
  • FIG. 6 is a flow chart illustrating an embodiment of a method for sensing the physical activity level and the heart sounds by using the circuit of FIGS. 3 and 5 .
  • FIG. 7 is a flow chart illustrating an embodiment of a method for sensing the physical activity level and the heart sounds by using the circuit of FIGS. 4 and 5 .
  • references to “an”, “one”, or “various” embodiments in this disclosure are not necessarily to the same embodiment, and such references contemplate more than one embodiment.
  • the cardiac rhythm management system includes, for example, an implantable medical device including such as a pacemaker, a pacemaker/defibrillator, a pacemaker/drug delivery device, or a cardiac resynchronization therapy (CRT) device.
  • the implantable medical device provides for rate responsive pacing and heart sound sensing.
  • Rate response pacing also referred to as rate adaptive pacing, uses an indication of a patient's gross physical activity level to adjust a pacing rate, such that the cardiac output as a result of pacing meets or approaches the patient's metabolic need.
  • rate responsive pacing using acceleration to adjust the pacing rate is discussed in U.S. Pat. No. 5,179,947, entitled “ACCELERATION-SENSITIVE CARDIAC PACEMAKER AND METHOD OF OPERATION,” assigned to Cardiac Pacemakers, Inc., which is hereby incorporated by reference in its entirety.
  • Known and studied heart sounds include the “first heart sound,” or S1, the “second heart sound,” or S2, the “third heart sound,” or S3, the “fourth heart sound,” or S4, and their various sub-components.
  • S1 is known to be indicative of, among other things, mitral valve closure, tricuspid valve closure, and aortic valve opening.
  • S2 is known to be indicative of, among other things, aortic valve closure and pulmonary valve closure.
  • S3 is known to be a ventricular diastolic filling sound often indicative of certain pathological conditions including heart failure.
  • S4 is known to be a ventricular diastolic filling sound resulted from atrial contraction and is usually indicative of pathological conditions.
  • heart sound hereinafter refers to any heart sound (e.g., S1) and any components thereof (e.g., M1 component of S1, indicative of Mitral valve closure and Mitral regurgitation).
  • Heart sounds are used, for example, to calculate pacing parameters for improving the patient's hemodynamic performance and diagnosing a pathological condition such as heart failure. Examples of such uses are discussed in U.S. patent application Ser. No. 10/307,896, now issued as U.S. Pat. No. 7,123,962, entitled “PHONOCARDIOGRAPHIC IMAGE-BASED ATRIOVENTRICULAR DELAY OPTIMIZATION,” and U.S. patent application Ser. No.
  • An accelerometer can be used to sense both the physical activity level for rate responsive pacing and the heart sounds because the two signals feature substantially distinguishable spectrums.
  • the acceleration measured in the direction normal to a person's chest wall is indicative of both the physical activity level and the heart sounds.
  • the sensor specifications required for sensing the physical activity level and the sensor specifications required for sensing the heart sounds, such as bandwidth, sensitivity, noise floor, robustness, size, and power consumption are sufficiently close such that they can be satisfied by a single accelerometer having adequate size and power consumption for used in an implantable medical device.
  • a sensor processing circuit processes the signal sensed by such an accelerometer to produce an activity level signal indicative of the physical activity level for rate responsive pacing and a heart sound signal from which heart sounds of each type can be detected.
  • a “heart sound signal” includes audible and inaudible mechanical vibrations of the heart that can be sensed with a sensor such as an accelerometer.
  • a “heart sound” refers to a recognized event in the heart sound signal.
  • S1, S2, S3, and S4 refer to the first, second, third, and fourth heart sounds, respectively, as a heart sound type, or as one or more occurrences of the corresponding type heart sounds, depending on the context.
  • An “electrogram” includes an electrocardiogram (ECG) sensed with at least an intracardiac electrode placed in the heart or an epicardial electrode placed on the heart.
  • ECG electrocardiogram
  • a “user” includes a physician or other caregiver who examines and/or treats a patient using one or more of the methods and apparatuses discussed in the present document.
  • FIG. 1 is a block diagram illustrating an embodiment of a cardiac rhythm management system 100 , and portions of an environment in which it is used.
  • System 100 includes an implantable medical device 110 , a lead system 108 , an external system 170 , and a wireless telemetry link 160 .
  • implantable medical device 110 operates within a body 102 to sense activities of a heart 105 and deliver one or more therapies to heart 105 .
  • Implantable medical device 110 includes a pacemaker capable of rate responsive pacing.
  • implantable medical device 110 is an implantable pacemaker.
  • implantable medical device 110 includes a pacemaker module and one or more other therapeutic modules, such as a cardioversion-defibrillation module and a drug delivery module.
  • the pacemaker includes a cardiac resynchronization therapy module capable of delivering multi-site biventricular pacing.
  • Implantable medical device 110 senses an activity level for rate responsive pacing purposes and heart sounds for various diagnostic and/or therapy control purposes.
  • a dual-use sensor such as an accelerometer is used for sensing both the activity level and the heart sounds. In one embodiment, the dual-use sensor is within implantable medical device 110 .
  • Lead system 108 provides one or more electrical connections between implantable medical device 110 and heart 105 . It includes one or more pacing leads each having one or more electrodes for electrogram sensing and pacing pulse delivery. In one embodiment, the dual-use sensor is incorporated into a lead of lead system 108 and connected to implantable medical device through the lead.
  • External system 170 communicates with implantable medical device 110 . It allows a user and/or a patient to communicate and/or to control the operation of implantable medical device 110 .
  • external system 170 includes an external programmer.
  • external system 170 includes an advanced patient management system, such as discussed in U.S. patent application Ser. No. 10/323,604, entitled “ADVANCED PATIENT MANAGEMENT FOR DEFINING, IDENTIFYING AND USING PREDETERMINED HEALTH-RELATED EVENTS,” assigned to Cardiac Pacemakers, Inc., the specification of which is incorporated herein by reference in its entirety.
  • the advanced patient management system allows the user to access implantable medical device 110 from a remote location.
  • Telemetry link 160 provides for data transmissions between implantable medical device 110 and external system 170 .
  • telemetry link 160 is an inductive telemetry link.
  • telemetry link 160 is a far-field radio-frequency telemetry link.
  • Telemetry link 160 provides for data transmission from implantable medical device 110 to external system 170 . This may include, for example, transmitting real-time physiological data acquired by implantable medical device 110 , extracting physiological data acquired by and stored in implantable medical device 110 , extracting therapy history data stored in implantable medical device 110 , and extracting data indicating an operational status of implantable medical device 110 (e.g., battery status and lead impedance).
  • Telemetry link 160 also provides for data transmission from external system 170 to implantable medical device 110 .
  • This may include, for example, programming implantable medical device 110 to acquire physiological data, programming implantable medical device 110 to perform at least one self-diagnostic test (such as for a battery status and lead impedance status), and programming implantable medical device 110 to deliver at least one therapy.
  • signals represented by the physiological data include, but are not limited to, electrograms, heart sounds or signals indicative of heart sounds, activity level signals, and respiratory signals.
  • the physiological data also include parameters measured from one or more of these signals.
  • external system 170 or a user determines and/or adjusts a therapy based on these signals and/or physiological data.
  • FIG. 2A is a block diagram illustrating an embodiment of a circuit of implantable medical device 110 .
  • Implantable medical device 110 includes a sensing circuit 212 , a pacing circuit 214 , a dual-use sensor 216 , a sensor processing circuit 218 , a heart sound detector 220 , an implant controller 222 , a memory circuit 224 , and an implant telemetry module 226 .
  • these circuit elements, and possibly additional circuit elements of implantable medical device 110 are encapsulated in a hermetically sealed implantable housing.
  • some of these circuit elements, such as dual-use sensor 216 or implant telemetry module 224 are located outside of the hermetically sealed implantable housing.
  • Sensing circuit 212 and pacing circuit 214 are both electrically coupled to heart 105 via lead system 108 .
  • Sensing circuit 212 includes an amplifier circuit suitable for sensing one or more electrograms from heart 108 through lead system 108 .
  • Pacing circuit 214 includes a pulse generator generating electrical pacing pulses that are delivered to heart 105 through lead system 108 .
  • Dual-use sensor 216 senses a signal indicative of two activities, events, or quantities having distinguishable frequency characteristics.
  • the term “dual-use” refers to the fact that the two activities, events, or quantities are extracted separately from the signal and used for different purposes serving the functions of system 100 .
  • dual-use sensor 216 includes a single accelerometer that senses an acceleration signal indicative of a patient's gross physical activity level and heart sounds of the patient.
  • dual-use sensor 216 is an integrated circuit accelerometer.
  • a specific example of such an integrated circuit accelerometer is a piezoelectric accelerometer made by Endevco Corporation (Model 12 Picochip Accelerometer). Other examples include piezoresistive and capacitive accelerometers.
  • dual-use sensor 216 is encapsulated in the hermetically sealed implantable housing. This embodiment provides the accelerometer with an environment ensuring a stable operation. In an alternative embodiment, dual-use sensor 216 is incorporated into a lead of lead system 108 . This embodiment allows the accelerometer to be located in or near heart 105 , thus being more sensitive to the heart's mechanical activities such as vibrations (heart sounds).
  • Sensor processing circuit 218 processes the acceleration signal to produce an activity level signal indicative of the patient's gross physical activity level and a heart sound signal indicative of the patient's heart sounds. Embodiments of sensor processing circuit 218 are discussed below, with reference to FIGS. 3-5 .
  • heart sound detector 220 detects heart sounds from the heart sound signal produced by sensor processing circuit 218 .
  • implantable controller 222 receives the detected heart sounds use it, in addition to the activity level signal, for rate responsive pacing purposes.
  • implantable controller 222 uses the detected heart sounds for adjusting atrioventricular and/or interventricular pacing delays, such as in a cardiac resynchronization therapy for heart failure.
  • the detected heart sounds, and/or parameters measured from the detected heart sounds are also transmitted to external system 170 through telemetry link 160 for further analysis by the system or the user.
  • the heart sound signal is transmitted to external system 170 though telemetry link 160 .
  • External system 170 detects and analyzes the heart sound signal for diagnostic and/or pacing control purposes.
  • Heart sound detector 220 is configured and/or programmed by external system 170 to detect one or more of the S1, S2, S3, and S4 type heart sounds.
  • Implant controller 222 controls the operation of the entire implantable medical device 110 .
  • An embodiment of implantable device 222 is discussed below, with reference to FIG. 2B .
  • implant controller 222 is implemented using a microprocessor.
  • Memory circuit 224 provides a storage medium for a device control code, parameters for the operation of implantable medical device 110 , and the data acquired by implantable medical device 110 .
  • memory circuit 224 includes a buffer for storing the signal sensed by dual-use sensor 216 , the activity level signal produced by sensor processing circuit 218 , and/or the heart sound signal produced by sensor processing circuit 218 .
  • the buffer also stores the one or more electrograms sensed by sensing circuit 212 .
  • implant controller 222 includes an event detector to detect cardiac events and a maker generator to generate event markers representing the cardiac events. Examples of such cardiac events include sensed events (intrinsic depolarizations) and paced events (paced contractions or pulse deliveries) associated with one or more cardiac sites. Each event mark is indicative of the type and the timing of one cardiac event.
  • the buffer further stores the event markers.
  • the activity level signal and/or the heart sound signal are synchronized with the event markers such that the event markers serve as a timing reference relating the activity level and/or heart sound to the cardiac events.
  • implant controller 222 includes an analog-to-digital converter to digitize one or more of the signal sensed by dual-use sensor 216 , the activity level signal, the heart sound signal, and the electrograms for storage and/or further processing.
  • the analog-to-digital converter has a programmable sampling rate.
  • Implantable controller 222 includes a digitization control module to control this sampling rate. In one embodiment, the sampling rate is programmable through external system 170 .
  • Implant telemetry module 226 includes an antenna and a transceiver to support two-way communications with external system 170 via telemetry link 160 .
  • one or more of the electrograms, the event markers, the signal sensed by dual-use sensor 216 , the activity level signal, and the heart sound signal are transmitted to external system 170 in real time.
  • one or more of the electrograms, the event markers, the signal sensed by dual-use sensor 216 , the activity level signal, and the heart sound signal are stored in the buffer of memory circuit 224 and retrieved from the buffer when needed.
  • the retrieval occurs at predetermined times as controlled by implant controller 222 .
  • the retrieval occurs in response to a command from external system 170 .
  • FIG. 2B is a block diagram illustrating an embodiment of implant controller 222 .
  • Implant controller 222 executes the device control code stored in memory circuit 224 . It includes, among other control modules, a rate responsive pacing algorithm execution module 230 and a sensor processing circuit programming module 232 .
  • Rate responsive pacing algorithm execution module 230 controls the timing of the pacing pulse delivery from pacing circuit 214 , based on predefined pacing logic and timing rules and one or more of the activity level signal, the sensed electrograms, timing of previous pacing pulse deliveries, the detected heart sounds, and possibly other physiological signals indicative of electrical events, mechanical activities, and/or hemodynamic performance of heart 105 . It includes a pacing interval calculator to calculate a pacing interval based on at least the activity level signal and predetermined maximum and minimum pacing intervals. When the pacing interval calculator produces a new value for the pacing interval, rate responsive pacing algorithm execution module 230 updates the pacing interval with the new value. In one embodiment, rate responsive pacing algorithm execution module 230 performs the calculation and the update dynamically, for each and every heart beat.
  • sensor processing circuit programming module 232 controls the timing, gain, and/or frequency responses of sensor processing circuit 218 to produce the activity level signal and the heart sound signal.
  • the programming of sensor processing circuit 218 is discussed below with reference to FIGS. 3 and 4 .
  • FIG. 3 is a block diagram illustrating an embodiment of a circuit including an accelerometer 316 for sensing the acceleration signal and a sensor processing circuit 318 for producing the activity level signal and the heart sound signal from the acceleration signal.
  • Accelerometer 316 is one embodiment of dual-use sensor 216 or a portion thereof.
  • Sensor processing circuit 318 is one embodiment of sensor processing circuit 218 or a portion thereof.
  • Sensor processing circuit 318 includes an amplifier 340 , a band-pass filter 342 , and a demultiplexer (DEMUX) 343 . It produces the activity level signal and the heart sound signal from the acceleration signal sense by accelerometer 316 on a time-sharing basis. During predetermined first time periods, sensor processing circuit 318 produces the activity level signal. During predetermined second time periods, sensor processing circuit 318 produces the heart sound signal. The first and second time periods do not overlap. Sensor processing circuit programming module 232 controls the first time periods for producing the activity level signal and the second time periods for producing the heart sound signal by programming the gain of amplifier 340 , the cutoff frequencies of band-pass filter 342 , and the connections within demultiplexer 343 .
  • DEMUX demultiplexer
  • sensor processing circuit 318 has an input to receive the acceleration signal, an output representative of the activity level signal during the first periods, and another output representative of the heart sound signal during the second periods.
  • the gain and/or the cutoff frequencies are predetermined and stored in memory circuit 224 .
  • the gain and/or the cutoff frequencies are empirically determined based on data collected from the patient treated with system 100 , and programmed into implantable medical device 110 by using external system 170 .
  • the gain and/or the cutoff frequencies are adjustable by the user, when necessary, after the implantation of implantable medical device 110 . The adjustments may become necessary when, for example, the range of the amplitude of the sensed acceleration signal has significantly changed, or when a different type of the heart sound is sought.
  • Demultiplexer 343 receives the output of band-pass filter 342 and provides two outputs separately representing the activity level signal and the heart sound signal.
  • the gain of amplifier 340 is a first gain programmable in the range of 100 to 500.
  • the cutoff frequencies of band-pass filter 342 are a first set of cutoff frequencies including a first low cutoff frequency programmable in a range of 0.5 Hz to 2 Hz and a first high cutoff frequency programmable in a range of 5 Hz to 15 Hz.
  • sensor processing circuit programming module 232 programs the first gain to 125, the first low cutoff frequency to 1 Hz, and the first high cutoff frequency to 10 Hz during the predetermined first time periods.
  • the gain of amplifier 340 is a second gain programmable in the range of 500 to 2000.
  • the cutoff frequencies of band-pass filter 342 are a second set of cutoff frequencies including a second low cutoff frequency programmable in a range of 5 Hz to 10 Hz and a second high cutoff frequency programmable in a range of 50 Hz to 200 Hz.
  • sensor processing circuit programming module 232 programs the second gain to 1000, the second low cutoff frequency to 10 Hz, and the second high cutoff frequency to 100 Hz during the predetermined second time periods.
  • Sensor processing circuit 318 requires only one set of an amplifier and a filter to produce both the activity level signal and the heart sound signal. It is suitable for applications in which the activity level and the heart sounds need not be sensed concurrently. For an implantable pacemaker that already requires an accelerometer for the purpose of rate responsive pacing, sensor processing circuit 318 provides for heart sound sensing with minimal additional requirement for circuit size and energy consumption.
  • FIG. 4 is a block diagram illustrating another embodiment of the circuit including accelerometer 316 for sensing the acceleration signal and a sensor processing circuit 418 for concurrently producing the activity level signal and the heart sound signal from the acceleration signal.
  • Accelerometer 316 is one embodiment of dual-use sensor 216 or a portion thereof.
  • Sensor processing circuit 418 is one embodiment of sensor processing circuit 218 or a portion thereof.
  • Sensor processing circuit 418 includes a first processing circuit 450 A for producing the activity level signal and a second processing circuit 450 B for producing the heart sound signal.
  • First processing circuit 450 A includes a first amplifier 440 A having a first gain and a first band-pass filter 442 A having a first set of cutoff frequencies.
  • Second processing circuit 450 B includes a second amplifier 440 B having a second gain and a second band-pass filter 442 B having a second set of cutoff frequencies.
  • First processing circuit 450 A and second processing circuit 450 B operate in parallel to allow concurrent sensing of the physical activity level and the heart sounds.
  • sensor processing circuit 418 has an input to receive the acceleration signal, an output representative of the activity level signal, and another output representative of the heart sound signal.
  • the gains and/or the cutoffs frequencies are predetermined and stored in memory circuit 224 . While there is no need to program the gains and the cutoff frequencies for the time-sharing purpose, in one embodiment, the gains and/or the cutoffs frequencies are programmable to ensure proper sensing under each patient's particular circumstances. In one embodiment, the gain and/or the cutoff frequencies are empirically determined based on data collected from the patient, and programmed into implantable medical device 110 by using external system 170 . In one embodiment, the gain and/or the cutoff frequencies are adjustable by the user, when necessary, after the implantation of implantable medical device 110 .
  • the gain of amplifier 440 A (the first gain) is programmable in the range of 100 to 500.
  • the cutoff frequencies of band-pass filter 442 A include a first low cutoff frequency programmable in a range of 0.5 Hz to 2 Hz and a first high cutoff frequency programmable in a range of 5 Hz to 15 Hz.
  • sensor processing circuit programming module 232 programs the first gain to 125, the first low cutoff frequency to 1 Hz, and the first high cutoff frequency to 10 Hz during the predetermined first time periods.
  • the gain of amplifier 440 B (the second gain) is programmable in the range of 500 to 2000.
  • the cutoff frequencies of band-pass filter 442 B include a second low cutoff frequency programmable in a range of 5 Hz to 10 Hz and a second high cutoff frequency programmable in a range of 50 Hz to 200 Hz.
  • sensor processing circuit programming module 232 programs the second gain to 1000, the second low cutoff frequency to 10 Hz, and the second high cutoff frequency to 100 Hz during the predetermined second time periods.
  • Sensor processing circuit 418 allows concurrent sensing of the activity level and the heart sounds. With sensor processing circuit 418 , dual-use sensor 216 is usable for sensing the activity level and the heart sounds simultaneously when needed.
  • FIG. 5A is a block diagram illustrating an embodiment of the circuit of FIG. 3 with an additional preconditioning circuit 552 .
  • sensor processing circuit 218 includes preconditioning circuit 552 with its input connected to accelerometer 316 and its output connected to sensor processing circuit 318 .
  • FIG. 5B is a block diagram illustrating an embodiment of the circuit of FIG. 4 with an additional preconditioning circuit 552 .
  • sensor processing circuit 218 includes preconditioning circuit 552 with its input connected to accelerometer 316 and its output connected to sensor processing circuit 418 .
  • FIG. 5C is a block diagram illustrating an embodiment of a circuit of preconditioning circuit 552 .
  • Preconditioning circuit 552 provides for initial conditioning or processing of the acceleration signal before being processed for producing the activity level signal and the heart sound signal.
  • preconditioning circuit 552 includes a preconditioning amplifier 554 having a preconditioning gain and a preconditioning band-pass filter 556 having a set of preconditioning cutoff frequencies.
  • the preconditioning gain is programmable in the range of 100 to 500.
  • the overall gains for producing the activity signal and the heart sound signal are products of the preconditioning gain (gain of preconditioning amplifier 554 ) multiplied by the gains of sensor processing circuit 318 or 418 as discussed above.
  • the gains to be programmed to sensor processing circuit 318 or 418 are calculated by dividing the gains discussed above by the programmed preconditioning gain.
  • the gain of amplifier 340 includes a first gain in the range of 100 to 500 divided by the preconditioning gain for producing the activity signal, and a second gain in the range of 500 to 2000 divided by the preconditioning gain for producing the heart sound signal.
  • the gain of amplifier 440 A (the first gain) is in the range of 100 to 500 divided by the preconditioning gain.
  • the gain of amplifier 440 B (the second gain) is in the range of 500 to 2000 divided by the preconditioning gain.
  • the set of preconditioning cutoff frequencies includes a low preconditioning cutoff frequency programmable in the range of 0.5 to 2 Hz, and a high preconditioning cutoff frequency programmable in the range of 50 to 200 Hz.
  • the preconditioning gain is 125, the low preconditioning cutoff frequency is 1 Hz, the high preconditioning cutoff frequency programmable is 100 Hz, the first gain for amplifier 340 is 1, and the second gain for amplifier 340 is 8.
  • the preconditioning gain is 125, the low preconditioning cutoff frequency is 1 Hz, the high preconditioning cutoff frequency programmable is 100 Hz, the gain for amplifier 440 A is 1, and the gain for amplifier 440 B is 8.
  • preconditioning circuit 552 further includes an analog-to-digital converter (ADC) 558 to digitize the acceleration signal.
  • ADC analog-to-digital converter
  • sensor processing circuit 318 or sensor processing circuit 418 to be implemented with digital technology. That is, the activity level signal and the heart sound signal are digital signals produced from the digitized acceleration signal using digital signal processing.
  • ADC 558 has a programmable sampling rate
  • implantable controller 222 includes a digitization control module to control this sampling rate.
  • the sampling rate is programmable through external system 170 .
  • sensor processing circuit 218 can be implemented with hardware, software, and a combination of both.
  • FIG. 6 is a flow chart illustrating an embodiment of a method for sensing the physical activity level and the heart sounds with the circuit illustrated in FIGS. 3 and 5 .
  • the method illustrates by way of example, but not by way of limitation, a use of the circuit that includes accelerometer 316 , preconditioning circuit 552 , and sensor processing circuit 318 .
  • Accelerometer 316 senses an acceleration signal at 600 .
  • Preconditioning circuit 552 preconditions the sensed acceleration signal at 605 .
  • preconditioning circuit 552 amplifies and filters the sensed acceleration signal.
  • preconditioning circuit 552 digitizes the sensed acceleration signal. The digitization allows subsequent processing to be performed using digital signal processing technology.
  • Sensor processing circuit 318 is programmed with the first gain and the first set of cutoff frequencies for first time periods at 610 . During the first time periods, sensor processing circuit 318 amplifies and filters the acceleration signal to produce the activity level signal at 620 . Sensor processing circuit 318 is programmed with the second gain and the second set of cutoff frequencies for second time periods at 630 . During the second time periods, sensor processing circuit 318 amplifies and filters the acceleration signal to produce the heart sound signal at 640 . In one embodiment, the first and second time periods are programmed into memory circuit 224 for use by sensor processing circuit programming module 232 , which programs the gain and the cutoff frequencies of sensor processing circuit 318 . The first and second time periods do not overlap.
  • Rate responsive pacing algorithm execution module 230 adjusts a pacing parameter such as the pacing interval based on at least the activity level signal at 650 . In one embodiment, rate responsive pacing algorithm execution module 230 also adjusts the pacing interval and/or one or more other pacing parameters based on other signals such as the electrograms and the heart sound signal.
  • Heart sounds are detected from the heart sound at 660 .
  • heart sound detector 220 which is a part of implantable medical device 110 , detects the heart sounds from the heart sound signal.
  • the detected hearts sounds are used by implant controller 222 for pacing control purposes.
  • the heart sound signal and/or information extracted from the detected heart sounds are transmitted to external system 170 .
  • the heart sound signal is transmitted to external system 170 , which includes a heart sound detector to detect the heart sounds.
  • the heart sound detection includes detection of predetermined types of heart sounds including one or more of S1, S2, S3, and S4.
  • the heart sounds are analyzed at 670 .
  • the analysis includes measurement of, for example, one or more of amplitude of any type heart sound, relative amplitude between any two types of heart sounds, duration of each type heart sound, interval between any type or types of heart sounds, interval between any type heart sound and any type electrical event of the heart, fundamental frequency of each type heart sound, and harmonic frequency of each type heart sound.
  • the results of the analysis such as parameters generated from the above measurements, are used to determine a pacing parameter based on the heart sounds at 680 .
  • determining a pacing parameter based on the heart sounds is discussed in U.S. patent application Ser. No. 10/307,896.
  • one or more parameters generated from the above measurements are trended at 690 .
  • trending heart sound related parameters is discussed in U.S. patent application Ser. No. 10/334,694.
  • FIG. 7 is a flow chart illustrating an embodiment of a method for sensing the physical activity level and the heart sounds with the circuit illustrated in FIGS. 4 and 5 .
  • the method illustrates by way of example, but not by way of limitation, a use of the circuit that includes accelerometer 316 , preconditioning circuit 552 , and sensor processing circuit 418 .
  • Accelerometer 316 senses an acceleration signal at 700 .
  • Preconditioning circuit 552 preconditions the sensed acceleration signal at 705 .
  • preconditioning circuit 552 amplifies and filters the sensed acceleration signal.
  • preconditioning circuit 552 digitizes the sensed acceleration signal. The digitization allows subsequent processing to be performed using digital signal processing technology.
  • First processing circuit 450 A of sensor processing circuit 418 produces the activity level signal from the acceleration signal at 710 . This includes amplifying the acceleration signal with the first gain at 712 and filtering the acceleration signal with the first set of cutoff frequencies at 714 .
  • Rate responsive pacing algorithm execution module 230 adjusts a pacing parameter such as the pacing interval based on the activity level signal at 720 . In one embodiment, rate responsive pacing algorithm execution module 230 also adjusts the pacing interval and/or one or more other pacing parameters based on other signals such as the electrograms and the heart sound signal.
  • Second processing circuit 450 B of sensor processing circuit 418 produces the heart sound signal from the acceleration signal at 730 . This includes amplifying the acceleration signal with the second gain at 732 and filtering the acceleration signal with the second set of cutoff frequencies at 734 .
  • Heart sounds are detected from the heart sound signal at 740 and analyzed at 750 .
  • the results of the analysis are used to determine a pacing parameter based on the heart sounds at 760 .
  • the results of the analysis are used for trending one or more parameters measured from the heart sounds at 770 .
  • step 660 is identical or similar to step 740
  • step 670 is identical or similar to step 750
  • step 680 is identical or similar to step 760
  • step 690 is identical or similar to step 770 .
  • first processing circuit 450 A and second processing circuit 450 B are separate circuits producing distinguished signals from a common signal, step 710 (and its subsequent step 720 ) and step 730 (and its subsequent steps 740 , 750 , 760 , and 770 ) can be performed concurrently.
  • the sensor processing circuit can be expanded to produce additional signals from the acceleration signal, such as a respiration-indicative signal, if the additional signals each have a distinguishable spectrum.
  • additional signals such as a respiration-indicative signal

Abstract

An implantable medical device includes a dual-use sensor such as a single accelerometer that senses an acceleration signal. A sensor processing circuit processes the acceleration signal to produce an activity level signal and a heart sound signal. The implantable medical device provides for rate responsive pacing in which at least one pacing parameter, such as the pacing interval, is dynamically adjusted based on the physical activity level. The implantable medical device also uses the heart sounds for pacing control purposes or transmits a heart sound signal to an external system for pacing control and/or diagnostic purposes.

Description

    CROSS-REFERENCE TO RELATED APPLICATIONS
  • This application is a continuation of U.S. patent application Ser. No. 11/778,527, filed on Jul. 16, 2007, which is a continuation of U.S. patent application Ser. No. 10/703,175, filed on Nov. 6, 2003, now issued as U.S. Pat. No. 7,248,923, the specifications of which are incorporated herein by reference.
  • This application is related to commonly assigned U.S. patent application Ser. No. 10/307,896, entitled “PHONOCARDIOGRAPHIC IMAGE-BASED ATRIOVENTRICULAR DELAY OPTIMIZATION,” filed on Dec. 2, 2002, now issued as U.S. Pat. No. 7,123,962, and U.S. patent application Ser. No. 10/334,694, entitled “METHOD AND APPARATUS FOR MONITORING OF DIASTOLIC HEMODYNAMICS,” filed on Dec. 30, 2002, which are hereby incorporated by reference.
  • TECHNICAL FIELD
  • This document relates generally to cardiac rhythm management systems and particularly, but not by way of limitation, to such a system sensing heart sounds and delivering rate responsive pacing.
  • BACKGROUND
  • A heart is the center of a person's circulatory system. It includes an electromechanical system performing two major pumping functions. The left portions of the heart draw oxygenated blood from the lungs and pump it to the organs of the body to provide the organs with their metabolic needs for oxygen. The right portions of the heart draw deoxygenated blood from the organs and pump it into the lungs where the blood gets oxygenated. The body's metabolic need for oxygen increases with the body's physical activity level. The pumping functions are accomplished by contractions of the myocardium (heart muscles). An increase in the body's metabolic need for oxygen is satisfied primarily by a higher frequency of the contractions, i.e., a higher heart rate. In a normal heart, the sinoatrial node, the heart's natural pacemaker, generates electrical impulses, called action potentials, that propagate through an electrical conduction system to various regions of the heart to excite myocardial tissues in these regions. Coordinated delays in the propagations of the action potentials in a normal electrical conduction system cause the various regions of the heart to contract in synchrony such that the pumping functions are performed efficiently.
  • The functions of the sinoatrial node and the electrical conduction system are indicated by electrocardiography (ECG) with at least two electrodes placed in or about the heart to sense the action potentials. When the heart contracts irregularly or otherwise abnormally, one or more ECG signals indicate that contractions at various cardiac regions are chaotic and unsynchronized. Such conditions are known as cardiac arrhythmias. Cardiac arrhythmias result in a reduced pumping efficiency of the heart, and hence, diminished blood circulation.
  • Pacing therapy treats cardiac arrhythmias by using an implantable pacemaker to deliver electrical pulses that substitute for the action potentials to excite the myocardium, thereby restoring the functions of the sinoatrial note and/or the natural electrical conduction system. To ensure that the body receives sufficient oxygen to satisfy its metabolic needs, a pacing mode referred to as rate responsive pacing, or rate adaptive pacing, uses an indication of the body's physical activity level to dynamically adjust the pacing rate, which determines the frequency of the contractions.
  • Various mechanical functions of the heart, as well as electro-mechanical association between the electrical conduction system and the myocardium, are indicated by heart sounds. For example, amplitudes of the third heart sound (S3) and fourth heart sound (S4) are related to filing pressures of the left ventricle during diastole. Fundamental frequencies of S3 and S4 are related to ventricular stiffness and dimension. Chronic changes in S3 amplitude is correlated to left ventricular chamber stiffness and degree of restrictive filling. Change in the interval between atrial contraction and S4 is correlated to the changes in left ventricular end of diastolic pressure. Such parameters, being correlated to the heart's mechanical properties and electromechanical association, quantitatively indicate abnormal cardiac conditions such as heart failure, including degrees of severity, and need of appropriate therapies.
  • For these and other reasons, there is a need for an implantable pacemaker that senses the body's physical activity level and the heart sounds. Implantability requires that any circuit or functional module of the implantable pacemaker to be designed for the minimum size and energy consumption.
  • SUMMARY
  • An implantable medical device includes a dual-use sensor such as a single accelerometer that senses an acceleration signal. A sensor processing circuit processes the acceleration signal to produce an activity level signal and a heart sound signal. The implantable medical device provides for rate responsive pacing in which at least one pacing parameter, such as the pacing interval, is dynamically adjusted based on the physical activity level. The implantable medical device also uses the heart sounds for pacing control purposes or transmits a heart sound signal to an external system for pacing control and/or diagnostic purposes.
  • In one embodiment, a cardiac rhythm management system includes a sensing circuit, a pacing circuit, a dual-use sensor, a sensor processing circuit, and a controller. The sensing circuit senses at least one electrogram. The pacing circuit delivers pacing pulses. The dual-use sensor senses a signal indicative of activities and heart sounds. The sensor processing circuit produces an activity level signal and a heart sound signal from the sensed signal. The controller includes a rate responsive pacing algorithm execution module dynamically adjusting at least a pacing interval based on at least the activity level signal.
  • In one embodiment, a cardiac rhythm management system includes an accelerometer, a processing circuit, and a controller. The accelerometer senses an acceleration signal indicative of physical activities and heart sounds. The processing circuit has an input to receive the acceleration signal, an amplifier, and a band-pass filter. The amplifier has a programmable gain. The band-pass filter has one or more cutoff frequencies programmable for producing an activity level signal during first time periods and producing a heart sound signal during second time periods. The controller includes a processing circuit programming module adapted to program the gain and the cutoff frequencies.
  • In one embodiment, a cardiac rhythm management system includes an accelerometer to sense an acceleration signal, a first processing circuit, and a second processing circuit. The first processing circuit includes a first input to receive the acceleration signal, a first output indicative of a physical activity level, and a first gain-and-filter circuit to provide for a first gain and a first set of cutoff frequencies. The second processing circuit includes a second input to receive the acceleration signal, a second output indicative of heart sounds, and a second gain-and-filter circuit to provide for a second gain and a second set of cutoff frequencies.
  • In one embodiment, a signal indicative of activities and heart sounds is sensed using a single implantable sensor. The sensed signal is processed to produce an activity level signal and a heart sound signal. A rate responsive pacing algorithm dynamically adjusts at least one pacing parameter based on the activity level signal. At least one type of heart sounds is detected from the heart sound signal.
  • In one embodiment, an acceleration signal indicative of an activity level and heart sounds is sensed. An amplifier is programmed with a first gain suitable for sensing the activity level for a first time period. A band-pass filter is programmed with a first set of cutoff frequencies suitable for sensing the activity level for the first time period. The sensed acceleration signal is amplified and filtered to produce an activity level signal. The amplifier is programmed with a second gain suitable for sensing the heart sounds for a second time period. The band-pass filter is programmed with a second set of cutoff frequencies suitable for sensing the heart sounds for the second time period. The sensed acceleration signal is amplified and filtered to produce a heart sound signal.
  • In one embodiment, an acceleration signal is sensed. An activity level signal and a heart sound signal is produced concurrently from the acceleration signal by amplifying and filtering. The acceleration signal is amplified with a first gain and filtered with a first set of cutoff frequencies suitable for producing the activity level signal, and is amplified with a second gain and filtered with a second set of cutoff frequencies suitable for producing the heart sound signal.
  • This Summary is an overview of some of the teachings of the present application and not intended to be an exclusive or exhaustive treatment of the present subject matter. Further details about the present subject matter are found in the detailed description and appended claims. Other aspects of the invention will be apparent to persons skilled in the art upon reading and understanding the following detailed description and viewing the drawings that form a part thereof, each of which are not to be taken in a limiting sense. The scope of the present invention is defined by the appended claims and their equivalents.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • In the drawings, which are not necessarily drawn to scale, like numerals describe similar components throughout the several views. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.
  • FIG. 1 is a block diagram illustrating an embodiment of a cardiac rhythm management system, including an implantable medical device, and portions of an environment in which it is used.
  • FIG. 2A is a block diagram illustrating an embodiment of a circuit of the implantable medical device.
  • FIG. 2B is a block diagram illustrating an embodiment of a controller being a part of the circuit of the implantable medical device.
  • FIG. 3 is a block diagram illustrating an embodiment of a circuit including a dual-use sensor and a sensor processing circuit for sensing a physical activity level and a heart sound signal.
  • FIG. 4 is a block diagram illustrating another embodiment of the circuit including the dual-use sensor and the sensor processing circuit for sensing the physical activity level and the heart sound signal.
  • FIG. 5A is a block diagram illustrating an embodiment of the circuit of FIG. 3 in which the sensor processing circuit includes an additional preconditioning circuit.
  • FIG. 5B is a block diagram illustrating an embodiment of the circuit of FIG. 4 in which the sensor processing circuit includes an additional preconditioning circuit.
  • FIG. 5C is a block diagram illustrating an embodiment of a circuit of the additional preconditioning circuit.
  • FIG. 6 is a flow chart illustrating an embodiment of a method for sensing the physical activity level and the heart sounds by using the circuit of FIGS. 3 and 5.
  • FIG. 7 is a flow chart illustrating an embodiment of a method for sensing the physical activity level and the heart sounds by using the circuit of FIGS. 4 and 5.
  • DETAILED DESCRIPTION
  • In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are discussed in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that the embodiments may be combined, or that other embodiments may be utilized and that structural, logical and electrical changes may be made without departing from the spirit and scope of the present invention. The following detailed description provides examples, and the scope of the present invention is defined by the appended claims and their equivalents.
  • It should be noted that references to “an”, “one”, or “various” embodiments in this disclosure are not necessarily to the same embodiment, and such references contemplate more than one embodiment.
  • This document discusses, among other things, a cardiac rhythm management system including a dual-use sensor, such as a single accelerometer, for rate responsive pacing and heart sound sensing. The cardiac rhythm management system includes, for example, an implantable medical device including such as a pacemaker, a pacemaker/defibrillator, a pacemaker/drug delivery device, or a cardiac resynchronization therapy (CRT) device. The implantable medical device provides for rate responsive pacing and heart sound sensing.
  • Rate response pacing, also referred to as rate adaptive pacing, uses an indication of a patient's gross physical activity level to adjust a pacing rate, such that the cardiac output as a result of pacing meets or approaches the patient's metabolic need. One example of rate responsive pacing using acceleration to adjust the pacing rate is discussed in U.S. Pat. No. 5,179,947, entitled “ACCELERATION-SENSITIVE CARDIAC PACEMAKER AND METHOD OF OPERATION,” assigned to Cardiac Pacemakers, Inc., which is hereby incorporated by reference in its entirety.
  • Known and studied heart sounds include the “first heart sound,” or S1, the “second heart sound,” or S2, the “third heart sound,” or S3, the “fourth heart sound,” or S4, and their various sub-components. S1 is known to be indicative of, among other things, mitral valve closure, tricuspid valve closure, and aortic valve opening. S2 is known to be indicative of, among other things, aortic valve closure and pulmonary valve closure. S3 is known to be a ventricular diastolic filling sound often indicative of certain pathological conditions including heart failure. S4 is known to be a ventricular diastolic filling sound resulted from atrial contraction and is usually indicative of pathological conditions. The term “heart sound” hereinafter refers to any heart sound (e.g., S1) and any components thereof (e.g., M1 component of S1, indicative of Mitral valve closure and Mitral regurgitation). Heart sounds are used, for example, to calculate pacing parameters for improving the patient's hemodynamic performance and diagnosing a pathological condition such as heart failure. Examples of such uses are discussed in U.S. patent application Ser. No. 10/307,896, now issued as U.S. Pat. No. 7,123,962, entitled “PHONOCARDIOGRAPHIC IMAGE-BASED ATRIOVENTRICULAR DELAY OPTIMIZATION,” and U.S. patent application Ser. No. 10/334,694, entitled “METHOD AND APPARATUS FOR MONITORING OF DIASTOLIC HEMODYNAMICS,” both assigned to Cardiac Pacemakers, Inc., the specifications of which are incorporated herein by reference in their entirety.
  • An accelerometer can be used to sense both the physical activity level for rate responsive pacing and the heart sounds because the two signals feature substantially distinguishable spectrums. The acceleration measured in the direction normal to a person's chest wall is indicative of both the physical activity level and the heart sounds. The sensor specifications required for sensing the physical activity level and the sensor specifications required for sensing the heart sounds, such as bandwidth, sensitivity, noise floor, robustness, size, and power consumption are sufficiently close such that they can be satisfied by a single accelerometer having adequate size and power consumption for used in an implantable medical device. A sensor processing circuit processes the signal sensed by such an accelerometer to produce an activity level signal indicative of the physical activity level for rate responsive pacing and a heart sound signal from which heart sounds of each type can be detected.
  • Throughout this document, a “heart sound signal” includes audible and inaudible mechanical vibrations of the heart that can be sensed with a sensor such as an accelerometer. A “heart sound” refers to a recognized event in the heart sound signal. Unless noted otherwise, S1, S2, S3, and S4 refer to the first, second, third, and fourth heart sounds, respectively, as a heart sound type, or as one or more occurrences of the corresponding type heart sounds, depending on the context. An “electrogram” includes an electrocardiogram (ECG) sensed with at least an intracardiac electrode placed in the heart or an epicardial electrode placed on the heart. A “user” includes a physician or other caregiver who examines and/or treats a patient using one or more of the methods and apparatuses discussed in the present document.
  • FIG. 1 is a block diagram illustrating an embodiment of a cardiac rhythm management system 100, and portions of an environment in which it is used. System 100 includes an implantable medical device 110, a lead system 108, an external system 170, and a wireless telemetry link 160.
  • After implantation, implantable medical device 110 operates within a body 102 to sense activities of a heart 105 and deliver one or more therapies to heart 105. Implantable medical device 110 includes a pacemaker capable of rate responsive pacing. In one embodiment, implantable medical device 110 is an implantable pacemaker. In another embodiment, implantable medical device 110 includes a pacemaker module and one or more other therapeutic modules, such as a cardioversion-defibrillation module and a drug delivery module. In one specific embodiment, the pacemaker includes a cardiac resynchronization therapy module capable of delivering multi-site biventricular pacing. Implantable medical device 110 senses an activity level for rate responsive pacing purposes and heart sounds for various diagnostic and/or therapy control purposes. A dual-use sensor such as an accelerometer is used for sensing both the activity level and the heart sounds. In one embodiment, the dual-use sensor is within implantable medical device 110.
  • Lead system 108 provides one or more electrical connections between implantable medical device 110 and heart 105. It includes one or more pacing leads each having one or more electrodes for electrogram sensing and pacing pulse delivery. In one embodiment, the dual-use sensor is incorporated into a lead of lead system 108 and connected to implantable medical device through the lead.
  • External system 170 communicates with implantable medical device 110. It allows a user and/or a patient to communicate and/or to control the operation of implantable medical device 110. In one embodiment, external system 170 includes an external programmer. In another embodiment, external system 170 includes an advanced patient management system, such as discussed in U.S. patent application Ser. No. 10/323,604, entitled “ADVANCED PATIENT MANAGEMENT FOR DEFINING, IDENTIFYING AND USING PREDETERMINED HEALTH-RELATED EVENTS,” assigned to Cardiac Pacemakers, Inc., the specification of which is incorporated herein by reference in its entirety. The advanced patient management system allows the user to access implantable medical device 110 from a remote location.
  • Telemetry link 160 provides for data transmissions between implantable medical device 110 and external system 170. In one embodiment, telemetry link 160 is an inductive telemetry link. In an alternative embodiment, telemetry link 160 is a far-field radio-frequency telemetry link. Telemetry link 160 provides for data transmission from implantable medical device 110 to external system 170. This may include, for example, transmitting real-time physiological data acquired by implantable medical device 110, extracting physiological data acquired by and stored in implantable medical device 110, extracting therapy history data stored in implantable medical device 110, and extracting data indicating an operational status of implantable medical device 110 (e.g., battery status and lead impedance). Telemetry link 160 also provides for data transmission from external system 170 to implantable medical device 110. This may include, for example, programming implantable medical device 110 to acquire physiological data, programming implantable medical device 110 to perform at least one self-diagnostic test (such as for a battery status and lead impedance status), and programming implantable medical device 110 to deliver at least one therapy. Examples of signals represented by the physiological data include, but are not limited to, electrograms, heart sounds or signals indicative of heart sounds, activity level signals, and respiratory signals. In one embodiment, the physiological data also include parameters measured from one or more of these signals. In one embodiment, external system 170 or a user determines and/or adjusts a therapy based on these signals and/or physiological data.
  • FIG. 2A is a block diagram illustrating an embodiment of a circuit of implantable medical device 110. Implantable medical device 110 includes a sensing circuit 212, a pacing circuit 214, a dual-use sensor 216, a sensor processing circuit 218, a heart sound detector 220, an implant controller 222, a memory circuit 224, and an implant telemetry module 226. In one embodiment, these circuit elements, and possibly additional circuit elements of implantable medical device 110, are encapsulated in a hermetically sealed implantable housing. In another embodiment, some of these circuit elements, such as dual-use sensor 216 or implant telemetry module 224, are located outside of the hermetically sealed implantable housing.
  • Sensing circuit 212 and pacing circuit 214 are both electrically coupled to heart 105 via lead system 108. Sensing circuit 212 includes an amplifier circuit suitable for sensing one or more electrograms from heart 108 through lead system 108. Pacing circuit 214 includes a pulse generator generating electrical pacing pulses that are delivered to heart 105 through lead system 108.
  • Dual-use sensor 216 senses a signal indicative of two activities, events, or quantities having distinguishable frequency characteristics. The term “dual-use” refers to the fact that the two activities, events, or quantities are extracted separately from the signal and used for different purposes serving the functions of system 100. In one embodiment, dual-use sensor 216 includes a single accelerometer that senses an acceleration signal indicative of a patient's gross physical activity level and heart sounds of the patient. In one embodiment, dual-use sensor 216 is an integrated circuit accelerometer. A specific example of such an integrated circuit accelerometer is a piezoelectric accelerometer made by Endevco Corporation (Model 12 Picochip Accelerometer). Other examples include piezoresistive and capacitive accelerometers. In one embodiment, dual-use sensor 216 is encapsulated in the hermetically sealed implantable housing. This embodiment provides the accelerometer with an environment ensuring a stable operation. In an alternative embodiment, dual-use sensor 216 is incorporated into a lead of lead system 108. This embodiment allows the accelerometer to be located in or near heart 105, thus being more sensitive to the heart's mechanical activities such as vibrations (heart sounds).
  • Sensor processing circuit 218 processes the acceleration signal to produce an activity level signal indicative of the patient's gross physical activity level and a heart sound signal indicative of the patient's heart sounds. Embodiments of sensor processing circuit 218 are discussed below, with reference to FIGS. 3-5.
  • In one embodiment, heart sound detector 220 detects heart sounds from the heart sound signal produced by sensor processing circuit 218. In one embodiment, implantable controller 222 receives the detected heart sounds use it, in addition to the activity level signal, for rate responsive pacing purposes. In a further or alternative embodiment, implantable controller 222 uses the detected heart sounds for adjusting atrioventricular and/or interventricular pacing delays, such as in a cardiac resynchronization therapy for heart failure. The detected heart sounds, and/or parameters measured from the detected heart sounds, are also transmitted to external system 170 through telemetry link 160 for further analysis by the system or the user. In an alternative embodiment, the heart sound signal is transmitted to external system 170 though telemetry link 160. External system 170 detects and analyzes the heart sound signal for diagnostic and/or pacing control purposes. Heart sound detector 220 is configured and/or programmed by external system 170 to detect one or more of the S1, S2, S3, and S4 type heart sounds.
  • Implant controller 222 controls the operation of the entire implantable medical device 110. An embodiment of implantable device 222 is discussed below, with reference to FIG. 2B. In one embodiment, implant controller 222 is implemented using a microprocessor. Memory circuit 224 provides a storage medium for a device control code, parameters for the operation of implantable medical device 110, and the data acquired by implantable medical device 110. In one embodiment, memory circuit 224 includes a buffer for storing the signal sensed by dual-use sensor 216, the activity level signal produced by sensor processing circuit 218, and/or the heart sound signal produced by sensor processing circuit 218. In another embodiment, the buffer also stores the one or more electrograms sensed by sensing circuit 212. In a further embodiment, implant controller 222 includes an event detector to detect cardiac events and a maker generator to generate event markers representing the cardiac events. Examples of such cardiac events include sensed events (intrinsic depolarizations) and paced events (paced contractions or pulse deliveries) associated with one or more cardiac sites. Each event mark is indicative of the type and the timing of one cardiac event. In this embodiment, the buffer further stores the event markers. In one embodiment, the activity level signal and/or the heart sound signal are synchronized with the event markers such that the event markers serve as a timing reference relating the activity level and/or heart sound to the cardiac events. In one embodiment, implant controller 222 includes an analog-to-digital converter to digitize one or more of the signal sensed by dual-use sensor 216, the activity level signal, the heart sound signal, and the electrograms for storage and/or further processing. The analog-to-digital converter has a programmable sampling rate. Implantable controller 222 includes a digitization control module to control this sampling rate. In one embodiment, the sampling rate is programmable through external system 170.
  • Implant telemetry module 226 includes an antenna and a transceiver to support two-way communications with external system 170 via telemetry link 160. In one embodiment, one or more of the electrograms, the event markers, the signal sensed by dual-use sensor 216, the activity level signal, and the heart sound signal are transmitted to external system 170 in real time. In another embodiment, one or more of the electrograms, the event markers, the signal sensed by dual-use sensor 216, the activity level signal, and the heart sound signal are stored in the buffer of memory circuit 224 and retrieved from the buffer when needed. In one embodiment, the retrieval occurs at predetermined times as controlled by implant controller 222. In another embodiment, the retrieval occurs in response to a command from external system 170.
  • FIG. 2B is a block diagram illustrating an embodiment of implant controller 222. Implant controller 222 executes the device control code stored in memory circuit 224. It includes, among other control modules, a rate responsive pacing algorithm execution module 230 and a sensor processing circuit programming module 232.
  • Rate responsive pacing algorithm execution module 230 controls the timing of the pacing pulse delivery from pacing circuit 214, based on predefined pacing logic and timing rules and one or more of the activity level signal, the sensed electrograms, timing of previous pacing pulse deliveries, the detected heart sounds, and possibly other physiological signals indicative of electrical events, mechanical activities, and/or hemodynamic performance of heart 105. It includes a pacing interval calculator to calculate a pacing interval based on at least the activity level signal and predetermined maximum and minimum pacing intervals. When the pacing interval calculator produces a new value for the pacing interval, rate responsive pacing algorithm execution module 230 updates the pacing interval with the new value. In one embodiment, rate responsive pacing algorithm execution module 230 performs the calculation and the update dynamically, for each and every heart beat.
  • In one embodiment, sensor processing circuit programming module 232 controls the timing, gain, and/or frequency responses of sensor processing circuit 218 to produce the activity level signal and the heart sound signal. The programming of sensor processing circuit 218 is discussed below with reference to FIGS. 3 and 4.
  • FIG. 3 is a block diagram illustrating an embodiment of a circuit including an accelerometer 316 for sensing the acceleration signal and a sensor processing circuit 318 for producing the activity level signal and the heart sound signal from the acceleration signal. Accelerometer 316 is one embodiment of dual-use sensor 216 or a portion thereof. Sensor processing circuit 318 is one embodiment of sensor processing circuit 218 or a portion thereof.
  • Sensor processing circuit 318 includes an amplifier 340, a band-pass filter 342, and a demultiplexer (DEMUX) 343. It produces the activity level signal and the heart sound signal from the acceleration signal sense by accelerometer 316 on a time-sharing basis. During predetermined first time periods, sensor processing circuit 318 produces the activity level signal. During predetermined second time periods, sensor processing circuit 318 produces the heart sound signal. The first and second time periods do not overlap. Sensor processing circuit programming module 232 controls the first time periods for producing the activity level signal and the second time periods for producing the heart sound signal by programming the gain of amplifier 340, the cutoff frequencies of band-pass filter 342, and the connections within demultiplexer 343. Thus, sensor processing circuit 318 has an input to receive the acceleration signal, an output representative of the activity level signal during the first periods, and another output representative of the heart sound signal during the second periods. In one embodiment, the gain and/or the cutoff frequencies are predetermined and stored in memory circuit 224. In one specific embodiment, the gain and/or the cutoff frequencies are empirically determined based on data collected from the patient treated with system 100, and programmed into implantable medical device 110 by using external system 170. In one embodiment, the gain and/or the cutoff frequencies are adjustable by the user, when necessary, after the implantation of implantable medical device 110. The adjustments may become necessary when, for example, the range of the amplitude of the sensed acceleration signal has significantly changed, or when a different type of the heart sound is sought. Demultiplexer 343 receives the output of band-pass filter 342 and provides two outputs separately representing the activity level signal and the heart sound signal.
  • For producing the activity level signal, the gain of amplifier 340 is a first gain programmable in the range of 100 to 500. The cutoff frequencies of band-pass filter 342 are a first set of cutoff frequencies including a first low cutoff frequency programmable in a range of 0.5 Hz to 2 Hz and a first high cutoff frequency programmable in a range of 5 Hz to 15 Hz. In one specific embodiment, sensor processing circuit programming module 232 programs the first gain to 125, the first low cutoff frequency to 1 Hz, and the first high cutoff frequency to 10 Hz during the predetermined first time periods. For producing the heart sound signal, the gain of amplifier 340 is a second gain programmable in the range of 500 to 2000. The cutoff frequencies of band-pass filter 342 are a second set of cutoff frequencies including a second low cutoff frequency programmable in a range of 5 Hz to 10 Hz and a second high cutoff frequency programmable in a range of 50 Hz to 200 Hz. In one specific embodiment, sensor processing circuit programming module 232 programs the second gain to 1000, the second low cutoff frequency to 10 Hz, and the second high cutoff frequency to 100 Hz during the predetermined second time periods.
  • Sensor processing circuit 318 requires only one set of an amplifier and a filter to produce both the activity level signal and the heart sound signal. It is suitable for applications in which the activity level and the heart sounds need not be sensed concurrently. For an implantable pacemaker that already requires an accelerometer for the purpose of rate responsive pacing, sensor processing circuit 318 provides for heart sound sensing with minimal additional requirement for circuit size and energy consumption.
  • FIG. 4 is a block diagram illustrating another embodiment of the circuit including accelerometer 316 for sensing the acceleration signal and a sensor processing circuit 418 for concurrently producing the activity level signal and the heart sound signal from the acceleration signal. Accelerometer 316 is one embodiment of dual-use sensor 216 or a portion thereof. Sensor processing circuit 418 is one embodiment of sensor processing circuit 218 or a portion thereof.
  • Sensor processing circuit 418 includes a first processing circuit 450A for producing the activity level signal and a second processing circuit 450B for producing the heart sound signal. First processing circuit 450A includes a first amplifier 440A having a first gain and a first band-pass filter 442A having a first set of cutoff frequencies. Second processing circuit 450B includes a second amplifier 440B having a second gain and a second band-pass filter 442B having a second set of cutoff frequencies. First processing circuit 450A and second processing circuit 450B operate in parallel to allow concurrent sensing of the physical activity level and the heart sounds. Thus, sensor processing circuit 418 has an input to receive the acceleration signal, an output representative of the activity level signal, and another output representative of the heart sound signal. In one embodiment, the gains and/or the cutoffs frequencies are predetermined and stored in memory circuit 224. While there is no need to program the gains and the cutoff frequencies for the time-sharing purpose, in one embodiment, the gains and/or the cutoffs frequencies are programmable to ensure proper sensing under each patient's particular circumstances. In one embodiment, the gain and/or the cutoff frequencies are empirically determined based on data collected from the patient, and programmed into implantable medical device 110 by using external system 170. In one embodiment, the gain and/or the cutoff frequencies are adjustable by the user, when necessary, after the implantation of implantable medical device 110.
  • The gain of amplifier 440A (the first gain) is programmable in the range of 100 to 500. The cutoff frequencies of band-pass filter 442A (the first set of cutoff frequencies) include a first low cutoff frequency programmable in a range of 0.5 Hz to 2 Hz and a first high cutoff frequency programmable in a range of 5 Hz to 15 Hz. In one specific embodiment, sensor processing circuit programming module 232 programs the first gain to 125, the first low cutoff frequency to 1 Hz, and the first high cutoff frequency to 10 Hz during the predetermined first time periods. The gain of amplifier 440B (the second gain) is programmable in the range of 500 to 2000. The cutoff frequencies of band-pass filter 442B (the second set of cutoff frequencies) include a second low cutoff frequency programmable in a range of 5 Hz to 10 Hz and a second high cutoff frequency programmable in a range of 50 Hz to 200 Hz. In one specific embodiment, sensor processing circuit programming module 232 programs the second gain to 1000, the second low cutoff frequency to 10 Hz, and the second high cutoff frequency to 100 Hz during the predetermined second time periods.
  • Sensor processing circuit 418 allows concurrent sensing of the activity level and the heart sounds. With sensor processing circuit 418, dual-use sensor 216 is usable for sensing the activity level and the heart sounds simultaneously when needed.
  • FIG. 5A is a block diagram illustrating an embodiment of the circuit of FIG. 3 with an additional preconditioning circuit 552. In this embodiment, sensor processing circuit 218 includes preconditioning circuit 552 with its input connected to accelerometer 316 and its output connected to sensor processing circuit 318.
  • FIG. 5B is a block diagram illustrating an embodiment of the circuit of FIG. 4 with an additional preconditioning circuit 552. In this embodiment, sensor processing circuit 218 includes preconditioning circuit 552 with its input connected to accelerometer 316 and its output connected to sensor processing circuit 418.
  • FIG. 5C is a block diagram illustrating an embodiment of a circuit of preconditioning circuit 552. Preconditioning circuit 552 provides for initial conditioning or processing of the acceleration signal before being processed for producing the activity level signal and the heart sound signal.
  • In one embodiment, preconditioning circuit 552 includes a preconditioning amplifier 554 having a preconditioning gain and a preconditioning band-pass filter 556 having a set of preconditioning cutoff frequencies. In one embodiment, the preconditioning gain is programmable in the range of 100 to 500. The overall gains for producing the activity signal and the heart sound signal are products of the preconditioning gain (gain of preconditioning amplifier 554) multiplied by the gains of sensor processing circuit 318 or 418 as discussed above. The gains to be programmed to sensor processing circuit 318 or 418 are calculated by dividing the gains discussed above by the programmed preconditioning gain. That is, the gain of amplifier 340 includes a first gain in the range of 100 to 500 divided by the preconditioning gain for producing the activity signal, and a second gain in the range of 500 to 2000 divided by the preconditioning gain for producing the heart sound signal. The gain of amplifier 440A (the first gain) is in the range of 100 to 500 divided by the preconditioning gain. The gain of amplifier 440B (the second gain) is in the range of 500 to 2000 divided by the preconditioning gain. In one embodiment, the set of preconditioning cutoff frequencies includes a low preconditioning cutoff frequency programmable in the range of 0.5 to 2 Hz, and a high preconditioning cutoff frequency programmable in the range of 50 to 200 Hz. In one specific embodiment, with sensor processing circuit 318, the preconditioning gain is 125, the low preconditioning cutoff frequency is 1 Hz, the high preconditioning cutoff frequency programmable is 100 Hz, the first gain for amplifier 340 is 1, and the second gain for amplifier 340 is 8. In an alternative specific embodiment, with sensor processing circuit 418, the preconditioning gain is 125, the low preconditioning cutoff frequency is 1 Hz, the high preconditioning cutoff frequency programmable is 100 Hz, the gain for amplifier 440A is 1, and the gain for amplifier 440B is 8.
  • In one embodiment, preconditioning circuit 552 further includes an analog-to-digital converter (ADC) 558 to digitize the acceleration signal. This allows sensor processing circuit 318 or sensor processing circuit 418 to be implemented with digital technology. That is, the activity level signal and the heart sound signal are digital signals produced from the digitized acceleration signal using digital signal processing. In one embodiment, ADC 558 has a programmable sampling rate, and implantable controller 222 includes a digitization control module to control this sampling rate. In one further embodiment, the sampling rate is programmable through external system 170. In general, sensor processing circuit 218 can be implemented with hardware, software, and a combination of both.
  • FIG. 6 is a flow chart illustrating an embodiment of a method for sensing the physical activity level and the heart sounds with the circuit illustrated in FIGS. 3 and 5. The method illustrates by way of example, but not by way of limitation, a use of the circuit that includes accelerometer 316, preconditioning circuit 552, and sensor processing circuit 318.
  • Accelerometer 316 senses an acceleration signal at 600. Preconditioning circuit 552 preconditions the sensed acceleration signal at 605. In one embodiment, preconditioning circuit 552 amplifies and filters the sensed acceleration signal. In a further embodiment, preconditioning circuit 552 digitizes the sensed acceleration signal. The digitization allows subsequent processing to be performed using digital signal processing technology.
  • Sensor processing circuit 318 is programmed with the first gain and the first set of cutoff frequencies for first time periods at 610. During the first time periods, sensor processing circuit 318 amplifies and filters the acceleration signal to produce the activity level signal at 620. Sensor processing circuit 318 is programmed with the second gain and the second set of cutoff frequencies for second time periods at 630. During the second time periods, sensor processing circuit 318 amplifies and filters the acceleration signal to produce the heart sound signal at 640. In one embodiment, the first and second time periods are programmed into memory circuit 224 for use by sensor processing circuit programming module 232, which programs the gain and the cutoff frequencies of sensor processing circuit 318. The first and second time periods do not overlap.
  • Rate responsive pacing algorithm execution module 230 adjusts a pacing parameter such as the pacing interval based on at least the activity level signal at 650. In one embodiment, rate responsive pacing algorithm execution module 230 also adjusts the pacing interval and/or one or more other pacing parameters based on other signals such as the electrograms and the heart sound signal.
  • Heart sounds are detected from the heart sound at 660. In one embodiment, heart sound detector 220, which is a part of implantable medical device 110, detects the heart sounds from the heart sound signal. In one embodiment, the detected hearts sounds are used by implant controller 222 for pacing control purposes. In another embodiment, the heart sound signal and/or information extracted from the detected heart sounds are transmitted to external system 170. In an alternative embodiment, the heart sound signal is transmitted to external system 170, which includes a heart sound detector to detect the heart sounds. The heart sound detection includes detection of predetermined types of heart sounds including one or more of S1, S2, S3, and S4. The heart sounds are analyzed at 670. The analysis includes measurement of, for example, one or more of amplitude of any type heart sound, relative amplitude between any two types of heart sounds, duration of each type heart sound, interval between any type or types of heart sounds, interval between any type heart sound and any type electrical event of the heart, fundamental frequency of each type heart sound, and harmonic frequency of each type heart sound. In one embodiment, the results of the analysis, such as parameters generated from the above measurements, are used to determine a pacing parameter based on the heart sounds at 680. One example of determining a pacing parameter based on the heart sounds is discussed in U.S. patent application Ser. No. 10/307,896. In one embodiment, one or more parameters generated from the above measurements are trended at 690. One example of trending heart sound related parameters is discussed in U.S. patent application Ser. No. 10/334,694.
  • FIG. 7 is a flow chart illustrating an embodiment of a method for sensing the physical activity level and the heart sounds with the circuit illustrated in FIGS. 4 and 5. The method illustrates by way of example, but not by way of limitation, a use of the circuit that includes accelerometer 316, preconditioning circuit 552, and sensor processing circuit 418.
  • Accelerometer 316 senses an acceleration signal at 700. Preconditioning circuit 552 preconditions the sensed acceleration signal at 705. In one embodiment, preconditioning circuit 552 amplifies and filters the sensed acceleration signal. In a further embodiment, preconditioning circuit 552 digitizes the sensed acceleration signal. The digitization allows subsequent processing to be performed using digital signal processing technology.
  • First processing circuit 450A of sensor processing circuit 418 produces the activity level signal from the acceleration signal at 710. This includes amplifying the acceleration signal with the first gain at 712 and filtering the acceleration signal with the first set of cutoff frequencies at 714. Rate responsive pacing algorithm execution module 230 adjusts a pacing parameter such as the pacing interval based on the activity level signal at 720. In one embodiment, rate responsive pacing algorithm execution module 230 also adjusts the pacing interval and/or one or more other pacing parameters based on other signals such as the electrograms and the heart sound signal.
  • Second processing circuit 450B of sensor processing circuit 418 produces the heart sound signal from the acceleration signal at 730. This includes amplifying the acceleration signal with the second gain at 732 and filtering the acceleration signal with the second set of cutoff frequencies at 734. Heart sounds are detected from the heart sound signal at 740 and analyzed at 750. In one embodiment, the results of the analysis are used to determine a pacing parameter based on the heart sounds at 760. In one embodiment, the results of the analysis are used for trending one or more parameters measured from the heart sounds at 770. In one embodiment, step 660 is identical or similar to step 740, step 670 is identical or similar to step 750, step 680 is identical or similar to step 760, and step 690 is identical or similar to step 770.
  • Because first processing circuit 450A and second processing circuit 450B are separate circuits producing distinguished signals from a common signal, step 710 (and its subsequent step 720) and step 730 (and its subsequent steps 740, 750, 760, and 770) can be performed concurrently.
  • It is to be understood that the above detailed description is intended to be illustrative, and not restrictive. For example, the sensor processing circuit can be expanded to produce additional signals from the acceleration signal, such as a respiration-indicative signal, if the additional signals each have a distinguishable spectrum. Other embodiments will be apparent to those of skill in the art upon reading and understanding the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims (20)

1. An implantable medical device, comprising:
a pacing circuit configured to deliver pacing pulses;
an accelerometer configured to sense an acceleration signal indicative of physical activities and heart sounds;
a preconditioning circuit coupled to the accelerometer and configured to digitize the acceleration signal;
a sensor processing circuit coupled to the preconditioning circuit and programmable for producing an activity level signal and a heart sound signal using the preconditioned acceleration signal, the activity level signal indicative of a level of the physical activities, the heart sound signal indicative of the heart sounds, the sensor processing circuit including a first set of cutoff frequencies suitable for producing the activity level signal and a second set of cutoff frequencies suitable for producing the heart sound signal;
a controller coupled to the pacing circuit and the sensor processing circuit, the controller configured to program the sensor processing circuit and control the delivery of the pacing pulses using the activity level signal and the heart sound signal; and
an implantable housing encapsulating at least the pacing circuit, the preconditioning circuit, the sensor processing circuit, and the controller.
2. The device of claim 1, wherein the controller comprises a sensor processing circuit programming module configured to program the sensor processing circuit to produce the activity level signal using the first set of cutoff frequencies during a first time period and produce the heart sound signal using the second set of cutoff frequencies during a second time period, wherein the first time period and the second time period do not overlap.
3. The device of claim 1, wherein the controller comprises a sensor processing circuit programming module configured to program the sensor processing circuit for producing the activity level signal and the heart sound signal concurrently.
4. The device of claim 1, wherein the accelerometer comprises an integrated circuit accelerometer and is encapsulated in the implantable housing.
5. The device of claim 4, wherein the sensor processing circuit comprises a first band-pass filter having the first set of cutoff frequencies and a second band-pass filter having the second set of cutoff frequencies.
6. The device of claim 4, wherein the sensor processing circuit comprises a band-pass filter having cutoff frequencies programmable to one of the first set of cutoff frequencies and the second set of cutoff frequencies after implantation of the implantable medical device.
7. The device of claim 4, wherein the first set of cutoff frequencies comprises a first low cutoff frequency programmable in a range of 0.5 Hz to 2 Hz and a first high cutoff frequency programmable in a range of 5 Hz to 15 Hz.
8. The system of claim 7, wherein the second set of cutoff frequencies comprises a second low cutoff frequency programmable in a range of 5 Hz to 10 Hz and a second high cutoff frequency programmable in a range of 50 Hz to 200 Hz.
9. The device of claim 4, comprising a heart sound detector coupled to the sensor processing circuit, encapsulated in the implantable housing, and configured to detect at least one type of heart sound from the heart sound signal.
10. The device of claim 9, wherein the controller comprises a rate responsive pacing algorithm execution module adapted to dynamically adjust at least a pacing interval using the activity level signal.
11. A method for operating an implantable medical device, the method comprising:
sensing an acceleration signal indicative of physical activities and heart sounds using an accelerometer;
digitizing the acceleration signal;
producing an activity level signal by filtering the digitized acceleration signal using a first set of cutoff frequencies, the activity level signal indicative of a level of the physical activities;
producing a heart sound signal by filtering the digitized acceleration signal using a second set of cutoff frequencies, the heart sound signal indicative of the heart sounds; and
controlling delivery of cardiac pacing pulses from the implantable medical device using the activity level signal and the heart sound signal.
12. The method of claim 11, comprising:
producing the activity level signal and the heart sound signal using a band-pass filter having programmable cutoff frequencies;
programming the programmable cutoff frequencies to the first set of cutoff frequencies for a first time period; and
programming the programmable cutoff frequencies to the second set of cutoff frequencies for a second time period that does overlap with the first time period.
13. The method of claim 11, comprising:
producing the activity level signal using a first band-pass filter having the first set of cutoff frequencies; and
producing the activity level signal using a second band-pass filter having the second set of cutoff frequencies.
14. The method of claim 11, comprising detecting at least one type of heart sounds from the heart sound signal using a heart sound detector in the implantable medical device.
15. The method of claim 14, comprising executing a rate responsive pacing algorithm dynamically adjusting at least one pacing parameter using the activity level signal.
16. The method of claim 14, further comprising:
measuring one or more parameters associated with the detected heart sounds; and
trending the one or more parameters.
17. The method of claim 16, further comprising transmitting one or more of the acceleration signal, the activity level signal, and the heart sound signal from the implantable medical device to an external system in real time.
18. An implantable medical device, comprising:
means for sensing an acceleration signal indicative of physical activities and heart sounds using an accelerometer;
means for digitizing the acceleration signal;
means producing an activity level signal by filtering the digitized acceleration signal using a first set of cutoff frequencies and producing a heart sound signal by filtering the digitized acceleration signal using a second set of cutoff frequencies, the activity level signal indicative of a level of the physical activities, the heart sound signal indicative of the heart sounds; and
means for controlling delivery of cardiac pacing pulses from the implantable medical device using the activity level signal and the heart sound signal.
19. The device of claim 18, comprising means for producing the activity level signal during a first time period and producing the heart sound signal during a second time period that does overlap with the first time period.
20. The device of claim 18, comprising means for producing the activity level signal and the heart sound signal concurrently.
US12/955,065 2003-11-06 2010-11-29 Dual-use sensor for rate responsive pacing and heart sound monitoring Abandoned US20110077707A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US12/955,065 US20110077707A1 (en) 2003-11-06 2010-11-29 Dual-use sensor for rate responsive pacing and heart sound monitoring

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US10/703,175 US7248923B2 (en) 2003-11-06 2003-11-06 Dual-use sensor for rate responsive pacing and heart sound monitoring
US11/778,527 US7844334B2 (en) 2003-11-06 2007-07-16 Dual-use sensor for rate responsive pacing and heart sound monitoring
US12/955,065 US20110077707A1 (en) 2003-11-06 2010-11-29 Dual-use sensor for rate responsive pacing and heart sound monitoring

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US11/778,527 Continuation US7844334B2 (en) 2003-11-06 2007-07-16 Dual-use sensor for rate responsive pacing and heart sound monitoring

Publications (1)

Publication Number Publication Date
US20110077707A1 true US20110077707A1 (en) 2011-03-31

Family

ID=34551832

Family Applications (3)

Application Number Title Priority Date Filing Date
US10/703,175 Active 2025-03-09 US7248923B2 (en) 2003-11-06 2003-11-06 Dual-use sensor for rate responsive pacing and heart sound monitoring
US11/778,527 Active 2025-01-22 US7844334B2 (en) 2003-11-06 2007-07-16 Dual-use sensor for rate responsive pacing and heart sound monitoring
US12/955,065 Abandoned US20110077707A1 (en) 2003-11-06 2010-11-29 Dual-use sensor for rate responsive pacing and heart sound monitoring

Family Applications Before (2)

Application Number Title Priority Date Filing Date
US10/703,175 Active 2025-03-09 US7248923B2 (en) 2003-11-06 2003-11-06 Dual-use sensor for rate responsive pacing and heart sound monitoring
US11/778,527 Active 2025-01-22 US7844334B2 (en) 2003-11-06 2007-07-16 Dual-use sensor for rate responsive pacing and heart sound monitoring

Country Status (1)

Country Link
US (3) US7248923B2 (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8758260B2 (en) 2005-06-08 2014-06-24 Cardiac Pacemakers, Inc. Ischemia detection using a heart sound sensor
US9399140B2 (en) 2014-07-25 2016-07-26 Medtronic, Inc. Atrial contraction detection by a ventricular leadless pacing device for atrio-synchronous ventricular pacing
US20190082288A1 (en) * 2017-09-14 2019-03-14 Qualcomm Incorporated Opportunistic signal reception for mobile device position location estimation
US10925573B2 (en) 2017-10-04 2021-02-23 Ausculsciences, Inc. Auscultatory sound-or-vibration sensor
WO2021121089A1 (en) * 2019-12-16 2021-06-24 青岛歌尔智能传感器有限公司 Potting method for heart rate module
US11207527B2 (en) 2016-07-06 2021-12-28 Cardiac Pacemakers, Inc. Method and system for determining an atrial contraction timing fiducial in a leadless cardiac pacemaker system
US11284827B2 (en) 2017-10-21 2022-03-29 Ausculsciences, Inc. Medical decision support system

Families Citing this family (92)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030036746A1 (en) 2001-08-16 2003-02-20 Avi Penner Devices for intrabody delivery of molecules and systems and methods utilizing same
US6973349B2 (en) * 2001-12-05 2005-12-06 Cardiac Pacemakers, Inc. Method and apparatus for minimizing post-infarct ventricular remodeling
US8043213B2 (en) 2002-12-18 2011-10-25 Cardiac Pacemakers, Inc. Advanced patient management for triaging health-related data using color codes
US20040122294A1 (en) 2002-12-18 2004-06-24 John Hatlestad Advanced patient management with environmental data
US7468032B2 (en) 2002-12-18 2008-12-23 Cardiac Pacemakers, Inc. Advanced patient management for identifying, displaying and assisting with correlating health-related data
US7983759B2 (en) 2002-12-18 2011-07-19 Cardiac Pacemakers, Inc. Advanced patient management for reporting multiple health-related parameters
US20040122487A1 (en) 2002-12-18 2004-06-24 John Hatlestad Advanced patient management with composite parameter indices
US8391989B2 (en) 2002-12-18 2013-03-05 Cardiac Pacemakers, Inc. Advanced patient management for defining, identifying and using predetermined health-related events
US7123962B2 (en) * 2002-12-02 2006-10-17 Cardiac Pacemakers, Inc. Phonocardiographic image-based atrioventricular delay optimization
US7972275B2 (en) 2002-12-30 2011-07-05 Cardiac Pacemakers, Inc. Method and apparatus for monitoring of diastolic hemodynamics
US8951205B2 (en) 2002-12-30 2015-02-10 Cardiac Pacemakers, Inc. Method and apparatus for detecting atrial filling pressure
US7378955B2 (en) * 2003-01-03 2008-05-27 Cardiac Pacemakers, Inc. System and method for correlating biometric trends with a related temporal event
US7248923B2 (en) * 2003-11-06 2007-07-24 Cardiac Pacemakers, Inc. Dual-use sensor for rate responsive pacing and heart sound monitoring
US7215997B2 (en) * 2003-12-22 2007-05-08 Cardiac Pacemakers, Inc. Dynamic device therapy control for treating post myocardial infarction patients
US7115096B2 (en) 2003-12-24 2006-10-03 Cardiac Pacemakers, Inc. Third heart sound activity index for heart failure monitoring
US7480528B2 (en) * 2004-07-23 2009-01-20 Cardiac Pacemakers, Inc. Method and apparatus for monitoring heart failure patients with cardiopulmonary comorbidities
US7559901B2 (en) * 2004-07-28 2009-07-14 Cardiac Pacemakers, Inc. Determining a patient's posture from mechanical vibrations of the heart
US20060064142A1 (en) 2004-09-17 2006-03-23 Cardiac Pacemakers, Inc. Systems and methods for deriving relative physiologic measurements using an implanted sensor device
ATE484232T1 (en) * 2004-11-24 2010-10-15 Remon Medical Technologies Ltd IMPLANTABLE MEDICAL DEVICE WITH INTEGRATED ACOUSTIC TRANSDUCER
US7813808B1 (en) 2004-11-24 2010-10-12 Remon Medical Technologies Ltd Implanted sensor system with optimized operational and sensing parameters
US7662104B2 (en) 2005-01-18 2010-02-16 Cardiac Pacemakers, Inc. Method for correction of posture dependence on heart sounds
US9314633B2 (en) 2008-01-25 2016-04-19 Cyberonics, Inc. Contingent cardio-protection for epilepsy patients
US8260426B2 (en) 2008-01-25 2012-09-04 Cyberonics, Inc. Method, apparatus and system for bipolar charge utilization during stimulation by an implantable medical device
US8565867B2 (en) 2005-01-28 2013-10-22 Cyberonics, Inc. Changeable electrode polarity stimulation by an implantable medical device
US20080021336A1 (en) 2006-04-24 2008-01-24 Dobak John D Iii Devices and methods for accelerometer-based characterization of cardiac synchrony and dyssynchrony
US20060178586A1 (en) * 2005-02-07 2006-08-10 Dobak John D Iii Devices and methods for accelerometer-based characterization of cardiac function and identification of LV target pacing zones
US7424321B2 (en) * 2005-05-24 2008-09-09 Cardiac Pacemakers, Inc. Systems and methods for multi-axis cardiac vibration measurements
US7670298B2 (en) * 2005-06-01 2010-03-02 Cardiac Pacemakers, Inc. Sensing rate of change of pressure in the left ventricle with an implanted device
US8972002B2 (en) 2005-06-01 2015-03-03 Cardiac Pacemakers, Inc. Remote closed-loop titration of decongestive therapy for the treatment of advanced heart failure
US7634309B2 (en) * 2005-08-19 2009-12-15 Cardiac Pacemakers, Inc. Tracking progression of congestive heart failure via a force-frequency relationship
US7570998B2 (en) * 2005-08-26 2009-08-04 Cardiac Pacemakers, Inc. Acoustic communication transducer in implantable medical device header
US7615012B2 (en) * 2005-08-26 2009-11-10 Cardiac Pacemakers, Inc. Broadband acoustic sensor for an implantable medical device
US7742815B2 (en) 2005-09-09 2010-06-22 Cardiac Pacemakers, Inc. Using implanted sensors for feedback control of implanted medical devices
US8108034B2 (en) 2005-11-28 2012-01-31 Cardiac Pacemakers, Inc. Systems and methods for valvular regurgitation detection
US8682428B2 (en) * 2005-11-30 2014-03-25 St. Jude Medical Ab Implantable medical device with therapy control
US7580746B2 (en) * 2005-12-07 2009-08-25 Cardiac Pacemakers, Inc. Implantable medical device for generating cardiac pressure-volume loop and optimizing therapy
WO2007069963A1 (en) * 2005-12-16 2007-06-21 St. Jude Medical Ab Implantable medical device with condition detection
US7996079B2 (en) 2006-01-24 2011-08-09 Cyberonics, Inc. Input response override for an implantable medical device
US7713213B2 (en) * 2006-03-13 2010-05-11 Cardiac Pacemakers, Inc. Physiological event detection systems and methods
US7780606B2 (en) * 2006-03-29 2010-08-24 Cardiac Pacemakers, Inc. Hemodynamic stability assessment based on heart sounds
EP2026874B1 (en) * 2006-03-29 2015-05-20 Dignity Health Vagus nerve stimulation system
US7962220B2 (en) 2006-04-28 2011-06-14 Cyberonics, Inc. Compensation reduction in tissue stimulation therapy
US7869885B2 (en) * 2006-04-28 2011-01-11 Cyberonics, Inc Threshold optimization for tissue stimulation therapy
US8005543B2 (en) 2006-05-08 2011-08-23 Cardiac Pacemakers, Inc. Heart failure management system
US8000780B2 (en) 2006-06-27 2011-08-16 Cardiac Pacemakers, Inc. Detection of myocardial ischemia from the time sequence of implanted sensor measurements
US20080027350A1 (en) * 2006-07-13 2008-01-31 Advanced Cardiovascular Systems, Inc. Methods and apparatus for localization, diagnosis, contact or activity detection of bio-electric tissue
US7912548B2 (en) * 2006-07-21 2011-03-22 Cardiac Pacemakers, Inc. Resonant structures for implantable devices
EP2043740A2 (en) * 2006-07-21 2009-04-08 Cardiac Pacemakers, Inc. Ultrasonic transducer for a metallic cavity implanted medical device
US7955268B2 (en) 2006-07-21 2011-06-07 Cardiac Pacemakers, Inc. Multiple sensor deployment
US20080072677A1 (en) * 2006-09-26 2008-03-27 Sorah Rhee Bending mode accelerometer
US20080072671A1 (en) * 2006-09-26 2008-03-27 Eldon Eller Leveraged shear mode accelerometers
US7869867B2 (en) 2006-10-27 2011-01-11 Cyberonics, Inc. Implantable neurostimulator with refractory stimulation
US20080119749A1 (en) * 2006-11-20 2008-05-22 Cardiac Pacemakers, Inc. Respiration-synchronized heart sound trending
US8096954B2 (en) 2006-11-29 2012-01-17 Cardiac Pacemakers, Inc. Adaptive sampling of heart sounds
US7736319B2 (en) * 2007-01-19 2010-06-15 Cardiac Pacemakers, Inc. Ischemia detection using heart sound timing
US7853327B2 (en) * 2007-04-17 2010-12-14 Cardiac Pacemakers, Inc. Heart sound tracking system and method
US7974701B2 (en) * 2007-04-27 2011-07-05 Cyberonics, Inc. Dosing limitation for an implantable medical device
US8825161B1 (en) 2007-05-17 2014-09-02 Cardiac Pacemakers, Inc. Acoustic transducer for an implantable medical device
AU2008266678B2 (en) 2007-06-14 2013-06-20 Cardiac Pacemakers, Inc. Multi-element acoustic recharging system
US7731658B2 (en) * 2007-08-16 2010-06-08 Cardiac Pacemakers, Inc. Glycemic control monitoring using implantable medical device
US9986926B2 (en) * 2007-10-26 2018-06-05 Inovise Medical, Inc. Q-onset ventricular depolarization detection in the presence of a pacemaker
US8725260B2 (en) 2008-02-11 2014-05-13 Cardiac Pacemakers, Inc Methods of monitoring hemodynamic status for rhythm discrimination within the heart
WO2009102640A1 (en) 2008-02-12 2009-08-20 Cardiac Pacemakers, Inc. Systems and methods for controlling wireless signal transfers between ultrasound-enabled medical devices
US8204603B2 (en) 2008-04-25 2012-06-19 Cyberonics, Inc. Blocking exogenous action potentials by an implantable medical device
EP2334230A1 (en) 2008-10-10 2011-06-22 Cardiac Pacemakers, Inc. Systems and methods for determining cardiac output using pulmonary artery pressure measurements
US8577448B2 (en) * 2008-10-14 2013-11-05 Inovise Medical, Inc. Differential apneic detection in aid of diagnosis and treatment
US8457747B2 (en) 2008-10-20 2013-06-04 Cyberonics, Inc. Neurostimulation with signal duration determined by a cardiac cycle
US8632470B2 (en) 2008-11-19 2014-01-21 Cardiac Pacemakers, Inc. Assessment of pulmonary vascular resistance via pulmonary artery pressure
US20100191304A1 (en) 2009-01-23 2010-07-29 Scott Timothy L Implantable Medical Device for Providing Chronic Condition Therapy and Acute Condition Therapy Using Vagus Nerve Stimulation
WO2011057116A1 (en) * 2009-11-05 2011-05-12 Inovise Medical, Inc. Detection and differentiation of sleep disordered breathing
US8697159B2 (en) * 2010-01-25 2014-04-15 General Mills, Inc. Coated food product and method of preparation
US8649853B2 (en) 2010-06-29 2014-02-11 Cardiac Pacemakers, Inc. Cardiac function monitor using information indicative of lead motion
US8491488B1 (en) 2010-10-01 2013-07-23 Blaufuss Medical Multimedia Laboratories, LLC Method and system for identifying cardiopulmonary findings by using a heart and lung sounds builder
US8375793B2 (en) * 2011-02-10 2013-02-19 Dytran Instruments, Inc. Accelerometer for high temperature applications
US8617082B2 (en) 2011-05-19 2013-12-31 Medtronic, Inc. Heart sounds-based pacing optimization
US20120296387A1 (en) 2011-05-19 2012-11-22 Xusheng Zhang Phrenic nerve stimulation detection using heart sounds
US8777874B2 (en) 2011-05-24 2014-07-15 Medtronic, Inc. Acoustic based cough detection
US8886311B2 (en) 2012-01-27 2014-11-11 Medtronic, Inc. Techniques for mitigating motion artifacts from implantable physiological sensors
US9095718B2 (en) 2012-04-04 2015-08-04 Medtronic, Inc. Heart-sounds based adaptive cardiac resynchronization therapy timing parameter optimization system
US8548588B1 (en) * 2012-09-21 2013-10-01 Inovise Medical, Inc. CRM-device ventricular-pacing blanking control
US10335592B2 (en) 2012-12-19 2019-07-02 Viscardia, Inc. Systems, devices, and methods for improving hemodynamic performance through asymptomatic diaphragm stimulation
JP6285956B2 (en) 2012-12-19 2018-02-28 ヴィスカルディア インコーポレイテッド Improved hemodynamic performance through asymptomatic diaphragm stimulation
US9345410B2 (en) * 2013-03-15 2016-05-24 Cardiac Pacemakers, Inc. Diagnostic and optimization using exercise recovery data
WO2015200707A1 (en) * 2014-06-25 2015-12-30 Hunter William L Devices, systems and methods for using and monitoring heart valves
US10542961B2 (en) 2015-06-15 2020-01-28 The Research Foundation For The State University Of New York System and method for infrasonic cardiac monitoring
US10537735B2 (en) 2016-04-29 2020-01-21 Viscardia, Inc. Implantable medical devices and methods for real-time or near real-time adjustment of diaphragmatic stimulation parameters to affect pressures within the intrathoracic cavity
US10434317B2 (en) * 2016-10-31 2019-10-08 Cardiac Pacemakers, Inc. Systems and methods for activity level pacing
WO2018081713A1 (en) * 2016-10-31 2018-05-03 Cardiac Pacemakers, Inc Systems for activity level pacing
JP2023500778A (en) 2019-09-26 2023-01-11 ヴィスカルディア インコーポレイテッド Implantable medical systems, devices, and methods for influencing cardiac function through diaphragmatic stimulation and for monitoring diaphragmatic health
US11529102B2 (en) 2019-12-02 2022-12-20 Analog Devices, Inc. Heart sound normalization
CN111528831B (en) * 2020-05-20 2022-09-13 广东工业大学 Cardiopulmonary sound collection method, device and equipment
CN116671928A (en) * 2023-07-27 2023-09-01 中国科学技术大学 Bimodal cardiac electromechanical physiological source imaging system

Citations (74)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4173971A (en) * 1977-08-29 1979-11-13 Karz Allen E Continuous electrocardiogram monitoring method and system for cardiac patients
US4291699A (en) * 1978-09-21 1981-09-29 Purdue Research Foundation Method of and apparatus for automatically detecting and treating ventricular fibrillation
US4586514A (en) * 1983-08-10 1986-05-06 Biotronics Instruments Phonoangiographic spectral analysing apparatus
US4702253A (en) * 1985-10-15 1987-10-27 Telectronics N.V. Metabolic-demand pacemaker and method of using the same to determine minute volume
US4796639A (en) * 1987-11-05 1989-01-10 Medical Graphics Corporation Pulmonary diagnostic system
US4830006A (en) * 1986-06-17 1989-05-16 Intermedics, Inc. Implantable cardiac stimulator for detection and treatment of ventricular arrhythmias
US5179947A (en) * 1991-01-15 1993-01-19 Cardiac Pacemakers, Inc. Acceleration-sensitive cardiac pacemaker and method of operation
US5206283A (en) * 1989-04-14 1993-04-27 The Yokohama Rubber Co., Ltd. Rubber composition for automobile tires
US5305745A (en) * 1988-06-13 1994-04-26 Fred Zacouto Device for protection against blood-related disorders, notably thromboses, embolisms, vascular spasms, hemorrhages, hemopathies and the presence of abnormal elements in the blood
US5411531A (en) * 1993-09-23 1995-05-02 Medtronic, Inc. Method and apparatus for control of A-V interval
US5544661A (en) * 1994-01-13 1996-08-13 Charles L. Davis Real time ambulatory patient monitor
US5554177A (en) * 1995-03-27 1996-09-10 Medtronic, Inc. Method and apparatus to optimize pacing based on intensity of acoustic signal
US5620472A (en) * 1995-01-12 1997-04-15 Pacesetter, Inc. Apparatus and method for dynamically interpreting and displaying a real-time telemetry link
US5792195A (en) * 1996-12-16 1998-08-11 Cardiac Pacemakers, Inc. Acceleration sensed safe upper rate envelope for calculating the hemodynamic upper rate limit for a rate adaptive cardiac rhythm management device
US5935081A (en) * 1998-01-20 1999-08-10 Cardiac Pacemakers, Inc. Long term monitoring of acceleration signals for optimization of pacing therapy
US6002777A (en) * 1995-07-21 1999-12-14 Stethtech Corporation Electronic stethoscope
US6044297A (en) * 1998-09-25 2000-03-28 Medtronic, Inc. Posture and device orientation and calibration for implantable medical devices
US6048319A (en) * 1998-10-01 2000-04-11 Integrated Medical Systems, Inc. Non-invasive acoustic screening device for coronary stenosis
US6058329A (en) * 1998-10-13 2000-05-02 Cardiac Pacemakers, Inc. Optimization of pacing parameters based on measurement of acoustic noise
US6076015A (en) * 1998-02-27 2000-06-13 Cardiac Pacemakers, Inc. Rate adaptive cardiac rhythm management device using transthoracic impedance
US6208900B1 (en) * 1996-03-28 2001-03-27 Medtronic, Inc. Method and apparatus for rate-responsive cardiac pacing using header mounted pressure wave transducer
US6272377B1 (en) * 1999-10-01 2001-08-07 Cardiac Pacemakers, Inc. Cardiac rhythm management system with arrhythmia prediction and prevention
US20020072684A1 (en) * 1998-11-09 2002-06-13 Stearns Scott Donaldson Acoustic window identification
US20020091415A1 (en) * 2000-05-13 2002-07-11 Lovett Eric G. Rate smoothing control
US20020128563A1 (en) * 2001-03-08 2002-09-12 Carlson Gerrard M. Cardiac rhythm management system using time-domain heart rate variablility indicia
US20020151938A1 (en) * 2000-11-17 2002-10-17 Giorgio Corbucci Myocardial performance assessment
US20020151812A1 (en) * 2001-04-11 2002-10-17 Cardiac Pacemakers, Inc. Apparatus and method for outputting heart sounds
US6477406B1 (en) * 1999-11-10 2002-11-05 Pacesetter, Inc. Extravascular hemodynamic acoustic sensor
US6480733B1 (en) * 1999-11-10 2002-11-12 Pacesetter, Inc. Method for monitoring heart failure
US20030014083A1 (en) * 2001-04-27 2003-01-16 Bernhard Kupper Implantable medical device system with sensor for hemodynamic stability and method of use
US6542775B2 (en) * 1998-05-08 2003-04-01 Cardiac Pacemakers, Inc. Cardiac pacing using adjustable atrio-ventricular delays
US20030105497A1 (en) * 2001-12-03 2003-06-05 Cardiac Pacemakers, Inc. Implantable cardiac disease management device with trigger-stored polysomnogram and phonocardiogram
US20030144702A1 (en) * 1998-05-08 2003-07-31 Yinghong Yu Method and apparatus for optimizing stroke volume during DDD resynchronization therapy using adjustable atrio-ventricular delays
US20030144703A1 (en) * 1998-05-08 2003-07-31 Yinghong Yu Method and apparatus for optimizing ventricular synchrony during DDD resynchronization therapy using adjustable atrio-ventricular delays
US6643548B1 (en) * 2000-04-06 2003-11-04 Pacesetter, Inc. Implantable cardiac stimulation device for monitoring heart sounds to detect progression and regression of heart disease and method thereof
US20030208240A1 (en) * 2002-05-03 2003-11-06 Pastore Joseph M. Method and apparatus for detecting acoustic oscillations in cardiac rhythm
US20030233132A1 (en) * 2002-06-14 2003-12-18 Pastore Joseph M. Method and apparatus for detecting oscillations in cardiac rhythm
US20040039295A1 (en) * 2002-08-23 2004-02-26 Olbrich Craig A. Multi-function sensor device and methods for its use
US20040073093A1 (en) * 2002-10-11 2004-04-15 Cardiac Pacemakers, Inc. Methods and devices for detection of context when addressing a medical condition of a patient
US20040102712A1 (en) * 2002-11-25 2004-05-27 Andres Belalcazar Impedance monitoring for detecting pulmonary edema and thoracic congestion
US20040106961A1 (en) * 2002-12-02 2004-06-03 Siejko Krzysztof Z. Method and apparatus for phonocardiographic image acquisition and presentation
US20040106960A1 (en) * 2002-12-02 2004-06-03 Siejko Krzysztof Z. Phonocardiographic image-based atrioventricular delay optimization
US20040127792A1 (en) * 2002-12-30 2004-07-01 Siejko Krzysztof Z. Method and apparatus for monitoring of diastolic hemodynamics
US20040176810A1 (en) * 2001-10-30 2004-09-09 Medtronic, Inc. Implantable medical device employing sonomicrometer output signals for detection and measurement of cardiac mechanical function
US6804558B2 (en) * 1999-07-07 2004-10-12 Medtronic, Inc. System and method of communicating between an implantable medical device and a remote computer system or health care provider
US20040215265A1 (en) * 2003-04-23 2004-10-28 Keizer Diederick M. Sensing techniques for implantable medical devices
US20040215264A1 (en) * 2003-04-23 2004-10-28 Van Bentem Maarten Detecting heart tones to identify heart deterioration
US20050004485A1 (en) * 2003-05-19 2005-01-06 Ischemia Technologies, Inc. Apparatus and method for risk stratification of patients with chest pain of suspected cardiac origin
US20050065448A1 (en) * 2003-09-18 2005-03-24 Cardiac Pacemakers, Inc. Methods and systems for assessing pulmonary disease
US20050065556A1 (en) * 2003-09-23 2005-03-24 Medtronic Minimed, Inc. Implantable multi-parameter sensing system and method
US6885889B2 (en) * 2003-02-28 2005-04-26 Medtronic, Inc. Method and apparatus for optimizing cardiac resynchronization therapy based on left ventricular acceleration
US20050102001A1 (en) * 2003-11-06 2005-05-12 Maile Keith R. Dual-use sensor for rate responsive pacing and heart sound monitoring
US20050137831A1 (en) * 2003-12-19 2005-06-23 Dubal Scott P. Method, system, and article of manufacture for running diagnostics related to a device
US20050148896A1 (en) * 2003-12-24 2005-07-07 Siejko Krzysztof Z. Method and apparatus for third heart sound detection
US6942622B1 (en) * 1999-11-10 2005-09-13 Pacesetter, Inc. Method for monitoring autonomic tone
US6951593B2 (en) * 2001-01-15 2005-10-04 Lintec Corporation Laminating device and laminating method
US20050256542A1 (en) * 2002-03-26 2005-11-17 Cardiac Pacemakers, Inc. Method and apparatus for detecting oscillations in cardiac rhythm with electrogram signals
US20060020294A1 (en) * 2004-06-10 2006-01-26 Marina Brockway Method and apparatus for optimization of cardiac resynchronization therapy using heart sounds
US20060020295A1 (en) * 2004-07-23 2006-01-26 Cardiac Pacemakers, Inc. Method and apparatus for monitoring heart failure patients with cardiopulmonary comorbidities
US20060025699A1 (en) * 2004-07-28 2006-02-02 Cardiac Pacemakers, Inc. Determining a patient's posture from mechanical vibrations of the heart
US20060030892A1 (en) * 2004-08-09 2006-02-09 Veerichetty Kadhiresan Cardiopulmonary functional status assessment via heart rate response dectection by implantable cardiac device
US20060161070A1 (en) * 2005-01-18 2006-07-20 Cardiac Pacemakers, Inc. Method for correction of posture dependence on heart sounds
US20060167518A1 (en) * 2005-01-25 2006-07-27 Jong Gill System and method for distinguishing among cardiac ischemia, hypoglycemia and hyperglycemia using an implantable medical device
US7115096B2 (en) * 2003-12-24 2006-10-03 Cardiac Pacemakers, Inc. Third heart sound activity index for heart failure monitoring
US7139609B1 (en) * 2003-01-17 2006-11-21 Pacesetter, Inc. System and method for monitoring cardiac function via cardiac sounds using an implantable cardiac stimulation device
US20060270939A1 (en) * 2005-05-24 2006-11-30 Cardiac Pacemakers, Inc. Systems and methods for multi-axis cardiac vibration measurements
US20060282000A1 (en) * 2005-06-08 2006-12-14 Cardiac Pacemakers, Inc. Ischemia detection using a heart sound sensor
US7194306B1 (en) * 2003-09-05 2007-03-20 Pacesetter, Inc. Cardiac optimization through low-frequency analysis of hemodynamic variables
US7226422B2 (en) * 2002-10-09 2007-06-05 Cardiac Pacemakers, Inc. Detection of congestion from monitoring patient response to a recumbent position
US20070149890A1 (en) * 2005-12-22 2007-06-28 Dan Li Method and apparatus for morphology-based arrhythmia classification using cardiac and other physiological signals
US20070162081A1 (en) * 2003-12-22 2007-07-12 Cardiac Pacemakers, Inc. Dynamic device therapy control for treating post myocardial infarction patients
US20070239218A1 (en) * 2006-03-29 2007-10-11 Carlson Gerrard M Hemodynamic stability assessment based on heart sounds
US20070299356A1 (en) * 2006-06-27 2007-12-27 Ramesh Wariar Detection of myocardial ischemia from the time sequence of implanted sensor measurements
US20080177191A1 (en) * 2007-01-19 2008-07-24 Cardiac Pacemakers, Inc. Ischemia detection using heart sound timing

Family Cites Families (84)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3149949A (en) * 1961-02-27 1964-09-22 Corning Glass Works Downflow sheet drawing method and apparatus
BE627976A (en) * 1962-02-05
FR1447205A (en) * 1965-04-12 1966-07-29 Saint Gobain Improvements in the manufacture of sheets of thermoplastic materials, such as glass, by drawing
US3536463A (en) * 1967-06-26 1970-10-27 Ppg Industries Inc Method and apparatus for controlling temporary stresses during the formation of a glass ribbon from a molten pool
GB1452071A (en) * 1973-08-13 1976-10-06 Pilkington Brothers Ltd Annealing of patterned glass
US4289141A (en) 1976-08-19 1981-09-15 Cormier Cardiac Systems, Inc. Method and apparatus for extracting systolic valvular events from heart sounds
US4094308A (en) 1976-08-19 1978-06-13 Cormier Cardiac Systems, Inc. Method and system for rapid non-invasive determination of the systolic time intervals
CH632403A5 (en) 1977-09-08 1982-10-15 Avl Ag METHOD AND DEVICE FOR DETERMINING SYSTOLIC TIME INTERVALS.
US4649930A (en) 1981-03-06 1987-03-17 Siemens Gammasonics, Inc. Apparatus for beat buffering techniques varified by arrhythmias detection for stopaction frames of cardiac function
US4548204A (en) 1981-03-06 1985-10-22 Siemens Gammasonics, Inc. Apparatus for monitoring cardiac activity via ECG and heart sound signals
US4686987A (en) 1981-06-18 1987-08-18 Cardiac Pacemakers, Inc. Biomedical method and apparatus for controlling the administration of therapy to a patient in response to changes in physiologic demand
US4428378A (en) 1981-11-19 1984-01-31 Medtronic, Inc. Rate adaptive pacer
US4981139A (en) 1983-08-11 1991-01-01 Pfohl Robert L Vital signs monitoring and communication system
JPS61202653A (en) 1985-03-07 1986-09-08 マルハ株式会社 Apparatus for removing kidney skin of fish body
DE3535504A1 (en) 1985-10-04 1987-04-09 Siemens Ag HEART PACEMAKER
JPS63109103U (en) 1986-12-29 1988-07-13
JPS63290544A (en) 1987-05-22 1988-11-28 Koorin Denshi Kk Stertor detector
US4905706A (en) 1988-04-20 1990-03-06 Nippon Colin Co., Ltd. Method an apparatus for detection of heart disease
US4989611A (en) 1988-08-19 1991-02-05 Seismed Instruments, Inc. Cardiac compression wave measuring system and method
US4913720A (en) * 1988-09-29 1990-04-03 Glasstech, Inc. Glass sheet modulated quenching
US4915113A (en) 1988-12-16 1990-04-10 Bio-Vascular, Inc. Method and apparatus for monitoring the patency of vascular grafts
US4945909A (en) 1989-06-06 1990-08-07 Cook Pacemaker Corporation Pacemaker with activity-dependent rate limiting
US5697375A (en) 1989-09-18 1997-12-16 The Research Foundation Of State University Of New York Method and apparatus utilizing heart sounds for determining pressures associated with the left atrium
EP0520015A1 (en) 1990-03-16 1992-12-30 Seismed Instruments, Inc. Myocardial ischemia detection system
US5205283A (en) * 1991-07-30 1993-04-27 Medtronic, Inc. Method and apparatus for tachyarrhythmia detection and treatment
JP2981692B2 (en) 1992-03-11 1999-11-22 西川ゴム工業株式会社 Weather strip
US5342404A (en) 1992-04-03 1994-08-30 Intermedics, Inc. Implantable medical interventional device
JPH06277189A (en) 1993-03-26 1994-10-04 Shogo Nakamura Method for cancelling noise and noise cancelling circuit in electrocardiograph
DK63193D0 (en) 1993-06-02 1993-06-02 Bang & Olufsen Tech As HEART SIGNAL MEASUREMENT APPARATUS
US5628777A (en) 1993-07-14 1997-05-13 Pacesetter, Inc. Implantable leads incorporating cardiac wall acceleration sensors and method of fabrication
US5654057A (en) * 1994-12-28 1997-08-05 Hoya Corporation Sheet glass flattening method, method of manufacturing glass substrate for an information recording disk using flattened glass, method of manufacturing a magnetic recording disk using glass substrate, and magnetic recording medium
US5593431A (en) 1995-03-30 1997-01-14 Medtronic, Inc. Medical service employing multiple DC accelerometers for patient activity and posture sensing and method
US5725562A (en) 1995-03-30 1998-03-10 Medtronic Inc Rate responsive cardiac pacemaker and method for discriminating stair climbing from other activities
US5687738A (en) 1995-07-03 1997-11-18 The Regents Of The University Of Colorado Apparatus and methods for analyzing heart sounds
US5836987A (en) 1995-11-15 1998-11-17 Cardiac Pacemakers, Inc. Apparatus and method for optimizing cardiac performance by determining the optimal timing interval from an accelerometer signal
US5674256A (en) 1995-12-19 1997-10-07 Cardiac Pacemakers, Inc. Cardiac pre-ejection period detection
US6152884A (en) 1996-04-25 2000-11-28 Bjoergaas; Per Samuel Method and instrument for examination of heart/arteries using microphones
SE9603573D0 (en) 1996-09-30 1996-09-30 Pacesetter Ab Implantable medecal device
SE9604320D0 (en) 1996-11-25 1996-11-25 Pacesetter Ab Medical device
US5700283A (en) 1996-11-25 1997-12-23 Cardiac Pacemakers, Inc. Method and apparatus for pacing patients with severe congestive heart failure
US6050950A (en) 1996-12-18 2000-04-18 Aurora Holdings, Llc Passive/non-invasive systemic and pulmonary blood pressure measurement
JP3671568B2 (en) * 1996-12-26 2005-07-13 旭硝子株式会社 Method for producing cathode ray tube panel glass
US5951593A (en) * 1997-08-29 1999-09-14 Lu; Richard Apparatus for preventing atrial fibrillation using precursors
US5991661A (en) 1997-10-17 1999-11-23 Pacesetter, Inc. System and method for measuring cardiac activity
US6193668B1 (en) 1997-11-10 2001-02-27 Medacoustics, Inc. Acoustic sensor array for non-invasive detection of coronary artery disease
JP2000060846A (en) 1998-08-24 2000-02-29 Nippon Colin Co Ltd Biological sound detector
US6026324A (en) 1998-10-13 2000-02-15 Cardiac Pacemakers, Inc. Extraction of hemodynamic pulse pressure from fluid and myocardial accelerations
US6298269B1 (en) 1999-04-19 2001-10-02 Cardiac Pacemakers, Inc. Cardiac rhythm management system with ultrasound for autocapture or other applications
JP2000316825A (en) 1999-05-12 2000-11-21 Toshio Ochi Device for constantly monitoring heart sound
US6351672B1 (en) 1999-07-22 2002-02-26 Pacesetter, Inc. System and method for modulating the pacing rate based on patient activity and position
FR2797627B1 (en) * 1999-08-19 2001-10-26 Stein Heurtey IMPROVEMENTS RELATING TO FLAT GLASS COLLECTION RACKS
US6415033B1 (en) 1999-09-15 2002-07-02 Ilife Systems, Inc. Physiological condition monitors utilizing very low frequency acoustic signals
US6572560B1 (en) 1999-09-29 2003-06-03 Zargis Medical Corp. Multi-modal cardiac diagnostic decision support system and method
US6440082B1 (en) 1999-09-30 2002-08-27 Medtronic Physio-Control Manufacturing Corp. Method and apparatus for using heart sounds to determine the presence of a pulse
US7127290B2 (en) 1999-10-01 2006-10-24 Cardiac Pacemakers, Inc. Cardiac rhythm management systems and methods predicting congestive heart failure status
US6273856B1 (en) 1999-10-19 2001-08-14 Cardiac Pacemakers, Inc. Apparatus and methods for METS measurement by accelerometer and minute ventilation sensors
US6409675B1 (en) 1999-11-10 2002-06-25 Pacesetter, Inc. Extravascular hemodynamic monitor
US6527729B1 (en) 1999-11-10 2003-03-04 Pacesetter, Inc. Method for monitoring patient using acoustic sensor
US6491639B1 (en) 1999-11-10 2002-12-10 Pacesetter, Inc. Extravascular hemodynamic sensor
US6466821B1 (en) 1999-12-08 2002-10-15 Pacesetter, Inc. AC/DC multi-axis accelerometer for determining patient activity and body position
US6650940B1 (en) 2000-02-02 2003-11-18 Cardiac Pacemakers, Inc. Accelerometer-based heart sound detection for autocapture
JP4352558B2 (en) 2000-02-18 2009-10-28 オムロンヘルスケア株式会社 Heart sound detection device, and precursor period measurement device and pulse wave velocity information measurement device using the heart sound detection device
JP2001224564A (en) 2000-02-18 2001-08-21 Nippon Colin Co Ltd Cardiac sound detector and pulse wave propagating speed information measuring instrument using it
US6575916B2 (en) 2000-03-24 2003-06-10 Ilife Solutions, Inc. Apparatus and method for detecting very low frequency acoustic signals
JP2002051997A (en) 2000-08-09 2002-02-19 Nippon Colin Co Ltd Heart sound analyzer
US6368283B1 (en) 2000-09-08 2002-04-09 Institut De Recherches Cliniques De Montreal Method and apparatus for estimating systolic and mean pulmonary artery pressures of a patient
JP3754882B2 (en) * 2000-09-29 2006-03-15 キヤノン株式会社 Manufacturing method of image display device
US6567700B1 (en) 2000-10-19 2003-05-20 Robert Turcott Implantable cardiac stimulation device and method which optimizes pacing effectiveness
KR100387201B1 (en) 2000-11-16 2003-06-12 이병훈 Diaortic apparatus
JP2002224065A (en) 2001-02-07 2002-08-13 Nippon Colin Co Ltd Cardiac sound detecting device and cardiac sound detecting method
JP3587798B2 (en) 2001-04-04 2004-11-10 コーリンメディカルテクノロジー株式会社 Continuous blood pressure monitor
US6665564B2 (en) 2001-05-21 2003-12-16 Cardiac Pacemakers, Inc. Cardiac rhythm management system selecting A-V delay based on interval between atrial depolarization and mitral valve closure
US6625493B2 (en) 2001-08-24 2003-09-23 Pacesetter, Inc. Orientation of patient's position sensor using external field
US6658292B2 (en) 2001-08-24 2003-12-02 Pacesetter, Inc. Detection of patient's position and activity status using 3D accelerometer-based position sensor
US6826929B2 (en) * 2001-09-19 2004-12-07 Premakaran T. Boaz Method for simultaneously heating and cooling glass to produce tempered glass
FR2829917B1 (en) 2001-09-24 2004-06-11 Ela Medical Sa ACTIVE MEDICAL DEVICE INCLUDING MEANS FOR DIAGNOSING THE RESPIRATORY PROFILE
US7062323B2 (en) 2001-10-19 2006-06-13 Cardiac Pacemakers, Inc. Maximum atrial tracking rate for cardiac rhythm management system
US20030093002A1 (en) 2001-11-13 2003-05-15 Kuo Terry B.J. Function indicator for autonomic nervous system based on phonocardiogram
US6892095B2 (en) 2001-12-31 2005-05-10 Cardiac Pacemakers, Inc. Method and apparatus for monitoring left ventricular work or power
US7236821B2 (en) * 2002-02-19 2007-06-26 Cardiac Pacemakers, Inc. Chronically-implanted device for sensing and therapy
US6963777B2 (en) 2002-03-13 2005-11-08 Cardiac Pacemakers, Inc. Cardiac rhythm management system and method using time between mitral valve closure and aortic ejection
US7228175B2 (en) 2002-05-15 2007-06-05 Cardiac Pacemakers, Inc. Cardiac rhythm management systems and methods using acoustic contractility indicator
US7020521B1 (en) 2002-11-08 2006-03-28 Pacesetter, Inc. Methods and apparatus for detecting and/or monitoring heart failure
US7986994B2 (en) 2002-12-04 2011-07-26 Medtronic, Inc. Method and apparatus for detecting change in intrathoracic electrical impedance

Patent Citations (90)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4173971A (en) * 1977-08-29 1979-11-13 Karz Allen E Continuous electrocardiogram monitoring method and system for cardiac patients
US4291699A (en) * 1978-09-21 1981-09-29 Purdue Research Foundation Method of and apparatus for automatically detecting and treating ventricular fibrillation
US4586514A (en) * 1983-08-10 1986-05-06 Biotronics Instruments Phonoangiographic spectral analysing apparatus
US4702253A (en) * 1985-10-15 1987-10-27 Telectronics N.V. Metabolic-demand pacemaker and method of using the same to determine minute volume
US4830006B1 (en) * 1986-06-17 1997-10-28 Intermedics Inc Implantable cardiac stimulator for detection and treatment of ventricular arrhythmias
US4830006A (en) * 1986-06-17 1989-05-16 Intermedics, Inc. Implantable cardiac stimulator for detection and treatment of ventricular arrhythmias
US4796639A (en) * 1987-11-05 1989-01-10 Medical Graphics Corporation Pulmonary diagnostic system
US5305745A (en) * 1988-06-13 1994-04-26 Fred Zacouto Device for protection against blood-related disorders, notably thromboses, embolisms, vascular spasms, hemorrhages, hemopathies and the presence of abnormal elements in the blood
US5206283A (en) * 1989-04-14 1993-04-27 The Yokohama Rubber Co., Ltd. Rubber composition for automobile tires
US5179947A (en) * 1991-01-15 1993-01-19 Cardiac Pacemakers, Inc. Acceleration-sensitive cardiac pacemaker and method of operation
US5411531A (en) * 1993-09-23 1995-05-02 Medtronic, Inc. Method and apparatus for control of A-V interval
US5544661A (en) * 1994-01-13 1996-08-13 Charles L. Davis Real time ambulatory patient monitor
US5620472A (en) * 1995-01-12 1997-04-15 Pacesetter, Inc. Apparatus and method for dynamically interpreting and displaying a real-time telemetry link
US5554177A (en) * 1995-03-27 1996-09-10 Medtronic, Inc. Method and apparatus to optimize pacing based on intensity of acoustic signal
US6002777A (en) * 1995-07-21 1999-12-14 Stethtech Corporation Electronic stethoscope
US6208900B1 (en) * 1996-03-28 2001-03-27 Medtronic, Inc. Method and apparatus for rate-responsive cardiac pacing using header mounted pressure wave transducer
US5792195A (en) * 1996-12-16 1998-08-11 Cardiac Pacemakers, Inc. Acceleration sensed safe upper rate envelope for calculating the hemodynamic upper rate limit for a rate adaptive cardiac rhythm management device
US5935081A (en) * 1998-01-20 1999-08-10 Cardiac Pacemakers, Inc. Long term monitoring of acceleration signals for optimization of pacing therapy
US6076015A (en) * 1998-02-27 2000-06-13 Cardiac Pacemakers, Inc. Rate adaptive cardiac rhythm management device using transthoracic impedance
US20030144702A1 (en) * 1998-05-08 2003-07-31 Yinghong Yu Method and apparatus for optimizing stroke volume during DDD resynchronization therapy using adjustable atrio-ventricular delays
US20030144703A1 (en) * 1998-05-08 2003-07-31 Yinghong Yu Method and apparatus for optimizing ventricular synchrony during DDD resynchronization therapy using adjustable atrio-ventricular delays
US6542775B2 (en) * 1998-05-08 2003-04-01 Cardiac Pacemakers, Inc. Cardiac pacing using adjustable atrio-ventricular delays
US6684103B2 (en) * 1998-05-08 2004-01-27 Cardiac Pacemakers, Inc. Cardiac pacing using adjustable atrio-ventricular delays
US6044297A (en) * 1998-09-25 2000-03-28 Medtronic, Inc. Posture and device orientation and calibration for implantable medical devices
US6048319A (en) * 1998-10-01 2000-04-11 Integrated Medical Systems, Inc. Non-invasive acoustic screening device for coronary stenosis
US6058329A (en) * 1998-10-13 2000-05-02 Cardiac Pacemakers, Inc. Optimization of pacing parameters based on measurement of acoustic noise
US20020072684A1 (en) * 1998-11-09 2002-06-13 Stearns Scott Donaldson Acoustic window identification
US6804558B2 (en) * 1999-07-07 2004-10-12 Medtronic, Inc. System and method of communicating between an implantable medical device and a remote computer system or health care provider
US6272377B1 (en) * 1999-10-01 2001-08-07 Cardiac Pacemakers, Inc. Cardiac rhythm management system with arrhythmia prediction and prevention
US6942622B1 (en) * 1999-11-10 2005-09-13 Pacesetter, Inc. Method for monitoring autonomic tone
US6477406B1 (en) * 1999-11-10 2002-11-05 Pacesetter, Inc. Extravascular hemodynamic acoustic sensor
US6480733B1 (en) * 1999-11-10 2002-11-12 Pacesetter, Inc. Method for monitoring heart failure
US6643548B1 (en) * 2000-04-06 2003-11-04 Pacesetter, Inc. Implantable cardiac stimulation device for monitoring heart sounds to detect progression and regression of heart disease and method thereof
US20020091415A1 (en) * 2000-05-13 2002-07-11 Lovett Eric G. Rate smoothing control
US20020151938A1 (en) * 2000-11-17 2002-10-17 Giorgio Corbucci Myocardial performance assessment
US6792308B2 (en) * 2000-11-17 2004-09-14 Medtronic, Inc. Myocardial performance assessment
US6951593B2 (en) * 2001-01-15 2005-10-04 Lintec Corporation Laminating device and laminating method
US20020128563A1 (en) * 2001-03-08 2002-09-12 Carlson Gerrard M. Cardiac rhythm management system using time-domain heart rate variablility indicia
US20020151812A1 (en) * 2001-04-11 2002-10-17 Cardiac Pacemakers, Inc. Apparatus and method for outputting heart sounds
US20030014083A1 (en) * 2001-04-27 2003-01-16 Bernhard Kupper Implantable medical device system with sensor for hemodynamic stability and method of use
US20040176810A1 (en) * 2001-10-30 2004-09-09 Medtronic, Inc. Implantable medical device employing sonomicrometer output signals for detection and measurement of cardiac mechanical function
US20030105497A1 (en) * 2001-12-03 2003-06-05 Cardiac Pacemakers, Inc. Implantable cardiac disease management device with trigger-stored polysomnogram and phonocardiogram
US20050256542A1 (en) * 2002-03-26 2005-11-17 Cardiac Pacemakers, Inc. Method and apparatus for detecting oscillations in cardiac rhythm with electrogram signals
US20030208240A1 (en) * 2002-05-03 2003-11-06 Pastore Joseph M. Method and apparatus for detecting acoustic oscillations in cardiac rhythm
US20030233132A1 (en) * 2002-06-14 2003-12-18 Pastore Joseph M. Method and apparatus for detecting oscillations in cardiac rhythm
US6733464B2 (en) * 2002-08-23 2004-05-11 Hewlett-Packard Development Company, L.P. Multi-function sensor device and methods for its use
US20040039295A1 (en) * 2002-08-23 2004-02-26 Olbrich Craig A. Multi-function sensor device and methods for its use
US7226422B2 (en) * 2002-10-09 2007-06-05 Cardiac Pacemakers, Inc. Detection of congestion from monitoring patient response to a recumbent position
US20040073093A1 (en) * 2002-10-11 2004-04-15 Cardiac Pacemakers, Inc. Methods and devices for detection of context when addressing a medical condition of a patient
US20040102712A1 (en) * 2002-11-25 2004-05-27 Andres Belalcazar Impedance monitoring for detecting pulmonary edema and thoracic congestion
US20040106960A1 (en) * 2002-12-02 2004-06-03 Siejko Krzysztof Z. Phonocardiographic image-based atrioventricular delay optimization
US20040106961A1 (en) * 2002-12-02 2004-06-03 Siejko Krzysztof Z. Method and apparatus for phonocardiographic image acquisition and presentation
US7123962B2 (en) * 2002-12-02 2006-10-17 Cardiac Pacemakers, Inc. Phonocardiographic image-based atrioventricular delay optimization
US20040127792A1 (en) * 2002-12-30 2004-07-01 Siejko Krzysztof Z. Method and apparatus for monitoring of diastolic hemodynamics
US8636669B2 (en) * 2002-12-30 2014-01-28 Cardiac Pacemakers, Inc. Method and apparatus for monitoring of diastolic hemodynamics
US7139609B1 (en) * 2003-01-17 2006-11-21 Pacesetter, Inc. System and method for monitoring cardiac function via cardiac sounds using an implantable cardiac stimulation device
US6885889B2 (en) * 2003-02-28 2005-04-26 Medtronic, Inc. Method and apparatus for optimizing cardiac resynchronization therapy based on left ventricular acceleration
US20040215264A1 (en) * 2003-04-23 2004-10-28 Van Bentem Maarten Detecting heart tones to identify heart deterioration
US20040215265A1 (en) * 2003-04-23 2004-10-28 Keizer Diederick M. Sensing techniques for implantable medical devices
US20050004485A1 (en) * 2003-05-19 2005-01-06 Ischemia Technologies, Inc. Apparatus and method for risk stratification of patients with chest pain of suspected cardiac origin
US7194306B1 (en) * 2003-09-05 2007-03-20 Pacesetter, Inc. Cardiac optimization through low-frequency analysis of hemodynamic variables
US20050065448A1 (en) * 2003-09-18 2005-03-24 Cardiac Pacemakers, Inc. Methods and systems for assessing pulmonary disease
US20050065556A1 (en) * 2003-09-23 2005-03-24 Medtronic Minimed, Inc. Implantable multi-parameter sensing system and method
US20050102001A1 (en) * 2003-11-06 2005-05-12 Maile Keith R. Dual-use sensor for rate responsive pacing and heart sound monitoring
US7248923B2 (en) * 2003-11-06 2007-07-24 Cardiac Pacemakers, Inc. Dual-use sensor for rate responsive pacing and heart sound monitoring
US7844334B2 (en) * 2003-11-06 2010-11-30 Cardiac Pacemakers, Inc. Dual-use sensor for rate responsive pacing and heart sound monitoring
US20050137831A1 (en) * 2003-12-19 2005-06-23 Dubal Scott P. Method, system, and article of manufacture for running diagnostics related to a device
US20070162081A1 (en) * 2003-12-22 2007-07-12 Cardiac Pacemakers, Inc. Dynamic device therapy control for treating post myocardial infarction patients
US8504155B2 (en) * 2003-12-22 2013-08-06 Cardiac Pacemakers, Inc. Dynamic device therapy control for treating post myocardial infarction patients
US7115096B2 (en) * 2003-12-24 2006-10-03 Cardiac Pacemakers, Inc. Third heart sound activity index for heart failure monitoring
US20050148896A1 (en) * 2003-12-24 2005-07-07 Siejko Krzysztof Z. Method and apparatus for third heart sound detection
US20070078491A1 (en) * 2003-12-24 2007-04-05 Cardiac Pacemakers, Inc. Third heart sound activity index for heart failure monitoring
US20060020294A1 (en) * 2004-06-10 2006-01-26 Marina Brockway Method and apparatus for optimization of cardiac resynchronization therapy using heart sounds
US20090132000A1 (en) * 2004-07-23 2009-05-21 Cardiac Pacemakers, Inc. Method and apparatus for monitoring heart failure patients with cardiopulmonary comorbidities
US7480528B2 (en) * 2004-07-23 2009-01-20 Cardiac Pacemakers, Inc. Method and apparatus for monitoring heart failure patients with cardiopulmonary comorbidities
US20060020295A1 (en) * 2004-07-23 2006-01-26 Cardiac Pacemakers, Inc. Method and apparatus for monitoring heart failure patients with cardiopulmonary comorbidities
US20060025699A1 (en) * 2004-07-28 2006-02-02 Cardiac Pacemakers, Inc. Determining a patient's posture from mechanical vibrations of the heart
US20060030892A1 (en) * 2004-08-09 2006-02-09 Veerichetty Kadhiresan Cardiopulmonary functional status assessment via heart rate response dectection by implantable cardiac device
US7662104B2 (en) * 2005-01-18 2010-02-16 Cardiac Pacemakers, Inc. Method for correction of posture dependence on heart sounds
US20100099997A1 (en) * 2005-01-18 2010-04-22 Siejko Krzysztof Z Method for correction of posture dependence on heart sounds
US20060161070A1 (en) * 2005-01-18 2006-07-20 Cardiac Pacemakers, Inc. Method for correction of posture dependence on heart sounds
US20060167518A1 (en) * 2005-01-25 2006-07-27 Jong Gill System and method for distinguishing among cardiac ischemia, hypoglycemia and hyperglycemia using an implantable medical device
US7424321B2 (en) * 2005-05-24 2008-09-09 Cardiac Pacemakers, Inc. Systems and methods for multi-axis cardiac vibration measurements
US20060270939A1 (en) * 2005-05-24 2006-11-30 Cardiac Pacemakers, Inc. Systems and methods for multi-axis cardiac vibration measurements
US20060282000A1 (en) * 2005-06-08 2006-12-14 Cardiac Pacemakers, Inc. Ischemia detection using a heart sound sensor
US20090287106A1 (en) * 2005-06-08 2009-11-19 Yi Zhang Ischemia detection using a heart sound sensor
US20070149890A1 (en) * 2005-12-22 2007-06-28 Dan Li Method and apparatus for morphology-based arrhythmia classification using cardiac and other physiological signals
US20070239218A1 (en) * 2006-03-29 2007-10-11 Carlson Gerrard M Hemodynamic stability assessment based on heart sounds
US20070299356A1 (en) * 2006-06-27 2007-12-27 Ramesh Wariar Detection of myocardial ischemia from the time sequence of implanted sensor measurements
US20080177191A1 (en) * 2007-01-19 2008-07-24 Cardiac Pacemakers, Inc. Ischemia detection using heart sound timing

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8758260B2 (en) 2005-06-08 2014-06-24 Cardiac Pacemakers, Inc. Ischemia detection using a heart sound sensor
US9399140B2 (en) 2014-07-25 2016-07-26 Medtronic, Inc. Atrial contraction detection by a ventricular leadless pacing device for atrio-synchronous ventricular pacing
USRE48197E1 (en) 2014-07-25 2020-09-08 Medtronic, Inc. Atrial contraction detection by a ventricular leadless pacing device for atrio-synchronous ventricular pacing
US11207527B2 (en) 2016-07-06 2021-12-28 Cardiac Pacemakers, Inc. Method and system for determining an atrial contraction timing fiducial in a leadless cardiac pacemaker system
US20190082288A1 (en) * 2017-09-14 2019-03-14 Qualcomm Incorporated Opportunistic signal reception for mobile device position location estimation
US10511929B2 (en) * 2017-09-14 2019-12-17 Qualcomm Incorporated Opportunistic signal reception for mobile device position location estimation
US10827300B2 (en) 2017-09-14 2020-11-03 Qualcomm Incorporated Opportunistic signal reception for mobile device position location estimation
US10925573B2 (en) 2017-10-04 2021-02-23 Ausculsciences, Inc. Auscultatory sound-or-vibration sensor
US11896420B2 (en) 2017-10-04 2024-02-13 Ausculsciences, Inc. Auscultatory sound-or-vibration sensor
US11284827B2 (en) 2017-10-21 2022-03-29 Ausculsciences, Inc. Medical decision support system
WO2021121089A1 (en) * 2019-12-16 2021-06-24 青岛歌尔智能传感器有限公司 Potting method for heart rate module

Also Published As

Publication number Publication date
US7844334B2 (en) 2010-11-30
US20080015652A1 (en) 2008-01-17
US7248923B2 (en) 2007-07-24
US20050102001A1 (en) 2005-05-12

Similar Documents

Publication Publication Date Title
US7844334B2 (en) Dual-use sensor for rate responsive pacing and heart sound monitoring
EP1581302B1 (en) Apparatus for monitoring of diastolic hemodynamics
US20190381315A1 (en) System and metod for pacing parameter optimization using heart sounds
US9668713B2 (en) Third heart sound activity index for heart failure monitoring
EP1768566B1 (en) Apparatus for individual intraventricular delay optimization
US6810287B2 (en) Implantable cardiac disease management device with trigger-stored polysomnogram and phonocardiogram
AU2017308071B2 (en) Diastolic endocardial accelerations for heart failure monitoring
US7996084B2 (en) Implantable medical device with automatic ischemia threshold determination
EP3148442B1 (en) Apparatus for detecting atrial tachyarrhythmia using heart sounds
US20150126886A1 (en) Method and apparatus for detecting atrial filling pressure
US20220296906A1 (en) Indirect sensing mechanism for cardiac monitoring
WO2022194817A1 (en) Indirect sensing mechanism for cardiac monitoring
CN117042681A (en) Indirect sensing mechanism for cardiac monitoring

Legal Events

Date Code Title Description
STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION