A method and apparatus for detecting failure or impending failure of a lead and for providing a warning to a patient or a patient's physician. The impedance of the lead is repeatedly measured and compared with certain impedance limits. If the measured impedance falls outside of these ...http://www.google.com.au/patents/US5814088?utm_source=gb-gplus-sharePatent US5814088 - Cardiac stimulator with lead failure detector and warning system
