An improved ECG system for on-line analysis of the signals received from exercise ECGs whereby the signals from at least a pair of electrodes are differentiated and compared to find maximum slopes of the same sign occuring at the same time, which characteristics are deemed indicative of "R" waves....http://www.google.com.au/patents/US4617938?utm_source=gb-gplus-sharePatent US4617938 - Method and system for distinguishing R-wave electrocardiograph signals for synchronizing purposes
