R-wave detection for demand pacing--the superiority of intramyocardial over endocardial electrodes.
D000818:Animals; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004285:Dogs; D004562:Electrocardiography; D004566:Electrodes; D004699:Endocardium; D009206:Myocardium; D010138:Pacemaker, Artificial