Cardiac pacemakers.
D001145:Arrhythmias, Cardiac / Q000209:etiology; D006321:Heart / Q000502:physiology; D006326:Heart Auscultation; D006327:Heart Block / Q000628:therapy; D006329:Heart Conduction System / Q000502:physiology; D006339:Heart Rate; D006801:Humans; D010138:Pacemaker, Artificial