Abstract
Modification of the existing portable electric cardiac pacemakers to produce programmed interval pacing increases their usefulness and safety. The currently available pacemakers function by continually stimulating the heart at a preset interval. During ventricular asystole or with a slow ventricular rate, the artificial pacemaker governs the heart with periodic interference by the natural pacemaker. This competition between natural and artificially induced beats is capable of producing bizarre arrhythmias when atrioventricular (AV) conduction disturbances are transient or when higher ventricular rates recur. The new pacemaker which stimulates only on demand, reduces the competition and interference thus obviating hazardous arrhythmias.
