Repetitive Ventricular Arrhythmia Resulting from Artificial Internal Pacemaker

Abstract

We have presented a case summary of a patient in whom several periods of repetitive ventricular arrhythmia—at times indistinguishable from fibrillation—were induced by artificial internal pacemaker stimuli falling in the T wave of a preceding cycle (the vulnerable period). Ours is the third such case to be reported and, although this repetitive response is said to be rare, the exact incidence remains to be determined. The theoretical and clinical implications are discussed and possible explanations are given for why such small artificial stimuli are capable of evoking such serious arrhythmias in certain patients. We also have suggested measures that might reduce the likelihood for this complication to arise.