Self-conversion of drug resistant ventricular tachycardia by rapid atrial pacing.

A 523-year-old man with recurrent ventricular tachycardia two months post myocardial infarction is described. The tachycardia resulted in low output and heart failure at the time of presentation. Following electrocardioversion of ventricular tachycardia, sinus rhythm would last for only a few seconds, and ventricular tachycardia could not be terminated or prevented by drugs, nor by overdrive pacing. Over a 20-hour period, asynchronous right ventricular pacing at 30/min resulted in repeated random interruption of successive paroxysms of ventricular tachycardia, resulting in maintenance of sinus rhythm about 60 to 70% of the time. This produced marked hemodynamic improvement and a decrease in the frequency of paroxysms of tachycardia which, however, continued to recur once every few days. Despite their reduced frequency, these paroxysms continued to be resistant to drugs and had to be terminated by cardioversion. At this point it was discovered that rapid atrial pacing was able to terminate the patient's tachycardia reliably and reproducibly. A permanent right atrial externally activated radio frequency pacemaker device was inserted and over the ensuing eighteen-month period the patient self-terminated over fifty discrete episodes of ventricular tachycardia.