Reversion of supraventricular tachyarrhythmias by means of atrial stimulation.

Thirteen patients with different forms of supraventricular tachyarrhythmia were treated by means of right atrial pacing. Reversion of arrhythmia was obtained in nine out of ten patients with atrial tachycardia or flutter. The remaining three patients, with atrial fibrillation, did not respond to the procedure. The effective pacing rate in converting arrhythmia ranged from 110 to 2400/min, however in five cases it was lower than the atrial rate. The duration of pacing at an effective rate ranged from 20 seconds to 5 minutes in 5 cases, while in the remaining patients it lasted 10 minutes. In two patients the original arrhythmia was converted to atrial fibrillation during stimulation, but in one it disappeared with pacing at 110/min, and in the other, reversion to sinus rhythm occurred spontaneously 4 hours later. No complications were observed. It is concluded that atrial pacing may be useful aid to treat paroxysmal atrial tachycardia or flutter, and can be considered as an alternative procedure whenever there is no response to customary medical treatment or when transthoracic direct current cardioversion is potentially dangerous.