Right Atrial Stimulation

Pervenous electrical stimulation of the right atrium was successful in converting 15 episodes of supraventricular tachyarrhythmia in 9 of 15 patients. This included 13 conversions of atrial flutter, one each of atrial tachycardia and junctional tachycardia. The procedure was performed at the bedside, without complication', using intracardiac electrography to direct catheter position. Indirect evidence from this series supports all three proposed mechanisms for· the conversion of atrial flutter by atrial stimulation: 1) interruption of a re-entry circuit, 2) introduction of an impulse in the atrial vulnerable period creating atrial fibrillation, and 3) overdrive suppression of a rapid firing ectopic focus. The method has certain advantages over DC cardioversion: 1) there is less potential for serious post-conversion arrhythmias, 2) serum enzyme profiles are not altered, 3) concomitant digitalis therapy is possible, and 4) continuous intracardiac electrographic monitoring IS available w1th the potential for repeated conversions.