Cardioversion of atrial tachycardia and flutter by atrial stimulation

Abstract

Electrical stimulation of the right atrium using a bipolar electrode catheter terminated 9 episodes of atrial flutter in 8 patients and 32 episodes of atrial tachycardia in 1 patient. Six episodes of flutter were converted directly to sinus rhythm, and 3 were converted initially to atrial fibrillation with a slower ventricular rate and then to sinus rhythm. Conversion of atrial flutter to sinus rhythm by pacing rates slower than the atrial rates implies that interruption of a reentry circuit was responsible for termination of the arrhythmia. Two separate mechanisms were found to terminate atrial tachycardia: (1) overdrive suppression, and (2) interruption of a reentry circuit by delivery of a single appropriately timed stimulus. Attempts to convert atrial fibrillation to sinus rhythm by right atrial stimulation were unsuccessful. This technique is a safe and effective method for terminating atrial tachycardia and flutter, especially in patients receiving large doses of digitalis. It may be performed repetitively at the bedside without anesthesia and without discomfort to the patient.