Conversion of Supraventricular Tachycardias with Atrial Stimulation

Abstract

Atrial stimulation at rates less than the atrial rate was effective in terminating junctional tachycardia and atrial flutter in two patients. Analysis of the stimulus response in the patient with junctional tachycardia defined an atrial excitable and refractory period and a critical interval, the first 12 milliseconds of the excitable period, during which atrial stimulation terminated the tachycardia. The termination of atrial flutter appeared to occur simultaneously with capture of the atrial rate by the slower atrial stimulus. Atrial fibrillation did not occur. These observations suggest that a variety of tachycardias are supported by re-entry mechanisms and that the response to atrial stimulation may be useful in recognizing and treating such arrhythmias.