Use of edrophonium (Tensilon) in the evaluation of supraventricular tachycardias

A rapid intravenous dose (10 mg.) of edrophonium was administered to 24 patients with a variety of supraventricular tachycardias. Four with rapid sinus tachycardia showed transient sinus slowing. In 6 patients with rapid atrial flutter and in 3 with atrial fibrillation, edrophonium transiently increased atrioventricular block, and the atrial flutter or fibrillation waves became evident at the slowed ventricular response. In 11 patients with 12 episodes of paroxysmal atrial tachycardia, edrophonium converted the arrhythmia to normal sinus rhythm on six occasions. No complications were noted with the use of this drug, though minor side effects such as transient salivation, perspiration and tachypnea did occur. Edrophonium is a safe and useful pharmacologic agent in the differentiation of supraventricular tachycardias and in the conversion of paroxysmal atrial tachycardia to normal sinus rhythm.