[Closed chest interruption of A-V conduction in the treatment of refractory supraventricular tachyarrhythmias. A clinical contribution]

Abstract

The AA. describe a technique for interrupting the A-V conduction using a direct-current shock delivered from a cardioversion unit to the A-V junctional tissue by means of a conventional electrode-catheter. The method was used in 2 patients with refractory supraventricular tachycardias. After the procedure both patients received a programmable A-V sequential pacemaker. The first patient, with cardiomyopathy and intermittent W-P-W syndrome, had a 2-year history of iterative reciprocating tachycardia and occasional episodes of atrial flutter-fibrillation. The second patient, with coronary heart disease, had recurrent episodes of atrial flutter for at least 2 years. In patient 1 the shock caused a suprahisian first-degree block. Atrial pacing at 580 ms cycle length provoked a 2:1 block and ventricular pacing showed no retrograde conduction. The patient, who is not pacemaker-dependent, is now free from reciprocating tachycardia and, during atrial flutter-fibrillation episodes, the ventricular rate varies from 62 to 75 bpm. In patient 2 the shock caused a persistent complete A-V block and neither antegrade nor retrograde conduction was observed during atrial and ventricular pacing. During a long episode of atrial flutter, there was a complete A-V block with a ventricular rate between 40 and 48 bpm. The follow-up is 9 months in both patients. We conclude that the technique used, which does not require open heart surgery, can be effectively used in patients with disabling supraventricular tachyarrhythmias resistant to drug treatment.