Comparative efficacy of transvenous cardioversion and pacing in patients with sustained ventricular tachycardia: A prospective, randomized, crossover study

Abstract

We performed a prospective, randomized crossover study to evaluate the comparative efficacy of transvenous cardioversion and rapid ventricular pacing for termination of induced ventricular tachycardia in patients with spontaneous ventricular tachycardia and organic heart disease. Sixty-two episodes of ventricular tachycardia were induced in 15 patients, mean age 60 ± 10 years, during electrophysiologic studies. All patients underwent a preselected electrical therapy protocol in an randomized crossover sequence. Transvenous cardioversion was performed by an incremental protocol of three sequential shocks (0.5, 1.1, and 2.7 J). Six asynchronous sequential bursts of rapid ventricular pacing (10 and 15 paced stimuli at 90%, 75%, and 65% and ventricular tachycardia cycle length) were used. Mean cycle length of ventricular tachycardia for the study population was 391 ± 85 msec. The morphology of the tachycardia was left bundle branch block in 27, right bundle branch block in 32, and indeterminate in three. Characteristics of ventricular tachycardia terminated by the two techniques were comparable. Rate of success for termination of tachycardia with the two methods was also comparable (transvenous cardioversion 83%, rapid ventricular pacing 80%; p>.1) and these responses were concordant in 78%. The modes of termination of ventricular tachycardia were similar. The incidence of acceleration of ventricular tachycardia per episode with these preselected protocols was also comparable (transvenous cardioversion 11%, rapid ventricular 6%; p.2). Transient supraventricular tachyarrhytmias were more frequent after transvenous cardioversion (23%) than after rapid ventricular pacing (3$). Significant patient discomfort occurred only after transvenous cardiovascular (incidence of 57%). We conclude that transvenous cardioversion and rapid ventricular pacing have comparable and usually concordant efficacy for termination of ventricular tachycardia. Transvenous cardioversion results in a higher incidence of postcardioversion arrhythmias and poorer patient tolerance than does rapid ventricular pacing.