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

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. Sixtytwo 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 a 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% of 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 pacing 6%; p > .2). Transient supraventricular tachyarrhythmias were more frequent after transvenous cardioversion (23%) than after rapid ventricular pacing (3%). Significant patient discomfort occurred only after transvenous cardioversion (incidence of 57%). We conclude that transvenous cardioversion and rapid ventricular pacing have comparable and usually concordant efflcacy for termination of ventricular tachycardia. Transvenous cardioversion results in a higher incidence of postcardioversion arrhythmias and poorer patient tolerance than does rapid ventricular pacing. Circulation 72, No. 1, 153-160, 1985. TERMINATION of sustained ventricular tachycardia by the use of different techniques of internal electrical cardiac stimulation has been reported.1 The comparative efficacy and safety of each technique and its potential role in clinical practice remain to be defined. Bursts of rapid ventricular pacing have been used to terminate sustained ventricular tachycardia in man for over a decade.2 More recently the efficacy of intracaviFrom the Section of Cardiac Electrophysiology, Division of Cardiology, Newark Beth Israel Medical Center, and University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark. Address for correspondence: Sanjeev Saksena, M.D., Co-Director, Division of Cardiology, Newark Beth Israel Medical Center, 201 Lyons Ave., Newark, NJ 07112. Received Dec. 31, 1984; revision accepted April 4, 1985. Presented in part at the 57th Scientific Sessions, American Heart Association, Miami Beach, 1984. Vol. 72, No. 1, July 1985 tary cardioversion of ventricular tachycardia with a transvenous electrode catheter has been documented during experimental studies and uncontrolled clinical trials.3'4 We have recently examined its clinical efficacy and safety in a controlled prospective randomized study.5 However, there has been no controlled prospective study of the comparative efficacy of transvenous cardioversion and rapid ventricular pacing in terminating sustained ventricular tachycardia in the same patient population. In this report we examined the comparative clinical efficacy and safety of these two modes of electrical termination of tachycardia using a prospective randomized crossover study design.