Biventricular pacing diminishes the need for implantable cardioverter defibrillator therapy

OBJECTIVES We sought to test the postulate that biventricular pacing dimini shes the need for appropriate tachycardia therapy. We reviewed the frequenc y of therapy in patients, serving as their own controls, who were enrolled in the Ventak CHF (congestive heart failure) biventricular pacing study. BACKGROUND It is well established that both acute and chronic CHF contribut e to the need for tachyarrhythmia therapy in recipients of an automatic imp lantable cardioverter defibrillator (ICD). Synchronized biventricular (BV) pacing is a new and promising therapy for symptomatic improvement of CHF in selected patients (low ejection fraction, intraventricular conduction dela y). We postulate that this pacing therapy will diminish the need for tachya rrhythmia therapy. METHODS Participants in the Ventak CHF trial received a triple-chamber bive ntricular ICD with a transvenous right ventricular lead and a left ventricu lar (LV) lead placed via thoracotomy. Of 54 patients enrolled in the Ventak CHF trial, 32 could be analyzed, with each completing three blinded months programmed to BV VDD pacing and a second randomly assigned three-month per iod of no pacing. RESULTS Of the 32 patients, 13 (41%) received appropriate therapy for a ven tricular tachyarrhythmia at least once in the six-month monitoring period p ostimplant. Five patients (16%) had at least one tachyarrhythmic episode wh ile programmed to BV pacing, whereas 11 (34%) had at least one episode whil e programmed to no pacing. Three patients (9%) received therapy in both pac ing periods, two with BV pacing only. The decrease in necessary tachycardia therapy during the BV pacing period was statistically significant (p = 0.0 35). CONCLUSIONS In patients with standard ICD indications who also have CHF, LV dysfunction, and an intraventricular conduction delay, ICD therapy is less common with BV pacing. The mechanism for this improvement is unclear but m ay be related to hemodynamic improvement in CHF. Although BV pacing does no t obviate the need for an ICD, it does diminish the need for appropriate ta chyarrhythmia therapy in selected patients. (C) 2000 by the American Colleg e of Cardiology.