All Patients With Hemodynamically Tolerated Postinfarction Ventricular Tachycardia Do Not Require an Implantable Cardioverter-Defibrillator

Abstract

Several randomized clinical trials have been published in the last decade to evaluate the clinical efficacy of the implantable cardioverter-defibrillator (ICD) for secondary prevention of sudden cardiac arrest.1–4 However, none of those trials included patients with hemodynamically tolerated ventricular tachycardia (VT). In the largest of these trials, the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial, patients with VT were included only if the VT produced syncope or if the “ejection fraction was 0.40 or less and symptoms suggesting severe hemodynamic compromise” were present.1 The Canadian Implantable Defibrillator Study (CIDS) trial included patients with VT if it produced syncope or caused presyncope or angina.2 The other 2 trials included only cardiac arrest survivors.3,4 Thus, no information is available from randomized clinical trials about outcome in patients with hemodynamically tolerated VT. Response by Callans p 1212 Despite decades of active research focused on post–myocardial infarction (MI) VT, information on the clinical outcome of sustained monomorphic VT patients is limited. Several reasons account for the limited information. First, because post-MI VT has always been considered a life-threatening condition, it has been considered unethical to leave these patients without specific antiarrhythmic therapy for group comparisons. Second, VT recurrences during follow-up have been considered in some studies together with sudden cardiac death (SCD)5 despite the fact that both events are distinctly different; the recurrence of a well-tolerated VT may require medical attention, but in most instances, the patient leaves the hospital alive and without any sequelae. Third, because ICD and catheter ablation therapy have been used increasingly in recent years, outcome information is likely to be more homogeneous in relatively old studies. Fourth, several outcome studies have included patients with a variety of sustained ventricular arrhythmias, but the prognosis of patients with ventricular fibrillation (VF) may not be the same as …