Treatment of ventricular arrhythmias by United States cardiologists: a survey before the cardiac arrhythmia suppression trial results were available

Abstract

To define the practice habits of United States cardiologists and the treatment of ventricular arrhythmias, a random sample of 1,000 of 12,000 cardiologists was sent a pretested questionnaire. After follow-up procedures, 252 responded, of which 18% were academically-based, 29% were hospital-based and 53% were office-based. Attitudes about antiarrhythmic drug therapy for the treatment of ventricular arrhythmias were influenced by the presence and severity of cardiac disease, the presence of symptoms and the type of ventricular arrhythmias. In this survey, only 1% of cardiologists treated patients with asymptomatic ventricular premature complexes and no heart disease, but 17% treated such patients if unsustained ventricular tachycardia was present. The treatment rate among cardiologists increased to 38% when coronary artery disease with left ventricular dysfunction was present in patients with asymptomatic ventricular premature complexes. The presence of any cardiac disease and symptomatic ventricular arrhythmias increased the treatment rate to 80 to 100%. Approximately 50% of responding physicians treated patients comparable to the Cardiac Arrhythmia Suppression Trial study population with antiarrhythmic drugs. Beta blockers were the most common antiarrhythmic drug class chosen as the most appropriate initial therapy in new patients with ventricular arrhythmias. Whereas no cardiologists thought that amiodarone was appropriate to initiate in new patients with benign or potentially malignant ventricular arrhythmias, as many as 33 to 43% of cardiologists would use amiodarone for refractory patients with such arrhythmias, a response contradictory to the approved labeling for this drug. Less than one half of cardiologists recognize the high potential organ toxicity for quinidine, procainamide and tocainide. Cardiologists believed that antiarrhythmic agents with class IA and IC action were equally proarrhythmic in patients with potentially malignant ventricular arrhythmias. Antiarrhythmic drugs were initiated only in-hospital by about 25 to 50% of cardiologists. Etectrophysiologic testing was always used by 63% of cardiologists for evaluation of sustained ventricular tachycardia; 33% never used such testing for patients with potentially malignant ventricular arrhythmias. There were no differences in these results based on the geographic location of the responding cardiologists. Thus, significant lack of consensus exists on the toxicity of antiarrhythmic drugs, use of electrophysiologic testing and in- versus out-of-hospital drug initiation. At the time of the survey, most cardiologists treated patients with asymptomatic and symptomatic potentially malignant ventricular arrhythmias, although the interim results of the Cardiac Arrhythmia Suppression Trial indicate reconsideration for therapy in such patients.