A Randomized Clinical Trial of the Noninvasive and Invasive Approaches to Drug Therapy of Ventricular Tachycardia

Abstract

There is controversy over whether therapy to prevent ventricular tachyarrhythmias should be selected noninvasively (by trying drugs and monitoring the patient electrocardiographically) or invasively (by selecting a drug that prevents induction of the arrhythmia by programmed stimulation). We randomly assigned 57 patients with symptomatic and demonstrable ventricular tachyarrhythmias to therapy selected either noninvasively or invasively. The tachyarrhythmias involved were sustained ventricular tachycardia (35 patients), nonsustained ventricular tachycardia with hypotension (15 patients), and ventricular fibrillation (7 patients). The noninvasive approach sought reduction of ventricular premature beats by more than 80 percent and of couplets by more than 90 percent, with elimination of three or more successive ventricular beats on ambulatory monitoring and exercise testing. The invasive approach sought to prevent the induction of five or more repetitive beats by programmed stimulation. The noninvasive approach required fewer drug trials (3.2 +/- 1.8 [mean +/- SD] vs. 5.5 +/- 2.8, P less than 0.001) and fewer hospital days (20 +/- 15 vs. 33 +/- 24, P = 0.01) and identified a therapy predicted to be effective for more patients than did the invasive approach (29 of 29 vs. 15 of 28, P less than 0.001). When a predicted effective therapy was not found, amiodarone was prescribed despite persisting inducibility of ventricular tachycardia. Patients randomly assigned to the noninvasive approach had more symptomatic recurrences of tachyarrhythmia than those treated by the invasive approach (two-year actuarial probabilities of 0.50 +/- 0.10 vs. 0.20 +/- 0.08, P = 0.02). Similar differences were observed when amiodarone recipients were excluded. There were only three deaths from recurrent ventricular tachyarrhythmias--two in the group whose treatment was selected noninvasively and one in the group whose treatment was selected invasively (not significant). We conclude that therapy selected by the invasive approach prevents recurrences of ventricular tachyarrhythmias better than that selected by the noninvasive approach.