DEFINITION OF PREDICTED EFFECTIVE ANTIARRHYTHMIC DRUG-THERAPY FOR VENTRICULAR TACHYARRHYTHMIAS BY THE ELECTROPHYSIOLOGIC STUDY APPROACH - RANDOMIZED COMPARISON OF PATIENT RESPONSE CRITERIA

Objectives, We sought to compare efficacies of therapy for ventricular tachyarrhythmias selected by programmed stimulation using two differe nt patient response efficacy criteria: <5 versus <16 repetitive ventri cular responses. Background. Therapy selection for ventricular tachyar rhythmias by programmed stimulation requires definition of a patient r esponse that predicts long-term efficacy. Such definitions have not be en previously compared prospectively. Methods. Patients with sustained ventricular tachyarrhythmias were randomized to therapy selection usi ng either the <5 or <16 repetitive response criterion of predicted eff ective therapy, The primary end point was sudden death or recurrence o f ventricular tachyarrhythmia requiring intervention. Results. Predict ed effective drug therapy was found for 23 (34%) of 68 patients random ized to the <5 criterion and 29 (36%) of 81 patients randomized to the <16 criterion (p = NS), Definition of therapy required 3.0 +/- 1.6 dr ug trials (mean +/- SD) in patients randomized to the <5 criterion and 2.9 +/- 1.6 trials in patients randomized to the <16 criterion (p = N S), Patients randomized to the <5 criterion had a lower 2-year probabi lity of the primary end point (0.20 +/- 0.05) than did patients random ized to the <16 criterion (0.33 +/- 0.05, one-tailed p = 0.004), The a dvantage of the <5 criterion was also seen in subgroup analyses involv ing patients with and without an initial drug efficacy prediction, Con clusions. The programmed stimulation approach to the selection of anti arrhythmic therapy for ventricular tachyarrhythmias using a patient re sponse criterion of <5 repetitive ventricular responses results in a l ower probability of recurrence of ventricular tachyarrhythmia than doe s use of a <16 repetitive response criterion. (C) 1997 by the American College of Cardiology.