Multiple monomorphic ventricular tachycardia configurations predict failure of antiarrhythmic drug therapy guided by electrophysiologic study.

Objectives: The purpose of this study was to determine whether the induction at electrophysiologic study of sustained monomorphic ventricular tachycardias with multiple QRS complex configurations predicted failure of subsequent serial electrophysiologic study guided antiarrhythmic drug testing.
Background: Ventricular tachycardias with multiple QRS complex configurations are associated with failure of surgical therapy for ventricular tachycardia. As such, the presence of multiple monomorphic QRS complex ventricular tachycardias during electrophysiologic testing may predict failure of subsequent medical therapy.
Methods: Fifty-one consecutive patients with coronary artery disease had reproducible induction of monomorphic ventricular tachycardia during a baseline electrophysiologic study. Each patient then underwent a mean of 1.5 antiarrhythmic drug trials. An antiarrhythmic drug regimen that suppressed induction of ventricular tachycardia was identified in 13 (26%) of the 51 patients.
Results: Patients with only one inducible monomorphic QRS complex ventricular tachycardia at baseline study were more likely to have an antiarrhythmic drug regimen identified that suppressed inducible ventricular tachycardia than were patients with multiple monomorphic QRS complex ventricular tachycardias (12[36%] of 33 patients vs. 1 [6%] of 18, p = 0.04). In seven patients with only one induced configuration of ventricular tachycardia, a second monomorphic ventricular tachycardia with a different QRS complex configuration occurred during attempts at pacing termination of the induced ventricular tachycardia. None of these seven patients then had successful drug suppression of inducible ventricular tachycardia. Thus, 12 (46%) of 26 patients with a single monomorphic QRS complex ventricular tachycardia observed at baseline study had successful serial drug testing compared with 1 (4%) of 25 patients with multiple QRS complex ventricular tachycardia configurations (p = 0.002).
Conclusions: The induction or observation of multiple monomorphic QRS complex ventricular tachycardias at baseline electrophysiologic study predicted failure of subsequent serial electrophysiologic study--guided antiarrhythmic drug therapy.