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 ind uction at electrophysiologic study of sustained monomorphic ventricula r tachycardias with multiple QRS complex configurations predicted fail ure of subsequent serial electrophysiologic study guided antiarrhythmi c drug testing. Background. Ventricular tachycardias with multiple QRS complex configurations are associated with failure of surgical therap y for ventricular tachycardia. As such, the presence of multiple monom orphic QRS complex ventricular tachycardias during electrophysiologic testing may predict failure of subsequent medical therapy. Methods. Fi fty-one consecutive patients with coronary artery disease had reproduc ible induction of monomorphic ventricular tachycardia during a baselin e electrophysiologic study. Each patient then underwent a mean of 1.5 antiarrhythmic drug trials. An antiarrhythmic drug regimen that suppre ssed induction of ventricular tachycardia was identified in 13 (26%) o f the 51 patients. Results. Patients with only one inducible monomorph ic QRS complex ventricular tachycardia at baseline study were more lik ely to have an antiarrhythmic drug regimen identified that suppressed inducible ventricular tachycardia than were patients with multiple mon omorphic 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 ventric ular tachycardia with a different QRS complex configuration occurred d uring attempts at pacing termination of the induced ventricular tachyc ardia. None of these seven patients then had successful drug suppressi on of inducible ventricular tachycardia. Thus, 12 (46%) of 26 patients with a single monomorphic QRS complex ventricular tachycardia observe d 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 basel ine electrophysiologic study predicted failure of subsequent serial el ectrophysiologic study-guided antiarrhythmic drug therapy.