title: Predictors of antiarrhythmic drug efficacy in patients with malignant ventricular tachyarrhythmias.
abstract: The relationship between arrhythmia density observed during ambulatory monitoring, left ventricular ejection fraction (EF), and response to antiarrhythmic drug therapy was evaluated in 94 patients presenting with ventricular fibrillation (VF) (n = 20) or ventricular tachycardia (VT) (n = 74). Following baseline studies, an average of 4.9 antiarrhythmic drugs were tested singly in each patient. Univariate and multivariate analyses revealed that the density of VT on baseline ambulatory monitoring and initial left ventricular EF were independent predictors of drug efficacy. The 45 patients with an EF less than or equal to 35% responded to 34 +/- 29% of drugs tested, whereas the 49 with an EF greater than 35% had arrhythmia suppression with 46 +/- 28% of agents (p less than 0.038). Patients exhibiting VT during greater than or equal to 50% of monitoring hours responded to 32 +/- 26% of drugs, whereas those with VT during less than 50% of hours showed arrhythmia suppression with 48 +/- 29% of antiarrhythmic agents tested (p = 0.009). During a mean follow-up period of 12.9 months, the annual sudden death mortality for all patients was 9.3%. However, 8 of the 55 patients responding to less than 50% of drugs tested died suddenly and 17 had recurrent VT. By contrast, only 1 of the 39 patients responding to greater than or equal to 50% of the antiarrhythmic drugs tested died suddenly and two experienced recurrent VT (p = 0.00005).(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000553:Ambulatory Care; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D004594:Electrophysiology; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000187:drug effects; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D009200:Myocardial Contraction / Q000187:drug effects; D013318:Stroke Volume / Q000187:drug effects; D013610:Tachycardia / Q000188:drug therapy / Q000503:physiopathology*; D014693:Ventricular Fibrillation / Q000188:drug therapy / Q000503:physiopathology*
chemical_list: D000889:Anti-Arrhythmia Agents