Value of electropharmacologic testing in idiopathic dilated cardiomyopathy and sustained ventricular tachyarrhythmias.

Electrophysiologic studies in 64 patients with idiopathic dilated cardiomyopathy who had sustained ventricular tachycardia or ventricular fibrillation were performed. A sustained ventricular tachyarrhythmia was induced in 43 patients (67%). Electropharmacologic testing predicted an antiarrhythmic drug effective in 15 of 35 patients in whom sustained monomorphic ventricular tachycardia could be induced reproducibly (43% of tested patients, 23% of all patients). During median follow-up of 1.6 years, there were 32 arrhythmia recurrences and 24 cardiac arrests. Multivariate regression analysis identified treatment with a drug predicted to be effective at electropharmacologic testing as the only predictor of freedom from arrhythmia recurrence (p = 0.01); and treatment with a drug predicted to be effective at electropharmacologic testing and lower New York Heart Association functional class as independent predictors of freedom from cardiac arrest (p = 0.03 and p = 0.02, respectively). At median follow-up, the incidences of freedom from arrhythmia recurrence and from cardiac arrest were both 100% during treatment with a drug predicted to be effective at electropharmacologic testing versus 54 +/- 8% and 62 +/- 7%, respectively, during other treatments. These findings indicate that results of electropharmacologic testing accurately predict freedom from arrhythmia recurrence and cardiac arrest in patients with idiopathic dilated cardiomyopathy and sustained ventricular tachyarrhythmias.