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Value of electropharmacologic testing in idiopathic dilated cardiomyopathy and sustained ventricular tachyarrhythmias
1Cardiology Division, Stanford University Medical Center, California 94305.
Insights
Electropharmacologic testing accurately predicts antiarrhythmic drug effectiveness in patients with idiopathic dilated cardiomyopathy and ventricular tachyarrhythmias. This approach significantly reduces arrhythmia recurrence and cardiac arrest risk.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Idiopathic dilated cardiomyopathy (IDC) is a significant cause of heart failure.
- Sustained ventricular tachyarrhythmias (VT/VF) in IDC patients carry a high risk of recurrence and sudden cardiac death.
Purpose of the Study:
- To evaluate the predictive accuracy of electropharmacologic testing (EPT) in guiding antiarrhythmic drug therapy for IDC patients with sustained VT/VF.
- To determine if EPT-guided therapy improves freedom from arrhythmia recurrence and cardiac arrest.
Main Methods:
- Electrophysiologic studies were conducted in 64 IDC patients with sustained VT/VF.
- Antiarrhythmic drug efficacy was assessed via EPT in patients with inducible sustained monomorphic VT.
- Patient outcomes (arrhythmia recurrence, cardiac arrest) were tracked during a median 1.6-year follow-up.
Main Results:
- Sustained VT/VF was induced in 67% of patients.
- EPT predicted effective antiarrhythmic drugs in 43% of tested patients.
- Treatment with EPT-predicted effective drugs was the sole predictor of freedom from arrhythmia recurrence (p=0.01) and a predictor of freedom from cardiac arrest (p=0.03).
- Freedom from recurrence and cardiac arrest was 100% with EPT-guided therapy versus 54% and 62% with other treatments, respectively.
Conclusions:
- EPT results accurately predict freedom from arrhythmia recurrence and cardiac arrest in IDC patients with sustained ventricular tachyarrhythmias.
- EPT-guided antiarrhythmic drug selection improves clinical outcomes in this high-risk population.
- EPT is a valuable tool for optimizing management of ventricular arrhythmias in IDC.
Abstract:
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.