Abstract 2691: Prophylactic Implantable Defibrillator in Patients with Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia and No Prior Sustained Ventricular Tachyarrhythmias: Therapy-Based Risk Stratification During a Long Term Follow-up
Background: patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) who survived an episode of cardiac arrest have a risk of recurrent ventricular tachycardia/ fibrillation so high as to justify implantable defibrillator (ICD) therapy. The risk stratification with regard to prophylactic ICD in ARVC/D patients without a previous documentation of sustained ventricular tachyarrhythmias is a completely unsolved issue.
Methods:the study population comprised 82 consecutive patients who fulfilled Task Force diagnostic criteria for ARVC/D (49 men and 33 women;mean age 32±17 years) and received a prophylactic ICD with electrogram storage capability. The predominant clinical reasons for ICD implantation were unexplained syncope in 41, asymptomatic nonsustained ventricular tachycardia (NSVT) on either Holter or exercise testing in 22 and a family history of sudden death (SD) in 19; no patients previously experienced either spontaneous sustained ventricular tachycardia (VT) or ventricular fibrillation (VF).
Results:during a mean follow-up of 58.3±35.7 months, 25 of the 82 patients (30%) had ICD interventions for a first episode of ventricular tachyarrhythmia. The mean time to first event was 9.6±3.2 months. Ten patients had VT and 15 had VF. Young age (p=0.01), syncope (p=0.001), NSVT (0.009), and left ventricular involvement (p=0.02) were significantly associated with the ICD intervention. Unexplained syncope was the only significant independent predictor of arrhythmic risk (RR=3.9, 95% CI 1.4 – 6.7;p=0.008); NSVT was associated with a trend toward higher arrhythmic risk (RR= 1.9; 95% CI 0.8–3.9;p=0.09). None of the asymptomatic patients who were implanted because of a family history of SD experienced appropriate ICD interventions. Programmed ventricular stimulation was of limited value in predicting ICD discharge.
Conclusion:Thirty percent of patients with ARVC/D and no previous sustained ventricular tachyarrhythmias experienced a first episode of VT or VF that was successfully treated by ICD. Unexplained syncope was the most important predictor of life-threatening ventricular arrhythmias. A prophylactic ICD implantation is not justified in asymptomatic patients because of their low arrhythmic risk