Background: The Defibrillator in Arrhythmogenic Right Ventricular Cardiomyopathy International (DARVIN) study was a multicenter investigation that enrolled patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) who received an implantable defibrillator (ICD) for either secondary or primary prevention of sudden death.
Methods: In this DARVIN substudy, we examined whether programmed ventricular stimulation (PVS) is able to predict the arrhythmic risk in a large cohort of 201 ARVC patients (133 males, 68 females, aged 36 ± 12 years) who received an ICD. Implant indications were a history of cardiac arrest in 13 (6%) patients; sustained ventricular tachycardia (VT) in 82 (41%); syncope in 42 (21%); asymptomatic nonsustained VT in 40 (20%); and a family history of sudden death in 24 (12%). PVS prior to ICD implantation was carried out in 143 of 201 patients (71%). All antiarrhythmic drugs were discontinued ≥ 5 half-lives (≥ 6 weeks for amiodarone) before the study. PVS included a minimum of 2 drive cycles length and up to 3 ventricular extrastimuli while pacing from two right ventricular sites.
Results: One hundred-nine patients (76%) were inducible to either sustained VT (patients 70; 64%), with a mean cycle length of 287 ± 66ms (range 220 to 410 ms), or ventricular fibrillation/flutter (VF) (patients 39; 36%). Of 109 patients who were inducible at PVS, 56 (52%) did not experience ICD therapy during a mean follow-up of 47 ± 22 months, whereas 11 of 34 (33%) noninducible patients had appropriate ICD interventions. Overall, the positive predictive value of PVS was 48%, the negative predictive value 67%, and the test accuracy 53%. The incidence of ICD discharges on VF, which in all likelihood would have been fatal in the absence of ICD therapy, did not differ between patients who were and were not inducible at PVS (26 of 109, 24% vs 7 of 34, 21%; p=0.87), regardless of clinical presentation. The type of ventricular arrhythmia inducible at PVS did not predict VF during the follow-up.
Conclusions: The presence (or absence) of an inducible arrhythmia on PVS did not correlate with subsequent appropriate ICD interventions, suggesting a limited role for PVS in arrhythmic risk stratification of ARVC patient population. A negative PVS may not indicate better prognosis.
Improved selection of patients for programmed ventricular stimulation by frequency analysis of signal-averaged electrocardiograms.
