Sympathetic denervation in ARVC and risk of recurrent ventricular tachyarrhythmias

Objectives Patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) typically present with ventricular tachyarrhythmias often provocable by stress or catecholamines. This indicates an involvement of the cardiac adrenergic system in arrhythmogenesis. Previous studies showed abnormalities of the presynaptic uptake-1 assessed by ¹²³I-MIBG scintigraphy (¹²³I-MIBG-SPECT). We investigated the potential role of adrenergic dysfunction on the arrhythmia profile in patients with ARVCM.

Methods In 42 patients with ARVCM (mean age 43±14 years), ¹²³I-MIBG-SPECT was performed. Results were compared to those obtained from 10 control subjects (mean age 43±12 years) without identifiable structural heart disease. ¹²³I-MIBG images were acquired four hours post injection and analysed for regional ¹²³I-MIBG uptake in a standardized 33-segment bull’s eye scheme.

Results Abnormal tracer uptake was detected in 25 patients with ARVCM (59%). During long-term follow-up of 11.9±4.1 years, patients with an abnormal ¹²³I-MIBG-SPECT experienced life-threatening ventricular tachyarrhythmias more often than those with a normal sympathetic innervation (22 of 25 (88%) patients vs. 6 of 17 (35%) patients; P<0.0002).

Conclusions An impairment of adrenergic innervation appears to account for a higher risk for VT recurrences in patients with ARVCM suggesting a future role of ¹²³I-MIBG-SPECT for individualized risk stratification in these patients.