Background:
Patients (pts) with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) typically present with ventricular tachyarrhythmias often provokable by stress or catecholamines thereby indicating an involvement of the cardiac adrenergic system in the arrhythmogenesis. Previous studies demonstrated abnormalities of the presynaptic uptake-1 assessed by 123I-MIBG scintigraphy (MIBG-SPECT). In this study, we investigated the potential role of adrenergic dysfunction on the arrhythmia profile in pts with ARVC/D.
Methods:
In 42 pts with ARVC/D (mean age 43±14 years), MIBG-SPECT was performed. Results were compared to those obtained from 10 control subjects (n=10; mean age 43±12 years) without identifiable structural heart disease. 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:
Overall, an abnormal tracer uptake was detected in 25 pts with ARVC/D (59%). The extent of right ventricular dilatation and regional wall motion abnormalities as well as electrocardiographic markers of re-/depolarisation (e.g. T-wave inversion, epsilon-potential, maximal QRS-duration in right precordial leads) were not significantly different between pts with a normal and an abnormal MIBG-SPECT. However, during long-term follow-up of 9.2±3.4 years, pts with abnormal MIBG-SPECT experienced life-threatening ventricular tachyarrhythmias more often than those with a normal sympathetic innervation (21 of 25 pts (84%) vs. 7 of 17 pts (41%);
P
<0.01).
Conclusions:
An impairment of adrenergic innervation appears to account for a higher risk for VT recurrences in pts with ARVC/D. These results suggest a future role of MIBG-SPECT for individualized risk stratification in pts with ARVC/D.
Microvolt T-wave alternans complemented with electrophysiologic study for prediction of ventricular tachyarrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy
