Comparison of radionuclide angiographic synchrony analysis to echocardiography and magnetic resonance imaging for the diagnosis of arrhythmogenic right ventricular cardiomyopathy.

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heritable arrhythmia syndrome entailing a high risk of sudden cardiac death. Discernment from benign arrhythmia disorders, particularly right ventricular outflow tract ventricular tachycardia (RVOT VT), may be challenging, providing an impetus to explore alternative modalities that may facilitate evaluation of patients with suspected ARVC.

Objective: We evaluated the role of equilibrium radionuclide angiography (ERNA) as a diagnostic tool for ARVC.

Methods: ERNA measures of ventricular synchrony-synchrony (S) and entropy (E)-were examined in patients with ARVC (n = 16), those with RVOT VT (n = 13), and healthy controls (n = 49). The sensitivity and specificity of ERNA parameters for ARVC diagnosis were compared with those of echocardiography (ECHO) and cardiovascular magnetic resonance (CMR).

Results: ERNA right ventricular synchrony parameters in patients with ARVC (S = 0.91 ± 0.07; E = 0.61 ± 0.1) differed significantly from those in patients with RVOT VT (S = 0.99 ± 0.01 [P = .0015]; E = 0.46 ± 0.05 [P < .001]) and healthy controls (S = 0.97 ± 0.02 [P = .003]; E = 0.48 ± 0.07 [P = .001]). The sensitivity of ERNA synchrony parameters for ARVC diagnosis (81%) was higher than that for ECHO (38%; P = .033) and similar to that for CMR (69%; P = .162), while specificity was lower for ERNA (89%) than that for ECHO and CMR (both 100%; P = .008).

Conclusion: ERNA right ventricular synchrony parameters can distinguish patients with ARVC from controls with structurally normal hearts, and its performance is comparable to that of ECHO and CMR for ARVC diagnosis. These findings suggest that ERNA may serve as a valuable imaging tool in the diagnostic evaluation of patients with suspected ARVC.