Imaging Study of Ventricular Scar in Arrhythmogenic Right Ventricular Cardiomyopathy: Comparison of 3D Standard Electroanatomical Voltage Mapping and Contrast-Enhanced Cardiac Magnetic Resonance.

Background- The hallmark lesion of arrhythmogenic right ventricular cardiomyopathy (ARVC) is fibrofatty scar replacement. We compared endocardial voltage mapping (EVM) and contrast-enhanced cardiac magnetic resonance (CE-CMR) for imaging scar lesions in ARVC patients. Methods and Results- We studied 23 consecutive ARVC patients (16 males; mean age, 38±12 years) who underwent RV EVM and CE-CMR and 37 control subjects. In 21 (91%) of 23 ARVC patients, RV EVM was abnormal, with a total of 45 electroanatomical scars (EAS): 17 (38%) in the inferobasal region, 12 (26.6%) in the anterolateral region, 8 (17.7%) in the RV outflow tract (RVOT), and 8 (17.7%) in the apex. RV delayed contrast enhancement (DCE) was found in 9 (39%) of 23 patients, with a total of 23 RV DCE scars: 4 (17.4%) in the inferobasal region, 9 (39.1%) in the anterolateral region, 4 (17.4%) in the RVOT, and 6 (26.1%) in the apex. There was a mismatch in 24 RV scars, with 22 EAS not confirmed by DCE and 2 DCE scars (both in the RVOT) undetected by EVM. In 9 (75%) of 12 patients with abnormal RV EVM/normal RV DCE, ≥1 DCEs were identified in the left ventricle (LV). Overall, ventricular DCE was detected in 78% of patients. No control subjects showed either EAS or DCE. Conclusions- EVM and CE-CMR allow identification of RV scar lesions in most ARVC patients. CE-CMR is less sensitive than EVM in identifying RV scar lesions. The high prevalence of LV DCE confirms the frequent biventricular involvement and indicates the diagnostic relevance of LV scar detection by CE-CMR.