Abstract 415: Imaging Study of Fibrofatty Scar in Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia: Contrast-enhanced Magnetic Resonance Imaging versus Electroanatomic Voltage Mapping
Background: Three-dimensional electroanatomic voltage mapping (EVM) by CARTO system has been demonstrated to reliably identify low voltage regions (“electroanatomic scar”) which in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) correspond to areas of myocardial depletion. Delayed contrast enhancement (DCE) by cardiac magnetic resonance is an emerging non-invasive technique for detection of scar in different pathologic settings. This study was designed to compare EVM and DCE for detection of fibrofatty scar in ARVC/D.
Methods: 21 patients (15 males and 6 females; mean age 38±12 yrs) with a clinical diagnosis of ARVC/D based on the ISFC/ESC criteria and validated by right ventricular (RV) EVM. RV electroanatomic scars (i.e. low amplitude areas with bipolar electrogram <0.5 mV) were identified by sampling multiregional RV bipolar electrograms. All patients underwent a complete magnetic resonance study.
Results: RV DCE was found in 9 of 21 (43%) patients with positive EVM evidence. A total of 26 RV DCE scars were identified in the 9 patients: 8 (31%) in the anterolateral region, 6 (23%) in the apex, 4 (15%) in the infundibular region, 8 (31%) in the inferobasal region. Regional comparison of DCE zones and electroanatomic low-voltage areas showed a mismatch in 16 RV scar areas, with presence of 14 electroanatomic scars not confirmed on the DCE (3 in anterolateral region, 1 on apex, 4 in infundibular and 6 in the inferobasal walls), and 2 DCE scars (both in the infundibulaum) undetected by the EVM reconstruction. Left ventricular (LV) DCE was found in 14 of 21 patients (67%), either as isolated-LV involvement in 9 patients (42.8%) or in the form of biventricular involvement in 5 (23.8%). LV DCE predominantly involved the subepicardial and/or mid-wall layers of the anterolateral (10 patients), inferolateral (9 patients), anterior (2 patients), and posteroseptal (1 patient) regions. Overall, any ventricular DCE scars were detected in 87% of ARVC/D patients.
Conclusions: In patients with ARVC/D, DCE shows a significant lower sensitivity than EVM for identification of RV fibrofatty scars. LV DCE, either isolated or associated with RV involvement, is a more common finding and provides higher diagnostic sensitivity.