Abstract 3321: Characterization of Fibrofatty Scar in Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia: Concordance Between Contrast-Enhanced Cardiac Magnetic Resonance and 3-D Electroanatomic Voltage Mapping
Background: Electroanatomic voltage mapping (EVM) has been demonstrated to reliably identify low voltage regions (electroanatomic scar) which in patients with ARVC/D correspond to areas of fibrofatty myocardial replacement at endomyocardial biopsy (EMB).Contrast-enhanced magnetic resonance (CEMR) is an emerging non-invasive technique for demonstrating ventricular scar in different pathologic settings.We assessed diagnostic accuracy of CEMR in a patient population in which clinical diagnosis of ARVC/D was validated by EVM and EMB.
Methods:The study group comprised 17 patients (12 males, 5 females;mean age 28±8 years) presenting with ventricular tachycardia (VT) of RV origin, who underwent detailed clinical study including EMB, EVM and CEMR.Delayed-enhancement MR images were analyzed in long-axis (2C, LAX, 4C), short axis and RV 2-chamber views after intravenous injection of 0.02 mmol/kg of Gd-DTPA.
Results:Eight (47%) of the 17 patients fulfilled the Task Force diagnostic criteria for ARVC/D and showed electroanatomic RV scar and histopathologic fibrofatty replacement; the other 9 patients had normal clinical and instrumental findings and were diagnosed as having idiopathic RV tachycardia.Seven (88%) of the 8 patients with clinical diagnosis of ARVC/D had RV delayed-enhancement, compared with none of the patients with idiopathic RV tachycardia (p<0.01).The most frequently involved RV regions were anterolateral in 5 patients, apical in 4, infundibular in 2 and inferobasal in 2.A concordance between location of delayed-enhancement and electroanatomic low-voltage areas was found for all the analyzed regions, except for the inferobasal (subtricuspidal) where CEMR showed a significantly lower sensitivity for scar detection.All patients with delayed-enhancement had histopathologic findings suggestive for ARVC/D (p=0.02) and VT inducibility at programmed ventricular stimulation (p=0.01).None of the patients without clinical ARVC/D had any abnormalities either on CEMR or EVM/EBM.
Conclusion:CEMR reliably allows identification of fibrofatty myocardial replacement in patients with ARVC/D.CEMR findings show an excellent correlation with clinical diagnosis, scar tissue demonstration by EVM and EMB, and VT inducibility