Abstract 3004: Electroanatomic And Histologic Findings In Patients With Clinical And Instrumental Diagnosis Of Arrhythmogenic Right Ventricular Cardiomyopathy
Objectives: Electroanatomic mapping (EAM) has been proposed as a new tool to distinguish arrhythmogenic right ventricular cardiomyopathy (ARVC) from other right ventricular (RV) disorders. We compared EAM and myocardial biopsy findings in patients with clinical and instrumental diagnosis of ARVC.
Methods: We studied 30 consecutive patients (16M/14F, 41 ± 16 yrs) with a diagnosis of ARVC according to recent criteria. All patients underwent 3D-EAM, cardiac magnetic resonance (CMR) and cardiac catheterization with multiple RV biopsies obtained from regions with abnormal electrograms. The EAM color display ranged from red, (scar tissue, amplitude <0.5 mV), to purple (normal tissue amplitude 1.5 mV). Results. Clinical presentation was sustained (n=7) or non-sustained (n=14) ventricular tachycardia (n=14) and frequent ventricular ectopic beats (n=9). All patients showed RV wall motion abnormalities and/or enlargement at angiography and CMR. Twenty-one patients (70%) had an abnormal EAM. Myocardial biopsy confirmed the diagnosis of ARVC in 13 cases (43%), while showed the presence of active myocarditis in the remaining 14 cases (57%) (Figure 1⇓), including the 9 patients with normal EAM. Abnormal voltages in the RV outflow tract were observed in all ARVC patients but only in 6 pts (35%) with myocarditis; in the latter septal, lateral and apical RVwall were most frequently involved.
Conclusions. Myocarditis of the RV may produce electroanatomic abnormalities causing ventricular arrhythmias and mimicking ARVC. EAM may guide endomyocardial biopsy improving its diagnostic sensitivity and contributing to distinguish the pathological substrate of ventricular arrhythmias.