Parietal block, defined as intra right ventricular (RV) conduction slowing is a major diagnostic criterion for ARVD/C.
We evaluated the utility of total RV endocardial activation duration (EAD) measured by 3D electroanatomic mapping during sinus rhythm in the diagnosis of ARVD/C.
25 consecutive patients with frequent LBBB morphology PVCs who underwent electroanatomic mapping as a part of the evaluation for ARVD/C were included in the study. All patients were evaluated using standard protocol that included, ECG, signal averaged ECG, Holter, Echocardiography, and MRI. Invasive testing was performed as indicated. Total RV EAD was measured as the time interval between the onset of RV activation to the latest activated region in the RV.
Mean age of the study subjects was 38±11 and 32% were men. 14 subjects were diagnosed as ARVD/C using task force criteria and the remainder had idiopathic VT. While the surface QRS durations were similar, the total RV EAD was significantly prolonged in ARVD/C compared with idiopathic VT (83.9±10 msec vs. 50.8±7 msec, p<0.001). None of the idiopathic VT subjects had RV EAD of > 65 msec. RV EAD also showed significant negative correlation with RV ejection fraction.
Total RV EAD obtained by 3D electroanatomic mapping is a sensitive marker of intra RV conduction delay in ARVD/C and a total RV EAD of >65 msec accurately differentiates ARVD/C from idiopathic VT.