Electrocardiographic Repolarization Abnormalities and Electroanatomic Substrate in Arrhythmogenic Right Ventricular Cardiomyopathy

Background: Repolarization abnormalities in arrhythmogenic right ventricular (RV) cardiomyopathy and their relationship to ventricular tachycardia substrate are incompletely understood. Methods and Results: In 40 patients (29 men, mean age 38 years) with arrhythmogenic RV cardiomyopathy, we compared the extent and location of abnormal T (NegT) waves ≥1 mm in depth (n=32) and downsloping elevated ST segment (n=13), in ≥2 adjacent leads, to area and location of endocardial bipolar (<1.5 mV) and unipolar (<5.5 mV) and epicardial bipolar (<1.0 mV) voltage abnormalities. Abnormal unipolar RV endocardial area of 33.4±19.3% was present in 8 patients without NegT waves. Patients with NegT waves extending beyond lead V 3 (n=20) had larger low bipolar (31.4±18.9% versus 16.5±14.6%; P =0.008) and unipolar endocardial areas (66.0±19.6% versus 47.4±25.1%; P =0.013) and larger epicardial low bipolar area (56.0±19.3% versus 40.1±24.9%; P =0.030) compared with those with NegT waves limited to leads V 1 through V 3 (n=20). ECG location of NegT waves regionalized to location of substrate. Patients with downsloping elevated ST segment, all localized to leads V 1 and V 2 , had more unipolar endocardial abnormalities (71.8±18.1% versus 49.4±23.5%; P =0.005) involving outflow and mid-RV, compared with patients without downsloping elevated ST segment. Conclusions: In arrhythmogenic RV cardiomyopathy, abnormal electroanatomic mapping areas are proportional to extent of T-wave inversion on 12-lead ECG. Marked voltage abnormalities can exist without repolarization change. Downsloping elevated ST-segment pattern in V 1 and V 2 occurs with more unipolar endocardial voltage abnormality, consistent with more advanced transmural disease.