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 (n=20) had larger low bipolar (31.4±18.9% versus 16.5±14.6%; =0.008) and unipolar endocardial areas (66.0±19.6% versus 47.4±25.1%; =0.013) and larger epicardial low bipolar area (56.0±19.3% versus 40.1±24.9%; =0.030) compared with those with NegT waves limited to leads V through V (n=20). ECG location of NegT waves regionalized to location of substrate. Patients with downsloping elevated ST segment, all localized to leads V and V, had more unipolar endocardial abnormalities (71.8±18.1% versus 49.4±23.5%; =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 and V occurs with more unipolar endocardial voltage abnormality, consistent with more advanced transmural disease.