Electrocardiographic ventricular repolarization during cardiovascular autonomic function testing in patients with arrhythmogenic right ventricular cardiomyopathy

OBJECTIVES: Patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) experience exercise-related malignant arrhythmias possibly based on delayed repolarization in the diseased right ventricle (RV). Autonomic interventions might unveil repolarization abnormalities in RV. DESIGN: We recorded 25-lead electrocardiograms from nine symptomatic ARVC patients and nine controls during rest, Valsalva maneuver, mental stress, handgrip and supine exercise. Interventricular repolarization gradient was defined as difference of QT intervals between left ventricular (LV) and RV type leads. T-wave peak to T-wave end interval (TPE) was defined as the electrocardiographic (ECG) equivalent of transmural dispersion of repolarization. RESULTS: ARVC patients showed longer QT and TPE intervals in RV than in LV whereas control subjects showed the opposite. Valsalva strain reversed the interventricular repolarization gradient from -5+/-13 to 4+/-20 ms (p<0.02) and induced fluctuation of TPE in ARVC patients. CONCLUSIONS: ARVC patients show ECG interventricular repolarization gradient from RV to LV and increased ECG transmural dispersion of repolarization in RV. Valsalva strain induces fluctuation of interventricular repolarization gradient and of transmural dispersion of repolarization in RV possibly modifying the substrate for arrhythmias.