Regional Wall Motion and Abnormalities of Electrical Depolarization and Repolarization in Patients After Surgical Repair of Tetralogy of Fallot

Abstract

Background —Abnormal depolarization-repolarization in patients with repaired tetralogy of Fallot (TOF) is a risk factor for malignant ventricular tachycardia and sudden death. It is unclear whether ECG abnormalities are associated with abnormal regional right ventricular (RV) function. Methods and Results —Seventy-four patients (37 patients <18 and 37 >18 years old) who had had TOF repair at 4.0 years old (0.1 to 47 years old) were examined when they were 18.7 years old (1.7 to 61.1 years old), as were 112 control subjects with normal hearts. Regional function was evaluated with tissue Doppler imaging of the RV and left ventricular (LV) free wall and the septum. Myocardial velocities were sampled continuously from base to apex. Synchronous ECG was analyzed for QRS, QT, and JT duration and QRS, QT, and JT dispersion. All 74 TOF patients had normal LV myocardial velocities. Forty-eight patients (24 patients <18 and 24 >18 years old) had reversed myocardial velocities in diastole in the RV free wall, which were associated with reversed systolic myocardial velocities in 22 and additional reverse diastolic myocardial velocities in the septum in 19. Those 48 patients had a longer QRS duration (151±31 versus 124±27 ms) and greater QRS (47±18 versus 29±12 ms), QT (73±27 versus 52±22 ms), and JT (96±31 versus 67±35 ms) dispersion. Compared with normal control subjects, all 74 TOF patients had decreased systolic and diastolic myocardial velocities and a longer isovolumic relaxation time. Conclusions —RV wall-motion abnormalities are a common finding late after TOF repair and are associated with repolarization-depolarization abnormalities. These data further underscore a likely mechanoelectrical interaction as an important part of the pathogenesis of RV disease in these patients.