Global changes of ventricular repolarization in arrhythmogenic right ventricular dysplasia

Background. In arrhythmogenic right ventricular dysplasia (ARVD), repolarization disorders precede structural heart changes. Objective. The aim of this work was to evaluate repolarization changes in ARVD patients with various degree of electrocardiographic (ECG) changes. Design and methods . The standard ECG and vectorcardiograms (VCG) of patients with a confirmed ARVD diagnosis (N = 22, 13 men 51 ± 16 years and 9 women 50 ± 12 years), observed in the Medical Centre of V.A. Almazov, were analyzed. The degree of ECG changes was assessed by the number of precordial leads with negative T-wave, the global dispersion of repolarization — on the basis of the maximum interval between the peak and the end of T-wave, the spatial repolarization sequence — by T-vector direction, the action potential duration (APD) — on the basis of Q-Tpeak and Q-Tend intervals. Results. At no T-wave inversion in precordial leads, the latest repolarization took place in the posterior regions of ventricular base, at T-wave inversion only in the right precordial leads — in the lateral part of the right ventricle, at T-wave inversion in all precordial leads — in the antero-apical parts of the ventricles. Depending on the degree of ECG changes, the duration of repolarization increased in such a way that the shorter APD increased more than the longer ones; the global dispersion of repolarization was not increased. Conclusion. In ARVD, the increase of repolarization ECG changes is a result of inhomogeneous APD prolongation and the changes in ventricular repolarization sequence (up to it’s inversion), not accompanied with a growth of global dispersion of repolarization.