Repolarization abnormalities in Duchenne-type muscular dystrophy Duchenne musküler distrofisinde repolarizasyon anormallikleri

Objectives: Duchenne-type muscular dystrophy (DMD) is an X-linked recessive inherited disease affecting mainly the skeletal and cardiac muscles. We aimed to seek associations between the incidence of ventricular arrhythmias and corrected QT (QTc) dispersion and its component, corrected JT (JTc) dispersion in patients with DMD. Study design: The study included 43 consecutive male patients (mean age 8.8±3.0 years; range 3 to 17 years) with DMD. On standard 12-lead electrocardiograms (ECG) the QT and JT intervals and the corrected QT (QTc) and JTc dispersions were calculated. Ventricular extrasystoles were assessed on 24-hour Holter ECG recordings. Ventricular dysrhythmic patterns were evaluated according to the Lown-Wolf classification. The results were compared with those of a control group of 34 healthy children (mean age 9.5±3.1 years). Results: The mean QTc and JTc dispersion values were significantly higher in DMD patients compared to controls (QTc: 78.0±20.6 msec vs. 50.9±16.5 msec; JTc: 77.6±20.5 msec vs. 50.8±17.7 msec; p 0.05). Conclusion: Similar QTc and JTc dispersion values detected in patients with and without ventricular extrasystoles may suggest that ventricular repolarization abnormalities occur in early life and may predispose to the development of ventricular arrhythmias in the long-term.