Evaluation of dysrhythmia in children with muscular dystrophy

Myocardial involvement and dysrhythmia are common findings with muscular dy strophy and are among the leading causes of death. The authors evaluated rh ythm and conduction abnormalities in children with muscular dystrophy by el ectrocardiography, signal averaged electrocardiography, and Holter monitori ng. Twenty-nine patients (mean age, 8 years) and 29 healthy control subject s were included in the study. Sixty-two percent of patients had electro cardiographic abnormalities defin ed as deep Q waves in V-6, tall R waves in V-1, and QRS axis deviation. The cardiomyopathy index was significantly greater in the patient group wherea s QT and QTc dispersion values showed no significant difference. Holter mon itoring revealed premature atrial and ventricular contractions more frequen tly than normal. However all were classified as Lown I and II. Mean heart r ate was significantly higher in the patient group. The electrocardiograms o f 41% of the patients showed late potentials. No relationship with these ch anges and cardiac function was observed. During the study, one patient died whose cardiomyopathy index was longer and had late potentials detected wit h signal-averaged electrocardiography. In conclusion, standard electrocardiography, cardiomyopathy index, signal-a veraged electrocardiography, and Holter monitoring are valuable and reliabl e monitoring methods in children with muscular dystrophy.