Evaluation of dysrhythmia in children with muscular dystrophy

Myocardial involvement and dysrhythmia are common findings with muscular dystrophy and are among the leading causes of death. The authors evaluated rhythm and conduction abnormalities in children with muscular dystrophy by electrocardiography, signal-averaged electrocardiography, and Holter monitoring. Twenty-nine patients (mean age, 8 years) and 29 healthy control subjects were included in the study. Sixty-two percent of patients had electrocardiographic abnormalities defined as deep Q waves in V6, tall R waves in V1, and QRS axis deviation. The cardiomyopathy index was significantly greater in the patient group whereas QT and QTc dispersion values showed no significant difference. Holter monitoring revealed premature atrial and ventricular contractions more frequently than normal. However all were classified as Lown I and II. Mean heart rate was significantly higher in the patient group. The electrocardiograms of 41% of the patients showed late potentials. No relationship with these changes and cardiac function was observed. During the study, one patient died whose cardiomyopathy index was longer and had late potentials detected with signal-averaged electrocardiography. In conclusion, standard electrocardiography, cardiomyopathy index, signal-averaged electrocardiography, and Holter monitoring are valuable and reliable monitoring methods in children with muscular dystrophy.