Cardiac manifestations of myotonic dystrophy

Twenty-four patients with Myotonic Dystrophy (MyD), age 19-66 years, underwent non-invasive cardiac evaluation which included physical examination, resting and 24 h ECG recording, echocardiography, and multigated radionuclide (Tc99) scanning (MUGA) to assess left ventricular ejection fraction (LVEF). Only 4 of the 24 patients studied did not display any cardiac pathology. Though most patients (20 out of 24) were free of cardiac symptomatology, 15 had abnormal resting ECG. In 12 of the patients mild rhythm disturbances were present in the 24 h ECG monitoring. Left ventricular contraction impairment was a most striking feature; it was noted in 8 patients, in whom the LVEF was below 50%. The apical region was the most affected. Seventeen patients showed abnormal echocardiographic findings: mitral valve prolapse was noted in 8, dilatation of left atrium in 5 and of the left ventricle in 2 of the 24 patients. No correlation between the severity of muscular impairment and the cardiac manifestation was seen. No correlation was found between disease duration or severity (as judged by the functional capacity of the patients) and its cardiac manifestations.