Echocardiographie Features of Myotonic Dystrophy

Thirty adult patients with myotonic dystrophy from a defined population in northern Sweden were examined by echocardiography. The patients were subdivided into three groups according to the severity of the disease. Abnormal echocardiograms were found in 1 of 7 (14%) patients with mild disease, 7 of 13 (54%) patients with moderate disease, and 6 of 10 (60%) patients with severe disease. Two main types of échocardiographie changes occurred, namely left ventricular dilatation which was found in 6 (20%) of 30 patients and left ventricular wall hypertrophy which was found in 4 (13%) of 30 patients. Half of the patients with dilated left ventricle had coincident impaired left ventricular systolic function measured as ejection fraction. We found no greater prevalence of mitral valve prolapse in this series than would be expected in the normal population. This study shows that there is a myocardial disease associated with myotonic dystrophy which may take two disparate forms, left ventricular dilatation or left ventricular hypertrophy. This myocardial disease seems to be progressive and can be detected by echocardiography in patients with moderate and severe neurological disability.