Myotonic dystrophy is frequently associated with cardiac abnormalities including defects of the cardiac conduction system. In the present study 19 patients with Steinert's disease were evaluated by standard electrocardiography, Holter electrocardiography, ambulatory blood pressure monitoring, and echocardiography. Although no cardiac symptoms were referred by the patients, disorders of cardiac conduction and rhythm were found in many of them. Ultrasound examination did not reveal alterations in the geometry or systolic function of the teft ventricle, whereas impairment of the diastolic function and dilatation of right ventricle chamber were observed in a substantial percentage of patients. All abnormalities were independent of duration and severity of neuromuscular disease. Average 24-hour systolic and diastolic blood pressure levels in patients with myotonic dystrophy were lower than those of the normal population with high percentage of «non dippers», suggesting the presence of abnormal mechanisms in the regulation of blood pressure homeostasis.
