Left ventricular dysfunction and cardiac arrhythmias are frequent in type 2 myotonic dystrophy: A case control study

In contrast with Steinert’s disease (DM1), type 2 muscular dystrophy (DM2) is not known to be associated with a high prevalence of cardiac involvement. Our objective was to compare the results of detailed cardiac investigations in populations of DM2 and DM1 patients, and in controls.Thirty-eight DM2 patients (17 males; age = 57.1 ± 15.2 years) were investigated for possible heart involvement, and their results compared with 76 age–sex matched DM1 patients and 76 controls. Cardiac abnormalities were present in 15 DM2 patients, including conductive defects in 14, systolic dysfunction in 6, supraventricular arrhythmias in 6 and stroke in 5 patients and were significantly more frequent than in controls. When compared to DM1 patients, conductive defects were less frequent, supraventricular arrhythmias had similar prevalence and there was a trend towards more frequent left ventricular dysfunction in DM2 patients. Our study suggests that systematic cardiac investigations should be recommended in these patients.