Risk of arrhythmia in type I myotonic dystrophy: the role of clinical and genetic variables

Objective:To examine the association between the presence of arrhythmia in type 1 myotonic dystrophy (DM1) and clinical–genetic variables, evaluating their role as predictors of the risk of arrhythmia.Methods:245 patients with genetically proven DM1 underwent clinical and non-invasive cardiological evaluation. Severity of muscular involvement was assessed according to the 5 point Muscular Disability Rating Score (MDRS). Data were analysed by univariate and multivariate models.Results:245 patients were examined and cardiac arrhythmias were found in 63 subjects, 40 of whom required a device implant. Statistical analyses revealed that men had more than double the risk of developing arrhythmias compared with women (p = 0.018). Addition of each year of age caused an increased risk of arrhythmia equal to 3% (p = 0.030). Subjects with MDRS 5 had a risk of arrhythmia 12 times higher than patients with MDRS 1–2 (p