Cardiac involvement represents a major problem in the clinical management of patients, so that cardiac complications represent one of the primary causes of premature death in DM1. In particular there is a high incidence of sudden death, ranging from 2 to 30% of cases, so far principally related to the development of conduction blocks. However, literature reports of sudden death in patients implanted with pacemakers, as well as of spontaneous ventricular tachycardia would suggest a potential etiologic role also for ventricular arrhythmias. The lack of clinical research studies conducted on a large number of patients does not make available definite data regarding the etiology and the epidemiology of arrhythmic events in DM1. For the same reasons, other considerable topics, such as prognostic stratification of the arrhythmic risk and clinical management of life-threatening arrhythmias in DM1 patients, are still undefined.