Myotonic dystrophy leads to multiple systemic complications and the age of death is earlier in myotonic dystrophy patients than in the general population. These patients have a high frequency of sudden death related to respiratory failure, cardiac arrhythmias and in particular to cardiac conduction disturbances. Prophylactic pacemaker implantation should be considered in asymptomatic myotonic dystrophy patients, which in the early stages of disease present minor conduction disturbances in 12-leads ECG. Even if the rate of progression of conduction abnormalities is usually slow, fast progression has been often observed thus making the clinical course of individual patients rather unpredictable.