It is reported on a 39-year-old patient who revealed pathological ECG-findings of the most different kind during several years. Since there were no clues to a myocarditis, later on, however, pareses of atrophical skeletal muscles developed and a distropia myotonica could be diagnosed, the cardiological disturbances are to be regarded as a symptom of this disease. When also a participation of the myocardium in the distrophia myotonica is not unknown, so even in our case the frequently changing disturbances of the nervous impulses of the heart, of the ventricular stimulus conduction and of the replolarisation of different expression as well as the pronounced hypersensitivity to heart glycosides are remarkable individual findings. The interpretation of these findings is problematic. Morphologic and dystrophic changes of the myocardium as well as functional myotonic disturbances on the membraneous system may influence the process of stimulation and may cause the clinical appearances.