The case of a 53-year-old patient with scapulo-humero-peroneal wasting, early flexion contractures of the elbows and ankles, abnormal cardiac conduction and probable X-related heredity is reported. Histology was suggestive of a primary and very slowly progressive muscular disorder. CT scan revealed fatty muscle degeneration which was more extensive than suggested by clinical findings. Electrophysiological studies revealed right atrial paralysis, left atrial tachycardia and supra and, above all, infra-His block. Sustained episodes of ventricular tachycardia, an anomaly described only rarely in pathology of this type, occurred some time after the fitting of a permanent pacemaker. The originality of this case of Emery-Dreifuss progressive muscular dystrophy lies in the usefulness of muscle CT scan and the existence of life-threatening arrhythmias.