[Auricular flutter preceding by several years the discovery of Steinert's disease. 3 cases]

The large frequency of arrhythmias and conduction disorders in the course of Steinert's myotonic dystrophy is well known; most of the time, the muscle disease is already known when the heart disease is discovered. The authors report three cases of young subjects (2, 31 and 35 years) in whom an atrial flutter without obvious etiology preceded by several years (14, 2.5 and 2 years) the diagnosis of muscular disease. On this occasion, the characteristics of the heart involvement in Steinert's disease are reminded: large frequency of atrial and also ventricular rhythm disorders, distalic conduction disorders. Our cases emphasize the importance of diagnosing Steinert's disease by clinical examination, electromyography and neuro-muscular biopsy in front of a rhythm disorder--especially atrial flutter--or an interventricular conduction disorders occurring, without obvious etiology, in a young subject.