Myotonia Atrophica

Myotonia atrophica is a familial degenerative disorder marked especially by atrophy and myotonia of skeletal muscle groups, but capable of affecting any muscles of the body. Although electrocardiographic evidence of myocardial involvement is found in the majority of these patients, symptomatic cardiovascular disease is uncommon and it is rare for cardiac symptoms to precede obvious skeletal muscle disease. This report describes a patient who presented with complete heart block and Stokes-Adams attacks and was treated with cardiac pacemaker implantation before developing overt manifestations of myotonic dystrophy. Patient Summary A 50-year-old white woman was first admitted to the University of Minnesota Hospitals in January 1964, for evaluation of "black-out spells" of three months' duration. She had been an adopted child and knew nothing of her family. Her physical development had been normal, but she was slow in school. She had six pregnancies, four terminating in stillborn infants. One apparently healthy male