HEART DISEASE AS THE PRESENTING FEATURE IN MYOTONIA ATROPHICA

Abstract

Nearly 20 years ago Evans (1944) suggested that the cardiac abnormalities that are associated with myotonia atrophica might in some cases be an important aid to the early diagnosis of this disease.This report concerns a patient who was first thought to be a case of non-specific myo- carditis, but who later proved to be one of cardiomyopathy due to myotonia atrophica after a family history of this disease was uncovered.Case Report A 65-year-old woman had an attack of right pleural pain in January 1961, without preceding or subsequent chest symptoms.Her temperature was raised for 24 hours, she had a slow irregular pulse, blood pressure 110/70 mm.Hg, and there were rales at the right base.Cardiomegaly was seen on the radiograph, and atrial fibrillation, low voltage QRS complexes, and low or flat T waves were present in the electrocardio- gram.Before this episode she had been well except for tiredness and somnolence during the previous year.Treatment with thyroxine for six weeks had not brought improvement.On admission to hospital in March 1961, she had no complaints except for the increasing tiredness and loss of energy, but despite these she had been curling during the early winter.She denied having had mus- cular weakness, shortness of breath, angina, or ankle cedema.Inquiry into her family history had negative results.Her skin was dry and she had frontal baldness.There was an immature cataract in the left eye.The pulse was irregular and slow and varied in rate from 40 to 65 a minute.The cardiac apex beat was 13 cm.from the mid-line in the fifth intercostal space, and there was a soft systolic murmur at the apex.The blood pressure was 110/70 to 130/96 mm.Hg.The electrocardiogram (Fig. 1) showed the changes previously noted and multifocal premature ventricular contractions.Fluoroscopy with barium swallow showed enlargement of all four chambers but especially of the left ventricle.Laboratory investigation included a normal urinalysis, h2emoglobin 14-8 g./100 ml., sedimentation rate 26 mm., serum cholesterol 240 mg./100 ml., serum protein-bound iodine 7 6 ,ug./100 ml., serum iron 130 ,tg./100 ml., negative tests for