[Treadmill exercise testing in patients with idiopathic cardiomyopathy (author's transl)]

Multistage treadmill stress testing was performed in 24 patients with idiopathic cardiomyopathy using Bruce protocol. 5 patients were considered to have hypertrophic obstructive cardiomyopathy (HOCM), 12 hypertrophic nonobstructive cardiomyopathy (HCM) and 7 congestive cardiomyopathy (CCM). Heart rate, systemic blood pressure, electrocardiographic changes and exercise tolerance were observed. The effect of propranolol on exercise tolerance was investigated in HOCM and HCM. 1) Exercise duration was less in patients with HCM and HOCM than in normal subjects (50 subjects) and greater than in 50 anginal patients. In CCM, exercise duration was the least. 2) Electrocardiographic changes observed in HCM and HOCM were increase of T waves and lessening of ST depression. In CCM, appearance of ventricular arrhythmia was noted in 4 of 7 patients. 3) Maximam exercise tolerance was reached at Bruce state III-IV in HOCM, stage III in HCM and stage II in CCM. 4) Propranolol administration resulted in improvement of exercise tolerance in 3 of 7 patients with HOCM and HCM.