[Tolerance of the cardiovascular system of hypothyroidism patients for physical loading]

Twenty-one patients with primary hypothyroidism were subjected to electro- and echocardiography, and 10 patients, to bicycle ergometry, to examine their central and intracardiac hemodynamics at rest and cardiovascular response to exercise. The results were compared with the respective parameters of 18 normal subjects. Hypothyroidism was shown to be associated with increased left-ventricular myocardial weight (echocardiographic evidence in the presence of normal myocardial contractility at rest, lowered stress tolerance due to a smaller chronotropic reserve of the heart, and myocardial metabolic disorders.