CARDIOPULMONARY EXERCISE TESTING IN HYPER THYROIDISM

Spiroergometry might be applicable to detect alterations of cardiopulm onary functions related to hyperthyroidism. Thus, cardiac and respirat ory changes as well as work capacity in hyperthroid female patients we re to be assessed with the help of the Cardiopulmonal Exercise Test Sy stem. Twelve female hyperthyroid patients with Graves' disease of whom all were controlled in euthyroidism, were examined. Eighteen euthyroi d female patients in whom intracardiac catheter examination ruled out cardiopulmonary disease served as controls. The anaerobic threshold wa s determined by means of the V-slope method. An echocardiography was p erformed in all patients. Ergometry was performed in a semisupine posi tion using a continuous ramp protocol of 20 watt/min. A markedly reduc ed work capacity, and a high heart rate in rest and exercise were foun d. In the ratio heart rate/oxygen uptake a lower rise (p = 0.001) due to a decreased growth in the heart rate was noticed. Regarding the pul monary system a decreased tidal volume in hyperthyroidism (p = 0.021), and a higher breathing frequency (p = 0.003) were recognized, as well as an impaired oxygen consumption, in comparison with the euthyroid s tate. Also, echocardiographically an increased cardiac index (p = 0.00 8) and a markedly reduced stroke volume (p = 0.005) in comparison to t he control group were observed. Heart rate, work capacity, oxygen upta ke, and the ratio heart rate to oxygen uptake were normalized in euthy roidism. With the help of the CPX-System noninvasive measure of marked cardiopulmonary changes in hyperthyroidism are possible, especially t he lower growth of the heart rate in exercise, which might be the limi ting factor of work capacity.