Hemodynamics of hyperthyroidism. The effects of autonomic nervous blocking and anti-thyroid drug treatment

This work was intended to analyze the sympathetic and parasympathetic factors affecting the hemodynamics of hyperthyroidism. Seven patients with hyperthyroidism, diagnosed based on the determinations of BMR, 131I-uptake, T3-resin sponge uptake (T3-RSU), and serum level of thyroxine (T4) were subjected to the study. The hemo-dynamic estimation was done (1) at rest, (2) after vagus blocking by the injection of 0.04 mg/Kg b.wt. atropine and 0.2 mg/Kg b.wt. propranolol before (hyperthyroid state=H) and after (euthyroid state=E) anti-thyroid drug therapy. Cardiac output was measured by the dye-dilution method, and the valve was calculated according to the standard Hamilton formula. The following results were obtained. (1) The vagal tone is lower in H than in E, on the other hand, sympathetic beta-receptor tone is higher in H than in E. (2) The sympathetic alpha-receptor tone in H may be equivalent to that in E. (3) There might exist inotropic factors which affect the hemo-dynamics, other than autonomic nervous system in H.