[Sensitivity of thyrotoxic heart to adrenergic influences]

Sensitivity of the cardiovascular system of patients suffering from thyrotoxicosis to exogenous adrenaline was studied. In difference from healthy persons, a single injection of 1 ml of 0.1% adrenaline solution to patients with thyrotoxicosis of moderate severity caused a significant elevation of the arterial pressure, frequency of cardiac contractions, systolic and minute output, myocardiac inotropism indices. An increased inderal reactivity was noted in these patients. Thus, greater sensitivity to adrenergic actions and to beta-adrenoblock was observed in conditions of an excess of thyroid hormones. A coincident administration of adrenaline and inderal balanced the positive chronoinotropic effect of the former, but failed to prevent the hypertensive effect of adrenaline.