Properties of Hyperthyroid Rat Myocardium

Abstract

Electric and mechanical properties of right and left ventricular muscle of hyperthyroid rats have been studied in vitro. Excitability was not modified but refractory period was lengthened in left ventricular muscle. Developed tension was significantly reduced in both ventricles, the greater reduction being on the right. The results suggest direct and disproportionate effects of thyroid hormone on right and left ventricular myocardium.