Effects of Thyroid Hormone on Cardiac Function - The Relative Importance of Heart Rate, Loading Conditions, and Myocardial Contractility in the Regulation of Cardiac Performance in Human Hyperthyroidism

The cardiovascular manifestations of thyroid hormone excess, including tachycardia, a widened pulse pressure, a brisk carotid and peripheral arterial pulsation, a hyperkinetic cardiac apex, and loud first heart sound have long been recognized and are a cornerstone for clinical diagnosis (1-9). A number of studies in the past decades have provided critical insights into the mechanisms that are responsible for the hyperdynamic cardiocirculatory state in overt hyperthyroid patients, suggesting that it probably results from the combined effects of thyroid hormone on certain molecular pathways on the heart and vasculature, at both the genomic and nongenomic level