“…Although hyperpyrexia occurs in approximately 40 percent of storm patients, it is not considered to be pathognomonic for the disease. 1,4 An estimated 50 percent of thyroid storm patients have some form of cardiac involvement: most commonly sinus tachycardias, atrial fibrillation, premature ventricular contractions, congestive heart failure, or angina. Thyroid hormones are thought to have positive chronotropic effects on the heart by direct action on mitochondrial phosphatebond synthesis in the myocardium, by stimulating the synthesis of macromolecular proteins in the myocardium, and by increasing myocardial sensitivity to endogenous catecholamines.…”