Congestive heart failure, dilated cardiac ventricles, and sudden death in hyperthyroidism

Symptoms and signs of cardiac dysfunction are common in patients with untreated hyperthyroidism. The symptoms may be due to the thyroid condition alone or they may be due to aggravation of an underlying cardiac condition by the thyroid disorder. 1–3 Left ventricular dilatation, congestive heart failure, and death have been reported in humans with hyperthyroidism and in spontaneously hyperthyroid non-human animals without other associated cardiac diseases. 4–8 This report describes tindings in 2 young women with fatal hyperthyroidism unassociated with another cardiac abnormality which in itself could have produced the cardiac dysfunction.