Cardiovascular Complications of Hyperthyroidism

Abstract

Thyrotoxicosis is a clinical syndrome caused by an excess of thyroid hormones circulating in the body. Myocardium and blood arteries have thyroid hormone receptors; hence, an increase or decrease in thyroid hormone levels can alter cardiovascular function. Cardiovascular complications are obvious in-patient with hyperthyroidism. Palpitations, tachycardia, exercise intolerance, dyspnea with exertion, expanded pulse pressure, and on occasion atrial fibrillation are associated with hyperthyroidism, excessive endogenous thyroid hormone production, and thyrotoxicosis, the condition caused by excess thyroid hormone. In the early stages of hyperthyroidism, a high cardiac output and hypertrophy of the left ventricle are observed, followed by biventricular dilatation and congestive heart failure. Atrial fibrillation and pulmonary arterial hypertension can contribute to the higher morbidity associated with untreated hyperthyroidism. Therefore, early and effective treatment of hyperthyroidism is required to prevent thyrotoxic cardiomyopathy.