Hyperthyroidism-induced dilated cardiomyopathy

Abstract

Hyperthyroidism is a common endocrine disorder with a prevalence of 1.3% in the generalpopulation, affecting more women than men. Prolonged hyperthyroidism without appropriatemanagement may lead to high output cardiac failure characterized by increases in heart rate,cardiac contractility, and cardiac output and by reductions in peripheral systemic vascularresistance. Dilated cardiomyopathy with impaired systolic function is rare and occurs in lessthan 1% of patients with thyrotoxicosis. The exact mechanism of hyperthyroidism-induceddilated cardiomyopathy is not well established. The combination of direct toxic effects of excessthyroid hormone along with prolonged tachycardia, arrhythmia, and a hyperdynamic state couldbe contributing factors. We present a case of a young woman with prolonged sinus tachycardiadue to a long history of medication non-compliance who developed dilated cardiomyopathywith low output heart failure. Early detection and management of hyperthyroidism are crucialto restore cardiac function.