THYROTOXIC CARDIOMYOPATHY MANIFESTING AS HEART FAILURE WITH SUPRANORMAL EJECTION FRACTION: A CASE REPORT

Abstract

Thyrotoxic cardiomyopathy is classified as a rare metabolic cardiomyopathy and typically presents with high-output heart failure accompanied by a supranormal left ventricular ejection fraction. In recent years, heart failure with supranormal ejection fraction (HFsnEF) has been increasingly regarded as a distinct heart failure phenotype, associated with a worse prognosis and suboptimal treatment response compared with the group with preserved ejection fraction. Despite the profound cardiovascular effects of thyrotoxicosis, heart failure occurs infrequently, with a reported prevalence of approximately 6%. In this report, we present a clinical case of a patient admitted with fatigue, palpitations, and diarrhea. After comprehensive integration of clinical findings, laboratory test results, and imaging data, the patient was ultimately diagnosed with thyrotoxicosis accompanied by heart failure with supranormal ejection fraction. The patient was treated with a combination of antithyroid medication and a beta-blocker. After seven days of therapy, the patient demonstrated marked improvement in clinical symptoms as well as cardiac function on echocardiographic assessment. Early identification of thyrotoxic cardiomyopathy is crucial, as it represents a rare but treatable cause of heart failure with favorable reversibility.