Thyrotoxicosis-Induced Reversible Dilated Cardiomyopathy: A Case Report

Thyrotoxicosis-induced cardiomyopathy (TCM) is a rare but severe complication of thyrotoxicosis, characterized by significant left ventricular systolic dysfunction. While heart failure (HF) symptoms may be common in patients with thyrotoxicosis, true cardiomyopathy remains uncommon, affecting less than 1% of these individuals. A 27-year-old previously healthy woman who presented with symptoms of severe thyrotoxicosis, including irritability, hair loss, persistent dry cough, hypertension, and tachycardia is reported. Thyroid tests revealed elevated levels of free triiodothyronine and thyroxine, with suppressed thyroid-stimulating hormone. Thiamazole and propranolol therapy were initiated. Two months later, her condition worsened, with fatigue, leg and abdominal swelling, and persistent cough. Echocardiography showed a severely reduced ejection fraction (EF 19%) and dilated cardiac chambers. N-terminal pro–B-type natriuretic peptide levels were elevated. She was managed with diuretics, beta-blockers, angiotensin-converting enzyme inhibitors, and continued thyroid treatment. After 7 days, EF improved to over 40%, with reduced ventricular dimensions. Continued treatment led to progressive recovery. At the 18-month follow-up, echocardiography documented normalized chamber dimensions and preserved EF, confirming complete reversal of TCM. This case highlights the importance of early recognition and intervention, as prompt restoration of thyroid function and appropriate HF management are crucial for reversing cardiac dysfunction and improving outcomes. Cite this article as: Georgiev A, Manev N, Jankulovska A. Thyrotoxicosis-induced reversible dilated cardiomyopathy: a case report. Endocrinol Res Pract. 2026;30(1):64-67.