Thyrotoxicosis and the Heart: An Underrecognized Trigger of Acute Coronary Syndromes.

Background: Thyrotoxicosis is a systemic condition with well-documented cardiovascular effects, but its role as a precipitant of acute coronary syndromes (ACS) is often overlooked. This review summarizes clinical cases and original studies from the last 20 years, describing ACS triggered by thyrotoxicosis. Methods: Following PRISMA 2020 guidelines, we searched PubMed, Scopus, and Embase for reports published between 2004-2025. Only case reports and original articles were included. Data extracted included demographics, ECG findings, angiography results, thyroid function, etiology of hyperthyroidism, and outcomes. Results: A total of 35 cases were identified. The mean age was in the fourth decade of life, with a female predominance (57%, 20 out of 35). More than half of the patients presented with ST-segment elevation myocardial infarction (STEMI) or STEMI equivalents (21 out of 35; 60%). Electrocardiographic abnormalities most often involved anterior or inferior leads. Coronary angiography revealed normal vessels or diffuse vasospasm in 18 cases (51%), while thrombotic occlusion was observed in 4 cases (11%), spontaneous dissection in 2 cases (6%), and myocardial bridging in 3 cases (9%). The leading cause of thyrotoxicosis was Graves' disease (≈65%), followed by painless thyroiditis, iatrogenic causes, and gestational hyperthyroidism. Thyroid storm was reported in approximately 20% of cases and was associated with malignant ventricular arrhythmias or sudden cardiac death. Conclusions: Thyrotoxicosis should be recognized as a rare but important trigger of ACS, especially in young patients without traditional risk factors. Pathophysiological mechanisms include coronary vasospasm, increased myocardial oxygen demand, and hypercoagulability. Early recognition may prevent unnecessary revascularization and optimize outcomes through integrated endocrine and cardiac management.