Eur Heart J Case Rep. 2026 Sep 12;10(10):ytag684. doi: 10.1093/ehjcr/ytag684. eCollection 2026 Oct.
ABSTRACT
BACKGROUND: Cardiovascular manifestations of thyrotoxicosis are common, typically presenting as tachyarrhythmias or high-output physiology. Coronary artery spasm (CAS) is an uncommon but increasingly recognized complication, usually causing transient ischaemia rather than malignant ventricular arrhythmias. Cardiac arrest due to thyrotoxicosis-induced CAS is exceedingly rare. Early recognition is vital because management differs from that of typical acute coronary syndromes (ACS).
CASE SUMMARY: A 63-year-old man suffered an out-of-hospital cardiac arrest with an initial shockable rhythm, achieving return of spontaneous circulation (ROSC) after a single defibrillation. Initial evaluation revealed inferior ST-segment elevation, leading to urgent coronary angiography, which demonstrated severe right coronary artery spasm that resolved after intracoronary nitrate administration. Laboratory studies confirmed significant hyperthyroidism, and recurrent ST-segment changes in the intensive care unit further supported thyrotoxicosis-induced CAS as the underlying mechanism. The patient made a full neurological and cardiac recovery following temperature management, intensification of antithyroid therapy, and vasodilator treatment.
DISCUSSION: This case underscored an unusual presentation of cardiac arrest triggered by thyrotoxicosis-related CAS in the absence of underlying coronary artery disease. Elevated thyroid hormone levels can impair endothelial function and heighten vascular smooth muscle reactivity, creating a predisposition to diffuse, therapy-resistant vasospasm. Recognizing this reversible yet potentially fatal condition is crucial, as prompt initiation of antithyroid therapy and vasodilators can rapidly alleviate ischaemia and reduce the risk of recurrence. The favourable outcome in this patient illustrates how early identification of the underlying cause can guide swift and effective management.
PMID:42891396 | PMC:PMC13674800 | DOI:10.1093/ehjcr/ytag684