Sudden Cardiac Arrest in a Previously Healthy Young Male: Perimyocarditis Presenting as Myocardial Infarction With Non-obstructive Coronary Arteries.

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a heterogeneous clinical entity that may mimic acute coronary syndromes despite the absence of significant epicardial coronary artery disease. Inflammatory myocardial conditions, such as myocarditis and perimyocarditis, represent important non-ischemic causes of MINOCA and may present with life-threatening complications, including malignant ventricular arrhythmias and sudden cardiac arrest. We report a case of a 37-year-old previously healthy male who presented with chest discomfort, syncope, and sudden cardiac arrest due to ventricular fibrillation. Post-cardiac arrest electrocardiography revealed extensive anterior ST-segment elevation, with markedly elevated cardiac biomarkers and transient severe left ventricular systolic dysfunction. Coronary angiography demonstrated non-obstructive epicardial coronary arteries, leading to the diagnosis of MINOCA. Cardiac magnetic resonance imaging revealed late gadolinium enhancement in a pattern consistent with perimyocarditis. The patient required advanced life support and intensive care management for cardiogenic shock, followed by progressive clinical improvement with complete recovery of left ventricular function. This case highlights perimyocarditis as a rare but critical cause of MINOCA presenting with sudden cardiac arrest and malignant ventricular arrhythmias in a young patient. It underscores the importance of a systematic diagnostic approach and emphasizes cardiac magnetic resonance as a key tool for etiological diagnosis, guiding appropriate management and enabling full functional recovery.