S6334 When the Gut Mimics the Heart: A Rare Case of Acute Mesenteric Ischemia Masquerading as STEMI in a Young Athlete

Introduction: Non-occlusive mesenteric ischemia (NOMI) is a life-threatening condition typically seen in older or critically ill patients with hypoperfusion or vasoconstriction. It is rarely seen in young, healthy individuals. We report a unique case of NOMI in a 27-year-old endurance athlete, whose initial presentation mimicked ST-elevation myocardial infarction (STEMI), highlighting a diagnostic challenge and the need for broad differential consideration. Case Description/Methods: A 27-year-old man triathlete with no prior medical history presented with acute substernal chest pain radiating to the back, associated with nausea, diaphoresis, and mild abdominal discomfort. Vitals revealed hypotension (BP 88/60 mmHg) and tachycardia (HR 110 bpm). Electrocardiogram showed ST-segment elevations in leads II, III, and aVF. Serum troponin was mildly elevated at 0.04 ng/mL. Emergent coronary angiography revealed normal coronary arteries. Despite fluid resuscitation, hypotension persisted. Laboratory tests demonstrated leukocytosis, elevated lactate (6.2 mmol/L), and mildly elevated creatinine. A chest computed tomography (CT) angiogram ruled out aortic dissection but revealed jejunal pneumatosis. Abdominal CT angiography showed diffuse small bowel wall thickening, mesenteric stranding, and a patent but prominent superior mesenteric artery, raising concern for non-occlusive mesenteric ischemia (NOMI). Diagnostic laparoscopy revealed dusky but viable small bowel without necrosis. Intra-arterial papaverine and aggressive intravenous fluid resuscitation were administered intraoperatively, leading to improved bowel perfusion. Small bowel biopsies confirmed ischemic enteritis without infarction. The patient recovered uneventfully and was discharged in stable condition. Discussion: This case demonstrates a rare presentation of NOMI in a healthy young athlete, likely triggered by dehydration and sympathetic overdrive causing splanchnic vasoconstriction. The ST elevations and chest pain mimicked cardiac ischemia, but normal coronaries and high lactate pointed toward visceral hypoperfusion. NOMI should be considered when hypotension and elevated lactate accompany vague abdominal symptoms, even in young individuals. Prompt recognition, imaging, and intervention can prevent bowel infarction and improve outcomes.