Unexpected twist: large marginal branch occlusion of the left circumflex artery unveiled by immediate and pivotal cardiac magnetic resonance imaging in a 19-year-old with suspected myocarditis—a case report

This case highlights the essential role of early cardiac MRI in guiding clinical decision-making, particularly in young patients with non-specific symptoms. Although rare, endocarditis-related septic embolism must be considered in the differential diagnosis of acute myocardial infarction in this population.