Inferior wall ST-elevation myocardial infarction in a patient with a single coronary artery from the right coronary cusp trifurcating into the left anterior descending, left circumflex, and right coronary arteries: a rare coronary anomaly, case report.

Background: Abnormal origin of a coronary artery is a rare congenital condition that can significantly affect clinical outcomes especially when associated with acute coronary syndromes. Among these, the presence of a single coronary artery trifurcating from the right coronary cusp into all major coronary branches is exceptionally rare and poorly represented in the literature. Case summary: A 35-year-old man presented with an inferior ST-elevation myocardial infarction. Emergency angiography revealed a single coronary artery arising from the right coronary cusp. The culprit was the right coronary artery. It was effectively treated with intravascular-guided percutaneous coronary intervention, and the remaining coronaries demonstrated normal flow, as shown in subsequent imaging. The patient recovered uneventfully, rehabilitated without complications. He was discharged on guideline directed medical therapy. Discussion: Although the anomalous coronary anatomy was not the direct cause of infarction, it introduced significant procedural challenges that could have delayed or compromised revascularization. Our case highlights the importance of recognizing and anticipating coronary anomalies in acute settings. Multimodality imaging and anatomical classification systems help provide timely diagnosis, procedural planning, and risk assessment from a long-term perspective.