A case of triple trouble: malignant inter-arterial course of RCA with its high transcommissural origin and deep intramyocardial bridging presenting as chest pain

Coronary artery anomalies are uncommon in routine clinical practice, but some variants can have important clinical implications when they compromise coronary blood flow. One such pattern is an anomalous origin of the right coronary artery (RCA) with an inter-arterial course with deep intramyocardial bridging and transcommissural origin, which is considered a potentially high-risk configuration. We report a 57-year-old man who presented with exertional chest pain and was diagnosed with non-ST elevation myocardial infarction. To better delineate the anatomy, ECG-gated cardiac computed tomography (CT) angiography was performed. CT angiography demonstrated a high transcommissural origin of the RCA above the sinotubular junction. The RCA then coursed between the aortic root and the right ventricular outflow tract, consistent with an inter-arterial trajectory, with evidence of luminal compression along this segment. A short intramyocardial (myocardial bridging) segment measuring approximately 1.28 cm was also identified, contributing to dynamic narrowing. No significant atherosclerotic stenosis was noted in the other coronary arteries. The coexistence of a high take-off RCA, malignant inter-arterial course, and myocardial bridging likely contributed to the patient's ischaemic symptoms. This case underscores the value of cardiac CT angiography in clearly defining complex coronary anatomy and supporting appropriate clinical decision-making.