A Single Coronary Artery with an Absent Right Coronary and a Superdominant Left Circumflex Giving off a Branch Supplying the Right Coronary Artery Territory

An absent right coronary artery (RCA) with single left coronary artery (LCA) originating from left aortic sinus with a superdominant left circumflex (LCX) and giving off an RCA branch is one of the rarest coronary artery anomalies. It occurs with an incidence of less than 0.1%. Usually, patients are asymptomatic and abnormality is found incidentally on cardiac catheterisation or CT angiography. We present a case report of an unusual coronary anomaly in a patient who presented with anterior myocardial infarction. Patient was subjected to coronary angiography, which revealed absent RCA originating from distal LCX artery, supplying the base of heart and RCA territory. He underwent primary percutaneous intervention (PCI) with stenting to the left anterior descending (LAD) artery. This type of anomaly, in which single LCA from which dominant LCX continues as RCA, is important to diagnose and manage if diseased, as stenosis of the dominant LCX artery in such cases can jeopardise a large portion of myocardium, which can lead to increased morbidity and mortality, if left untreated.