Coronary artery anomalies (CAAs) are congenital disorders observed anywhere along the trajectory of the coronary arteries with an incidence around 0.6-1.3%¹. The right coronary artery (RCA) is dominant in 85% of the general population and supplies the posterior descending artery (PDA) and posterolateral artery (PLA) branches¹. The term superdominant has been coined to describe a coronary artery with one or more additional branches which take over the perfusion of a territory that is normally perfused by the other coronary artery which, in this case, is missing one of its main branches¹.

In this specific case, we have incidentally identified an extremely rare variant of the coronary circulation with an hypoplastic left circumflex artery (LCx) (Fig. 1A red arrow) and a prominent so-called ‘superdominant’ RCA (Fig.1B red arrow) which after delivering a normal interventricular R-PDA (Fig. 1B white arrow) extends leftwards beyond the crux cordis and continues within the atrioventricular sulcus to deliver a second PDA, namely, the R-PLA (Fig. 1B yellow arrow), parallel to the original one, to supply the inferior and posterolateral walls of the left ventricle, normally perfused by the LCx. While several previous studies suggested an increased risk for atherosclerosis in patients with CAA, there is as yet no established consensus on the precise implications of coronary anomalies on the long-term prognosis².

Figure 1 Volume rendered images of the heart demonstrating (A) hypoplasia of the LCX (white arrow) and the presence of (B) the ‘super dominant’ RCA (red arrow), which gives off a double PDA, that is, R-PDA (white arrow) and a long R-PLV branch (yellow arrow), the latter supplying the posterolateral wall of the left ventricle, normally supplied by LCX.