Congenital coronary artery variations are implicated in out of hospital ventricular fibrillation and in increased risk of developing coronary atherosclerosis within the unusual vessel. As ischemic heart disease remains the leading cause of loss of adult life within the growing global population, awareness of the possible variable origin and course of a coronary vessel is important. While angiographic series are valuable they may not reflect the population at large since asymptomatic patients rarely undergo coronary angiography. Anatomical studies are more representative of the prevalence of variant coronary anatomy but more difficult to obtain. Here is reported an anatomical study in continuous series of anatomical donors from the general adult population, describing a variant aortic sinusal origin of the left circumflex artery (LCX) originated from the right aortic sinus and coursing behind the aortic annulus before reaching its usual position into the left atrioventricular groove, between the left atrial appendage and the pulmonary trunk. This is the first LCX variation in a continuous series of 338 human hearts studied, a prevalence of 0.3% in this anatomical series. From a clinical standpoint, unusual origin of the LCX from an independent ostium within the right aortic sinus of Valsalva should be considered when LCX circulation cannot be visualized as a branch of the left main coronary artery.
