Coronary Artery Anomaly and Myocardial Infarction 167 reported the incidence as 1.07%, which included a 0.92% rate of ectopic RCA originating from the left sinus and a 0.15% rate of ectopic LCA arising from the right sinus.1 An anomalous RCA might originate from the anterior aspect of the ascending aorta usually above the sinotubular line (high anterior take-off), from the left sinus of Valsalva with a separate ostium from the left main coronary artery, from the left main coronary artery (as a single coronary artery), or from the pulmonary trunk. It is well known that an anomalous origin of the RCA can lead to angina pectoris, a myocardial in- farction, ventricular tachycardia, ventricular fibril- lation, syncope and sudden death. The pathophysiological mechanism of these clinical phenomena is still a concern. However, the usual explanation is the mechanical com- pression of the right coronary artery by the great vessels, the aorta and the pulmonary artery. In addition, an abnormal slit-like RCA ostium in the aortic wall and an acute angulation of the RCA can lead to these pathologic results. Hutchins et al.2 suggested that the unusual angle of take-off and the more tortuous course of the proximal portion of the anomalous coronary artery can accelerate the rate of atherosclerosis. Liu et al.3 suggested that the junction point of the bound portion and the free portion of an anomalous artery as it wraps around the aorta is an area that is susceptible to lipid accumulation. These mecha- nisms can explain the obstructive lesion in the coronary artery of our patient. It is important to identify the culprit vessel as soon as possible in an acute myocardial infarction. However, in a patient with a coronary artery with an anomalous origin, it is difficult to quickly and precisely cannulate all three coronary arteries and to determine the subsequent treatment strategy. The selective cannulation of anomalous arteries can be a formidable challenge due to the unusual ostial location, take-off orientation and aberrant course of the artery. Some authors emphasize the importance of selecting a guiding catheter by "trial and error." Hon-Kan et al.4 suggested that Amplatz guiding catheters be considered when an anomalous-origin RCA has an anterior-superior take-off because these catheters offer stable seating and superior back-up support. However, if an anomalous-origin RCA arises from the left sinus of Valsalva, one should first consider Judkins left guiding catheters with a secondary curve 0.5 cm longer than the diagnostic catheter for the left coronary artery. This is because they can easily be manipulated through clockwise or counter-clockwise rotation and usually are able to engage the RCA without any difficulty under a fluoroscope by the lateral view. At coronary angiography, the precise course of the anomalous vessel may be difficult to delineate due to its complex three-dimensional geometry shown in two dimensions fluoroscopically. One study used multidetector computed tomography (MDCT) to image the monocuspal origin of all three coronary arteries from the right sinus.5 In our case, MDCT was found to be a useful, accurate, and convenient complementary tool for coronary angiography. Although there are some limitations in using this diagnostic modality in urgent direct PTCA cases, it is a valuable tool for precisely depicting the anomalous origin and relationships between the coronary vessel, great vessel, and ventricles. Although this topic is still open in cardiology, the right coronary artery originating from the left coronary sinus is a more common anomaly, and its prognosis and treatment are better known than for other coronary anomalies. It should be noted that in our case, the LCA originated from the posterior sinus. Left ACAOS is less frequent and its treatment is less clearly defined. A case of a coronary artery anomaly involving more than one coronary artery is quite rare. Fineschi M. reported a rare case of the anomalous origin of all three major coronary arteries from the right sinus, which included the anomalous origin of LCX and the common origin of the LAD and RCA.6 To our knowledge, our coronary anomaly, in which the RCA originated from the left sinus and the LCA originated from the right sinus separately, is the first case reported. We report using MDCT to successfully treat an inferior wall myocardial infarction with an uncom- mon coronary artery anatomy, where the RCA originated above the left coronary sinus of Valsalva and the LCA originated separately from the pos- terior coronary sinus of Valsalva. The rarity and Yonsei Med J Vol. 50, No. 1, 2009