ABSTRACT
Right Coronary Artery The RCA courses in the right atrioventricular groove and circumscribes the tricuspid valve annulus (Fig. 16.6). The first branch arising from the RCA is frequently the conus or infundibular branch, which courses anteriorly to supply the muscular right ventricular outflow tract or infundibulum. Alternatively, in 30% to 50% of angiograms the conus artery may arise from a separate ostium close to the RCA ostium or from a common aortic ostium shared with the RCA (19,28). Another important proximal branch of the RCA is the sinus node artery. The reported frequency of the sinus node artery arising from the proximal RCA 50% to 70% with a dual blood supply from both the RCA and LCx in 3% (29,30). In its midportion, the RCA provides one or more branches that supply flow to the right ventricular free wall (right ventricular marginal branches). The RCA also
Figure 16.4 3-D reconstruction of 64-slice CT angiogram illustrating the coronary tree in a left posterior oblique projection. Note the circumflex running posteriorly under the left atrial appendage to reach the left atrioventricular groove. Abbreviations: PA, pulmonary artery; LAD, left anterior descending; OMB, obtuse marginal branch; LA, left atrium; LCx, left circumflex. Source: Courtesy of Dr John Rumberger, Princeton Longevity Center.
