Right coronary sinus shot
Right coronary aortic sinus injection is done to check the position of the origin of the right coronary artery when there is difficulty in engaging the right coronary ostium during attempted right coronary angiography. Sinus shot is also taken when the catheter gets wedged in the right coronary artery repeatedly with damping of the catheter tip pressure tracing, to exclude a right coronary ostial lesion. In this case, the sinus shows separate origin of the right coronary artery (Prox RCA; yellow arrow) and the conus artery (Conus; black arrow). The right coronary artery has a proximal chronic total occlusion and it is a non dominant artery. Usually the conus artery is one of the first branches of the right coronary artery (RCA) and supplies anastamotic vessels to the left anterior descending coronary artery (LAD) branches. They become important in cases of LAD occlusion. Catheter tip is marked by the red arrow and dye in the right coronary aortic sinus by the green arrow.