Posterior myocardial infarction caused by superdominant circumflex occlusion over an absent right coronary artery

Figure 1. The initial electrocardiogram demonstrates ST-segment elevation in aVR and ST-segment depression in precordial leads V2 to V4.

Figure 2. A, CAG demonstrates a total occlusion in the proximal shaft of the LCX (yellow arrows). B, C, After deploying a sirolimus-eluting coronary stent system (BioMime, Meril Life) in the occlusive lesion, the interim CAG shows marked improvement in the distal flow and 2 big branches from the LCX, among which one (red arrow) follows the LCX distribution course, and another one (blue arrow) followed the RCA distribution course. D, Aortography demonstrates the lack of a separate ostium of the RCA within the right coronary cusp. CAG = coronary angiography, LCX = left circumflex coronary artery, RCA = right coronary artery.

Figure 3. A, B, Coronary CTA demonstrates a normal LAD course, without calcified or noncalcified plaque formation. However, the ostium of the RCA is absent, except for only a small protruding branch from the LCC into the conus branch. Instead, a large branch originating from the LCX passes through the atrioventricular groove, supplying the RCA distribution. CTA = computed tomography angiography, LAD = left anterior descending coronary artery, LCC = left coronary cusp, LCX = left circumflex coronary artery, RCA = right coronary artery.