Under some circumstances, the left main artery may be open, but occlusion might exist in branches such as left circumflex and left anterior descending arteries. This condition can be described as "left main equivalent", meaning that although the left main artery is normal, significant ischemia may occur with further coronary blood flow reduction as though left main artery is involved. More than 70% proximal LAD and LCX stenosis are considered as LMCA equivalent.
The ECG demonstrates the classical pattern of left main coronary artery (LMCA) occlusion in these cases. Widespread horizontal ST depression, most prominent in leads I, II and V4-6 ST elevation in aVR ≥ 1mm ST elevation in aVR ≥ V1 I have seen around five cases out of the 2000 cases of CAG analysed so far and needs careful planning for procedures because of the risk of sudden death due to the same risk of LMCA block in a…
