Left main stenosis

Left main occlusion and stenosis are commonly confused. A Left Main Coronary Artery (LMCA) stenosis can cause widespread ST depression and ST elevation in aVR, but unlike with a proximal LAD occlusion, the ST elevation in aVR is greater than in V1. It is likely that many cases reported as left main occlusion with this pattern have sub-total occlusion (stenosis). A true occlusion has a high risk of cardiac arrest and may show widespread massive ST elevation with ST depression in aVR.