When you think of acute left main coronary syndrome the electrocardiographic picture that probably comes to mind is that of multi-lead ST depression with elevation in aVR. At least that's what I tend to think and have blogged the concept many times. It's true but it's not the whole story. It applies to left main ischemia but what about occlusion or near total occlusion of the left main? Well, that's a different pattern altogether and not often seen. How many of those folks make it to the hospital, after all? It's a unique and frightening combination of electrocardiographic features with a few variations an the theme. Here's a post at EMS 12 Lead with some examples and links.