Acute myocardial infarction caused by thrombosis of left main coronary artery generate acute cardiac failure, cardiogenic shock and death. Along with the clinical history, the electrocardiogram (EKG) is the most useful tool for its recognition and timely management. Classically the EKG shows ST elevation > 1 mm in aVR or V1 with ST depression in the other leads. Urgent coronary angiography with percutaneous coronary angioplasty using drug eluting stents is recommended when the diagnosis is made. We report two cases to exemplify the clinical presentation, EKG and angiographic findings and therapeutic approach.