Spontaneous Coronary Artery Dissection (SCAD) is a rare but potentially lethal event. A 46-year-old woman presented to her local hospital at 11:30 pm with an abrupt onset of severe chest pain, which occur one hour before. Diagnosis of acute myocardial infarction non-STEMI was set. The autopsy as a direct cause of death revealed cardiac tamponade from a ruptured dissection of ascending aorta that start with a rupture of right coronary artery. Microscopic examination of coronary artery revealed that a rupture occurred on junction between normal and abnormal intima and thin subintimal-media layer, because of loose of collagen fibers. Our case confirmed association of primary coronary artery dissections with female sex. As a direct cause of primary coronary artery dissection we identified loose of collagen fibers in intimal and subintimal-media layer .