Myocardial infarction in patients without atherosclerotic coronary artery disease is a rare syndrome. Several pathophysiologic mechanisms have been proposed, such as spontaneous coronary dissection, intramural hematoma, coronary vasospasm and thrombosis. Diagnosis can be confirmed by coronary angiography and intravascular ultrasound, while the presence of an inflammatory process within the coronary artery wall can be detected from local heat production by intracoronary thermography. We present two women with acute coronary syndrome, due to a limited spontaneous coronary dissection and an intramural hematoma detected by coronary angiography and intravascular ultrasound.