Dampening of the arterial line waveform during surgery is always a major concern for the operating team. During cardiovascular surgery the etiology may be very serious and require immediate diagnosis, as the surgical plan may need be altered urgently.

We present a case of a Type A aortic intramural hematoma repair where the arterial line waveform acutely dampened during weaning from cardiopulmonary bypass and the course of action that took place.