An unusual presentation of ascending aortic arch dissection.

The following case report is that of a young man who collapsed on a golf course during a heat advisory. The prehospital presentation suggested that the patient was suffering from heat exhaustion. In the Emergency Department, the patient's condition continued to deteriorate despite aggressive rehydration and cooling efforts. Aggressive evaluation and treatment of the patient led to the diagnosis of an acute painless dissection of the ascending aorta.