By Peggy O'Farrell
The Cincinnati Enquirer

An aortic dissection, the heart condition that killed actor John Ritter, is rare, strikes without warning and often is fatal.

About half the people who show up at emergency rooms with aortic dissections die, said Dr. Daniel Snavely, a University of Cincinnati cardiologist.

The dissection is a tear in the main artery that carries blood out of the heart to the major organs. Usually, the middle layer of the artery tears and blood leaks within the artery, often cutting off blood flow to the heart or brain - resulting in heart attack or stroke - or to the lungs or kidneys. If the tear is severe enough, the patient could bleed to death.

But Snavely and Dr. Charlie Hattemer, a cardiologist with Greater Cincinnati Cardiovascular Consultants, stress that aortic dissections can be successfully treated if diagnosed early. The tear can be repaired with surgery or an arterial graft, and beta blockers can be prescribed to lower blood pressure and reduce the heartbeat.

"There are a lot of people walking around Cincinnati with treated aortic dissections," Hattemer says.

Symptoms include sudden, severe pain in the chest and back.

Long-term high blood pressure is the most common risk factor for aortic dissection. Hypertension weakens the arterial walls and causes the heart to pump harder, increasing its force against weakened blood vessel walls.

Connective tissue disorders, including Marfan's syndrome, can also cause aortic dissection. Weakness of the aorta also can be congenital.

"If people are interested in prevention, they should go with excellent blood pressure control," Hattemer says.