New Study Reveals Dangers of 'Silent Heart Attacks'

— -- A new study reveals that nearly half of all heart attacks may be “silent,” which can be especially dangerous because they can go undetected and untreated.

The study, published this week in the medical journal Circulation, found that these “silent heart attacks” – which often come without the classic heart attack symptoms of chest pain and shortness of breath -- are more common among men, but are more dangerous for women.

The study of 9,500 middle-aged adults was led by Dr. Zhu-Ming Zhang of Wake Forest Baptist Medical Center in Winston-Salem, North Carolina.

The study found that following a silent heart attack, women were 58 percent more likely to die than women with no heart attacks. In addition, black women were found to be at the highest risk of death.

“About 45 percent of all heart attacks are silent,” ABC News Chief Women’s Health Correspondent Dr. Jennifer Ashton, who was not involved in the study, said today on “Good Morning America.” “These often go unrecognized, undiagnosed and untreated."

Ashton added that having a "silent heart attack" triples the risk of death from coronary heart disease.

Ashton said these attacks can be diagnosed by cardiologists with an ECG or EKG test but prevention is really the key.

“Eating a heart-healthy diet, being active, knowing your numbers and...stop smoking," Ashton recommended. "Eighty percent of heart disease is preventable."