‘Silent’ heart attacks more common and dangerous than previously thought – here’s what you need to know

New research suggests that half of people who experience a heart attack may not even know it. It’s especially concerning since “silent” heart attack sufferers are unlikely to receive proper medical care and are more likely to die from heart disease or other causes.

Researchers from Wake Forest Baptist Medical Center in Winston-Salem, N.C., analyzed medical records from a heart study of more than 9,500 middle-aged adults. Nearly 10 years after the start of the study, they found that, while 386 participants experienced heart attacks with clinical symptoms, another 317 had symptomless “silent” heart attacks and didn’t even know it. As they continued following the patients, they found silent heart attacks accounted for 45 percent of all heart attacks. They also increased the chances of dying from heart disease by three times and increased the chances of dying from all causes by 34 percent. The findings were published in Circulation, the Journal of the American Heart Association.

Dr. Elsayed Z. Soliman, MSc., M.S., senior author and director of the cardiology research center at Wake Forest Baptist Medical Center, said these heart attacks are just as bad, if not worse, as ones where patients are aware they are happening. While classic symptoms of a heart attack can include chest pain, shortness of breath, cold sweats and nausea, silent heart attack symptoms are so subtle the person doesn’t notice them. In many cases, they may not find out for months, even years, after they’ve had a heart attack after a routine checkup or blood test. Only after an EKG to measure the heart’s electrical activity do these patients learn they had a heart attack.

“And because patients don’t know they have had a silent heart attack, they may not receive the treatment they need to prevent another one,” Soliman says.

Because a heart attack usually creates permanent scarring and tissue damage, those who have one are at greater risk of having another. Fortunately, due to modern medicine and technology, patients are more likely to survive and recover from heart attacks than they were in the past. Post-heart-attack treatment can involve major lifestyle changes, medications and procures such as a stent or angioplasty. Yet obtaining the right treatment is dependent on the person recognizing the symptoms and acting quickly. A 2005 survey found that while 92 percent of people identified chest pain as a sign of a heart attack, only 27 percent were aware of all major symptoms. The Cleveland Clinic says even subtle things like unusual fatigue, sweating or mild pain in the neck, jaw or back, could be a sign of a heart attack.

The Centers for Disease Control and Prevention reports that more than 735,000 Americans suffer heart attacks annually and that it is the leading cause of death in the U.S. – roughly one in every four deaths. A heart attack, or myocardial infarction (MI), is damage to the heart muscles that occurs when a coronary artery becomes blocked.

While doctors have always known silent heart attacks occur, the research shows they may be much more frequent than previously thought. Researchers say it underlines the need for more awareness of heart attack symptoms and how to reduce risk through exercise and healthy eating.

“The modifiable risk factors are the same for both kinds of heart attacks. Doctors need to help patients who have had a silent heart attack quit smoking, reduce their weight, control cholesterol and blood pressure, and get more exercise,” Soliman says.