They may remain undetected for years.
According to a new study published in the journal Circulation, silent heart attacks account for over 45 percent of all heart attacks in the United States, but that doesn’t mean they’re any less deadly than heart attacks with clear symptoms.
“The outcome of a silent heart attack is as bad as a heart attack that is recognized while it is happening,” senior study author Elsayed Z. Soliman, director of the epidemiological cardiology research center at Wake Forest Baptist Medical Center, said in a press release. “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.”
The researchers analyzed the records of nearly 9,500 middle-aged adults who were enrolled in the Atherosclerosis Risk in Communities (ARIC), which is a study analyzing the outcomes of atherosclerosis, or the hardening of arteries. The study is sponsored by the National Heart, Lung, and Blood Institute, and began back in 1987.
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Over the course of a nine-year period, 317 people in the study sample had silent heart attacks and 386 had heart attacks with symptoms, according to the new findings.
Heart attacks occur when when a blood vessel in the body gets blocked and can no longer carry blood to the muscle tissue of the heart. The common symptoms of a heart attack include chest pain, dizziness, and shortness of breath. However, in silent heart attacks, the heart muscle tissue can be damaged with symptoms so mild that an individual won’t even realize he or she is having a heart attack, or no symptoms at all.
In fact, people may not know they’ve had a silent heart attack for years following the attack. Live Science reports that, in many cases, doctors discover evidence of a silent attack accidentally while testing for something else. Soliman said that doctors can recognize signs of a previous silent heart attack using a test that measures the heart’s electrical activity, an echocardiogram (EKG). Even years following a silent heart attack, the heart’s electrical activity is altered.
Soliman clarifies that the results of this study don’t suggest that doctors should use EKGs to scan for silent heart attacks in healthy patients — just that doctors should take it seriously if they spot signs of a silent heart attack, and move forward with follow-up testing.
The study results also revealed that silent heart attacks increased the chances of dying from heart disease by 3 times and increased the chance of dying from all causes by 34 percent.
Additionally, silent heart attacks were more common in men, but they were more likely to cause death in women. “Our study also suggests that blacks may fare worse than whites,” Soliman said in the press release, “but the number of blacks may have been too small to say that with certainty.”
The study wasn’t designed to investigate why these differences exist between men and women, Soliman told Live Science, but the results highlight the importance of caring for men and women differently when it comes to heart health.
This isn’t the first study to indicate that silent heart attacks are almost as common as symptomatic ones, but it’s the largest one to date.