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Ejection fraction is the fraction (expressed as a percentage) of the blood that the heart "ejects" out to the rest of the body when it contracts. Low ejection fraction signals one form of heart failure. An echocardiogram is the standard test to measure ejection fraction.

As many as 60% of heart attacks go unnoticed when they occur. So-called silent heart attacks occur for a variety of reasons, including differences in pain perception and people not recognizing symptoms or dismissing them. People may assume heart attack symptoms are limited to the chest, but nerves in the heart can send signals to the surrounding nerves, causing pain that radiates to the stomach, back, neck, arm, or jaw. Sometimes people assume their chest pain is caused by a respiratory infection or heartburn when they're actually having a heart attack.

Approximately 88 million Americans—more than one in three—have prediabetes, a condition in which the average amount of sugar in the blood (glucose) is high but not high enough to be diagnosed as diabetes. Among people who develop prediabetes, older ones are less likely than younger ones to eventually develop full-blown diabetes. Still, they should have their glucose levels checked, as prediabetes can put them at high risk for heart attack and stroke.

Silent heart attacks often go unnoticed because they don't produce any symptoms or only mild symptoms that are mistaken for something else, such as heartburn or muscle pain. They are thought to make up from 20% to 60% of heart attacks and can raise risk of a future heart attack or related problem. Both women and men are at substantial risk. Making lifestyle changes and being proactive about managing risk factors for heart disease can help prevent future heart-related problems.

People who get migraines with aura have a slightly higher risk of heart attack, stroke, or death from cardiovascular disease than people who get migraines without aura or no migraines. But migraines are most common in younger women, whose baseline risk of cardiovascular problems is very low in the first place. Still, those who get migraine with aura should be sure to tell their primary care provider or gynecologist. Taking estrogen-containing birth control pills or hormone therapy may further raise stroke risk in these women.

A 2023 Harvard study found that regularly squeezing a week's worth of exercise (150 minutes) into just one or two days—a "weekend warrior" approach—is linked to the same heart-healthy benefits as daily exercise.

A polygenic risk score for heart disease is based on an analysis of more than three million common DNA variants and is expressed as a percentile. People can have zero, one, or two copies of any variant, each of which may either raise or lower the risk of coronary artery disease. Many of these variants occur in genes known to affect heart disease, such as those related to cholesterol, blood pressure, and blood clotting. Others aren't well understood and may provide targets for future research, potentially fueling new drug discovery efforts. For now, the potential benefits of this test are greatest for people under 50.

Older people who take low-dose aspirin every day may be more likely to develop anemia. Aspirin discourages blood clots, but the drug also blocks substances that help maintain and protect the delicate tissue lining the gastrointestinal tract. Long-term aspirin use can damage this protective layer, making bleeding more likely. Minor bleeding can go unrecognized and contribute to anemia, a condition marked by a reduced number of healthy red blood cells. People currently taking aspirin should check with their doctor to see if the practice still makes sense for them.

A 2023 study suggests taking testosterone replacement therapy does not raise the risk for heart attacks or stroke among men with cardiovascular disease or a high risk for it, but it could increase the risk of atrial fibrillation, acute kidney injury, and pulmonary embolism.

A 2023 study suggests eating enough of six categories of food common in popular heart-health diets is associated with a lower risk of cardiovascular disease, including heart attacks and strokes. The six groups are fruits, vegetables, legumes, nuts, fish, and dairy products.