When Heart Attacks Are Silent

Q. What is a silent heart attack?

A. From James L. Weiss, M.D., cardiology professor at Johns Hopkins University School of Medicine in Baltimore:

As its name suggests, a silent heart attack occurs when oxygen flow to your heart is reduced in the absence of obvious symptoms like chest pain. Essentially, you have a heart attack, otherwise known as a myocardial infarction, without knowing you’re having one. This is not as rare as it may seem.

A 2015 National Institutes of Health study used cardiac MRIs to screen for scarring of the heart, or myocardial scarring—evidence of a prior heart attack—in 936 older adults. The screening found that 21 percent of the subjects with diabetes and 14 percent without diabetes had scarring. None were aware they had suffered a heart attack.

Previous studies have estimated that about 20 percent of all heart attacks are silent. People who have silent heart attacks have the same risk factors as those who have recognized heart attacks. Some studies suggest that people with high blood pressure or type 2 diabetes have an increased tendency toward silent heart attacks.

You could mistake a heart attack for indigestion or muscle pain. If you suspect you may have had a silent heart attack, talk with your doctor, who will evaluate your health, risk factors, and suspicious symptoms and order testing if warranted.