Like most websites, we use cookies and other similar technologies for a number of reasons, such as keeping our website reliable and secure, personalizing content, providing social media features and to better understand how our site is used. By using our site, you are agreeing to our use of these tools. Learn More

Your Location is set to:

Published on December 10, 2019

Would you know if you had a heart attack?

Silent Heart Attack

Most people know the classic symptoms of a heart attack, such as chest pain, a pain in one arm and severe shortness of breath, but it is also possible to have a heart attack and not even know it. According to the American Heart Association, nearly half of all people who have heart attacks have ‘silent’ heart attacks, or silent myocardial infarction (SMI), which occur with few symptoms.

Those were the results of a study of 9,498 middle-aged people who were already enrolled in the Atherosclerosis Risk in Communities study. Over an average of nine years, 317 participants had silent heart attacks, while 386 had more classic heart attacks. Researchers found that SMI accounts for up to 45 percent of all heart attacks and they increase the chances of dying from heart disease by three times.

“Just because the heart attack is silent, doesn’t mean it’s benign,” said cardiologist John Guerin, MD, at Cape Cod Healthcare Cardiovascular Centers in Falmouth and Sandwich. “It could be just as risky, and maybe worse, because you don’t have the warning system to change your behavior. One small heart attack is not a big deal, but if you have a subsequent heart attack that’s additive then you have more damage done to the heart, which makes it weaker.”

A traditional heart attack often acts as a trigger to get people to start thinking about living a healthier lifestyle, he said. They might rethink eating at McDonald’s for lunch, stop smoking, lose weight and start exercising. But with an SMI, that trigger is missing.

“If everyone followed a healthy lifestyle, you really could reduce risks by 80 percent, but people don’t,” Dr. Guerin said. “In most cases people have to be hit over the head before they think to do something preventative.”

Long-term Considerations

Part of the problem is that people don’t see quick results from a healthy lifestyle. For example, if you cut your finger, a stitch will stop the bleeding. But, if you have high blood pressure, which raises your risk for a heart attack, you may not feel bad physically and any positive results from taking a blood pressure medication are effective only in the long-term. Because of this, patients may not be encouraged to take their medication, especially since many of them have side effects.

That means people must make future health considerations a priority over feeling better in the short-term. Not everyone does that. In fact a recent study showed that more than 50 percent of middle-aged people who were prescribed medications for high blood pressure either stopped taking them within a few months or didn’t take them as prescribed.

Fortunately, blood pressure medications are a lot better today than they used to be, Dr. Guerin said. Doctors used to let blood pressure run higher in the past because there weren’t a lot of options and the medicines were difficult to tolerate.

“Now we have so many different options and choices that for a majority of the people we can find something that they can take that they tolerate,” he said.

SMI Signs

There are ways to discover if you have had a silent heart attack, but without symptoms it is just not cost effective to test people to see if they’ve had one, Dr. Guerin said. Like other hidden diseases like pancreatic and lung cancer, oftentimes SMIs are only discovered by serendipity when a doctor orders a CAT scan for some other reason, he said. Some people are referred to a cardiologist to check for a silent heart attack if they have an abnormal EKG, but more often a second heart attack is what brings to light the first one.

Even though symptoms of an SMI are often so mild they are barely noticed, if at all, they are not always entirely symptomless. There can be mild chest discomfort, heartburn, nausea and shortness of breath. Since these symptoms are so vague, people rarely bring them up to their doctor.

That can be dangerous. A study of 935 men and women in Iceland who were followed for more than 13 years indicated that 17 percent had had a silent heart attack and 10 percent had had a recognized heart attack. After three years, there was no difference in death rates between those who had an SMI and those who had not had a heart attack. The death rate was 3 percent for both groups. However, over time, those with SMI fared a lot worse. By 10 years later, half the participants with a silent heart attack had died, which is about the same as the death rate for those who had a recognized heart attack.

The good news is that Dr. Guerin has seen an improvement in people’s lifestyle choices in recent years. Fewer adults smoke than at any time in history. The term “plant-based diet” is becoming increasingly trendy and about three-quarters of the patients he sees have a Fitbit device and try to get 10,000 steps a day.

“Outside of mass screening, the best way to prevent heart attacks and to ensure all around good health is to lead a healthy lifestyle,” he said. “Don’t smoke, exercise, control your weight, and control your blood sugar and your blood pressure. There’s a lot of good that happens with those things.”