Study: Half Of All Heart Attacks Are Silent And Aren’t Noticed Until After They’ve Struck

Here’s a thought that will keep you up at night: A massive study has discovered that half of all heart attacks are silent, but that doesn’t make them less deadly.

Heart attacks are considered silent if they don’t cause any of the classic symptoms that signal something is wrong, like chest pain, shortness of breath, and dizziness, or they’re mild enough that the person affected barely notices them, Live Science explained.

People may not even know they’ve suffered an episode until after the fact, when they undergo an electrocardiogram (EKG) during a routine visit to the doctor or a trip to the emergency room, NBC News noted.

Doctors can see the evidence through an EKG, which measures the organ’s electrical activity. This activity can still be altered years after this kind of heart attack.

Cardiologist Dr. Deborah Ekery said that people who suffer silent heart attacks are more likely to experience symptoms that are too general or subtle to associate with a life-threatening problem, like indigestion, the flu, a strained muscle, or long-term fatigue. These signs are often blamed on something else entirely.

And that’s not a good thing, said Dr. Elsayed Soliman, who led the research.

“The outcome of a silent heart attack is as bad as (one) that is recognized while it is happening. And because patients don’t know they have had (one), they may not receive the treatment they need to prevent another one.”

To reach this frightening conclusion, the analysis looked at the medical records of 9,500 middle-aged men and women. These people were part of a heart disease risk study that began in 1987.

Nine years into this study, 700 participants had heart attacks — about 317 of them, or 45 percent, were silent and 386 were accompanied by the noticeable signs and were noticed right away.

If half of all heart attacks are silent, that means half of them aren’t getting treated as quickly as they should be. These deadly episodes require particularly aggressive treatment because sufferers are three times as likely to die of heart disease and 34 more likely from other causes.

In other words, the silent half is just as deadly, according to Soliman. They’re more common in men, but women are more likely to die; and blacks “fare worse” than whites, a finding that may due more to the amount of diversity in the research than anything else.

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

These frightening episodes occur when a vessel bringing blood the organ’s muscle tissue is blocked. Without the blood it needs, the section of muscle begins to die and is replaced with scar tissue, which is stiffer.

The aggressive treatment for this silent but deadly half requires lowering cholesterol levels or blood pressure, helping patients stop smoking or lose weight, and encouraging exercise. Others may need blood thinners or low-dose aspirin.

Diets lower in salt, sugar, and the types of fat known to clog arteries and higher in fruits, vegetables, and whole grains lower the risks. Heart disease is the number one killer in the U.S.; poor diet, obesity, diabetes, and a sedentary lifestyle increase the risk.

Soliman isn’t suggesting that people who are healthy and experiencing no symptoms get EKGs on a hunt for silent episodes. Doctors are encouraged, however, to take any signs of previous attacks seriously should they spot one and make sure to perform follow-up tests.

The results bolster previous study conclusions and confirm what scientists already suspected to be the case: Our hearts can have trouble without us even noticing.

[Image via Hein Nouwens/Shutterstock]