Can you have a heart attack and not know it?

"Silent" heart attacks that don't produce noteworthy symptoms put you at the same future risks as the classic ones.

When you think of a heart attack, you probably picture a pretty dramatic event that includes someone experiencing intense chest pain, clutching their arm and dropping to the ground unconscious.

But in real life today, heart attacks aren't usually that extreme. Some produce no symptoms, or only produce mild symptoms that are so unremarkable that people mistake them for something else — heartburn from a lunchtime burrito, fatigue, or a chest muscle strain.

"The true incidence of silent heart attacks is not known, since by definition they go unnoticed," says Dr. Michelle O'Donoghue, a senior investigator with the TIMI Study Group, an academic research group studying cardiovascular disease at Harvard-affiliated Brigham and Women's Hospital. "However, estimates have placed them anywhere from 20% to 60% of all heart attacks." Both women and men are at risk, she says.

Identifying a silent heart attack

People often don't learn that they had a heart attack until they have an electrocardiogram (ECG) or a stress test and the doctor notices signs consistent with heart damage. As in traditional symptomatic heart attacks, a silent heart attack involves a blockage of blood flow to the heart. This injures and scars part of the heart muscle, leaving behind telltale signs.

Unfortunately, while a heart attack may go unnoticed, the injury it causes is real and puts you at higher risk for heart failure or a future heart attack.

Take action after a silent heart attack

If you do find out that you've had a silent heart attack, you should take steps to prevent or control cardiovascular risk factors, such as high blood pressure, high cholesterol, or diabetes, any of which can make another heart attack more likely.

Doctors don't completely understand why some people experience no symptoms — or only mild or unusual ones — during a heart attack, Dr. O'Donoghue says. To better identify silent heart attacks, she says, there needs to be more education about less common symptoms, which are often very different from the ones most people picture.

"I think the greatest misconception about a heart attack is that the chest discomfort is 'painful' — in fact, most patients describe the chest discomfort as a heaviness or squeezing sensation that can be quite mild in nature," she says. "Women may also experience more atypical symptoms, like shortness of breath, nausea, sweating, and tingling in the left arm or jaw."

If you do experience these symptoms, it's best to get them checked out immediately. Even if they don't turn out to be heart-related, it truly is better to be safe than sorry.

Managing risk factors

"Since heart attack symptoms can be missed, it is important to continue regular follow-up with your primary care provider," says Dr. O'Donoghue. She or he might want to order periodic ECGs, she says. "If a silent heart attack is identified, this may lead to more testing and appropriate treatments to help ensure another one doesn't occur and that the heart muscle is protected," says Dr. O'Donoghue.

Being proactive can also help ensure that your heart is healthy and that any risk factors you have for cardiovascular disease are managed appropriately.

Lifestyle changes, including diet improvements, smoking cessation, and exercise, can help protect you from additional heart problems, says Dr. O'Donoghue, even if you've already had a silent heart attack.

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