Is it possible to have a heart attack and not know it?

When we think of a person having a heart attack, the image is often of someone experiencing crushing chest pain that radiates down the arm.

But not everyone has these classic symptoms. In fact, some experience what’s called a silent heart attack — where there are no symptoms at all, mild symptoms or symptoms that are atypical (not commonly associated with a heart attack).

“People who experience silent heart attacks may not seek treatment right away because they don’t recognize what’s happening,” says Ravi Hira, MD, FACC, FAHA, FSCAI, an interventional cardiologist at MultiCare’s Pulse Heart Institute. “And unfortunately, time is muscle — delayed diagnosis and treatment can result in irreversible damage to the heart.”

What is a heart attack?

Heart attacks (also known as myocardial infarctions) occur when blood flow to the heart is blocked or restricted. Most of the time, this is due to a buildup of plaque — fat and cholesterol — in the arteries that deliver blood and oxygen to the heart. If a piece of the plaque breaks off, a clot forms around it, stopping or impeding the flow of blood.

In the U.S., someone experiences a heart attack about every 40 seconds, according to the American Heart Association. Studies show that silent heart attacks account for anywhere from 22 to 60 percent of heart attacks.

Who’s at risk for a silent heart attack?

While anyone can experience a silent heart attack, people with diabetes are at an increased risk. This is due in part to the close relationship between diabetes and heart disease, Dr. Hira says. In general, adults with diabetes are twice as likely to have a heart attack or stroke as those who don’t have diabetes.

Another factor that increases the risk of silent heart attack for people with diabetes is neuropathy. A common complication of diabetes, neuropathy refers to nerve damage. Often people with neuropathy experience sensations like numbness, tingling or weakness in the hands or feet. But they can also experience these sensations in other parts of the body.

“Neuropathy can affect autonomic nerves, which control the heart and other important organs,” Dr. Hira says. “People with this form of neuropathy may not feel chest pain at all, or they may experience it as slight discomfort or pressure.”

Another group that has an elevated risk for silent heart attacks? Women.

“It’s common for women to experience heart attack symptoms like nausea, indigestion or sweating that are more subtle or could be attributed to other health issues,” Dr. Hira says. “Because of their subtlety, women may be inclined to downplay or dismiss what they’re feeling.”

Signs of a silent heart attack

Some people experiencing silent heart attacks truly have no symptoms. However, others do experience subtle or non-specific symptoms that appear suddenly:

• Mild discomfort or pressure in the chest
• Nausea
• Indigestion or heartburn
• Fatigue or weakness
• Lightheadedness or dizziness
• Pain or discomfort in the jaw, neck, back or arms
• Shortness of breath without exertion
• Unexplained sweatiness

“If you experience any sort of acute change and start having these types of symptoms, you should go to the emergency department for an evaluation,” Dr. Hira says. “Don’t try to sleep it off or wait to see if it goes away.”

How silent heart attacks are diagnosed and treated

Silent heart attacks damage the heart, yet they are often not diagnosed until weeks, months or sometimes even years after they occur. Because treatment is often delayed, having a silent heart attack increases a person’s risk of heart failure and may increase the risk of stroke and cardiac arrest.

“Often what happens is that people go to their doctor when they start to experience symptoms of heart failure, like shortness of breath or swelling in the feet, legs or other parts of the body,” Dr. Hira says. “When we dig deeper, testing reveals that at some point they experienced a heart attack.”

Diagnostic tests such as an electrocardiogram and echocardiogram (cardiac ultrasound) can confirm damage to the heart from a heart attack.

Treatment options for a silent heart attack are similar to options for a regular heart attack, and may include medications such as statins or beta-blockers, as well as stents or bypass surgery. Treatment approaches vary depending on the nature of your situation and how much permanent muscle damage may have occurred.

How to prevent a heart attack

There are no routine screenings available that detect blockages in the heart, so your best protection against heart attacks is to follow a healthy lifestyle. Here are steps you can take to nurture your heart health.

Get regular checkups. Getting annual checkups with a primary care provider can help ensure you identify conditions, like Type 2 diabetes, high cholesterol or high blood pressure, early on and manage them appropriately. All three of these chronic conditions can increase the risk of cardiovascular events like heart attacks and strokes.

Exercise regularly. Regular physical activity can lower your risk of heart disease, boost your mood and lower your cholesterol, among many other benefits. Dr. Hira recommends engaging in at least 30 minutes of exercise a day that gets your heart rate up. Choose an activity that you enjoy, and keep in mind you don’t have to complete your 30 minutes all at once — for example, you could try three brisk 10-minute walks a day.

Stop smoking. Smoking harms both your heart and blood vessels, whether you inhale smoke directly or breathe it in secondhand. Explore free resources within your community to help you quit tobacco.

Eat a heart-healthy diet. A heart-healthy diet is rich in a variety of nutritious foods, from vegetables and fruits to lean meats, healthy fats and whole grains. And you don’t have to sacrifice taste or enjoyment to follow this type of eating plan. Visit the American Heart Association for heart-healthy recipes as well as cooking and grocery shopping tips.