Heart attack: Causes, symptoms, treatments and prevention

If you've ever had pain in your chest, you may have wondered, "Am I having a heart attack?" While chest pain is often considered the hallmark symptom of a heart attack, not all cases of chest discomfort are due to a heart attack. Plus, there are many other warning signs of a heart attack in addition to chest pain.

The heart needs oxygen to survive. A myocardial infarction, or heart attack, occurs when the blood flow that delivers oxygen to the heart is severely reduced or blocked completely. This causes damage or death to the heart muscle. A heart attack is a life-threatening emergency that requires prompt medical intervention.

The cause of heart attacks is usually atherosclerosis. In this condition, the coronary arteries that supply the heart become narrowed and hardened due to the buildup of plaque, which is made up of cholesterol, fat and other substances. This makes it more difficult for blood to flow through the arteries. If a blood clot forms, the flow of blood can become blocked, which causes a heart attack.

The exact cause of atherosclerosis is still being investigated, but it may start when the inner lining of the artery becomes damaged. This damage may be caused by smoking and having diabetes or high cholesterol, triglyceride and blood pressure levels.

A heart attack is a major medical event and requires prompt treatment. There are two main types of heart attacks. An electrocardiogram (ECG or EKG), a test that measures the electrical activity, heart rate and regularity of your heartbeat, is needed to tell which type occurred:

• ST-elevated myocardial infarction (STEMI): Often referred to as a massive heart attack, a STEMI is caused by a complete blockage in a coronary artery. These types of heart attacks are almost always fatal without emergency care due to the extent of the blockage and location.
• Non-ST-elevated myocardial infarction (NSTEMI): This is a type of heart attack caused by a partial blockage of a coronary artery. It severely reduces blood flow.

You may wonder, "What does a heart attack feel like?" If you think you could be having a heart attack, don't try to diagnose heart symptoms yourself. Instead, seek emergency medical help or call 911 right away. Heart attack symptoms can include:

• Pain, pressure, squeezing or fullness in the center of your chest that stays constant or comes and goes
• Pain or discomfort in one or both arms, neck, jaw, back or stomach
• Shortness of breath
• Breaking out in a cold sweat
• Nausea or vomiting
• Lightheadedness
• Fainting
• Tiredness
• Indigestion
• Palpitations or a fluttering feeling in the heart

It's important to note that not all heart attacks feel the same. Signs of a heart attack in men often include the well-known heart attack symptoms, like chest pain and pressure, jaw, neck or back pain, shortness of breath and nausea or vomiting. And while women can also experience these warning signs, heart attack symptoms in women may be less obvious. Symptoms in women can also involve pain or pressure in the lower chest or upper abdomen, fainting, indigestion and extreme fatigue.

However, some heart attacks occur without symptoms or with minimal or unrecognizable symptoms. This is called a "silent heart attack." When it causes symptoms, silent heart attack symptoms are the same as regular heart attack symptoms, but they may be less intense or mistaken for something else. For example, you may think you have the flu or a strained muscle in your chest or upper back. People who have silent heart attacks may not have their condition diagnosed until they go to their doctor complaining of fatigue or another symptom of heart disease. Their doctor may do an EKG and discover then that the person suffered a heart attack weeks or months ago.

A heart attack can last for 30 minutes or longer. However, you may feel symptoms before the heart attack occurs. In some cases, symptoms of a heart attack come on suddenly, but heart attack discomforts can also start hours, days or even weeks before the heart attack occurs. These early signs, or pre-heart attack symptoms, often include angina (chest pain or pressure triggered by physical activity that goes away with rest).

A heart attack can be diagnosed with the following tests:

• EKG: An EKG shows the flow of electrical activity that makes your heart beat and detects heart damage.
• Blood test: A blood test for heart attack checks for substances, such as cardiac enzymes, in your blood that are released by damaged heart tissue.
• Coronary angiography: This test uses dyes and special X-rays to see the inside of your arteries. It's often done during a heart attack to detect blockages in the coronary arteries. 

When it comes to a heart attack, the sooner you receive treatment, the better your prognosis. Early treatment for a heart attack can open up the blockage and prevent or limit damage to the heart muscle. This is why it's so important to seek emergency medical help at the first sign of heart attack symptoms. Treatments for heart attack may include medication, surgery and lifestyle changes. Medications used to treat heart attack include:

• Aspirin and other antiplatelet agents to keep blood from clotting.
• Thrombolytics or "clot-busting" drugs to improve blood flow to the heart. To work best, these medicines must be given within several hours of the start of heart attack symptoms.
• Anticoagulants (blood thinners) to keep blood from clotting or prevent blood clots from getting bigger.
• Vasodilators, or nitrates, to relax blood vessels and reduce chest pain.
• Beta-blockers to reduce blood pressure and how hard the heart works.
• Angiotensin-converting enzyme (ACE) inhibitors to control high blood pressure and help the heart pump blood better after a heart attack.
• Statins to help lower cholesterol levels.
• Pain medications to help relieve chest pain.

Surgical options to improve blood flow to your heart may include:

• Percutaneous coronary intervention (PCI) or coronary angioplasty with stent. In this procedure, a thin, flexible tube is threaded through a blood vessel, usually in the upper thigh, to the blocked artery. A stent is placed to open up the artery and restore blood flow.
• Procedures including coronary artery bypass graft (CABG) or an implantable device to create a new path for the blood to flow and even out your heart's rhythm.

You may also need to make lifestyle changes to lower your chance of a future heart attack. Healthy habits include losing weight, being physically active, eating nutritious foods, limiting sodium intake, easing stress, quitting smoking and avoiding or limiting alcohol. Your doctor may also suggest cardiac rehabilitation, a medically supervised program to improve your heart health.

The best way to lower your risk of another or a first heart attack is to have heart-healthy habits. Reach and maintain a healthy weight, get regular exercise, eat a nutritious diet, reduce stress and quit smoking. You should also keep up with doctor appointments and manage heart-related conditions well. If you have diabetes or high blood pressure, cholesterol or triglycerides, following your treatment plan can help reduce your chance of a heart attack.

Certain other heart problems can sometimes be mistaken for a heart attack:

• Cardiac arrest vs. heart attack: Sudden cardiac arrest and a heart attack are not the same. Sudden cardiac arrest occurs when the heart malfunctions and unexpectedly stops beating. A heart attack happens when blood flow to the heart is blocked.
• Stroke vs. heart attack: A stroke occurs when a blood vessel that supplies the brain becomes clogged or bursts, cutting off blood flow and oxygen to the brain. This reduced blood supply can cause cells to die, which can result in the loss of body functions controlled by the brain, like walking and talking. A stroke can be thought of as a "brain attack." A heart attack happens when a blood vessel that supplies the heart becomes blocked. This cuts off blood flow and oxygen to the heart, which causes death or damage to the heart muscle.
• Heartburn vs. heart attack: Unlike a heart attack, heartburn actually has nothing to do with the heart. Rather, heartburn is caused by stomach acid rising up into the esophagus. But since the esophagus and heart are located near each other, it can be tricky to tell the difference between chest pain caused by heartburn and chest pain caused by a heart attack. It's best to err on the side of caution and get any new, severe, prolonged or concerning chest pain checked by a doctor.

Heart attacks can be fatal, but treatments have greatly improved. If you have any signs of a heart attack, seek emergency medical attention or call 9-1-1 right away. Don't wait to get help.

Clinically reviewed and updated July 2023.