Heart Attack (Myocardial Infarction)

A heart attack (myocardial infarction) is a sudden drop in blood flow to your heart muscle. It’s usually due to a blockage in one of the arteries that supply blood to your heart (coronary arteries). Without steady blood flow, areas of your heart muscle can begin to die. This keeps your heart from pumping normally and reduces blood flow to the rest of your body.

A heart attack is a medical emergency. You need medical care immediately. Call 911 or your local emergency services number if you think you’re having a heart attack. The longer your heart goes without enough blood, the higher your risk of complications or death. The most common symptom is chest pain or discomfort (pressure, squeezing or heaviness). You might also have shortness of breath, nausea, vomiting or sweating.

Treatment restores blood flow to your heart muscle as quickly as possible. You’ll likely need a procedure to clear the blockage and keep your artery open. You may also receive medications to relieve chest pain, prevent complications and help your heart recover. You’ll follow up with a heart doctor for the rest of your life to lower your risk of another heart attack and protect your health.

Types of heart attacks (myocardial infarctions)

Healthcare providers who diagnose heart attacks need to quickly find out what type you’re having. This information guides your treatment. The two main types are:

• STEMI (ST-segment elevation myocardial infarction): This is a severe heart attack. It happens when one of your coronary arteries is totally blocked. A “widowmaker” is a specific type of STEMI where the blockage affects your left anterior descending (LAD) artery.
• NSTEMI (non-ST-segment elevation myocardial infarction): With this type, you have a partial blockage in a coronary artery that significantly reduces blood flow. This is still a serious condition.

You might also hear providers use these terms:

• Reinfarction: A heart attack that happens within 28 days of another one
• Recurrent heart attack: A heart attack that occurs more than 28 days after another one

Symptoms of a heart attack

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Chest pain or discomfort, which may spread to nearby areas, is the most common symptom of a heart attack. But you might have other symptoms along with the chest pain or instead of it.

Don’t wait to get help if you have any signs or symptoms of a heart attack. You may have early warning signs that start gradually. For example, you might have mild chest discomfort that comes and goes over the course of a few days or weeks. Or you might feel exhausted or unwell for no clear reason.

Chest pain is the most common symptom of a heart attack. You might notice pressure, squeezing or heaviness in your chest. A heart attack can also feel like you’re having indigestion or heartburn, or you need to burp. This chest discomfort usually lasts at least 10 minutes.

But some people, including some women, have different heart attack symptoms that may seem unrelated. For example, you might have shortness of breath, nausea and sweating (with or without chest pain). It’s also possible to feel achy or unwell, but not recognize it’s a heart attack, which people commonly call a “silent heart attack.”

In general, symptoms of a heart attack include:

• Chest pain or discomfort, which may spread to your jaw, neck, shoulder, arm or back
• Shortness of breath or trouble breathing
• Feeling very tired or weak for no clear reason
• Upset stomach, nausea or vomiting
• Anxiety or feeling like something bad is going to happen
• Sweating a lot
• Feeling dizzy or lightheaded
• Passing out

If you think you’re having a heart attack — or if you notice signs in someone near you — call emergency services right away. The dispatcher will tell you what to do until help arrives.

Heart attack causes

The most common cause of a heart attack is plaque buildup in the arteries that supply blood to your heart — a condition known as coronary artery disease. The plaque is most dangerous when its surface wears away or breaks open. Blood clots are drawn to that area. The clots can partly or completely block blood flow, leading to a heart attack.

It’s also possible for the plaque to take up so much space that there’s very little room for blood to get through. This severe narrowing reduces blood flow to your heart and may lead to a myocardial infarction.

Other heart attack causes include:

• Anomalous coronary arteries: You’re born with coronary arteries that start in the wrong location and can be compressed by muscle or nearby arteries.
• Coronary artery spasm: Your coronary arteries quickly tighten, reducing blood flow.
• Coronary embolism: A blood clot or air bubble from somewhere else in your body ends up in a coronary artery.
• Hypertensive emergency: Your blood pressure is dangerously high, causing stress on preexisting coronary artery disease.
• Microvascular coronary disease: Small vessels that branch off from your coronary arteries don’t work as they should. This doesn’t cause a heart attack in the classic sense (where there’s an artery blockage that requires a stent). But it can cause refractory symptoms despite relatively benign coronary artery disease.
• Spontaneous coronary artery dissection: There’s a tear in a coronary artery that slows or stops blood flow to your heart.
• Tachyarrhythmia: Your heart is beating very fast and out of rhythm for too long. This can cause what healthcare providers call a “type II NSTEMI,” in which there’s preexisting (but not severe) coronary artery disease. The tachyarrhythmia stresses your heart and leads to a mismatch between how much blood your heart needs and how much it’s receiving.

Risk factors

Your risk of a heart attack goes up if you:

• Are over age 45 (if you’re male)
• Are over age 50 or past menopause, whichever comes first (if you’re female)
• Have a history of heart disease in your biological family
• Have diabetes, high blood pressure, high cholesterol or obesity
• Smoke or use other tobacco products
• Often eat foods high in salt, sugar or saturated fat
• Drink too much alcohol
• Don’t get enough physical activity
• Use addictive substances, especially amphetamines or cocaine

A healthcare provider can help you find ways to lower your risk.

Complications of this condition

A myocardial infarction can damage your heart, leading to complications like:

• Arrhythmia: This is an abnormal heart rhythm that, in some cases, leads to sudden death.
• Cardiogenic shock: This is a sudden emergency where your heart can’t send enough blood to your body.
• Heart failure: This is a long-term problem with your heart’s ability to pump.
• Left ventricular (LV) thrombus: This is a blood clot in your heart that can break free and lead to stroke. This type of clot can occur when a heart attack involves your LAD artery, which is the vessel that supplies blood to the bottom tip (apex) of your heart.

These complications can occur if one or more of the following factors apply:

• Treatment is delayed.
• There’s a blockage in a major artery, like the LAD. This can harm the apex of your heart and put you at risk for an LV thrombus or heart failure.
• There’s a blockage in an artery that supplies blood to a large part of your heart muscle.

How doctors diagnose this condition

A heart attack diagnosis needs to happen fast. It usually starts when first responders reach you and then continues in the ambulance and emergency room. To diagnose a heart attack, healthcare providers will check your vital signs (like your blood pressure and pulse) and run tests to check your heart function. They’ll use two key tests to see if you’re having a heart attack, and if so, what type:

• Electrocardiogram (ECG/EKG): An EKG makes a graph of your heart’s electrical signals. This can show if heart muscle injury is occurring and whether you’re having a STEMI or NSTEMI. It can also show rhythm problems.
• Troponin test: This blood test checks for a protein called cardiac troponin (cTn). During a heart attack, the damage to your heart muscle makes cTn appear in your blood.

Providers in the ER will talk to you about your symptoms, if you’re able to speak. They might also ask someone who was with you to describe what happened.

You may need more tests to check your heart function, rule out other causes of chest pain and check for complications. Possible tests include:

• Echocardiogram: Shows how well your heart is squeezing and how well your heart walls are moving
• Coronary angiogram: Shows your heart’s blood vessels and checks for blockages
• Heart CT scan: Identifies any significant narrowing or hardening of your heart’s arteries
• Heart MRI: Checks for blood flow problems in your heart’s arteries
• SPECT scans or PET scans: Finds areas of your heart with reduced blood flow or injury

How is a heart attack treated?

Treatment focuses on getting blood flowing to your heart again as soon as possible. Usually, this means you have a procedure to clear the blockage from your coronary artery. The sooner this happens after your symptoms start, the more it can help you. You’ll likely also need several medications to help your heart work better and lower your risk of more problems.

Surgical procedures and therapies to restore blood flow

There are three main ways healthcare providers can get blood flowing back to the heart muscle:

• Percutaneous coronary intervention (PCI): Also called coronary angioplasty and stenting, this procedure opens your coronary artery. Providers use a thin tube (catheter) and a tiny balloon to clear the blockage. They usually also place a stent to keep your artery open.
• Coronary artery bypass grafting (CABG): Heart bypass surgery creates a new blood vessel that goes around the blockage. It helps if you have severe blockages that PCI can’t manage.
• Fibrinolytic therapy: If PCI or CABG isn’t possible, healthcare providers use medicine to break up blood clots in your coronary artery. They give it through an IV line or a catheter.

Medications

Medications you may need as part of your heart attack treatment include:

• ACE inhibitors or ARBs to lower your blood pressure and help your heart recover
• Antiarrhythmics to stop or prevent dangerous heart rhythms, which heart attacks can cause
• Anticoagulants to help your body break down any clots and keep new ones from forming
• Aspirin and a P2Y12 inhibitor (dual antiplatelet therapy) to lower the risk of blood clots in your heart’s arteries and on your stent after PCI
• Beta-blockers to slow down your heart rate so your heart can recover from the injury of a heart attack
• Nitroglycerin to relieve chest pain
• Statins to help stabilize the plaque in your heart’s arteries (so it’s less likely to break open) and reduce your blood cholesterol levels

Recovery time

Your heart attack symptoms should start to go away as you receive treatment. You’ll likely feel tired and weak during your hospital stay and for several days after.

Your healthcare provider will tell you how long you can expect to stay in the hospital. Usually, it’s anywhere from a few days to a couple of weeks. It depends on the treatments you receive and how your body responds. In general, PCI has a shorter hospital stay than CABG.

Heart attack recovery takes anywhere from two weeks to three months. Your provider will advise you on how to take care of yourself during this time. They’ll also say when it’s safe to go back to work, drive and do other things.

Cardiac rehabilitation

Cardiac rehab is a key part of recovery. This 12-week program includes supervised exercise, nutrition advice and more. It helps you feel better faster and lowers your risk of future heart problems.

Emotional recovery

Emotional recovery is also important. A heart attack is a major life event that can take a toll on your mental health and raise your risk for depression. It’s normal to feel sad or anxious for a few weeks. But if those feelings persist, tell a healthcare provider. They may suggest speaking with a therapist or joining a support group.

When should I see my healthcare provider?

Seek emergency care for a heart attack. As you recover, follow-up visits are vital. Be sure to follow the schedule your provider gives you.

After you finish cardiac rehab, you’ll likely see your provider every three months for the first year. Then, you’ll get down to every six months and eventually to once a year. At these visits, your provider will:

• Do tests to check your heart function
• Make sure you’re taking the right doses of your medications
• Talk with you about daily habits and changes you want to make

Call your provider if you have:

• New or changing symptoms
• Side effects from medications
• Sadness, worries or anxiety that won’t go away
• Questions about which activities are safe to do

What can I expect if I have a heart attack?

Once you have a heart attack, your risk for having another goes up. This means you’ll need to take prescribed medications and make changes to your daily habits.

Today, many people survive a heart attack. But lots of things affect your outlook, including how much heart damage occurred, your age and overall health. That’s why it’s important to work closely with your provider. They’ll do everything possible to protect your heart and help you live a long life.