What Is a Heart Attack?
A heart attack happens when something blocks the blood flow to your heart so it can’t get the oxygen it needs. It’s a medical emergency. Call 911 right away at the first sign of any symptoms. Don’t wait to see if the symptoms pass.
Heart attacks are also called myocardial infarctions (MIs). "Myo" means muscle, "cardial" refers to the heart, and "infarction" means death of tissue because of a lack of blood supply. This tissue death can cause lasting damage to your heart muscle..
Heart Attack Symptoms
Symptoms of a heart attack include:
- Discomfort, pressure, heaviness, tightness, squeezing, or pain in your chest or arm or below your breastbone
- Discomfort that goes into your back, jaw, throat, or arm
- Fullness, indigestion, or a choking feeling (it may feel like heartburn)
- Sweating, upset stomach, vomiting, or dizziness
- Severe weakness, anxiety, fatigue, or shortness of breath
- Fast or uneven heartbeat
Symptoms can be different from person to person or from one heart attack to another. Women are more likely to have these heart attack symptoms:
- Unusual fatigue
- Shortness of breath
- Nausea or vomiting
- Dizziness or lightheadedness
- Discomfort in your gut. It may feel like indigestion.
- Discomfort in the neck, shoulder, or upper back
With some heart attacks, you won’t notice any symptoms (a "silent" myocardial infarction). This is more common in people who have diabetes.
Facts About Heart Attacks
More than a million Americans have heart attacks each year. It happens every 40 seconds to someone in the U.S., according to the CDC.
Heart attacks happen to both men and women. Although they are more likely as you get old, there are many risk factors – including high blood pressure, high levels of LDL (“bad”) cholesterol, diabetes, and whether you smoke – that you can change.
Types of heart attacks: When someone has a heart attack, you may hear some of these terms used:
- STEMI: A heart attack where a coronary artery is completely blocked
- NSTEMI: A heart attack where a coronary artery is narrowed enough to greatly reduce blood flow but is not totally blocked
- MINOCA: A heart attack in which no blockages are seen in the main coronary arteries. MINOCA stands for myocardial infarction with non-obstructive coronary arteries.
A sudden cardiac arrest is actually not a heart attack. You can think of a heart attack as a problem within the heart’s arteries, and a sudden cardiac arrest as the heart’s electrical system suddenly not working right, causing the heart to stop pumping.
Angina also isn’t a heart attack. It’s a symptom, and sometimes it can signal a heart attack. It means chest pain. And while it can happen with a heart attack, it can also happen for other reasons. The sensations may occur with normal activities or exertion but then go away with rest or when you take nitroglycerin.
With angina, you may feel:
- Pressure, pain, squeezing, or a sense of fullness in the center of the chest
- Pain or discomfort in the shoulder, arm, back, neck, or jaw
Call 911 if it gets worse, lasts more than 5 minutes, or doesn't improve after you've taken nitroglycerin. Doctors call that “unstable” angina, and it’s an emergency that could be related to a heart attack that is about to happen.
If you instead have “stable” angina, which is the most common kind, your symptoms usually happen with predictable triggers (such as a strong emotion, physical activity, extreme high or low temperatures, or even a heavy meal). The symptoms go away if you rest or take nitroglycerin that your doctor has prescribed. If not, call 911.
Heart Attack Causes
Your heart muscle needs a constant supply of oxygen-rich blood. Your coronary arteries give your heart this critical blood supply. If you have coronary artery disease, those arteries become narrow, and blood can’t flow as well as it should. When your blood supply is blocked, you have a heart attack.
Fat, calcium, proteins, and inflammatory cells build up in your arteries to form plaques. These plaque deposits are hard on the outside and soft and mushy on the inside.
When the plaque is hard, the outer shell cracks. This is called a rupture. Platelets (disc-shaped things in your blood that help it clot) come to the area, and blood clots form around the plaque. If a blood clot blocks your artery, your heart muscle becomes starved for oxygen. The muscle cells soon die, causing permanent damage.
Rarely, a spasm in your coronary artery can also cause a heart attack. During this coronary spasm, your arteries restrict or spasm on and off, cutting off the blood supply to your heart muscle (ischemia). It can happen while you’re at rest and even if you don’t have serious coronary artery disease.
Each coronary artery sends blood to a different part of your heart muscle. How much the muscle is damaged depends on the size of the area that the blocked artery supplies and the amount of time between the attack and treatment.
Your heart muscle starts to heal soon after a heart attack. This takes about 8 weeks. Just like a skin wound, a scar forms in the damaged area. But the new scar tissue doesn’t move the way it should. So your heart can’t pump as much after a heart attack. How much that ability to pump is affected depends on the size and location of the scar.
What Do I Do if I Have a Heart Attack?
After a heart attack, you need quick treatment to open the blocked artery and lessen the damage. At the first signs of a heart attack, call 911. The best time to treat a heart attack is within 1 or 2 hours after symptoms begin. Waiting longer means more damage to your heart and a lower chance of survival.
If you’ve called emergency services and are waiting for them to arrive, chew an aspirin (325 milligrams). Aspirin is a potent inhibitor of blood clots and can lower the risk of death from a heart attack by 25%.
What Do I Do When Someone Else Has a Heart Attack?
Call 911 and start CPR (cardiopulmonary resuscitation) if someone goes into cardiac arrest, which is when the heartbeat has stopped and the person isn’t responsive. CPR doesn't restart the heart; but it keeps the person alive until medical help arrives.
An easy-to-use device called an AED (automated external defibrillator) is available in many public places and can be used by almost anyone to treat cardiac arrest. This device works by shocking the heart back into a normal rhythm.
Here’s how to use an AED:
1. Check responsiveness
- For an adult or older child, shout and shake the person to confirm whether they’re unconscious. Do not use AED on a conscious person.
- For an infant or young child, pinch their skin. Never shake a young child.
- Check breathing and pulse. If absent or uneven, prepare to use the AED as soon as possible.
2. Prepare to use the AED
- Make sure the person is in a dry area and away from puddles or water.
- Check for body piercings or outline of an implanted medical device, such as a pacemaker or implantable defibrillator.
- AED pads must be placed at least 1 inch away from piercings or implanted devices.
3. Use the AED
For newborns, infants, and children up to age 8, use a pediatric AED, if possible. If not, use an adult AED.
- Turn on the AED.
- Wipe the chest dry.
- Attach the pads.
- Plug in the connector, if necessary.
- Make sure no one is touching the person.
- Push the “Analyze” button.
- If a shock is advised, check again to make sure no one is touching the person.
- Push the “Shock” button.
- Start or resume compressions.
- Follow AED prompts.
4. Continue CPR
- After 2 minutes of CPR, check the person’s heart rhythm. If it’s still absent or uneven, give them another shock.
- If a shock isn’t needed, continue CPR until emergency help arrives or the person begins to move.
- Stay with the person until help arrives.
Heart Attack Diagnosis
Emergency medical workers will ask you about your symptoms and do some tests.
Tests to diagnose a heart attack
Your doctor may order tests, including:
EKG: Also known as an electrocardiogram or ECG, this is a simple test that records the electrical activity of the heart. It can tell how much your heart muscle has been damaged and where. It can also monitor your heart rate and rhythm.
Blood tests: Several blood tests, often done every 4 to 8 hours, can help diagnose a heart attack and spot any ongoing heart damage. Different levels of cardiac enzymes in your blood can indicate heart muscle damage. These enzymes are usually inside the cells of your heart. When those cells are injured, their contents – including the enzymes – spill into your bloodstream. By measuring the levels of these enzymes, your doctor can find out the size of the heart attack and when it started. Tests can also measure troponin levels. Troponins are proteins inside heart cells that are released when the cells are damaged by the lack of blood supply to your heart.
Echocardiography: In this ultrasound test, sound waves are bounced off your heart to create images. It can be used during and after a heart attack to learn how your heart is pumping and what areas aren’t pumping the way they should. The "echo" can also tell whether any parts of your heart (valves, septum, etc.) have been injured in the heart attack.
Cardiac catheterization: You might need cardiac catheterization, also called cardiac cath, during the first hours of a heart attack if medications aren’t helping with the ischemia or symptoms. The cardiac cath can give an image of the blocked artery and help your doctor decide on a treatment.
In this procedure, a catheter (a thin, hollow tube) is inserted into a blood vessel in your groin or wrist and threaded up to your heart. Dye is used to highlight your heart’s arteries. Your doctor can then identify blockages, which are often treated with angioplasty or stents to open the artery and restore blood flow. Your doctor may do several tests to assess your heart. Intravenous blood thinner is an option to open the artery if cardiac catheterization is not available.
Stress testing: Your doctor can do a treadmill test or a radionuclide scan to check whether other areas of the heart are still at risk for another heart attack.
Heart Attack Treatment
A heart attack is a medical emergency that needs care right away to prevent permanent heart damage or death. Treatment often begins in the ambulance if you called 911, or in the emergency room if someone else took you to the hospital.
What drugs are used to treat a heart attack?
At the emergency facility or hospital, you’ll quickly get drugs to prevent further blood clotting in the heart and ease the strain on the heart. Drug therapy aims to break up or prevent blood clots, stop platelets from collecting and sticking to the plaque, stabilize the plaque, and prevent more ischemia.
You should get these medications as soon as you can (within 1 or 2 hours from the start of your heart attack, if possible) to limit heart damage.
Drugs used during a heart attack may include:
- Aspirin to stop blood clotting that may make the heart attack worse
- Other antiplatelet drugs, such as clopidogrel (Plavix), prasugrel (Effient), or ticagrelor (Brilinta) to stop clotting
- Thrombolytic therapy ("clot busters") to dissolve blood clots in your heart's arteries
- Any combination of these
Other drugs given during or after a heart attack help your heart work better, widen your blood vessels, lower your pain, and help you avoid life-threatening heart rhythms.
Are there other treatments for a heart attack?
Treatment may also include a procedure to open the blocked arteries.
Cardiac catheterization: In addition to making a picture of your arteries, cardiac catheterization can be used for procedures (such as angiography or stent) to open narrowed or blocked arteries.
Balloon angioplasty: This treatment can be done, if needed, during cardiac catheterization. A balloon-tipped catheter (thin, hollow tube) is inserted into the blocked artery in the heart. The balloon is inflated gently to press plaque outward against the walls of the artery, to open the artery and improve blood flow. Most of the time, this is not done without putting in a stent.
Stent placement: In this procedure, a small tube is inserted through a catheter into a blocked artery to "prop" it open. The stent is usually made of metal and is permanent. It can also be made of a material that your body absorbs over time. Some stents have medicine that helps keep the artery from getting blocked again.
Bypass surgery: You might have bypass surgery in the days after a heart attack to restore the blood supply to your heart. Your surgeon will reroute blood flow around your blocked artery, usually using a blood vessel from your leg or chest. They can bypass multiple arteries.
What happens in the coronary care unit (CCU)?
If you’ve had a heart attack, you’ll usually stay in a CCU for at least 24 to 36 hours. Once past the critical phase, you’ll continue to get a variety of drugs, including:
- Beta-blockers to slow the heart
- Nitrates to increase heart blood flow
- Blood thinners such as aspirin, Brilinta, clopidogrel, Effient, heparin, or Plavix to prevent further clotting
- ACE inhibitors to help the heart muscle heal
- Statins – cholesterol-lowering drugs such as atorvastatin and simvastatin – to help the heart muscle heal and lower the risk of another heart attack
While you’re in the hospital, medical staff will constantly monitor your heart by EKG in case you get unusual heart rhythms.
Some people may need to be fitted with a pacemaker, a battery-powered device to help keep a steady heart rhythm. If you have a dangerous arrhythmia known as ventricular fibrillation, medical providers will give an electric shock to your chest.
Treatments don’t cure coronary artery disease. You can still have another heart attack. But you can take steps to make it less likely.
Tips for Heart Attack Prevention
The goal after your heart attack is to keep your heart healthy and lower your risk of having another heart attack. Take your medications as directed, make healthy lifestyle changes, see your doctor for regular heart checkups, and consider a cardiac rehabilitation program.
Why do I need to take medications after a heart attack?
You might take certain drugs after a heart attack to:
- Prevent blood clots
- Help your heart work better
- Prevent plaques by lowering cholesterol
You might take medications that treat an uneven heartbeat, lower your blood pressure, control chest pain, and treat heart failure.
Know the names of your medications, what they’re used for, and when you need to take them. Go over your medications with your doctor or nurse. Keep a list of all your medications, and take it to each of your doctor visits. If you have questions about them, ask your doctor or pharmacist.
It sounds obvious, but don't skip your medications. Many people don't take their medications the way their doctor told them to. Figure out what keeps you from taking your medicine – it could be side effects, cost, or forgetfulness – and ask your doctor for help.
What lifestyle changes are needed after a heart attack?
To keep heart disease from getting worse and to head off another heart attack, follow your doctor's advice. You might need to change your lifestyle. Here are some changes you can make that can cut your risk and put you on the path to a healthier life:
Stop smoking: Smoking dramatically raises your risk of both heart attacks and strokes. Talk to your doctor about how to quit. You'll also be doing your friends and family a favor, since secondhand smoke can also lead to heart disease. You also can call the hotline 800-QUIT-NOW (800-784-8669) and visit the smokefree.gov website.
Keep a healthy body weight: If you're overweight or obese, you don't have to get thin to reduce your risk for a heart attack or stroke, but your doctor may recommend some weight loss. If you lose 5% to 10% of your weight, you'll improve your cholesterol numbers and lower your blood pressure and blood sugar levels.
Follow an exercise plan: Moderate physical activity lowers your chances of a heart attack. It also can reduce your blood pressure and LDL or "bad" cholesterol, raise your HDL or "good" cholesterol, and help you stay at a healthy weight.
Aim for 30 minutes of exercise that gets your heart pumping at least 5 days a week. Brisk walking or swimming are some good choices. On the other 2 days, do strength training, like lifting weights. If you've got a tight schedule, break your exercise routine into small chunks.
Eat a heart-healthy diet: Fill your plate with different kinds of fruits, veggies, beans, and lean meats, such as poultry without the skin. Also up your intake of whole grains, like oatmeal, quinoa, and brown rice, and of fish, especially those with omega-3 fatty acids, such as salmon, trout, and herring.
Avocados, olive oil, and flaxseeds also have omega-3s, as do some nuts and seeds. Fat-free or low-fat dairy products such as milk, yogurt, and cheese also are better choices for your heart health than higher-fat versions.
Cut back on unhealthy foods: Stay away from processed or prepared foods that often are high in salt and added sugar. They're also filled with preservatives. Avoid fatty beef, butter, fried foods, and palm oil. All are high in saturated fats.
Skip sugary drinks like sodas and fruit punch, which can lead to weight gain. So can packaged baked goods such as cookies, cakes, and pies. They are high in trans fats and can raise your cholesterol levels.
Limit alcohol: If you don't drink already, don't start. If you do drink, limit how much you drink. The recommendation is no more than one drink a day if you are a woman and no more than two a day if you are a man. Drinking raises your heart rate and blood pressure. It also raises the level of fat in your blood and can cause weight gain.
Get regular checks of your cholesterol, blood pressure, and blood sugar (glucose) levels: If you have diabetes, make sure it’s controlled. Keeping a check on these numbers can help you be more aware of the changes you need to make to keep these levels within normal limits.
Control stress: You may feel anxious or frustrated at times. Open up to your family and friends about what’s going on. Support groups can help you learn how others adjusted to life after a heart attack or stroke.
You may want to talk to a mental health professional or ask your doctor about a stress management program. You can also reduce stress with plenty of physical activity and mind-body practices like meditation.
Pay attention to your symptoms: Don't just hope they'll go away. See your doctor if you feel anything unusual, like shortness of breath, changes in your heart rhythm, or extreme tiredness. Also, watch for pain in your jaw or back, nausea or vomiting, sweating, or flu-like symptoms.
Why should I take part in cardiac rehabilitation?
If you've had a heart attack or have been diagnosed with heart disease, your doctor may recommend cardiac rehabilitation. You'll work with a team of experts to boost your health and avoid future problems.
Your team may include doctors and nurses, as well as specialists in exercise, nutrition, physical therapy, occupational therapy, and mental health. They'll set up a program to fit your needs. They can also help you make changes in your daily life. If you stick with it, it can make a big difference in your recovery and overall well-being.
When will I see my doctor again after I leave the hospital?
Make a doctor's appointment for 4 to 6 weeks after you leave the hospital following a heart attack. Your doctor will want to check your recovery. You might need an exercise stress test on a regular basis. These tests can help your doctor find or slow blockages in your coronary arteries and plan your treatment.
Call your doctor if you have symptoms, such as chest pain that happens more often, gets stronger, lasts longer, or spreads to other areas; shortness of breath, especially while you’re resting; dizziness; or uneven heartbeats.