A heart attack occurs when the flow of blood to the heart is blocked. The blockage is most often a buildup of fat, cholesterol and other substances, which form a plaque in the arteries that feed the heart (coronary arteries).
The plaque eventually breaks away and forms a clot. The interrupted blood flow can damage or destroy part of the heart muscle.
A heart attack, also called a myocardial infarction, can be fatal, but treatment has improved dramatically over the years. It's crucial to call 911 or emergency medical help if you think you might be having a heart attack.
A heart attack occurs when an artery supplying your heart with blood and oxygen becomes blocked. Fatty deposits build up over time, forming plaques in your heart's arteries. If a plaque ruptures, a blood clot can form and block your arteries, causing a heart attack. During a heart attack, tissue in your heart muscle dies due to lack of blood flow through your heart's arteries.
Common heart attack signs and symptoms include:
Not all people who have heart attacks have the same symptoms or have the same severity of symptoms. Some people have mild pain; others have more severe pain. Some people have no symptoms; for others, the first sign may be sudden cardiac arrest. However, the more signs and symptoms you have, the greater the likelihood you're having a heart attack.
Some heart attacks strike suddenly, but many people have warning signs and symptoms hours, days or weeks in advance. The earliest warning might be recurrent chest pain or pressure (angina) that's triggered by exertion and relieved by rest. Angina is caused by a temporary decrease in blood flow to the heart.
Act immediately. Some people wait too long because they don't recognize the important signs and symptoms. Take these steps:
Call for emergency medical help. If you suspect you're having a heart attack, don't hesitate. Immediately call 911 or your local emergency number. If you don't have access to emergency medical services, have someone drive you to the nearest hospital.
Drive yourself only if there are no other options. Because your condition can worsen, driving yourself puts you and others at risk.
Take aspirin, if recommended. Taking aspirin during a heart attack could reduce heart damage by helping to keep your blood from clotting.
Aspirin can interact with other medications, however, so don't take an aspirin unless your doctor or emergency medical personnel recommend it. Don't delay calling 911 to take an aspirin. Call for emergency help first.
If you see someone who's unconscious and you believe is having a heart attack, first call for emergency medical help. Then check if the person is breathing and has a pulse. If the person isn't breathing or you don't find a pulse, only then should you begin CPR to keep blood flowing.
Push hard and fast on the person's chest in a fairly rapid rhythm — about 100 to 120 compressions a minute.
If you haven't been trained in CPR, doctors recommend performing only chest compressions. If you have been trained in CPR, you can go on to opening the airway and rescue breathing.
A heart attack occurs when one or more of your coronary arteries become blocked. Over time, a coronary artery can narrow from the buildup of various substances, including cholesterol (atherosclerosis). This condition, known as coronary artery disease, causes most heart attacks.
During a heart attack, one of these plaques can rupture and spill cholesterol and other substances into the bloodstream. A blood clot forms at the site of the rupture. If large enough, the clot can block the flow of blood through the coronary artery, starving the heart muscle of oxygen and nutrients (ischemia).
You might have a complete blockage or partial. A complete blockage means you've had an ST elevation myocardial infarction (STEMI). A partial blockage means you've had a non-ST elevation myocardial infarction (NSTEMI). Diagnostic steps and treatment might be different depending on which you've had.
Another cause of a heart attack is a spasm of a coronary artery that shuts down blood flow to part of the heart muscle. Using tobacco and illicit drugs, such as cocaine, can cause a life-threatening spasm.
Certain factors contribute to the unwanted buildup of fatty deposits (atherosclerosis) that narrows arteries throughout your body. You can improve or eliminate many of these risk factors to reduce your chances of having a first or another heart attack.
Heart attack risk factors include:
Complications are often related to the damage done to your heart during an attack, which can lead to:
It's never too late to take steps to prevent a heart attack — even if you've already had one. Here are ways to prevent a heart attack.
Ideally, your doctor should screen you during regular physical exams for risk factors that can lead to a heart attack.
If you're in an emergency setting for symptoms of a heart attack, you'll be asked about your symptoms and have your blood pressure, pulse and temperature checked. You'll be hooked up to a heart monitor and have tests to see if you're having a heart attack.
If you've had or are having a heart attack, doctors will take immediate steps to treat your condition. You might also have these additional tests.
Exercise stress test. In the days or weeks after your heart attack, you might also have a stress test to measure how your heart and blood vessels respond to exertion. You might walk on a treadmill or pedal a stationary bike while attached to an ECG machine. Or you might receive a drug intravenously that stimulates your heart similar to the way exercise does.
Another possibility is a nuclear stress test, which is similar to an exercise stress test, but uses an injected dye and special imaging techniques to produce detailed images of your heart while you're exercising.
Cardiac CT or MRI. These tests can be used to diagnose heart problems, including the extent of damage from heart attacks. In a cardiac CT scan, you lie on a table inside a doughnut-shaped machine. An X-ray tube inside the machine rotates around your body and collects images of your heart and chest.
In a cardiac MRI, you lie on a table inside a long tubelike machine that produces a magnetic field. The magnetic field aligns atomic particles in some of your cells. When radio waves are broadcast toward these aligned particles, they produce signals that vary according to the type of tissue they are. The signals create images of your heart.
Each minute after a heart attack, more heart tissue deteriorates or dies. Restoring blood flow quickly helps prevent heart damage.
Medications given to treat a heart attack might include:
In addition to medications, you might have one of these procedures to treat your heart attack:
Coronary angioplasty and stenting. In this procedure, also known as percutaneous coronary intervention (PCI), doctors insert a long, thin tube (catheter) that's passed through an artery in your groin or wrist to a blocked artery in your heart. If you've had a heart attack, this procedure is often done immediately after a cardiac catheterization, a procedure used to find blockages.
This catheter has a special balloon that, once in position, is briefly inflated to open a blocked coronary artery. A metal mesh stent might then be inserted into the artery to keep it open long term, restoring blood flow to the heart. Depending on your condition, you might get a stent coated with a slow-releasing medication to help keep your artery open.
Coronary artery bypass surgery. In some cases, doctors perform emergency bypass surgery at the time of a heart attack. If possible, however, you might have bypass surgery after your heart has had time — about three to seven days — to recover from your heart attack.
Bypass surgery involves sewing veins or arteries in place beyond a blocked or narrowed coronary artery, allowing blood flow to the heart to bypass the narrowed section.
Once blood flow to your heart is restored and your condition is stable, you're likely to remain in the hospital for several days.
Most hospitals offer programs that might start while you're in the hospital and continue for weeks to a couple of months after you return home. Cardiac rehabilitation programs generally focus on four main areas — medications, lifestyle changes, emotional issues and a gradual return to your normal activities.
It's extremely important to participate in this program. People who attend cardiac rehab after a heart attack generally live longer and are less likely to have another heart attack or complications from the heart attack. If cardiac rehab is not recommended during your hospitalization, ask your doctor about it.
To improve your heart health, take the following steps:
Having a heart attack is scary, and you might wonder how it will affect your life and whether you'll have another one.
Fear, anger, guilt and depression are all common after a heart attack. Discussing them with your doctor, a family member or a friend might help. Or consider talking to a mental health provider or joining a support group.
It's important to mention signs or symptoms of depression to your doctor. Cardiac rehabilitation programs can be effective in preventing or treating depression after a heart attack.
Some people worry about having sex after a heart attack, but most people can safely return to sexual activity after recovery. When you can resume sexual activity will depend on your physical comfort, psychological readiness and previous sexual activity. Ask your doctor when it's safe to have sex.
Some heart medications can affect sexual function. If you're having problems with sexual dysfunction, talk to your doctor.
A heart attack usually is diagnosed in an emergency setting. However, if you're concerned about your risk of heart attack, see your doctor to check your risk factors and talk about prevention. If your risk is high, you might be referred to a heart specialist (cardiologist).
Here's some information to help you prepare for your appointment.
When you make the appointment, ask if there's anything you need to do in advance, such as restrict your diet. You might need to fast before a cholesterol test, for example.
Make a list of:
Take a friend or relative along, if possible, to help you remember the information you're given.
Some questions to ask your doctor about heart attack prevention include:
Don't hesitate to ask other questions, as well.
Your doctor is likely to ask you questions, including:
It's never too early to make healthy lifestyle changes, such as quitting smoking, eating healthy foods and becoming more physically active. These are primary lines of defense against having a heart attack.