Skip to Content

Myocardial Infarction


What is a myocardial infarction?

A myocardial infarction (MI) is a heart attack. A heart attack happens when the blood vessels that supply blood to your heart (coronary arteries) are blocked. This can damage your heart. It can lead to an abnormal heart rhythm, heart failure, or may become life-threatening.

What are the signs and symptoms of an MI?

Chest pain is the most common symptom. Your chest may feel tight or heavy. You may feel pressure, crushing, squeezing, or burning. The discomfort may spread to your neck, jaw, shoulders, back, or arms. The chest pain can last 30 minutes or longer. The following are also signs and symptoms of an MI:

  • You have heartburn, abdominal pain, nausea, or vomiting.
  • You feel weak, dizzy, or like you are going to faint.
  • You cannot catch your breath.
  • You are cold and sweaty.
  • Your heart is beating very fast.
  • You may not have typical chest pain or pressure if you are a woman or an older adult, or have diabetes or a history of heart failure. You may have shortness of breath and no other symptoms. You may have no symptoms at all.

What is the difference between angina and an MI?

Angina is chest pain, tightness, or discomfort that comes and goes. It gets worse with activity or stress. It gets better with rest, medicine called nitroglycerin, or both. Angina does not damage the heart muscle, like an MI does. Angina may be a warning sign that you are at risk for an MI. Ask your healthcare provider for more information on angina.

What causes an MI?

  • Plaque , also called fatty deposits, can build up inside one or more of your coronary arteries. This can cause the arteries to become narrow and slow or block the blood flow. Small pieces can also break off and block blood flow.
  • Blood clots may form on each side of the plaque. This can slow or stop blood flow to your heart.
  • Heart spasm is when a coronary artery suddenly tightens and stops blood flow to part of the heart muscle.

What increases my risk for an MI?

  • You have high cholesterol, diabetes, or high blood pressure.
  • You smoke cigarettes or chew tobacco.
  • A family member has had an MI.
  • You are a man older than 55.
  • You are a woman who has gone through menopause.
  • You use illegal drugs such as cocaine and methamphetamines.
  • You are obese.

How is an MI diagnosed?

Your healthcare provider will ask when your chest pain started, what it feels like, and if anything makes it better or worse. He will ask if you took nitroglycerin or other medicines. He will ask you about your medical history and if you have had these signs and symptoms before. You may need the following tests:

  • Blood tests can help healthcare providers know if your heart muscle has been damaged.
  • A chest x-ray is a picture of your lungs and heart. Healthcare providers use it to look for an enlarged heart or fluid in your lungs.
  • An EKG test records your heart rhythm and how fast your heart beats. It is used to check for damage to your heart.
  • An echocardiogram is a type of ultrasound. Sound waves are used to show the structure and function of your heart.
  • An angiogram is a procedure to look for blockage in your coronary arteries, such as plaque or blood clots. A thin tube called a catheter is placed into an artery, usually in your groin. Dye is put through the catheter, and x-ray pictures are taken of the blood flow. Tell healthcare providers if you have ever had an allergic reaction to contrast dye.

How is an MI treated?

  • Medicines may be given to help the coronary arteries open so your heart can get the blood it needs. Medicine may also help decrease pain, blood pressure, or control your heart rate. You may also need medicine to help thin the blood to keep clots from forming. This medicine makes it more likely for you to bleed or bruise. After a heart attack, you may also be given medicine to decrease the amount of cholesterol and plaque in your blood.
    • Do not take certain medicines without asking your healthcare provider first. These include NSAIDs, herbal or vitamin supplements, or hormones (estrogen or progestin).
  • Angioplasty is a procedure to open an artery blocked by plaque. A small tube with a balloon on the end is threaded into the blocked artery. Once the tube is in the artery, the balloon is filled with liquid. As the balloon fills, it presses the plaque against the artery wall so blood can flow through the artery more easily.

  • Coronary intravascular stent placement is also called coronary artery stenting. The stent is a small mesh wire that is inserted into an artery to keep it open so blood can flow through it.
  • Coronary artery bypass graft (CABG) surgery is also known as heart bypass surgery or open heart surgery. A CABG can improve blood flow to the heart by sending blood around a blocked part of an artery. This surgery may also decrease your risk of having an MI in the future.

What should I do if I think I am having an MI?

If you have chest pain for 2 to 3 minutes, stop what you are doing. If the pain does not go away immediately, take 1 dose of nitroglycerin as directed. Call 911 if your chest pain does not go away or gets worse within 5 minutes. Sit or lie down while you wait for the ambulance. You can take up to 2 more doses of nitroglycerin (5 minutes apart) if your chest pain does not go away.

What changes to my lifestyle may I need to make after an MI?

  • Go to cardiac rehabilitation as directed. This is a program run by specialists who will help you safely strengthen your heart and prevent more heart disease. This plan includes exercise, relaxation, stress management, and heart-healthy nutrition. Healthcare providers will also check to make sure any medicines you are taking are working. The plan may also include instructions for when you can drive, return to work, and do other normal daily activities.
  • Eat a heart-healthy diet. Get enough calories, protein, vitamins, and minerals to help prevent poor nutrition and promote muscle strength. You may be told to eat foods low in cholesterol or sodium (salt). You also may be told to limit saturated and trans fats. Eat foods that contain healthy fats, such as walnuts, salmon, and canola and soybean oils. Eat foods that help protect the heart, including plenty of fruits and vegetables, nuts, and sources of fiber.
  • Do not smoke. If you smoke, it is never too late to quit. Smoking increases your risk of another MI.
  • Exercise. Ask your healthcare provider about the best exercise plan for you. Exercise makes your heart stronger, lowers blood pressure, and helps prevent an MI. The goal is 30 to 60 minutes a day, 5 to 7 days a week. Ask your healthcare provider how often and how long to exercise.
  • Maintain a healthy weight. Ask your healthcare provider how much you should weigh. Ask him to help you create a weight loss plan if you are overweight.
  • Manage your stress. Stress may slow healing and lead to illness. Learn ways to control stress, such as relaxation, deep breathing, and music. Talk to someone about things that upset you.
  • Get a flu vaccine every year as soon as it is available. The vaccine will help prevent the flu. Ask about other vaccinations you may need.

When should I contact my healthcare provider?

  • You have trouble taking your heart medicine.
  • You have questions or concerns about your condition or care.

When should I seek immediate care or call 911?

  • You have any of the following signs of a heart attack:
    • Squeezing, pressure, or pain in your chest that lasts longer than 5 minutes or returns
    • Discomfort or pain in your back, neck, jaw, stomach, or arm
    • Trouble breathing
    • Nausea or vomiting
    • Lightheadedness or a sudden cold sweat, especially with chest pain or trouble breathing
  • You are tired and cannot think clearly.
  • Your heart is beating faster than usual.
  • You are bleeding from your gums or nose.
  • You see blood in your urine or bowel movements
  • You urinate less than usual or not at all.
  • You have new or increased swelling in your feet or ankles.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

© 2017 Truven Health Analytics Inc. Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes. All illustrations and images included in CareNotes® are the copyrighted property of A.D.A.M., Inc. or Truven Health Analytics.

The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.