What Is a Non-ST-elevation Myocardial Infarction (NSTEMI)?

Medically Reviewed By Darragh O'Carroll, MD
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A non-ST-elevation myocardial infarction (NSTEMI) is a type of heart attack. It means the heart is getting some oxygen, but not enough. NSTEMIs can be less dangerous than a STEMI heart attack, but can still cause major complications. All heart attacks can be life threatening and having an NSTEMI heart attack could place you at risk for a more serious type of heart attack in the future. Risk factors for having any type of heart attack include smoking, being overweight or obese, having diabetes, high blood pressure, and a family history of heart problems, among other factors.

This article will provide more information about NSTEMI heart attacks, how doctors diagnose them, the outlook for an NSTEMI, and treatment.

What is an NSTEMI?

An older woman holding her chest
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Acute cardiac syndromes (ACS) occur when there is an inadequate supply of oxygen to meet the needs of the heart muscle. Factors like narrowed blood vessels, blood clots, fat plaques that collect on artery walls, or a combination of these can all lead to oxygen being cut off from the heart.

There are three forms of ACS, including NSTEMI:

  • Unstable angina: chest pain without electrocardiograph (ECG) changes or elevated cardiac enzymes that indicate cell death
  • NSTEMI: chest pain with elevated cardiac enzymes but without electrocardiographic (ECG) changes
  • STEMI: chest pain with both ECG changes and high cardiac enzymes

What are the symptoms of an NSTEMI?

Symptoms of an NSTEMI event may include but are not limited to:

  • chest pain, especially in the center or left side of your chest
  • shortness of breath
  • nausea or vomiting
  • sweating
  • pain radiating to the arms, jaw, or back
  • a feeling of pressure, as though something heavy is sitting on your chest

These classic symptoms are not always present. Sometimes people complain of vague, generalized symptoms such as:

  • dizziness/lightheadedness
  • weakness
  • upper abdominal pain

If you have other conditions that raise your risk of NSTEMI, or if you believe you are having an NSTEMI or another cardiac episode, call 911 immediately. This is an emergency condition.

Women may also experience different heart attack symptoms from men. If in doubt, seek care.

Click here to learn more about heart attack symptoms in females.

What are the causes of an NSTEMI?

Like other acute cardiac syndromes, conditions that negatively affect blood flow to the heart muscle can lead to an NSTEMI. These include, but are not limited to:

  • smoking
  • high cholesterol
  • diabetes
  • obesity and family history of obesity
  • lack of exercise
  • high blood pressure
  • a diet high in saturated fats and processed foods
  • substance use

How do doctors diagnose an NSTEMI?

Diagnosing NSTEMI is similar to diagnosing other types of acute cardiac syndromes. Your doctor may perform several tests that could include:

  • ECG, which will show your doctor what electrical activity changes are happening in your heart
  • blood tests, such as cardiac enzyme levels to confirm heart tissue death, a complete blood count (CBC) and basic blood chemistry, and lipase level and liver tests
  • chest X-ray, to give your doctor a visual image of your heart and rule out other causes

What are the treatments for an NSTEMI?

Treatment for NSTEMI is aimed at reestablishing blood flow to the heart muscle and preventing further damage. The best way to decrease the risk of an NSTEMI causing long-term complications is to get medical help as soon as possible.

If you are having symptoms you believe are related to a cardiac problem, you should seek medical attention right away.

Emergency care

Resuscitation or defibrillation may be necessary if your heart is not beating effectively. This may look like CPR or the use of a machine in the hospital to help beat your heart for you and circulate oxygen through the body.

Chest compressions circulate blood. Artificial respiration delivers oxygen to your lungs so that the blood can be oxygenated. However, studies suggest that supplemental oxygen should only be given to people with oxygen saturation levels below 90%. Defibrillation is the use of electrical pads or paddles that deliver a shock to your heart to stabilize heart rhythm.

Depending on your health history and other medications you take, your doctor may prescribe the following types of medications if you receive an NSTEMI diagnosis:

  • anticoagulants to prevent existing blood clots from getting larger
  • antiplatelet medications to prevent new clots from forming
  • pain medications
  • antihypertensives to lower blood pressure
  • medications that increase the effectiveness of your heart’s contractions
  • medications that dilate blood vessels such as nitroglycerin
  • medications that lower blood cholesterol

Hospital treatments

People with NSTEMI already have heart muscle damage, shown by elevated cardiac enzyme levels. Therefore, it is urgent that blood flow be restored to the heart muscle as soon as possible.

Your doctor will admit you to the hospital for ongoing care that could include treatments such as:

  • Cardiac catheterization/angiography: A doctor will place a catheter into your heart via one of the large arteries in your neck or groin. They may then place a stent, which is a small mesh tube, into the blocked coronary artery to keep it open. You may need more than one stent placed if multiple arteries are affected.
  • Coronary artery bypass graft (CABG): A cardiac or vascular surgeon will use pieces of healthy vein tissue to create a new pathway for blood to flow through. This bypasses the artery where the blockage is and restores blood flow.

How can you manage your condition after receiving treatment for an NSTEMI?

After you have been admitted to the hospital and even after your immediate treatment, your doctor will order ongoing management for your symptoms and to reduce the risk of future heart attacks.


As your condition stabilizes, your cardiologist will order further testing to track trends in laboratory values and may repeat ECG or imaging scans.

Medication management

You may be on medications that have a high risk of life threatening side effects like bleeding. Before discharge, your doctor will switch you to safer medications that give the same benefit.

Resuming activities

You may be referred to a cardiac rehab program designed to educate you about how to care for yourself, lower your risk of another heart attack, and improve your quality of life. One study from China showed that cardiac rehab results in better cardiovascular health.

Your doctor may suggest you wear an ambulatory monitor that can collect data about your heart’s function as you go about your day. These devices are shown to be reliable and user-friendly.

Can you prevent an NSTEMI?

If you have a history of a heart attack, your risk for another heart attack is higher. There are things you can do to lower your risk. These include:

  • eat a nutritious diet
  • exercise according to your doctor’s instructions
  • take any prescribed medications correctly
  • avoid smoking

If you have associated conditions like diabetes or high blood pressure, follow your doctor’s recommendations for managing those conditions as well.

Learning the signs and symptoms of acute cardiac syndrome saves lives. According to the American Heart Association (AHA), CPR can double or triple the survival rates for cardiac arrest. 350,000 cardiac arrest deaths occur in the United States each year.

By knowing the symptoms of a heart attack and taking a CPR class, you may be able to access emergency services faster or help someone else.


NSTEMI events can be both frightening and dangerous and should always be treated as an emergency. If you believe you or someone else is having an acute coronary event, activate emergency services immediately and be straightforward about your health and history.

Rapid diagnosis, treatment, and conscientious self-care can minimize damage and lower ongoing risks with an NSTEMI. Be diligent about your medications, diet, and exercise regimens, and work closely with your cardiac care team to promote your best heart health.

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Medical Reviewer: Darragh O'Carroll, MD
Last Review Date: 2022 Sep 28
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