A non-ST-elevation myocardial infarction (NSTEMI) is a type of heart attack that usually happens when your heart’s need for oxygen can’t be met. This condition gets its name because it doesn’t have an easily identifiable electrical pattern (ST elevation) like the other main types of heart attacks.
A non-ST-elevation myocardial infarction is a type of heart attack that happens when a part of your heart is not getting enough oxygen. This condition gets its name because — unlike an ST-elevation myocardial infarction (STEMI heart attack) — it doesn’t cause a very specific, recognizable change to your heart’s electrical activity.
Any heart attack, including an NSTEMI, is a life-threatening medical emergency and needs care immediately. If you or someone you’re with appears to be having a heart attack, call 911 (or the local emergency services number for your area) right away. Delaying medical care can be extremely dangerous and can lead to permanent heart damage or death.
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The medical term for a heart attack is myocardial infarction. An infarction is a lack of blood flow to a part of your body, and myocardial means it’s happening in your heart muscle. Without enough blood flow, the affected part of your heart muscle starts to die.
Your heart’s electrical activity is easily detectable by a test called an electrocardiogram. That test uses several sensors (usually 10) attached to your skin to detect your heart’s electrical activity. It then shows the electrical activity as a wave pattern on either a paper printout or a digital display. The wave pattern is also broken down into segments, with each part of the wave labeled with a letter of the alphabet from P to U.
STEMI heart attacks are diagnosed when part of the wave, the ST segment, rises higher than normal. In most cases, a STEMI heart attack happens because of a total blockage of one of the main coronary arteries that provide blood flow to your heart muscle. People with symptoms of heart attack who don’t have ST elevation could have an NSTEMI, which usually happens because of a partial coronary artery blockage or blockage in a branch off of your main coronary artery. Some electrical pattern changes are often visible with NSTEMI, but they’re often not as distinctive, making other tests much more important in diagnosing NSTEMI.
Several risk factors can increase your chances of a heart attack. Some of those factors can be modified, while others can’t.
The factors you can manage most are your lifestyle choices. These include:
Acute coronary syndrome (including NSTEMI) is very common in the United States. An estimated 780,000 cases of acute coronary syndrome are diagnosed each year. About 70%, or approximately 546,000, of those cases, are NSTEMIs.
NSTEMI is a type of acute coronary syndrome, which is an umbrella term for three conditions that cause a lack of blood flow to your heart. The other two conditions are STEMI and unstable angina (sudden chest pain from lack of blood flow, usually while resting, but not as dangerous as a heart attack).
Without a steady supply of blood, a problem called ischemia (pronounced iss-key-me-uh) happens. That means the affected part of your heart starts dying because it isn’t getting enough blood. Unlike other muscles, your heart muscle can’t regenerate or regrow. That means the damage will be permanent without quick restoration of blood flow.
NSTEMI can happen because of direct or indirect causes, including those listed below.
Several conditions can directly reduce your heart’s blood supply.
Though your rib cage and other structures surround and protect your heart, injuries are still possible. Injury-related causes of NSTEMI include:
Several conditions can interfere with your body’s ability to supply blood and oxygen to your cells. When your body can’t supply enough blood to meet the demand, this can cause an NSTEMI. Conditions that disrupt blood supply include:
People having a heart attack commonly describe these symptoms:
While women may experience any of the symptoms described above, they’re less likely to report symptoms of discomfort that feel like indigestion or pain in the center of their chest. They’re also more likely to report the following symptoms:
A physician diagnoses an NSTEMI based on a combination of tests and other types of information gathering. Combining these methods is especially important because an NSTEMI is more likely to have symptoms or test results that are less specific than those seen with STEMI or other conditions.
The first step in this process is a direct examination, where a healthcare provider listens to your heart and breathing, checks your blood pressure and more. Then, if you’re medically stable and can answer questions, they’ll also gather a “patient history,” which includes details about your current lifestyle, personal circumstances and your medical history.
A heart attack diagnosis can involve the following tests.
Electrocardiogram (EKG or ECG)
An electrocardiogram is one of the most important ways to diagnose a heart attack. As described earlier, this test detects your heart’s electrical activity and shows it as a wave. A heart attack can cause changes in the pattern that trained medical professionals can interpret and use for a diagnosis.
Where a STEMI causes the ST segment of the wave to be consistently taller, that doesn’t happen with an NSTEMI. Instead, the following changes may — but don’t always — show up on an EKG:
When there’s damage to your heart muscle cells or they die for any reason, they release a unique chemical called troponin. That chemical is detectable with blood tests, making those tests one of the most reliable ways to diagnose any kind of heart attack. However, it might be necessary to repeat a troponin test because it can take time to reach detectable levels (usually fewer than six hours).
Using imaging tests may also help with a diagnosis, especially if earlier tests were inconclusive. Some of these tests may involve exercise to try to provoke symptoms that were undetectable when you were resting.
Some of the most common imaging tests used include:
Treatment of all heart attacks is time-sensitive, and the faster the restoration of blood flow happens, the better. Oxygen may help if your blood oxygen levels are low, but this varies from person to person. Several other treatments and techniques are possible, some of them in sequence or at the same time.
Percutaneous coronary intervention is a procedure where an interventional cardiologist inserts a catheter device into a major blood vessel somewhere in your body (usually in your wrist or near your upper thigh). They then thread that device up to your heart and your artery in question. Once there, they inflate a balloon at the device’s tip, helping clear the blockage. Stent placement, which uses a scaffold-like device to help hold the blood vessel open, is also possible and common during PCI.
PCI works best when done sooner rather than later.
Several medications (some of which you’ll take before diagnosis confirmation) can help people who are having a heart attack. These include:
In cases where one or more of your heart’s arteries has significant narrowing or blockage, surgery may be a better option to restore blood flow. This surgery is known as coronary artery bypass grafting (often shortened to CABG, pronounced “cabbage”). Its other names include bypass surgery or open-heart surgery.
During CABG, a surgeon takes a blood vessel from somewhere else in your body (such as one of your legs or the inside of your chest wall). They then use that blood vessel to create a bypass around your heart’s blocked artery (or arteries). That allows blood flow to “bypass” the problem area.
There are several things you can do to help prevent a heart attack, or at least delay one. One key thing is to schedule a physical (also called a checkup or wellness visit) with your primary care provider.
Many health conditions — such as high blood pressure and diabetes — don’t cause symptoms until they’re very advanced. Before symptoms appear, however, these conditions can cause ongoing damage to your heart and coronary arteries, and greatly increase your risk of having a heart attack. But these conditions are easily detectable early on with simple, non-invasive tests done during your yearly visit. Your healthcare provider can also offer guidance and resources if they do find any potential problems or concerns.
Some of the best things you can do to avoid a heart attack include:
Unfortunately, some people may experience a heart attack even if they take all these preventive steps, particularly if they’re prone to heart attacks due to family history or another condition. However, you may be able to postpone when you have a heart attack or make it less severe if you follow the above guidelines. Being in good health also tends to make recovery easier and improves your overall outlook after a heart attack.
The length of your hospital stay depends on several factors, including the severity of your heart attack, your overall health, the treatments you underwent and more. The average hospital stay is between two and seven days, with PCI having shorter stays and surgeries having longer stays.
Your symptoms should start diminishing while you’re receiving treatment. Many people experience some weakness or fatigue after a heart attack, but these often go away within several days. Your healthcare provider will also advise you on your need for rest and recovery.
The outlook for an NSTEMI depends on several factors. The severity of your heart attack and your overall health may change your outlook greatly. Your healthcare provider is the best person to explain what you should expect, as well as any problems you should watch for or things to avoid.
If you’ve had a heart attack, your odds for having another go up. Follow-up care and preventive measures are important to avoid having another heart attack, so your healthcare provider will likely offer you some options, including:
The timeline of your recovery depends on your particular health situation and is something your healthcare provider is best prepared to explain. Talk to them and ask them questions about goals you can set and when you can resume certain activities such as driving, exercise, etc. Following their guidelines is the best way to pace yourself and ensure you don’t have any problems on the road to recovery.
Many of the tips listed above under the Prevention section are also good for helping take care of yourself after a heart attack. Focusing on diet and exercise, maintaining a healthy weight, managing other health conditions and going to your follow-up visits are all very important steps.
Your healthcare provider will advise you on what sort of issues or concerns to watch for and when you should contact them. They’ll also explain when you need medical attention immediately. You should contact your healthcare provider if you experience any new symptoms or your existing symptoms change, too, especially if the changes are sudden or they begin interfering with your life.
You should go to the hospital if you notice any sudden return of symptoms related to your heart or if symptoms unexpectedly worsen. Main symptoms meaning you need immediate medical attention include:
You shouldn’t drive yourself to the hospital if you think you’re having a heart attack because that puts you at risk in several different ways. There are also advantages to calling emergency services if you think you’re having a heart attack, including:
A note from Cleveland Clinic
Symptoms of a heart attack can be frightening and confusing. Fortunately, medical science has made great advances in improving the diagnosis and treatment of heart attacks. Treatment techniques, medication options and science’s understanding of the heart itself are always moving forward, which means your chances for a good outcome are always getting even better. If you or a loved one are experiencing symptoms of a heart attack, call for medical help immediately.
Last reviewed by a Cleveland Clinic medical professional on 12/28/2021.
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