NSTEMI is a non-ST-elevation myocardial infarction, a heart attack that frequently happens when your heart doesn’t get enough oxygen. ST-elevation myocardial infarction doesn’t cause any specific recognizable change to the heart’s electrical activity. NSTEMI is a life-threatening emergency condition and requires immediate medical attention. 

Myocardial infarction is a lack of blood flow to a portion of your body and affects the heart muscle. Your heart muscle begins to die in the damaged area due to insufficient blood flow.

An ECG is a simple test that can quickly identify your heart’s electrical activity. This test measures your heart’s electrical activity using several sensors (often 10) affixed to your skin. The electrical activity is displayed as a wave pattern on a digital display or a paper printout.

Call 911 instantly if you appear to be experiencing a heart attack. Delaying medical attention can put you at serious risk for death or irreversible cardiac damage.

When the ST section of the wave rises above average, a STEMI heart attack is identified. A STEMI heart attack typically results from a complete blockage or obstruction of one of the major coronary arteries, which delivers blood to your heart muscle. NSTEMI, which typically results from a partial or limited coronary artery blockage or blockage in a branch of the primary coronary artery, can occur in people with heart attack symptoms but no ST elevation. Although some electrical pattern abnormalities are frequently seen with NSTEMI, they are often not as noticeable; doing other tests are far more crucial in diagnosing NSTEMI.

Causes of NSTEMI:

The acute coronary syndrome includes three disorders that reduce blood flow to the heart; NSTEMI is one of its subtypes. The other two conditions are unstable angina and STEMI (sudden or frequent chest pain due to lack of blood flow, frequently during resting, but not as harmful or threatening as a heart attack).

Ischemia, pronounced “is-key-me-uh,” is a condition that develops when there isn’t a constant flow of blood. That indicates that the damaged area of your heart begins to die due to not receiving enough blood. In contrast to other muscles, your heart muscle cannot develop or regenerate. That means the injury will be irreversible if the blood flow is not quickly restored.

NSTEMI can occur due to direct or indirect factors, such as those listed below.

Direct causes of NSTEMI:

Several circumstances might directly decrease the blood flow to your heart.

  • Plaque: 

The wax-like substance is a result of blood cholesterol. Plaque accumulation can impede blood flow to your heart; in many ways, a clogged pipe might lead to a slow drain. Blood clots can form on eroded or broken plaques in your arteries, which can quickly constrict or block your artery (over minutes to hours).

  • Vasospasm: 

Your blood arteries have a smooth muscular lining that regulates how thin or wide they are. The muscle lining of your heart’s arteries can also cramp or spasm, much like the muscles in your legs or back do. This condition, called vasospasm, can restrict or obstruct blood flow and cause a heart attack. These are unusual.

  • Coronary embolism:

The blood clot partially or entirely restricts blood flow to your heart by becoming lodged in one of the arteries. These are incredibly uncommon.

  • Injury or trauma to the heart: 

The damage is still possible even if your heart is surrounded and shielded by your rib cage and other structures. NSTEMI’s injury-related causes are:

  • Myocarditis:

It is an inflammation of your heart’s muscle. One potential reason for your heart muscle being affected by an illness (often viral).

  • Toxins and poisons:

Certain drugs can harm the heart muscle and have toxic consequences, resulting in a heart attack. In general, this is unusual. Carbon monoxide poisoning is the most frequent cause of this.

  • Cardiac bruising:

A bruise is a contusion; bruising your heart muscle can result in swelling and an NSTEMI. These are uncommon and typically only occur with severe injuries, such as those from auto accidents.

Indirect causes of NSTEMI:

Several illnesses might obstruct the flow of blood and oxygen to your cells. An NSTEMI can occur when your body cannot produce enough blood to fulfill the demand. The circumstances that affect blood supply are:

  • Low blood pressure and extremely high blood pressure are also referred to as “malignant hypertension” or “hypertensive emergencies” (hypotension). Your heart naturally pumps more forcefully in response to low blood pressure. Your blood arteries may have higher blood flow resistance, resulting in high blood pressure. Your heart works harder in both scenarios, requiring more blood flow to keep up that level of effort.
  • Tachycardia (fast heart rate). Your heart becomes less effective and pumps less blood when it beats partially or entirely too quickly. Additionally, the cardiac muscle might require more oxygen than the blood flow can deliver.
  • Arterial stenosis. The aortic valve, the final valve blood passes through before leaving the heart, is narrowed in this illness. The heart muscle in persons with severe aortic stenosis must work extremely hard to compensate for the constriction and may require more oxygen than the blood flow can supply.
  • Respiratory embolism. It occurs when a blood clot lodges or groups in the lungs, preventing blood from passing through and absorbing oxygen before returning to the heart and leaving the body.

Symptoms of the NSTEMI:

People experiencing a heart attack usually mention the following signs:

  • Chest pain (angina).
  • Breathing difficulties or feeling out of breath
  • Nausea
  • Abdominal pain
  • Discomfort (may feel like indigestion or heartburn).
  • Heart flutters (the unpleasant feeling of your heartbeat; it may also feel like your heart is skipping or adding extra heartbeats).
  • Feeling faint, dizzy, or lightheaded.

Diagnosis of NSTEMI:

Based on a combination of tests and information gathered from other sources, a doctor can identify an NSTEMI. Since an NSTEMI is more likely to present with symptoms or test results that are less specific than those found with STEMI or other disorders, combining these approaches is crucial.

A direct examination is the initial stage of this procedure, during which a doctor listens to your heart and respiration, examines your blood pressure, and does other techniques. They will also compile a “patient history,” which contains information on your present way of life, current circumstances, and medical history, assuming you are healthy and able to respond to inquiries. The following tests are done to diagnose the NSTEMI;

  1. Electrocardiogram 
  2. Lab tests
  3. Echocardiography
  4. CT scan (computer tomography)
  5. MRI (magnetic resonance imaging)

Risk factors of NSTEMI:

Several risk factors can impact your likelihood of having a heart attack.

Things that you can control:

Your lifestyle choices are the things you have the most control over. These consist of:

  1. Using tobacco and smoking.
  2. Diet, particularly how much salt (blood pressure), sugar (diabetes), or fat you consume (cholesterol).
  3. The extent of your physical activities.
  4. Drug usage for fun (especially stimulants like amphetamines, cocaine, or other medications that affect your heart). 

Things that you can’t control:

    1. Age. Your risk of suffering a heart attack varies with age. The danger increases as you become older.
    2. Sex. Men typically experience heart attacks sooner than women. Men’s risk increases at age 45, while women’s risk increases at age 50 (or after you reach menopause, whichever is first).
  • Family background. If your mother, sister, or father were diagnosed with heart disease or had a heart attack before age 65, your risk increases sooner.
  1. Inherited conditions exist from birth. A heart attack can also increase your chance of having specific medical illnesses or disorders that impact other bodily systems. It covers both congenital (existing at birth) and genetic (inherited) diseases.

Prevention of NSTEMI:

You can take some different steps to help prevent or, at the very least, delay a heart attack. Scheduling a physical with your doctor, often known as a checkup or wellness visit, is essential.

Many medical disorders, including diabetes and high blood pressure, don’t show symptoms until they are highly advanced. However, these problems can harm your heart and coronary arteries over time before symptoms show, dramatically raising your risk of suffering a heart attack. But with quick, non-invasive tests performed during your yearly appointment, many diseases can be easily detected early on. If your doctor discovers potential issues or worries, they can provide advice and resources. The following are some of the most acceptable preventative measures;

  • Maintain a healthy weight.
  • Maintaining a healthy diet (your healthcare provider can recommend diets like the Mediterranean diet that work exceptionally well for heart health).
  • Maintaining an active lifestyle (at least 150 minutes per week of moderate-intensity exercise).
  • Taking care of existing medical issues. Make sure to continue taking all prescribed drugs precisely if you take them for any conditions.
  • Quitting will be especially beneficial in preventing a heart attack if you use tobacco in any way, including vaping goods.

Treatment of NSTEMI:

All heart attacks require prompt treatment, and the sooner blood flow is restored, the better. If your blood oxygen levels are less, oxygen may be helpful, but this varies from person to person. Some numerous additional therapies and methods can be used, some sequentially and others concurrently.

Percutaneous coronary intervention (PCI):

In a percutaneous coronary intervention process, an interventional cardiologist places a catheter device into a significant blood vessel somewhere in your body (wrist or near the upper thigh). They then thread that apparatus up to your heart and the problematic artery. When they arrive, they blow up a balloon at the device’s tip to aid in unclogging the obstruction. It is also possible and typical during PCI to install stents, which use a scaffold-like structure to help keep the blood vessel open.

PCI functions best when completed as soon as possible.

Coronary artery bypass grafting (CABG):

Surgery may be preferable to restore blood flow if one or more of your heart’s arteries are significantly narrowed or blocked. The procedure is called coronary artery bypass grafting, or CABG for short (pronounced “cabbage”). It also goes by the terms open heart surgery or bypass surgery. The surgeon removes a blood artery from another part of your body during CABG (maybe from your legs or the inside of the chest wall). They then use that blood vessel to make a bypass around the blocked artery in your heart (or arteries). It enables blood to “bypass” the problematic location.

Medications:

Several drugs can aid people with a heart attack (some of which you’ll take before the diagnosis is confirmed). These are:

  • Aspirin or additional antiplatelet drugs:

These medications prevent platelets from congregating and creating blood clots. It is crucial because it prevents clot-based obstructions from deteriorating further.

  • Anticoagulants: 

These interfere with clotting similarly to antiplatelet drugs, but they do so by interfering with the actual clotting procedure rather than the platelets.

  • Inhibitors of the angiotensin-converting enzyme (ACE): 

These drugs prevent your body from naturally converting a protein that increases blood pressure. Your blood pressure is lowered by stopping that process. You are more likely to use these medications if you have diabetes, high blood pressure, kidney disease, or heart failure. 

  • Beta-blockers: 

These drugs lower your heart rate and lessen the force it pumps. Both impacts are crucial because they reduce how hard your heart has to work, which lowers the amount of oxygen your body needs. If you have illnesses like low blood pressure, heart failure, or specific heart rhythm issues, these drugs might not be an option for you (arrhythmias).

  • Nitroglycerin: 

The medication’s tendency to expand blood vessels improves blood flow. It indicates that this medication works exceptionally well to relieve chest pain brought on by poor blood flow.

  • Statins: 

These drugs lower blood cholesterol levels and lessen the possibility of worsening coronary artery plaque.

References:

https://my.clevelandclinic.org/health/diseases/22233-nstemi-heart-attack

https://pubmed.ncbi.nlm.nih.gov/22624277/

https://www.baptisthealth.com/services/heart-care/conditions/non-st-elevation-myocardial-infarction

https://www.ncbi.nlm.nih.gov/books/NBK513228/

https://www.healthline.com/health/nstemi