A heart attack can be frightening and confusing. Discovering you had a heart attack prompts a multitude of questions. It is essential that you understand the type of heart attack that you suffered from, as well as the potential cause.
In this article, you’ll learn the two major types of heart attack and their differences. We will also focus on the standard methods of treatment. Being informed can empower you to make confident decisions about your heart health moving forward.
What is a Heart Attack?
A heart attack is known as a myocardial infarction (MI). An MI occurs when blockages in the arteries of your heart cause decreased blood flow to the heart muscle. Reduced blood flow causes heart muscle damage. These blockages consist of cholesterol and fat, called plaque. Plaque adheres to the walls inside of your coronary arteries. When plaque breaks off, a clot forms in the vessel.
What causes plaque to form in the first place? The answer is coronary artery disease (CAD). Did you know about 20.5 million U.S. adults have coronary artery disease? CAD is the most common type of heart disease in the United States. The four major risk factors for developing CAD are:
Obesity
Lack of physical inactivity
Unhealthy eating
Smoking
CAD can also be genetic, and if you have a family history of it, there is a chance you can develop it as well. CAD is preventable and treatable using medications prescribed by a doctor or by lifestyle and diet modifications.
Now that you know what causes an MI, you can learn about the different types of MI. MI’s consist of two major groups. Let’s discuss them and make them easy to understand.
What is a Type 1 MI?
Coronary artery disease is the cause of a Type 1 MI. The severity of the blockage in the artery determines what form of Type 1 MI you are diagnosed with. A Type 1 MI consists of two distinct forms:
STEMI (ST elevation MI)
NSTEMI (Non-ST Elevation MI)
STEMI
STEMI is the first form of Type 1 MI. This form of MI consists of 100% blockage of one or more coronary arteries supplying blood to your heart muscle. A STEMI will be evident on an EKG. When your provider performs an EKG, the result will show elevations of the ST segment.
Your provider will also order a Troponin level. Troponin is a protein that, when found in the blood, reflects damage to the heart muscle. When your provider diagnoses a STEMI, emergent intervention is required. Treatment of a Type 1 MI requires restoring blood flow to the vessel, achieved by cardiac catheterization.
The cardiologist will access the coronary artery through a larger artery in your arm or leg and use a catheter to place a stent inside the culprit coronary artery, restoring blood flow. Your provider will likely prescribe medications, if not contraindicated, such as:
Anticoagulants
Antithrombotics
Beta-blockers or ACE-inhibitors
Nitrates
Antiplatelets
After emergent treatment, you will work closely with your cardiology team to address underlying risk factors, such as diet modification, lifestyle changes, and smoking cessation.
NSTEMI
NSTEMI is the second form of Type 1 MI. It results from a partial coronary artery blockage preventing blood from reaching the heart muscle. An NSTEMI is diagnosed similarly to a STEMI, except your EKG will not show ST elevation.
You may still require intervention, but it is less time-sensitive than a STEMI. You might undergo cardiac catheterization and stent placement. However, this is not definite in 100% of cases.
Your provider will likely also prescribe some or all of the medications previously mentioned, such as an anticoagulant, antithrombotic, aspirin, beta-blocker, ACE inhibitor, nitrates, and antiplatelets.
What is a Type 2 MI?
A Type 2 MI is the result of an ischemic imbalance. Your heart is not receiving the oxygen needed to function correctly. Coronary artery disease does not play a role in this form of MI. A Type 2 MI results from processes occurring elsewhere in the body. These processes decrease the amount of oxygen sent to your heart, not a blockage. This lack of oxygen is known as an oxygen supply and demand mismatch.
Some causes of supply and demand mismatch of oxygen to your heart can include, but are not limited to:
Congestive heart failure
Severe anemia
Kidney Disease
Hypoxia
Hypotension
Tachycardia
Coronary artery spasm
Treatment of a Type 2 MI requires correcting the underlying cause of the oxygen supply and demand mismatch.
For example, if you present to the hospital with atrial fibrillation with a very high heart rate, this could cause Type 2 MI. To treat Type 2 MI, your provider will need to treat the cause of it, which would be correcting your heart rate back to a normal range.
How are they Different?
The primary difference between Type 1 and Type 2 MI is coronary artery disease (CAD). CAD is involved in Type 1 MI but not in Type 2 MI. This fundamental distinction influences the way your provider treats both forms of MI.
Treatment for a Type 1 MI usually consists of invasive cardiac catheterization to restore blood flow to the affected vessel. A Type 2 MI does not require this, as there is no blockage present inside the vessel.
Treatment for a Type 2 MI involves correcting the underlying cause. If you have another disease process at play, your provider will aim to control this so that your Type 2 MI will improve.
In Summary
Type 1 MI occurs when one or more coronary arteries become obstructed due to plaque formation. Type 2 MI results from a decreased amount of oxygen reaching the heart.
Treatment for Type 1 MI will be restoring blood flow to the affected area. Type 2 MI is treated by correcting the underlying cause of oxygen imbalance. Understanding the fundamental differences between the forms of MI is crucial so that you can play a role in managing your health with your treatment team.
References
Akbar H, Foth C, Kahloon RA, et al. Acute ST-Elevation Myocardial Infarction. [Updated 2023 Jul 31]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK532281/
Basit, H., Malik, A., & Huecker, M. R. (2023, July 10). Non–ST-Segment elevation myocardial infarction. StatPearls - NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK513228/#:~:text=NSTEMI%20is%20diagnosed%20in%20patients,absence%20of%20detectable%20troponin%20leak.
Coronary Artery Disease | Cdc.gov. (2021, July 19). Centers for Disease Control and Prevention. https://www.cdc.gov/heartdisease/coronary_ad.htm#:~:text=Coronary%20artery%20disease%20is%20caused,arteries%20to%20narrow%20over%20time.
Diagnosing Type 2 myocardial infarction - American College of Cardiology. (2016, May 18). American College of Cardiology. https://www.acc.org/latest-in-cardiology/articles/2016/05/18/13/58/diagnosing-type-2-myocardial-infarction
Troponin test. (2023). https://medlineplus.gov/lab-tests/troponin-test/
What is coronary heart disease? | NHLBI, NIH. (2023, December 20). NHLBI, NIH. https://www.nhlbi.nih.gov/health/coronary-heart-disease
What is a Heart Attack? (2024, January 9). www.heart.org. https://www.heart.org/en/health-topics/heart-attack/about-heart-attacks Assessed and Endorsed by the MedReport Medical Review Board
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