Types of Heart Attacks: Risk Factors, Causes, and Prevention

According to The World Health Organization (WHO), cardiovascular diseases (CVD) account for 17.9 million deaths globally, making it the number 1 cause of death. A majority of deaths are due to CVDs are due to heart attack and stroke. When compared to AIDS, tuberculosis, and malaria, CVDs are responsible for 46 times the overall causes of death and 11 times the burden of disease. In this article, we discuss the different types of heart attacks and what you can do to prevent them. 

Normal heart function

A healthy heart functions with a sequence of coordinated contractions of the heart that send deoxygenated blood to the lungs, which later send oxygenated blood throughout the body. A powerful organ such as the heart, capable of sending blood to distant organs throughout the entirety of one’s lifespan, also requires a constant flow of oxygen-rich blood for it to function. This is the responsibility of the coronary arteries, which also receive their blood flow from the heart. 

What is a heart attack?

A heart attack occurs when the coronary arteries become blocked and a section of the heart muscle does not receive blood (including oxygen and nutrients).

In cases such as this, if blood flow is not adequately and promptly restored, the affected section of heart muscle will die, a condition called myocardial infarction (MI).

Patients suffering from a myocardial infarction can manifest symptoms such as chest discomfort (With or without difficulty of breathing), nausea, nausea, lightheadedness or sudden dizziness, fatigue without previous exertion, and diaphoresis (cold sweat).

What causes a heart attack?

Most heart attacks are due to ischemic heart disease, a condition where the coronary arteries are blocked and cannot provide oxygenated blood to sections of heart muscle. This is due to plaque build up within the inner lining of coronary arteries, a condition with the name of atherosclerosis, which may take several years to produce symptoms.

As time goes on, the plaque will harden and eventually rupture, causing blood clots to form at the site of injury. As a result, the artery narrows even further, thus reducing blood flow to the specific section of heart muscle.

Having atherosclerosis also predisposes coronary arteries to be hyper-reactive and this may lead to coronary artery spasms (a less common cause of heart attacks), which is a series of severe spasms (contractions or narrowing) of a coronary artery that may reduce or completely obstruct blood flow.

These usually occur at sites affected by atherosclerosis. Atherosclerotic arteries are usually prone to spasms. Coronary artery spasms usually triggered by certain drugs such as the stimulant cocaine, emotional stress or pain, tobacco use, and exposure to extremely cold environments.

Types of heart attacks

Acute coronary syndrome refers to three types of coronary artery disease related to the mechanism of a heart attack.

Here are three types of heart attacks to watch out for:

ST Elevation Myocardial Infarction (STEMI)

Among the types of heart attacks, STEMI is a major one that occurs when the coronary artery is completely blocked. On an electrocardiogram, this will present as a ST-segment elevation.These usually occur at sites affected by atherosclerosis. Atherosclerotic arteries are usually prone to spasms. 

Non-ST Elevation Myocardial Infarction (NSTEMI)

In NSTEMI, affected coronary arteries are partially blocked. On an electrocardiogram, these do not present with ST-elevation, but there will likewise be elevations of cardiac enzymes (marker of cardiac injury).

Unstable Angina

This refers to the type of coronary artery syndrome that is due to a coronary spasm. It is not as common as the other two types of heart attacks.

Risk factors for heart attacks

Aside from knowing the types of heart attacks, it’s also important to know what predisposes us for it in the first place. There are several major risk factors in the development of a heart attack:

Modifiable risk factors

• Cigarette smoking
• High cholesterol
• Hypertension
• Obesity
• Physical inactivity
• Diets high in saturated and trans fat, cholesterol, and sodium
• Diabetes or insulin resistance

It is important to note that patients with a combination of obesity, hypertension, and diabetes have a condition termed “Metabolic Syndrome” and are twice as likely to develop cardiovascular disease.

Non-modifiable risk factors:

The following are non-modifiable risk factors of the different types of heart attacks.

• Age. In particular, men older than 45 years and women older than 55 years (or after menopause) are prone to developing heart disease.
• Preeclampsia (in pregnant women). This is hypertension that occurs during pregnancy with excess protein seen in the urine. Preeclampsia puts the patient at an increased risk for the development of heart disease.
• Previous family history of early onset heart disease. Patients with a family history of early onset heart disease are at an increased risk for developing cardiovascular disease.
• Certain infections such as COVID-19. Although still being studied, COVID-19 infection may affect the heart.

How to prevent a heart attack

Preventing the different types of heart attacks involves decreasing exposure to risk factors and controlling pre-existing conditions. This requires lifestyle modifications such as increasing physical activity, avoiding food high in cholesterol, fat, and salt, and losing weight.

Patients with comorbidities such as diabetes, hypertension, or hypercholesterolemia should consult their doctors on how to manage these conditions. 

Learn more about Heart Health here.