Heart attacks pose a serious health risk and can be life-threatening. They occur when a blockage in the coronary arteries disrupts blood flow to the heart, which can cause permanent damage.

Three types of coronary artery disease can lead to a heart attack. These are:

  • ST segment elevation myocardial infarction (STEMI)
  • non-ST segment elevation myocardial infarction (NSTEMI)
  • coronary artery spasm

In this article, we describe these three types of disease, their risk factors, and how they are treated.

What is a heart attack?

There are different types of heart attacks
A heart attack occurs when a blockage develops in the coronary arteries.

The coronary arteries carry blood to the heart, allowing it to function. A heart attack, also known as a myocardial infarction, occurs when a blockage develops in the coronary arteries and restricts the flow of blood to the heart.

Blockages occur when fat, cholesterol, and other substances build up, forming deposits called plaques in blood vessels. These plaques can become damaged over time and may release platelets.

Platelets can cause the blood to clot. They may collect around a plaque, eventually blocking blood flow.

By restricting blood flow, these blockages can damage the heart muscle. The severity of damage will depend on the size of the blockage. When blood is not reaching a significant segment of the heart, the damage will be more extensive.

A cardiac arrest is often mislabelled as a heart attack. However, a cardiac arrest occurs when the heart abruptly stops working.

Types

A heart attack results from one of the following types of coronary artery disease:

STEMI

A STEMI heart attack is severe and requires immediate attention.

These attacks occur when the coronary artery is fully blocked, preventing blood from reaching a large area of the heart. This causes progressive damage to the heart muscle, which can eventually stop it from functioning.

NSTEMI

NSTEMI heart attacks occur when the coronary artery is partially blocked and blood flow is severely restricted. While they are less dangerous than STEMI heart attacks, they can cause permanent damage.

Coronary artery spasm

These spasms are also called silent heart attacks or unstable angina. They occur when the arteries connected to the heart contract, preventing or restricting blood flow to the heart.

Symptoms do not cause permanent damage, and they are less severe than those of other types of coronary artery disease.

It is possible to mistake a coronary artery spasm for a minor condition, such as indigestion. However, having a coronary artery spasm can increase the risk of having a more severe heart attack.

Treatment

Oxygen therapy can be administered as treatment for all types of heart attacks
Oxygen therapy will often be administered in the immediate aftermath of a heart attack.

Regardless of the cause, all heart attacks require immediate medical attention. The treatment used will depend on the type of coronary artery disease.

In most cases, medical professionals will administer immediate treatment before determining the type or severity of the attack. This treatment may involve:

  • aspirin to reduce further blood clotting
  • oxygen therapy
  • nitroglycerin to support blood flow
  • efforts to reduce chest pain

Once a doctor has determined the type of heart attack, more treatment is needed to stimulate blood flow. When the underlying coronary artery disease is less severe, this can be done using medication, such as:

  • Clot busters, also known as thrombolytic medicines, which help to dissolve the blood clots causing blockages
  • Blood thinners, also known as anticoagulants, which prevent further clotting.
  • Blood pressure medications, such as ACE inhibitors, which help to maintain healthy blood flow and reduce pressure.
  • Statins, which can lower low-density lipoprotein cholesterol.
  • Beta-blockers, which can reduce the heart’s workload and chest pain.

Doctors may also perform a percutaneous coronary intervention. This involves inserting a thin tube, or catheter, into the narrowed or blocked coronary artery. The end of the tube is inflated, creating more space in the artery, so that more blood can reach the heart.

In some cases, a stent will also be inserted during the procedure. This small metal device is designed to prevent future blockages.

Surgery may be necessary in severe cases. The most common type is a coronary artery bypass, which involves moving a blood vessel from elsewhere in the body to the blocked artery. The added vessel will allow blood to flow around the blockage and reach the heart.

Recovery

Recovery can vary significantly, depending on the type of heart attack, its severity, and how it was treated.

A person can often return to normal activities within a week. However, when the underlying coronary artery disease was more severe, it may take months to recover from a heart attack.

Following any kind of heart attack, a doctor will often recommend cardiac rehabilitation, which can teach a person to maintain a healthful lifestyle and minimise the risk of another attack. Changes to levels of physical activity and diet may be suggested.

Risk factors

High blood pressure puts a person more at risk of all types of heart attacks
High blood pressure may increase the risk of a heart attack.

Some people may be more vulnerable to heart attacks. Common risk factors include:

  • high blood pressure
  • obesity or being overweight
  • a poor diet, particularly one high in trans or saturated fats
  • low levels of physical activity
  • smoking tobacco
  • older age
  • diabetes or high blood sugar levels
  • a family history of heart disease

Prevention

A person can lower their risk of having a heart attack by:

  • exercising for at least 150 minutes per week
  • reducing stress
  • not smoking
  • eating a diet rich in vegetables, fruits, whole grains, legumes, nuts, and oily fish
  • maintaining a healthy weight

Heart attacks are not always preventable because genetics is a factor. However, with simple lifestyle changes, a person can take significant steps toward reducing their risk.