What Causes a Heart Attack?

A heart attack, medically known as a myocardial infarction, happens when something blocks the blood flow in an artery (blood vessel) that feeds the heart. This lack of blood flow to the heart damages the heart muscle and can cause a heart attack, resulting in symptoms like chest discomfort, shortness of breath, and nausea.

Heart attacks are life-threatening and can lead to serious arrhythmias (abnormal heart rhythm) and heart failure. While atherosclerosis (buildup of plaque in the arteries) is the most common cause of a heart attack, several other lifestyle habits and underlying conditions can also raise your risk.

Atherosclerosis

Atherosclerosis is the buildup of cholesterol plaques in the inner lining of your blood vessels. When plaque becomes disrupted, it activates the body's blood clotting mechanism. A blood clot can form in the artery, which can partially or completely block blood flow. When a blood clot forms in a coronary artery in your heart, it can trigger a heart attack.

Blood Clot in the Heart

When a blood clot travels from elsewhere in the body and lodges in a coronary artery, it can obstruct blood flow and trigger a heart attack. Several conditions can increase your risk of developing blood clots in the heart. These include:

• Atrial fibrillation, a type of abno rmal heartbeat
• Cardiomyopathy, a type of heart muscle disease
• Endocarditis, an infection of the heart's chambers or valves
• Deep vein thrombosis, a blood clot in the legs that travels to the heart

Spontaneous Coronary Artery Dissection

While less common, you may experience a heart attack if you develop spontaneous coronary artery dissection (SCAD). This is a sudden tear that forms in the lining of a coronary artery, which causes blood to accumulate in between layers of the artery wall. As a result, the blood flow to and from your heart can become blocked.

Some studies report that SCAD is responsible for up to 4% of heart attacks overall. However, this condition causes up to 1 in 3 heart attack cases in people assigned female at birth who are 50 years old and younger.

Coronary Spasm

A coronary spasm is a sudden and temporary spasm or the narrowing of the coronary artery. Ths spasm usually goes away on its own, but spasms that are severe or last long enough can cause a heart attack.

Coronary Microvascular Dysfunction

In addition to the main coronary arteries that bring blood flow to the heart, the heart has a network of smaller arteries that supply blood, known as the microvascular circulation. Over the past few decades, researchers have recognized problems with this microvascular circulation, known as coronary microvascular dysfunction (CMD), as a possible cause of heart attack.

Are Heart Attacks Hereditary?

Many risk factors for heart attacks are hereditary, meaning your parents can pass them to you. If you have a family history of heart attack at a young age in your family, such as family members with a heart attack younger than 50 years, you are at increased risk of experiencing a heart attack, too.

Certain genetic conditions, like familial hypercholesterolemia, lead to abnormal cholesterol levels, which can also increase the risk of heart attacks significantly. This condition is autosomal dominant, meaning if one parent has one copy of the gene, there is a 25% chance of passing it to their children.

But, having a family history of heart attacks doesn't mean that you can prevent one from occurring. Several lifestyle changes can help lower your risk of experiencing a heart attack.

Who Gets Heart Attacks?

Some people are more likely to experience a heart attack than others. Heart attacks can happen to anyone of any age or sex but are more likely as you get older, particularly in males over 45 and females over 55. Research also suggests that people from some racial and ethnic backgrounds have a higher risk of heart disease, experience heart attacks more frequently, or have worse cardiovascular health outcomes.

For example, according to a Kaiser Family Foundation analysis of data from the 2022 Behavioral Risk Factor Surveillance System, American Indian and Alaska Native (AIAN) communities are more likely to have a heart attack than people of another racial and ethnic group. Non-Hispanic Black people are also more likely to have poorer health outcomes and experience higher rates of mortality than other races. However, research is still being done to understand what healthcare providers and public health experts can do to reduce racial disparities in heart health among Black and Indigenous communities.

Risk Factors

Researchers have identified many risk factors for heart disease. Some are modifiable, meaning you have the power to change them, whereas others, like age and genetics, are considered non-modifiable.

High Blood Pressure

High blood pressure (hypertension) is elevated pressure in your arteries. The condition is strongly linked to cardiovascular diseases, including heart attacks and strokes. It's important to see your healthcare provider for high blood pressure screening since it normally doesn't cause symptoms, and you may not otherwise know you have it.

Abnormal Cholesterol

Abnormal cholesterol, or dyslipidemia, is another major risk factor for heart disease that also may not cause symptoms. High levels of low-density lipoprotein (LDL) cholesterol, also known as "bad cholesterol", can increase heart attack risk. A simple blood test called a lipid panel can tell you your cholesterol levels.

Diabetes

Diabetes, a condition which leads to high blood sugar levels, is another risk factor for heart attacks. According to the National Institute of Diabetes and Digestive and Kidney Disorders, adults with diabetes are about twice as likely as those without diabetes to experience a heart attack or stroke at some point in their life.

Lifestyle Habits

Your lifestyle habits greatly influence your risk of future heart attacks. You may have a higher risk of developing a heart attack if you follow any of these lifestyle habits:

• Having a sedentary lifestyle without regular physical activity or exercise
• Smoking cigarettes
• Eating a diet high in ultra-processed foods, salt, trans fats, and saturated fats
• Getting poor quality or not enough sleep
• Not managing stress levels appropriately

However, your lifestyle habits are modifiable. You don't have to make these changes all at once, but trying to move your body gently each day, incorporating more nutritious meals, sleeping earlier, and talking to your provider about quitting if you smoke can slowly help lower your risk and improve your quality of life. Stress can also be hard to manage, but taking care of yourself and practicing techniques like meditation, yoga, journaling, or fun time with your loved ones can help reduce stress.

A Quick Review

A heart attack occurs when blood flow to the heart becomes blocked. The most common cause is atherosclerosis, but other conditions like a blood clot, spasm, or tear in your coronary arteries can also trigger a heart attack. Anyone can get a heart attack, but it occurs more commonly in older adults, those who have a family history of heart attacks, and people who live with conditions like high blood pressure. Poor diet, sleep, and exercise habits can also contribute to your risk.