What causes a heart attack?

Donato A. Sisto, MD
Thoracic Surgery (Cardiothoracic Vascular)
A heart attack is caused by a blockage of a major artery. Donato Sisto, MD from Portsmouth Regional Hospital explains what that means and further possible complications. Watch this video to learn more.
Ankit D. Parikh, MD
Cardiology (Cardiovascular Disease)
A cardiologist describes the circumstances that cause most heart attacks to occur. Watch this video with Ankit Parikh, MD from Northside Hospital.
Denise M. Dietz, MD
Cardiology (Cardiovascular Disease)
A heart attack occurs when one or more of your coronary arteries become blocked. The flow of oxygen-rich blood to a section of heart muscle suddenly becomes blocked and the heart can't get oxygen. Over time, a coronary artery can narrow from the buildup of various substances, including cholesterol (atherosclerosis). This condition, known as coronary artery disease, causes most heart attacks.
Stefano Sdringola-Maranga, MD
Cardiology (Cardiovascular Disease)
A heart attack is caused when a blood clot blocks blood flow to the heart muscle.
Jeremy G. Enslein, DO
Cardiology (Cardiovascular Disease)
A heart attack typically occurs when one or more of your coronary arteries become blocked. Over time, plaque can build up in the coronaries. The plaque can then rupture, and a clot can form at the site of the rupture and obstruct blood flow. Other less common causes of heart attacks include spasm of the coronary artery or a tear in the arterial wall.
Giridhar Vedala, MD
Cardiology (Cardiovascular Disease)
Most heart attacks (damage to the heart muscle) are caused from rupture/break of a partial blockage inside a blood vessel of the heart. After the break, a clot forms in the blood vessel and then nearly completely or completely blocks blood flow to part of the heart, causing damage to the heart muscle. Sometimes a heart attack may be caused by a spasm of a blood vessel, clot or material which blocks blood flow from another part of the heart, or damage to the heart from an infection or severe illness.
Jonathan A. Fialkow, MD
Cardiology (Cardiovascular Disease)
In this video, I will explain how doctors now know heart attacks are not necessarily caused by narrowed arteries but actually inflamed arteries. 
Penn Medicine
Coronary arteries bring blood and oxygen to the heart. If blood flow to part of the heart is blocked long enough and the heart is starved of oxygen, heart cells die and that part of the heart muscle is damaged or dies, resulting in a heart attack, more formally known as myocardial infarction.
Sameer A. Sayeed, MD
Cardiology (Cardiovascular Disease)
A heart attack is usually caused by coronary artery disease. The artery has blockage from a cholesterol plaque and damage to the artery wall caused rupture of the plaque, leading to the formation of a blood clot in the artery, which then effectively cuts off the blood and oxygen supply to the portion of the heart being supplied by the artery. This leads to injury to that portion of the heart and if the artery supplying that portion of the heart is not opened in a timely fashion, that portion of the heart muscle will die and form scar tissue with no further cardiac muscle function. A heart attack can also result when the heart beats too fast and beyond its own blood supply resulting usually in a small amount of injury.
Heart attacks are caused by heart disease, which is the number one cause of death among both men and women in the United States. According to the American Heart Association, every year in the United States roughly 785,000 people will have their first heart attack. And approximately 470,000 who have had a heart attack before will have another one.

An extensive blockage, especially in a major blood vessel, such as the left anterior descending artery, can cause a large heart attack. Large heart attacks that are not treated early and aggressively can lead to heart failure. The risk of death within five years of being diagnosed with certain types of heart failure can be 50 percent or more.
When blood flows more slowly at the site of a narrowing artery, it can become "sticky" and eventually form a clot. This blood clot can narrow the opening of the artery even further, which can reduce blood flow to the heart, leading to chest pain, or angina. If blood flow is nearly or completely blocked, a heart attack can occur, leading to the death of muscle cells in the heart. Because the cells cannot be replaced, the result is permanent heart damage. Each year, up to half a million American women suffer heart attacks, an all-too-frequent outcome of coronary heart disease.
Anthony L. Komaroff, MD
Internal Medicine
A heart attack, known medically as a myocardial infarction, occurs when a blood clot blocks one of the coronary arteries. Each coronary artery supplies blood to a specific part of the heart's muscular wall, so a blockage causes pain and malfunction in the area that the affected artery serves. Depending on the location and the amount of heart muscle involved, this malfunction can seriously interfere with the heart's ability to pump blood. Also, some of the coronary arteries supply areas of the heart that regulate heartbeat, so a blockage sometimes causes potentially fatal abnormal heartbeats called cardiac arrhythmias.
 Dr. Kathleen Handal, MD
Emergency Medicine
A heart attack can be caused by many possible factors. Your heart muscle requires a steady supply of blood and oxygen. A heart attack occurs when that supply is interrupted or blocked. The release of a blood clot from hardened coronary arteries is often the culprit. Many illnesses, as well as drugs, especially cocaine and contraceptive pill usage, can cause a heart attack.
Harris H. McIlwain, MD

The basic problem in most heart attacks is the narrowing and hardening of the arteries due to atherosclerosis. Again, this process does not happen overnight but takes years to build up. This narrowing and hardening of the arteries is same process that can cause heart failure, strokes, and kidney failure. Together these problems are the most common causes of serious illness and death in America. But the leading cause of death is still heart attack.

Researchers think atherosclerosis begins slowly with minor injuries or wear-and-tear of the inside lining of the arteries, especially the coronary arteries that supply the heart muscle. Changes in flow of blood at branches in the arteries, smoking cigarettes, and high blood cholesterol may all make these minor injuries happen more easily--and, all of these problems have solutions that only you control.

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Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)

Excessive plaque buildup can result in dangerously narrowed arteries. In the case of a heart attack, your coronary artery becomes completely blocked, cutting off the oxygen that your heart muscle needs, with possibly fatal results.

Weight loss lowers your blood pressure and cholesterol. Incredibly, just 10 pounds of weight loss can result in a greater than 50% risk reduction for heart attacks.

Piedmont Heart Institute
Heart attacks, which is a lay term for the medical condition myocardial infarction, occurs when the coronary artery (which is the blood vessel supplying oxygenated blood to the heart muscle) completely blocks off and reduces or eliminates the blood flow to the heart muscle. What causes this is a person who has pre-existing coronary atherosclerosis most of the time. Coronary atherosclerosis is a cholesterol plaque buildup within the walls of the artery. As these plaques begin to encroach on the lumen, or opening of the artery, there is turbulence that is established. In addition, these plaques may become unstable and they may fracture or fragment and release soft cholesterol material—all of which promotes blood clotting on top of the plaque. The final incident is when the blood clot completely blocks the artery superimposed on this cholesterol plaque, leading to a heart attack.
Mark L. Cohen, MD
Cardiology (Cardiovascular Disease)
A heart attack is when you have damage to the muscle of your heart. The heart muscle is just like any other part of your body and requires blood flow to survive. If there is insufficient blood flow, then the muscle is damaged. The overwhelming majority of heart attacks are caused when a blood clot forms in an artery to the heart. Almost always, this occurs because cholesterol has built up in the wall of the artery and then the blood clot forms, choking off the blood flow. The muscle begins to die and usually you will have chest pain. Emergency medical attention is absolutely necessary. There are some other rare causes of heart attacks. The most important message is that if you are experiencing chest pain or chest pressure, you should call 911 immediately.
Dede Bonner
Health Education

A heart attack is defined as the death of heart muscle due to the sudden blockage of a coronary artery by a ruptured blood vessel that causes a blood clot. Coronary arteries are the blood vessels that supply blood and oxygen to the heart.

A blockage causes injury to the heart muscle, chest pain, and the feeling of chest pressure or other symptoms. These other symptoms include sensations like indigestion; burning; tightness or heaviness - a feeling like a band or belt is tightening across your chest; jaw discomfort; back pain; numbness in your arms; shortness of  breath; or unusual fatigue.

Blockages are caused by plaque buildup in a process called atherosclerosis. Atherosclerosis has no symptoms, which is why heart attacks often surprise their victims and are called “silent killers.” Symptoms from atherosclerosis generally occur only after the blockage is greater than 70 percent. But many heart attacks are caused by blockages of less than 50 percent that rupture. When this happens, the result is a blood clot in the artery that causes a complete blockage and results in a heart attack.


The 10 Best Questions for Recovering from a Heart Attack: The Script You Need to Take Control of Your Health

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A heart attack is commonly caused by a blockage of the coronary artery. Cholesterol in the form of plaque builds up on the inside wall of the coronary artery. Over time, plaque accumulation can narrow the artery, reducing blood flow to the heart. This material can also break off and form a blood clot that limits or blocks blood flow to the heart. Less often, a heart attack is caused by a spasm of the heart that may result from drug usage, emotional pain or stress, severe cold, or smoking.

Eastside Medical Center
Causes of heart attacks include:
  • Spasm of your coronary artery
  • Trauma to the chest wall -- such as a baseball hitting the chest wall, which can injure the artery in the same way that an automobile accident could and may cause an electrical disturbance as well.
  • Plaque rupture is the most common mechanism where a cholesterol plaque in the artery causes a rupture of the inner layer of the artery, which then causes the artery to block off and stop the blood flow to the heart. This causes heart muscle damage and electrical instability, which may cause extensive damage to the heart and lead to stopping the heart or heart failure.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.