A heart attack occurs when the flow of blood to the heart is blocked, most often by a build-up of fat, cholesterol and other substances, which form a plaque in the arteries that feed the heart (coronary arteries). The interrupted blood flow can damage or destroy part of the heart muscle.
A heart attack, also called a myocardial infarction, can be fatal, but treatment has improved dramatically over the years. It’s crucial to call 911 or emergency medical help if you think you might be having a heart attack.
Common heart attack signs and symptoms include:
- Cold sweat
- Lightheadedness or sudden dizziness
- Nausea, indigestion, heartburn or abdominal pain
- Pressure, tightness, pain, or a squeezing or aching sensation in your chest or arms that may spread to your neck, jaw or back
- Shortness of breath
Heart attack symptoms vary
Not all people who have heart attacks have the same symptoms or have the same severity of symptoms. Some people have mild pain; others have more severe pain. Some people have no symptoms, while for others, the first sign may be sudden cardiac arrest. However, the more signs and symptoms you have, the greater the likelihood you’re having a heart attack.
Some heart attacks strike suddenly, but many people have warning signs and symptoms hours, days or weeks in advance. The earliest warning may be recurrent chest pain (angina) that’s triggered by exertion and relieved by rest. Angina is caused by a temporary decrease in blood flow to the heart.
A heart attack differs from a condition in which your heart suddenly stops (sudden cardiac arrest, which occurs when an electrical disturbance disrupts your heart’s pumping action and causes blood to stop flowing to the rest of your body). A heart attack can cause cardiac arrest, but it’s not the only cause.
A heart attack occurs when one or more of your coronary arteries become blocked. 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.
During a heart attack, one of these plaques can rupture and spill cholesterol and other substances into the bloodstream. A blood clot forms at the site of the rupture. If large enough, the clot can completely block the flow of blood through the coronary artery.
Another cause of a heart attack is a spasm of a coronary artery that shuts down blood flow to part of the heart muscle. Use of tobacco and of illicit drugs, such as cocaine, can cause a life-threatening spasm. A heart attack can also occur due to a tear in the heart artery (spontaneous coronary artery dissection).
Heart attack complications are often related to the damage done to your heart during a heart attack. This damage can lead to the following conditions:
Abnormal heart rhythms (arrhythmias). If your heart muscle is damaged from a heart attack, electrical “short circuits” can develop, resulting in abnormal heart rhythms, some of which can be serious, even fatal.
Heart failure. The amount of damaged tissue in your heart may be so great that the remaining heart muscle can’t do an adequate job of pumping blood out of your heart. Heart failure may be a temporary problem that goes away after your heart, which has been stunned by a heart attack, recovers. However, it can also be a chronic condition resulting from extensive and permanent damage to your heart following your heart attack.
Heart rupture. Areas of heart muscle weakened by a heart attack can rupture, leaving a hole in part of the heart. This rupture is often fatal.