Understanding Heart Attack: The Basics

Reviewed by Suzanne R. Steinbaum, MD on July 02, 2019


Other people mistake a heart attack for a symptom of the flu or reflux disease, which causes heartburn. 

A quarter of all heart attack victims die before reaching a hospital; others suffer life-threatening complications while in the hospital. Serious complications include stroke, persistent heart arrhythmias (irregular heart beats), heart failure, formation of blood clots in the legs or heart, and aneurysm, or bulging, in a weakened heart chamber. But those who survive the initial heart attack and are free from major problems a few hours later stand a better chance of full recovery.


Recovery is always a delicate process, because any heart attack weakens the heart to some degree. But generally, a normal life can be resumed. Depending on the severity of a heart attack, a person may experience:

  • Heart failure, where the heart doesn't pump well enough to meet the body's needs
  • Arrhythmias or abnormal heart rhythms
  • Cardiac arrest or sudden cardiac death, where the heart stops beating
  • Cardiogenic shock, where the heart is so damaged from the heart attack that a person goes into shock, which may result in damage of other vital organs like the kidneys or liver
  • Death


What Causes a Heart Attack?

Most heart attacks are the result of coronary artery disease, also known as atherosclerosis or "hardening of the arteries," a condition that clogs coronary arteries with fatty, calcified plaques over time. The typical trigger for a heart attack is often a blood clot that blocks the flow of blood through a coronary artery.


In the early 1980s, researchers confirmed that the trigger for nearly all heart attacks is not the obstructive plaque itself, but the sudden formation of a blood clot -- like a scab -- on top of plaque that cuts off blood flow in an already narrowed vessel. This is called "plaque rupture." Contrary to prior belief, doctors now recognize that the less severe plaques are the cause of most heart attacks: It's the milder blockages that rupture and then cause the blood clot to form.

Heart attacks may also be caused by coronary artery spasm, where a heart artery is temporarily constricted, although this is a fairly rare cause.


New research shows that inflammation also plays a role in the evolution of heart attacks. It appears that the coronary artery walls become inflamed over time, further increasing the buildup of fatty plaques.

While the step-by-step process leading to a heart attack is not fully understood, major risk factors for coronary artery disease are well-known. Some can be controlled, including high blood pressure, high cholesterol, obesity, smoking, and a sedentary lifestyle. Stress is also said to raise the risk, and exertion and excitement can act as triggers for a heart attack.

Other risk factors include having diabetes and having a family history of heart disease.

WebMD Medical Reference




American Heart Association.

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