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What is a heart attack?

A heart attack, also known as myocardial infarction, occurs when the flow of oxygenated blood through a coronary artery to the heart suddenly becomes blocked. If blood flow isn’t restored quickly, the section of heart muscle without oxygen begins to die. Heart attacks result mostly from coronary heart disease (CHD), a result of coronary artery disease (CAD or ischemia), in which a waxy substance called plaque builds up inside the coronary arteries. This condition also is called atherosclerosis.

The buildup of plaque occurs over time, and the plaque may rupture inside an artery, causing a blood clot to form on the plaque’s surface. If the clot grows enough, it can mostly or completely block blood flow, and healthy heart tissue is replaced with scar tissue. Some heart attacks are caused by a severe spasm of a coronary artery, which cuts off blood flow through the artery, and can occur in coronary arteries without atherosclerosis.

A heart attack can cause cardiac arrest, but cardiac arrest is not the same as a heart attack. Cardiac arrest (also called sudden cardiac death or SCD) happens when the heart’s electrical system malfunctions and the heart suddenly stops working properly. This is caused by arrhythmias: ventricular fibrillation, when the heart’s lower chambers suddenly start beating out of rhythm and don’t pump blood, is the most common one in cardiac arrest. Death occurs within minutes after the heart stops. Cardiac arrest may be reversed if CPR (cardiopulmonary resuscitation) is performed within a few minutes and a defibrillator is used to shock the heart and restore a normal heart rhythm.

These are the medical terms for a heart attack:

  • Myocardial infarction – When damage or death of part of the heart muscle (myocardium) occurs as a result of ischemia, it is called a heart attack or myocardial infarction. Ischemia blocks blood supply to the heart muscle, which cannot receive oxygen and nutrients. Though the damage may not be obvious, it may cause or be associated with severe or long-lasting problems such as heart failure and life-threatening arrhythmias
  • Coronary thrombosis – Formation of a clot in one of the arteries that conduct blood to the heart muscle. Also called coronary occlusion
  • Coronary occlusion – An obstruction of a coronary artery that prevents blood flow from getting to a particular part of the heart muscle


If you think you or someone you know is having a heart attack, call 911 immediately. When a heart attack happens, any delays in treatment can be deadly. Knowing what happens when a heart attack starts may save your life or the life of someone you know. Most heart attacks actually develop slowly with pain or discomfort that you may not always associate with your heart. Common symptoms of a heart attack include:

  • Chest pain or discomfort – Most heart attacks involve discomfort in the center of the chest that lasts longer than 15 minutes or goes away and comes back. Many people describe the discomfort as building to an uncomfortable pressure, squeezing, fullness or burning pain; others report an unbearable crushing pain or persistent tightness in the chest.
  • Discomfort in other areas of the upper body – Pain or discomfort may travel to one or both shoulders or arms, the back, neck and even the jaw or teeth. Some people experience a sustained, burning discomfort in the upper abdomen near the breastbone that may feel like indigestion.
  • Shortness of breath – During a heart attack, shortness of breath can accompany feelings of chest discomfort, but it also can occur before any chest pain is felt. Some people may also faint during a heart attack.
  • Other symptoms – Some people report breaking out in a cold sweat, feeling dizzy, lightheaded or nauseated, or belching or vomiting. Chest pain may not accompany these symptoms. Some people experience clammy skin or skin that turns pale or blue, particularly around the mouth.

Symptoms in women may be different. Most women will experience pain or discomfort in their chest but some may not. Other symptoms that a woman might experience include:

  • Extreme fatigue
  • Pain in the abdomen
  • Pain or discomfort in the center of the back or in the jaw


Causes for heart attack include:

  • Cardiovascular disease – Cardiovascular disease is a general term referring to various heart problems involving narrowed or blocked blood vessels that can lead to a heart attack, chest pain (angina) or stroke. Cardiovascular diseases can have numerous causes.
  • Coronary artery disease (CAD) – This condition involves the gradual narrowing or blockage of the coronary arteries, the blood vessels that supply blood to the heart. Coronary artery disease is the most common cause of heart disease and is the major reason people have heart attacks.
  • High cholesterol – Cholesterol is a fatty, wax-like substance that functions as a building block for cell membranes and some hormones. High cholesterol occurs when your body has more cholesterol than it needs to function properly. The extra cholesterol usually comes from eating high-fat foods. Over time, high cholesterol can clog arteries and lead to hardening of the arteries, heart attacks and strokes. High cholesterol has no symptoms, so a blood test is necessary to uncover the problem.

Risk factors

You could be at risk for heart disease if you:

  • Are overweight
  • Smoke
  • Have blood pressure 140/90 mm Hg or higher
  • Have total cholesterol levels of 200 mg/dL or higher, low levels of “good” cholesterol (HDL), or high levels of “bad” cholesterol (LDL)
  • Are a man older than 45 years
  • Are a woman beyond menopause
  • Do not get much exercise or lead a sedentary lifestyle
  • Have a family history of heart disease
  • Have diabetes
  • Use recreational drugs, such as cocaine and amphetamines


Clinical cardiologists provide a full range of noninvasive and minimally invasive testing, depending on your particular condition. These include:

  • Electrocardiographs (ECGs)
  • Stress tests
  • Cholesterol and blood pressure evaluations
  • Nuclear stress testing
  • Echocardiography (cardiac ultrasound)
  • Computed tomography (CT) angiography
  • Vascular studies
  • Heart monitoring