Definition of Heart attack:

A heart attack is when blood flow to a part of the heart is blocked, preventing enough oxygen from getting to the heart. The heart muscle dies or becomes permanently damaged. Your doctor calls this a myocardial infarction.

Causes, incidence, and risk factors:

Most heart attacks are caused by a blood clot that blocks one of the coronary arteries. The coronary arteries bring blood and oxygen to the heart. If the blood flow is blocked, the heart starves for oxygen and heart cells die.

A clot most often forms in a coronary artery that has become narrow because of the build-up of a substance called plaque along the artery walls. (See: atherosclerosis) Sometimes, the plaque cracks and triggers a blood clot to form.

Occasionally, sudden overwhelming stress can trigger a heart attack.

Risk factors for heart attack and coronary artery disease include:

• Being a middle-aged male
• Diabetes
• Family history of coronary artery disease (genetic or hereditary factors)
• High blood pressure
• Increasing age (over age 65)
• Smoking
• Too much fat in your diet
• Unhealthy cholesterol levels, especially high LDL ("bad") cholesterol and low HDL ("good") cholesterol