About Heart Attacks

A heart attack occurs when the supply of blood and oxygen to an area of heart muscle is blocked, usually by a clot in a coronary artery. Often, this blockage leads to arrhythmias (irregular heartbeat or rhythm) that cause a severe decrease in the pumping function of the heart and may bring about sudden death.

If the blockage is not treated within a few hours, the affected heart muscle will die and be replaced by scar tissue.

Heart Attack Symptoms

Chest discomfort. Most heart attacks involve discomfort in the center of the chest that lasts for more than a few minutes, or goes away and comes back. The discomfort can feel like uncomfortable pressure, squeezing, fullness, or pain. Heart attack pain can sometimes feel like indigestion or heartburn.

Discomfort in other areas of the upper body. Can include pain, discomfort, or numbness in one or both arms, the back, neck, jaw, or stomach.

Shortness of breath. Often comes along with chest discomfort. But it also can occur before chest discomfort.

Other symptoms. May include breaking out in a cold sweat, having nausea and vomiting, or feeling light-headed or dizzy.

Symptoms vary from person to person. In fact, if you have a second heart attack, your symptoms may not be the same as for the first heart attack. Some people have no symptoms. This is called a "silent" heart attack.

Causes of Heart Attacks

Most heart attacks are caused by a blood clot that blocks one of the coronary arteries (the blood vessels that bring blood and oxygen to the heart muscle). When blood cannot reach part of your heart, that area starves for oxygen. If the blockage continues long enough, cells in the affected area die.

Coronary Artery Disease (CAD) is the most common underlying cause of a heart attack. CAD is the hardening and narrowing of the coronary arteries by the buildup of plaque in the inside walls (atherosclerosis). Over time, plaque buildup in the coronary arteries can:

• Narrow the arteries so that less blood flows to the heart muscle
• Completely block the arteries and the flow of blood
• Cause blood clots to form and block the arteries.

A less common cause of heart attacks is a severe spasm (tightening)of the coronary artery that cuts off blood flow to the heart. These spasms can occur in persons with or without CAD. Artery spasm can sometimes be caused by:

• Taking certain drugs, such as cocaine
• Emotional stress
• Exposure to cold
• Cigarette smoking.

Restoring blood flow to the heart is vital to prevent or limit damage to the heart muscle and to prevent another heart attack. The main treatments are the use of thrombolytic ("clot-busting") drugs and procedures such as angioplasty.

Thrombolytic drugs ("clot busters") are used to dissolve blood clots that are blocking blood flow to the heart. When given soon after a heart attack begins, these drugs can limit or prevent permanent damage to the heart. To be most effective, they need to be given within 1 hour after of the start of heart attack symptoms.

Angioplasty procedures are used to open blocked or narrowed coronary arteries. A stent, which is a tiny metal mesh tube, may be placed in the artery to help keep it open.

Coronary artery bypass surgery uses arteries or veins from other areas in your body to bypass your blocked coronary arteries.

The largest published study on omega-3 fatty acids for heart attack prevention was the preliminary GISSI Prevenzione Trial, which reported that 850 mg of omega-3 fatty acids from fish oil per day for 3.5 years resulted in a 20% reduction in total mortality and a 45% decrease in sudden death.

Other investigators suggest that fish oil reduces the amount of heart muscle damage from a heart attack and enhances the effect of blood-thinning medication.

Reference for Heart Attack Symptoms Article

• Davini P, Bigalli A, Lamanna F, Boem A. Controlled study on L-carnitine therapeutic efficacy in post-infarction. Drugs Exp Clin Res 1992;18:355-65.
• [No authors listed]. Dietary supplementation with n-3 polyunsaturated fatty acids and vitamin E after myocardial infarction: results of the GISSI-Prevenzione trial. Gruppo Italiano per lo Studio della Sopravvivenza nell’Infarto miocardico. Lancet 1999;354:447-55.
• 155. Morrison LM. Reduction of ischemic coronary heart disease by chondroitin sulfate. Angiology 1971;22:165-74.
• National Institutes of Health