Most everyone has known someone who has suffered a heart attack.

And although heart attacks have been declining in recent years, they remain the No. 1 cause of death in the United States. A heart attack occurs when the blood supply to a part of the heart muscle is severely reduced or stopped because of an obstruction in one of the coronary arteries (these supply the heart with its blood). A buildup of fatty deposits along the coronary artery's inner wall is one reason for blood obstruction. The blood supply can also be cut when the artery goes into a spasm. Here are some things you should know about this serious ailment:PREVENTION:

A number of things can be done to reduce your chances of having a heart attack:

- Control your weight.

- Check your blood pressure regularly.

- Don't smoke or use drugs (unless prescribed by a physician).

- Exercise regularly (check with your physician if you haven't been exercising and are over 35 years of age).

- Eat a healthy diet of foods - avoid fats and increase soluble fiber in your diet.

HEART ATTACK SYMPTOMS:

The American Heart Association lists these as possible signs and symptoms of a heart attack:

- Uncomfortable pressure, fullness, squeezing or pain in the center of the chest lasting two minutes or longer.

- Pain spreading to the shoulders, neck or arms.

- Severe pain, dizziness, fainting, sweating, nausea or shortness of breath.

Not all of these warning signs occur in every heart attack. If some start to occur, however, don't wait. Time loss can seriously increase the risk of major damage. Get help immediately.

FIRST AID FOR A HEART ATTACK:

The American Heart Association identifies proper action to take in the event of a heart attack:

- Find out which hospitals have 24-hour emergency cardiac care.

- If chest discomfort lasts two minutes or more, call the emergency rescue service.

- If you can get to a hospital faster by going yourself and not waiting for an ambulance, have someone drive you there.

- If you're with someone experiencing the signs of a heart attack - and the warning signs last two minutes or longer - act immediately.

- Expect a denial. It's normal for someone with chest discomfort to deny the possibility of something as serious as a heart attack. But don't take no for an answer. Insist on taking prompt action.

- Give CPR (mouth-to-mouth breathing and chest compression) if it's necessary and you're properly trained.