"Sometimes it's impossible to tell the difference between the symptoms of heartburn, angina and heart attack," cautioned Prediman K. (P.K.) Shah, M.D., director of the Division of Cardiology and the Atherosclerosis Research Center at Cedars-Sinai Medical Center. "There are some useful pointers that might help a person know whether they're having a heart attack or not, but when in doubt, check it out."

Knowing your risk factors that may predispose you to a heart attack is the most important factor to keep in mind. They will determine whether you 'brush over' the symptoms or take them seriously.

Shah said: "If you smoke, have diabetes, high cholesterol, high blood pressure, are overweight or have a strong family history of heart disease and have any symptom related to the chest or heart, you should be suspicious." Heart attack symptoms include the sudden onset of tightness, pressure, squeezing, burning, or discomfort in the chest, throat, neck or either arm. You should be especially suspicious if these symptoms are accompanied by nausea, vomiting, sweating, shortness of breath or a fainting sensation, Shah warned. "That's when a bell should ring telling you that these symptoms may be indicating a heart attack."

Angina is the most often seen symptom of coronary heart disease. Angina is pain in the chest or discomfort that occurs when the heart muscles do not receive enough blood. The pain occur in the shoulders, arms, neck, jaw and/or back. Angina may feel like indigestion.

"Generally we recommend that if you think you're having a heart attack, call 9-1-1," said Shah. "It's the safest thing to do. We tell people to err on the side of caution and overreact instead of under react."

The symptoms of reflux or heartburn can look like a heart attack. If you've had heartburn all your life and the symptoms you're experiencing are identical to those you've had before then you're probably experiencing heartburn and not a heart attack. But if the symptoms are accompanied by feeling light-headed or sweaty, "then that type of heartburn should be taken more seriously," Shah said. "It could signal that you've having a heart attack."

A heart attack is caused when the supply of blood to the heart muscle is reduced or stopped. This happens when the coronary arteries that supply blood to the heart become blocked. Death or disability is dependent on the percentage of the heart muscle is damaged.

There is no way to predict the time of the day when a heart attack may occur, or the circumstances that may cause a heart attack. A heart attack can strike in the middle of the night, after a meal, in the middle of a rest period, during or after sexual activity or physical activity.

"Obviously, if you've been diagnosed with coronary heart disease, then any of these symptoms should ring a loud bell," said Shah.

Shah emphasized that many types of heart disease that he describes as different "flavors" do not produce pain but are as life-threatening as a typical heart attack.

A regular check-up by a physician when you reach middle age (between 45 and 50) or before beginning a heavy exercise program is essential, he said. "Certain heart conditions can remain hidden and put persons at risk for sudden death. It's important to point out that heart disease isn't just one flavor - there are many different flavors."