I always advise people that if they think someone they're with is having a heart attack, don’t discuss it. The person will most likely deny her symptoms and may even be embarrassed. The best thing to do is excuse yourself and call 911. Getting paramedics on the way as soon as possible can save a life.

If the person passes out, you will need to perform CPR until help arrives. Call 911 and put the dispatcher on speakerphone so he can talk you through the chest compressions. If the person wakes up, she may be confused and alarmed. Do your best to keep her calm and warm. Then let her know that help is on the way. Have her turn onto her side so that her breathing won’t be obstructed if she vomits.

If you are in a public place, find out if a defibrillator is available. Many airports, train stations, universities, restaurants, casinos, and sports facilities have portable defibrillators on site and staff trained to use them. They are called “automated external defibrillators” or AEDs. These are not the same units that hospitals and paramedics use, but they can save a life in an emergency.

AEDs are very user friendly. They have an electronic voice prompter that talks users through each step, even giving instructions on how to connect the electrodes to the patient. The device is programmed to diagnose a person’s heart rhythm and determine if a shock is needed.

Automatic models will administer the shock; semi-automatic models tell the user to push a button for the shock. Many lives have been saved with these devices.