"During a heart attack, act immediately. Take these steps:
* Call for emergency medical help. If you even suspect you're having a heart attack, don't hesitate. Immediately call 911 or your local emergency number. If you don't have access to emergency medical services, have someone drive you to the nearest hospital. Drive yourself only as a last resort, if there are absolutely no other options. Driving yourself puts you and others at risk if your condition suddenly worsens.
* Take nitroglycerin. If your doctor has prescribed nitroglycerin, take as instructed while awaiting the arrival of emergency medical personnel.
If you encounter someone who is unconscious from a presumed heart attack, call for emergency medical help and, if you have received training in emergency procedures, begin cardiopulmonary resuscitation (CPR). This helps deliver oxygen to the body and brain. If you're not trained in emergency procedures, doctors recommend skipping mouth-to-mouth rescue breathing and proceeding directly to chest compression. The reason is that if you're distracted by trying to perform unfamiliar breathing techniques, valuable lifesaving minutes might be lost for the person who needs help. The most important thing you can do is to proceed directly to chest compression in order to deliver blood to vital organs, particularly the brain and heart. Do chest compressions at a rate of 100 a minute."
I found this from this site
http://www.cnn.com/HEALTH/library/DS/00094.html