If the person is a previous cardiac patient, he should have nitroglycerin
pills. First thing, place one under his tongue.
If your area is served by 911, call 911. If no emergency transportation services are available, get the victim to an emergency room ASAP.
During all of these steps, if the victim is breathing, make him lie down and limit his movement. If the victim is not breathing, administer CPR.
If the victim has nitro, repeat the dose two more times ten minutes apart -- total of three pills. If the victim does not have nitro, give aspirin
. One aspirin is enough, one time. If the victim has nitro, he is almost certainly on aspirin therapy, so aspirin is not going to help him.
If the victim is not breathing, continue CPR until professional help is achieved.