1 Not all people who experience heart attacks have the same symptoms or the same severity of symptoms — there's lots of variability. 2  Some people also report feeling a sense of doom or impending death that is unique to the heart attack experience.
http://www.wikihow.com/Treat-a-Heart-Attack
Without enough oxygen and nutrients, the heart muscle begins to die and becomes dysfunctional, which leads to a heart attack (myocardial infarction) and potential cardiac arrest and eventual death. About every 34 seconds, someone in the U.S. has a heart attack.
http://www.wikihow.com/Treat-a-Heart-Attack
Recognize the most common symptoms of a heart attack. Most heart attacks do not occur suddenly or out of the blue.. Instead, they typically start slowly with mild chest pain or discomfort that builds over many hours or even days.
http://www.wikihow.com/Treat-a-Heart-Attack
The symptoms of a heart attack vary from one person to another. You may feel tightness, heaviness or pain in your chest. This may spread to your arms, neck, jaw, back or stomach.
https://www.bhf.org.uk/heart-health/conditions/heart-attack
The first thing to do if you think you're having a heart attack is to phone 999 immediately for an ambulance. You should then sit and rest while you wait for the ambulance to arrive. Do not get up and look around for an aspirin. This may put unnecessary strain on your heart.
https://www.bhf.org.uk/heart-health/conditions/heart-attack
Other common common symptoms of heart attack include: shortness of breath, cold sweats (with pale or ashen skin), dizziness or lightheadedness, moderate-to-severe fatigue, nausea, abdominal pain and a sensation of severe indigestion.
http://www.wikihow.com/Treat-a-Heart-Attack
Recognizing Heart Attack Symptoms. Heart attack symptoms vary from person to person. Not all heart attacks begin with the sudden, crushing chest pain that many people picture when they think of a heart attack. In fact, some heart attacks cause no symptoms at all. This is more common in people who have diabetes.
http://www.webmd.com/heart-disease/heart-attack-symptoms-emergency
Part 2 of 2: Treating Before Medical Help Arrives. 1. Put the person in a seated position, with knees raised. Most medical authorities recommend sitting a suspected heart attack sufferer down in the W position — semi-recumbent (sitting up at about 75 degrees to the ground) with knees bent.
http://www.wikihow.com/Treat-a-Heart-Attack
Chest pain and discomfort are the most common heart attack symptoms for both men and women. But, women are more likely than men to also experience other symptoms, too. These might include shortness of breath, nausea and vomiting, unexplained extreme fatigue, and neck, shoulder, upper back, or abdominal pain.
http://www.webmd.com/heart-disease/heart-attack-symptoms-emergency
A heart attack always causes some permanent damage to your heart muscle, but the sooner treatment is given, the more muscle it is possible to save. If a heart attack damages a significant amount of your heart muscle, this can affect the pumping action of your heart. The term used to describe this is heart failure.
https://www.bhf.org.uk/heart-health/conditions/heart-attack
what to do when someone is having a heart attack
When someone is having a heart attack phone 999 immediately for an ambulance,  then sit and rest while you wait for the ambulance to arrive do not get up and look around for an aspirin which may put unnecessary strain on your heart. When someone is having a heart attack, phone 999 immediately for an ambulance. You should then sit and rest while you wait for the ambulance to arrive. Do not get up and look around for an aspirin. This may put unnecessary strain on your heart.