A heart attack occurs when the flow of blood to the heart is blocked

A heart attack occurs when the flow of blood to the heart is blocked. The blockage is most often a buildup of fat, cholesterol and other substances, which form a plaque in the arteries that feed the heart (coronary arteries).

The plaque eventually breaks away and forms a clot. The interrupted blood flow can damage or destroy part of the heart muscle.

A heart attack, also called a myocardial infarction, can be fatal, but treatment has improved dramatically over the years. It’s crucial to call 911 or emergency medical help if you think you might be having a heart attack.

Symptoms
Common heart attack signs and symptoms include:

Pressure, tightness, pain, or a squeezing or aching sensation in your chest or arms that may spread to your neck, jaw or back
Nausea, indigestion, heartburn or abdominal pain
Shortness of breath
Cold sweat
Fatigue
Lightheadedness or sudden dizziness
Heart attack symptoms vary
Not all people who have heart attacks have the same symptoms or have the same severity of symptoms. Some people have mild pain; others have more severe pain. Some people have no symptoms; for others, the first sign may be sudden cardiac arrest. However, the more signs and symptoms you have, the greater the likelihood you’re having a heart attack.

Dr Rana Sanjay, Physician, at INDIA said that Some heart attacks strike suddenly, but many people have warning signs and symptoms hours, days or weeks in advance. The earliest warning might be recurrent chest pain or pressure (angina) that’s triggered by exertion and relieved by rest. Angina is caused by a temporary decrease in blood flow to the heart.

When to see a doctor
Act immediately. Some people wait too long because they don’t recognize the important signs and symptoms. Take these steps:

Call for emergency medical help. If you 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 if there are no other options. Because your condition can worsen, driving yourself puts you and others at risk.

Take nitroglycerin, if prescribed to you by a doctor. Take it as instructed while awaiting emergency help.
Take aspirin, if recommended. Taking aspirin during a heart attack could reduce heart damage by helping to keep your blood from clotting.

Aspirin can interact with other medications, however, so don’t take an aspirin unless your doctor or emergency medical personnel recommend it. Don’t delay calling 911 to take an aspirin. Call for emergency help first.

What to do if you see someone who might be having a heart attack
If you see someone who’s unconscious and you believe is having a heart attack, first call for emergency medical help. Then check if the person is breathing and has a pulse. If the person isn’t breathing or you don’t find a pulse, only then should you begin CPR to keep blood flowing.

Push hard and fast on the person’s chest in a fairly rapid rhythm — about 100 to 120 compressions a minute.

If you haven’t been trained in CPR, doctors recommend performing only chest compressions. If you have been trained in CPR, you can go on to opening the airway and rescue breathing.