The heart is a muscular pump that needs a continuous supply of oxygen. It obtains oxygen from the blood, which flows to the heart muscle through arteries on the heart's surface. These arteries are called the coronary arteries.

The underlying cause of heart attack is coronary heart disease (CHD) - the slow build-up of fatty deposits on the inner wall of the arteries that supply the heart muscle with blood. These fatty deposits, called plaque, gradually clog and narrow the inside channel of the arteries. It is a process that begins early in life and continues over the years.

A heart attack usually begins when an area of plaque cracks. Blood cells and other components of the blood stick over the damaged area and form a clot that suddenly and completely blocks the blood flow to the heart muscle. If the artery remains blocked, the lack of blood permanently damages the area of heart muscle supplied by that artery.

Know the signs of a heart attack, but be aware that symptoms can vary from person to person. Usual signs of a heart attack include chest pain, discomfort, heaviness or fullness in the chest, discomfort in arms, neck, jaw, stomach, shortness of breath, cold sweat or even nausea and vomiting. Sometimes these symptoms can come on suddenly but they can develop slowly. Not every chest pain is a heart attack, but it is impossible to know that before evaluation by a medical professional. Call 911 if you think you may be suffering from these symptoms. Do not drive yourself or anyone else to the hospital if these symptoms exist because during a heart attack, the possibility of life threatening rhythms exist, which can result in sudden loss of consciousness and death.

If you are rushed to hospital with a suspected heart attack, a number of tests will be performed to confirm the diagnosis and help your health care team decide on the best treatment for you.

These may include:

* Electrocardiogram (ECG) - During an ECG test, electrical leads are placed on your chest, arms and legs. These leads detect small electrical signals and produce a tracing on graph paper illustrating the electrical impulses travelling through the heart muscle.

* Blood tests

* Chest X-ray

* Angiogram - This is a special X-ray that shows whether your coronary arteries are narrowed or blocked. Under a local anaesthetic, a small tube (catheter) is inserted into an artery in your arm or groin and guided into the heart. Dye is injected through the catheter into the coronary arteries and X-rays are taken, giving detailed information about the condition of your coronary arteries.

Not every chest pain is a heart attack, but it is impossible to know without being evaluated by a medical professional. When having chest pain or related symptoms, it is best and safest to call 911. For those who have a history of coronary disease, previous coronary interventions (stents, angioplasty or open-heart surgery), transport to a PCI center is imperative. Primary PCI in the shortest amount of time is the best chance for survival and limiting of heart muscle damage.