The heart is actually a powerful muscular organ in our body. It is about the same size as our clenched fist and is made of strong cardiac muscles. It constantly pumps blood to different parts of the body, through veins capillaries and arteries, so that each cell gets the food and oxygen it needs. In an adult person, the heart goes on working at a rate of 70 to 80 beats per minute until death. It was the English doctor William Harvey (1587-1657), who discovered how the heart works. The blood in the arteries carries oxygen from the lungs and energy from the food we eat. Veins carry away waste products and return the dark, ‘tired’ cells to the heart to be recharged with oxygen from the lungs. When the heart stops beating, the body is starved of oxygen and quickly dies. The heart needs blood for its own functioning. The arteries that supply blood to the heart are called the ‘coronary arteries’. They provide the heart muscle, the oxygen it needs for functioning. If the coronary arteries get blocked, certain parts of the heart muscles die. It leads to a heart attack, which can be fatal. The blockage of coronary arteries is, usually caused by blood clots. In such a disease, the walls of the arteries become lumpy, rough and narrow. Such conditions are caused by excessive fats in the blood. This is why heart patients are advised not to take fatty substances. A heart attack can also be caused by rheumatic fever. This disease, usually, follows a sore throat caused by a bacteria called ‘Streptococci’. In this case, the heart gets inflamed. If the infection is serious it can cause heart failure. The effects of rheumatic fever may take 20 to 30 years to appear. The third type of heart attack occurs due to congenital factors, which are the factors one is born with. Sometimes, there is a faulty growth of a valve. It may be too tight or fail to close properly. Sometimes, a gap is left in the wall or septum between the two sides of the heart. It is estimated that one in every 200 babies is born with such defects. When the heart is defective, blood does not receive enough oxygen. The baby becomes breathless. The blood cannot get rid of carbon dioxide through the lungs. As a result, the baby appears blue. A heart attack is preceded by a severe pain in the chest and the left arm and the person suffering from this becomes breathless. The heartbeat goes up and the person feels suffocated. Under such conditions the person should be made to take complete rest and a heart specialist should be consulted.