Overview

Your heart is a muscle about the size of your fist that provides your body with the blood it needs to be healthy. On average, it beats more than 100,000 times each day and more than 2.5 billion times over the average lifetime. Each day, your heart pumps about 2,000 gallons of blood through your body.

The heart is made up of four chambers: two atria (the upper chambers) and two ventricles (the lower chambers). The left atria receives oxygen-rich blood from the lungs and the left ventricle then pumps the blood to the body. After traveling through the circulatory system, the blood, now depleted of oxygen, is returned to the heart through the right atria. The blood is then sent to the lungs by  the right ventricle, where it receives oxygen and the cycle begins again.

Blood carries oxygen and nutrients to your cells and removes carbon dioxide and waste products. A sick or failing heart is less able to pump enough blood to sustain the body. In some patients, the heart may swell or stiffen. Heart failure occurs when blood flow is interrupted or cannot keep up with the demands of the body. Vital organs like the kidneys, liver and brain are starved of blood. If adequate blood flow is not restored in time, tissue may die and vital organs can suffer permanent damage.