The heart has a built-in electrical system that is responsible for every heartbeat. In a steady, rhythmic pattern the electrical pathways run from the top of the heart to the bottom, causing contractions in the upper and lower chambers of the heart. This contraction pumps blood throughout the body and lungs. This well-orchestrated process occurs because of the heart's 'wiring,' which sends the electrical signals that tell the chambers of the heart when to contract.
To ensure the heart pumps an adequate amount of oxygen and nutrient-rich blood throughout the body, the heart chambers, blood vessels and electrical pathways all work together. However, if one item fails, the entire system may fail. For example, clogged vessels can cause a heart attack which, in turn, can kill a portion of the heart muscle. This reduces the heart's ability to pump blood. Furthermore, the area of the heart attack can produce abnormal heart rhythms which can further reduce the heart's pumping ability or even stop it entirely.
Typically, the heart beats 60-100 times a minute, or 100,000 times each day. This state is called ‘normal rhythm.’ Depending on the level of activity the body is experiencing, the heart may beat faster due to running, or slower, such as during sleep.
HEART FUNCTION 101
Your heart is a small muscle, about the size of a clenched fist, with a big job. Its function is simple: to continuously pump about 2,000 gallons of blood each day throughout your body. Blood flow is a complicated trip through parts of the heart. The heart contains four chambers: The right and left atria are the upper chambers; the right and left ventricles are the lower two chambers. There are 4 valves in the heart which allow the blood to flow only one way (the tricuspid vale, pulmonic valve, mitral valve and the aotic valve). First, blood returns to the heart from the rest of the body through the right atrium. This pumps blood through the tricuspid valve into the right ventricle which, in turn, pumps blood through the pulmonary valve to the lungs. Here the blood can receive a new supply of oxygen. Newly oxygenated blood then returns to the left atrium through the pulmonary veins, where it is sent through the mitral valve to the left ventricle. The left ventricle pumps blood through the aortic valve to the rest of the body. Our organs and tissues use up the oxygen and nutrients in the blood and the deoxygenated blood is returned back to the right atrium to start the cycle again.
The heart muscle only contracts when it is stimulated by an electrical signal. This signal comes from a small group of cells located in the right atrium known as the sinoatrial node (or the sinus node). This is the heart's natural pacemaker. The electrical signal travels across the atria and is picked up by another group of cells known as the atrioventricular (or AV) node. This group of special cells is responsible for sending the signals down to the ventricles of the heart. Without this connection, the ventricles would not receive a signal to pump.
Heart disease is the leading cause of death in the United States. The Hoffman Heart and Vascular Institute of Connecticut is a specialized concentration of high-quality medical care and advanced technology. Its programs are focused in the areas of prevention, diagnosis, research, treatment and rehabilitation.