The heart is a muscular organ that works as a pump to distribute oxygenated blood throughout the body. The heart is comprised of a right and left side with a septum which divides the two. The right and left sides of the heart each contain two chambers, the atrium and the ventricle. Heart valves prevent back flow of blood during the contraction phase, which is under the control of a complex electrical system. There are many cardiac diseases that may interfere with an efficiently pumping heart; the American Heart Association reports that four common diseases of the heart are coronary artery disease, congestive heart failure, arrhythmias and valvular disease.
Coronary Artery Disease
Coronary artery disease is caused by blockages in any or all of the coronary arteries. Interference of the normal blood flow to the heart causes injury or even death to the tissues of the cardiac muscle when they are deprived of essential oxygenation. Narrowing of the coronary arteries is usually caused by plaque, which develops over time and is caused by cholesterol or fat deposits that cling and harden along the lining of the arteries. Restriction of blood flow leads to a diminished oxygen supply to the cardiac muscle frequently resulting in cardiac pain called angina. Total obstruction of a coronary artery causes a myocardial infarction, better known as a heart attack.
Congestive Heart Failure
Congestive heart failure is pump failure. Many types of cardiac disease eventually result in heart failure. When the pump stops working efficiently, residual fluids build up in the lungs, organs and extremities causing symptoms such as shortness of breath, edema of the extremities, weight gain and pain consistent with lack of oxygen to organs and tissues.
Arrhythmias
The heart is regulated by very sophisticated electrical impulses known as the cardiac conduction system. This process begins and ends with electrophysiological pathways that transmit impulses causing contraction and the pumping of blood. Any disruption along the intricate pathways may result in disturbances to the electrical system and the normal functioning of the cardiac chambers. Atrial fibrillation is one common disorder of the conduction system; this is an example of an electrical malfunction which causes sporadic electrical impulses resulting in fibrillation rather than contraction of the atrial chamber. When this occurs, blood in the poorly functioning atrial chamber is not pumped out efficiently, the residual blood backs up, and clots may begin to form. Clots that are pumped out into the circulatory system result in blockages that disrupt the flow of blood to the brain, which may lead to a stroke.
Valve Disease
The heart is designed with four chambers and four valves which allow blood to pass from one chamber to the other. The valves are made of tissue and are described as a flap that allows blood to pass forward in one direction through each chamber. According to the National Institutes of Health, when a valve is damaged or diseased, the flaps of tissue are unable to prevent back flow efficiently.The result is a sluggish retention of blood in the chambers, the risk of clot formation, and a reduction of oxygenated blood to the body.
