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Congestive Heart Failure (CHF)

What is congestive heart failure (CHF)?

Heart failure describes the inability or failure of the heart to adequately meet the needs of organs and tissues for oxygen and nutrients. This decrease in cardiac output, the amount of blood that the heart pumps, is not adequate to circulate the blood returning to the heart from the body and lungs, causing fluid (mainly water) to leak from capillary blood vessels. This leads to the symptoms that may include shortness of breath, weakness, and swelling.

Understanding blood flow in the heart and body

The right side of the heart pumps blood to the lungs while the left side pumps blood to the rest of the body. Blood from the body enters the right atrium though the vena cava. It then flows into the right ventricle where it is pumped to the lungs through the pulmonary artery, which carries deoxygenated blood to the lungs. In the lungs, oxygen is loaded onto red blood cells and returns to the left atrium of the heart via the pulmonary veins. Blood then flows into the left ventricle where it is pumped to the organs and tissues of the body. Oxygen is downloaded from red blood cells into the various organs while carbon dioxide, a waste product of metabolism, is added to be removed in the lungs. Blood then returns to the right atrium to start the cycle again. The pulmonary veins are unusual in that they carry oxygenated blood, while the pulmonary artery carries deoxygenated blood. This is a reversal of duties versus the roles of veins and arteries in the rest of the body.

Picture of a cross section of the heart.
Picture of a cross section of the heart.

Left heart failure occurs when the left ventricle cannot pump blood to the body and fluid backs up and leaks into the lungs causing shortness of breath. Right heart failure occurs when the right ventricle cannot adequately pump blood to the lungs. Blood and fluid may back up in the veins that deliver blood to the heart. This can cause fluid to leak into tissues and organs.

It is important to know that both sides of the heart may fail to function adequately at the same time and this is called biventricular heart failure. This often occurs since the most common cause of right heart failure is left heart failure.

Reviewed on 5/19/2016

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