Congestive heart failure is a condition in which the heart fails to keep blood moving adequately. As a result, the supply of blood to the body's tissues decreases, lowering efficiency and endurance. With poor circulation, the kidneys fail to remove enough waste products, water and salt from the blood. In addition, the kidneys, because of the decreased blood flow presented to them, retain even more salt and water in an effort to increase blood volume.
The increased blood volume makes more work for the already overworked heart, which may enlarge and beat faster in an attempt to provide the body with oxygen-rich blood. The veins distend with fluid and the blood volume increases.
At the same time, there's a shift in the balance of pressures between fluids inside and outside the blood vessels, which causes fluid that normally stays in the bloodstream to leak into surrounding tissue. This fluid leakage is a primary factor in fluid overload in the lungs, abdomen and/or legs.
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