Pathophysiology of Chf
Pathophysiology of Congestive Heart Failure
I. Description: Congestive Heart Failure is more of a syndrome than a disease. Heart failure may be classified according to the side of the heart affected, (left- or right-sided failure), or by the cardiac cycle involved, (systolic or diastolic dysfunction). (Schilling-McCann p. 176). The word "failure" refers to the heart's inability to pump enough blood to meet the body's metabolic needs. (Schilling-McCann p. 176). When the heart fails to deliver adequate blood supply edema may develop. (Cadwallader p. 1141). Where edema occurs depends on what side of the heart is failing. Left-sided heart failure results from the inability of the left ventricle to function properly. Blood fails to get out to other parts of the body as quickly as it returns from the lungs. When blood doesn't get back to the heart, it backs up in the lungs blood vessels. Blood is then forced into the intracellular space in the lungs causing pulmonary edema. (Cadwallader pp. 1141 - 1142). Right-sided heart failure results from the inability of the right ventricle to function properly. Blood isn't pumped to the lungs as quickly as it returns from the other parts of the body. Fluid then begins to back up in the veins and pushes out into the tissues, causing edema, most often in the feet, lower legs, and ankles. (Cadwallader p. 1142). Sluggish blood flow also deprives organs of oxygen and other nutrients causing fatigue and difficultly with physical exertion. The heart tries to compensate for its lack of pumping ability by becoming hypertrophic. This causes the muscle in the heart's wall to thicken thus improving the hearts pumping ability. (Cadwallader p. 1142). The heart may also increase heart rate to improve output and circulation. The kidneys eventually join in by retaining salt and water to increase volume, but this extra fluid can cause edema and further complicate the situation. (Cadwallader p. 1142).