medxclusive: Heart failure is caused by any condition that damages or weakens the heart, reducing it
medxclusive: Heart failure is caused by any condition that damages or weakens the heart, reducing its ability to pump blood efficiently such as heart attacks, high blood pressure, coronary artery disease, or infection. Initially, the heart tries to make up for the loss of cardiac output, by developing more muscle mass, enlarging, and pumping faster. Changes may also occur in the circulatory system, as the body adjusts to lower cardiac output. For example, the blood vessels may narrow to increase blood pressure, and blood may be diverted away from less essential tissues and organs, such as the kidneys, as the body tries to compensate for the heart’s reduced power. Over time, the increased workload leads to changes in the heart muscle itself (known as remodeling), causing it to stiffen, and further reducing its ability to pump blood efficiently, which leads to worsening heart failure. As the heart increasingly struggles to keep up with the body’s demand for blood and oxygen, characteristic signs and symptoms of heart failure begin to appear.Heart failure can involve the left side, the right side, or both sides of the heart. The left ventricle is the stronger of the heart’s two pumps. Left-sided heart failure is more common, and may subsequently cause the right side to fail.Reduced cardiac output and blood supply may have multiple effects in various organs and tissues. These include:• An increased heart rate due to increased sympathetic nervous system activity, the part of the nervous system responsible for accelerating heart rate, constricting blood vessels and raising blood pressure. Although increased heart rate helps maintain cardiac output, it also means more oxygen is needed by the heart itself - increased cardiac perfusion may worsen coronary artery disease or cause arrhythmias, as well as stimulate increases in muscle mass leading to heart enlargement.• Increased blood pressure due to sympathetic nervous system activity (increases the amount of work the heart has to perform).Increased blood volume and blood pressure due to secretion of antidiuretic hormone in response to sympathetic nervous system activity, which causes fluid retention in the kidneys.• Salt and fluid retention by the kidneys caused as a result of reduced blood flow to the kidneys, which ultimately leads to the secretion of aldosterone, a hormone that stimulates the absorption of sodium (Na+) by the kidneys, and regulates the balance of salt and water in the bloodstream.• Heart muscle remodeling caused by chronically high levels of a number of hormones including catecholamines, renin, angiotensin, and aldosterone.• Decreased muscle strength due to skeletal muscle atrophy resulting from reduced perfusion.• Impaired liver function and jaundice caused by severe liver congestion. -- source link