In the aging heart, the most common change is in the myocardium, the thick layer of muscle. Lipofuscin pigment, a by-product of metabolism, collects and gives the heart a brown color. Muscle fibers decrease and some are replaced by fibrous tissue. Oxygen is used less efficiently.
Four sets of heart valves permit the flow of blood from the atria or upper chambers of the heart into the lower chambers or ventricles and from the ventricles into the aorta and pulmonary artery. With age these valves stiffen and become thicker as the collagen degenerates and fat accumulates. The pacemaker cells in the wall of the right atrium that cause the heart muscle to contract and relax decrease in number. Pulse irregularities are common in the aging.
Cardiac output, the amount of blood pumped into the aorta and the pulmonary artery during each beat, decreases by 25% in the older person. The aorta and other large arteries are less elastic with age. This is arteriosclerosis, a hardening of the arteries due to localized accumulations of fat. It has been said that a man is only as old as his arteries. Blood vessels, in general, are less elastic; they accumulate calcium deposits and become narrower. Peripheral blood flow, the circulation in the extremities, meets more resistance. Blood flow through the kidneys is decreased. A rise in blood pressure is associated with changes of aging. Heredity, diet, and disease are factors that contribute to the aging of the heart.
Under normal, nonstressful conditions, the older person`s heart will adapt well to its functional ability. When more is demanded of it-for instance, when that person climbs stairs or shovels snow-the heart will respond by beating too rapidly. It takes longer for the heart to slow down again in the aging person.
Under normal, nonstressful conditions, the older person`s heart will adapt well to its functional ability. When more is demanded of it-for instance, when that person climbs stairs or shovels snow-the heart will respond by beating too rapidly. It takes longer for the heart to slow down again in the aging person.
Farrell J : Nursing Care of the Older Person, J.B. Lippincott Company, Philadelphia, 1990.
