Hearst VhorstV William Randolph (b. April 29, 1863, San Fran¬ cisco, Calif., U.S.—d. Aug. 14,
1951, Beverly Hills, Calif.) U.S. newspaper publisher. Hearst in 1887 took over the struggling San Fran¬ cisco Examiner, which he remade into a successful blend of investiga¬ tive reporting and lurid sensational¬ ism. After buying the New York Morning Journal (later New York Journal-American) in 1895, he fought fierce circulation wars with other papers and helped bring about the era of yellow journalism, employ¬ ing circulation-boosting strategems that profoundly influenced U.S. jour¬ nalism. Distorted reportage in Hearst papers fanned public sentiment against Spain that led to the Spanish- American War. He served in Con¬ gress (1903-07) but ran unsuccessfully for other offices. In the 1920s he built a grandiose castle in San Simeon, Calif. At the peak of his fortune in 1935 he owned 28 major newspapers, 18 magazines, radio stations, movie companies, and news services. Extravagance and the Depression weakened him financially, and by 1940 he had lost control of his empire. He spent his last years in virtual seclusion.
heart Organ that pumps blood, circulating it to all parts of the body (see circulation). The human heart is a four-chambered double pump with its right and left sides fully separated by a septum and subdivided on both sides into an atrium above and a ventricle below. The right atrium receives venous blood from the superior and inferior venae cavae (see vena cava)
William Randolph Hearst, 1906.
LIBRARY OF CONGRESS, WASHINGTON, D.C.
© 2006 Encyclopaedia Britannica, Inc.
852 I heart attack ► heat pump
and propels it into the pulmonary circulation. The left atrium takes in blood from the pulmonary veins and sends it into the systemic circula¬ tion. Electrical signals from a natural pacemaker cause the heart muscle to contract. Valves in the heart keep blood flowing in one direction. Their snapping shut after each contraction causes the sounds heard as the heart¬ beat. See also cardiovascular system.
tricuspid
valve
right ventricle
inferior - vena cava
left common carotid artery -left subclavian artery
aorta
left
pulmonary artery
pulmonary trunk
left veins left atrium (auricle) mitral valve pulmonary valve
papillary
muscle
left
ventricle
septum
artery right
pulmonary artery superior vena cava
right pulmonary veins
right
atrium
Structure of the human heart. Oxygen-rich blood from the lungs enters the heart through the pulmonary veins, passing into the left atrium and on to the left ventricle. Contraction of the muscles of the left ventricle forces blood into the aorta. The mitral valve prevents blood from moving back into the left atrium during contraction. Vari¬ ous arteries branch off from the aorta to supply blood to all parts of the body. Oxygen-poor blood draining from the body into the superior vena cava and infe¬ rior vena cava flows to the right atrium, through the tricuspid valve, and into the right ventricle. As the right ventricle contracts, oxygen-poor blood passes through the pulmonary valve into the pulmonary arteries and on to the lungs to receive oxy¬
gen.
© MERRIAM-WEBSTER INC.
heart attack or myocardial infarction Death of a section of heart muscle when its blood supply is cut off, usually by a blood clot in a coro¬ nary artery narrowed by atherosclerosis. Hypertension, diabetes mellitus, high cholesterol, cigarette smoking, and coronary heart disease increase the risk. Symptoms include severe chest pain, often radiating to the left arm, and shortness of breath. Up to 20% of victims die before reaching the hos¬ pital. Diagnosis is done by electrocardiography and by analysis for enzymes in the blood. Treatment aims to limit the area of tissue death (infarct) and prevent and treat complications. Thrombolytic (clot-dissolving) drugs may be administered. Beta-blockers alleviate pain and slow the heart rate. Angioplasty or coronary bypass restores blood flow to heart muscle. Follow-up may include drugs, exercise programs, and counseling on diet and lifestyle changes.
heart clam See cockle
heart disease Any disorder of the heart. Examples include coronary HEART DISEASE, CONGENITAL HEART DISEASE, and PULMONARY HEART DISEASE, as well as rheumatic heart disease (see rheumatic fever), hypertension, inflamma¬ tion of the heart muscle (myocarditis) or of its inner or outer membrane (endocarditis, pericarditis), and heart valve disease. Abnormalities of the heart’s natural pacemaker or of the nerves that conduct its impulses cause arrhythmias. Some connective tissue diseases (notably systemic lupus erythe¬ matosus, rheumatoid arthritis, and scleroderma) can affect the heart. Heart failure may result from many of these disorders.
heart failure Inability of one or both sides of the heart to pump enough blood for the body. Causes include pulmonary heart disease, hypertension, and coronary atherosclerosis. A person with left-sided heart failure expe¬ riences shortness of breath after exertion, difficulty in breathing while
lying down and night breathlessness, and abnormally high pressure in the pulmonary veins. A person with right-sided failure experiences abnor¬ mally high pressure in the systemic veins, liver enlargement, and accu¬ mulation of fluid in the legs. A person with failure of both ventricles has an enlarged heart and a three-beat heartbeat. Treatment includes bed rest, medications such as digitalis, control of excess salt and water retention, and elimination of the underlying cause. See also congestive heart failure.
heart transplant Procedure to remove a diseased heart and replace it with a healthy one from a legally dead donor. The first was performed in 1967 by Christiaan Barnard. The diseased heart is removed (except for some atrial tissue to preserve nerve connections to the natural pacemaker). The new heart is put in place and connected to the recipient’s blood ves¬ sels. Patients and donors are matched for tissue type, but the patient’s immune system must still be suppressed to prevent rejection (see immuno¬ suppression). A successful transplant can enable the recipient to have an active life for many years.
heartwood Dead, central wood of trees. Its cells usually contain tan¬ nins or other substances that make it dark and sometimes fragrant. Heart- wood is mechanically strong, resistant to decay, and less easily penetrated by wood-preservative chemicals than other types of wood. One or more layers of living and functional sapwood cells are periodically converted to heartwood.
heartworm Species (Dirofilaria immitis) of filarial worm that parasit¬ izes mammals, especially dogs. Up to 500 adult heartworms, which can grow to 6-12 in. (15-30 cm) long, live in the dog’s heart, and the microfi¬ lariae (embryonic larvae) pass into the blood. Mosquitoes transfer infested blood from dog to dog. Both adult and larval heartworms tax the heart and restrict blood flow to the lungs, kidneys, and liver. By the time vis¬ ible symptoms (chronic cough, labored breathing, listlessness, heart fail¬ ure) develop, it may be too late for treatment. Preventive medicines and treatments, including surgery, exist.
heat Energy transferred from one body to another as the result of a dif¬ ference in temperature. Heat flows from a hotter body to a colder body when the two bodies are brought together. This transfer of energy usually results in an increase in the temperature of the colder body and a decrease in that of the hotter body. A substance may absorb heat without an increase in temperature as it changes from one phase to another—that is, when it melts or boils. The distinction between heat (a form of energy) and tem¬ perature (a measure of the amount of energy) was clarified in the 19th century by such scientists as J.-B. Fourier, Gustav Kirchhoff, and Ludwig Boltzmann.