patient is lying down. This puts further strain on the heart. See also heart attack: first aid. Heart failure, congestive (кэп jes'tiv). Congestive heart failure is a condition in which the heart is unable to main­tain the normal circulation of the blood. Heart failure does not mean that the heart stops suddenly (cardiac ar­rest), rather that it gradually becomes inefficient as the blood in the veins in­creases in volume and the veins be­come dilated. The lungs, liver, and in­testines become congested with blood. There are many causes of congestive heart failure: weakness of the heart muscle; hypertension (high blood pres­sure); heart attack; a chronic lung dis­ease (such as emphysema); disease of the heart valves; hyperthyroidism (overactivity of the thyroid gland); a viral illness; arrhythmia (irregular heart­beat); severe anemia; or pulmonary em­bolism. Untreated, the condition can be fatal.

Q: What are the symptoms of conges­tive heart failure? A: The symptoms include breathless- ness (as fluid backs up in the lungs), swollen ankles (a form of edema), and weakness. Q: How is congestive heart failure treated?

A: A physician may prescribe a di­uretic drug, which helps to relieve any swelling (edema) in the body tissues and reduces some strain on the heart. A salt-free diet is some­times recommended to help pre­vent any further retention of fluids. In addition, digitalis may be used to improve the strength of the heartbeat. In some cases, drugs may also be given that dilate the arteries, thus making it easier for the heart to pump blood. Bed rest with hospitalization, if necessary, is advised for acute congestive heart failure. Oxygen may be re­quired, and a source of oxygen should be kept available. Heart-lung machine is an apparatus that permits the heart to be operated on safely. This machine, which utilizes an oxygenator and a pump, allows the sur­geon to operate on a bloodless, unbeat- ing heart. The heart-lung machine not only temporarily takes over the pump­ing activities of the heart, but also oxy­genates the blood and removes carbon dioxide from it. Thus, the rest of the body is supplied with vital blood cir_cu lation during heart surgery. With this machine, many types of heart surgery that were previously impossible or ex­tremely dangerous can now be done with comparative safety. These include heart transplants, coronary by-passes removal and replacement of damaged valves, and repair of other structural defects.

Heart massage. See cardiac massage. Heart murmur (mer'mar) describes an abnormal noise produced by the blood flowing through the chambers and valves of the heart.

With any murmur, a physician must be consulted. Many heart murmurs re­quire no treatment, although a few may require some form of heart surgery. Be- fore undergoing surgery or dental work, a person with a heart murmur should inform his or her physician or dentist of the condition. Antibiotics may be needed before the procedure, in order to prevent bacterial endocarditis.

See also endocarditis. Heart pacemaker. See pacemaker, ar­tificial; pacemaker, natural.

Heart Stoppage, or cardiac arrest, is a temporary or permanent failure of nor­mal heart muscle contractions. When the heart stops, blood ceases to be pumped around the body. Various tis­sues, particularly those of the brain, then become adversely affected by the lack of oxygen.

Heart stoppage may be caused by a severe electric shotik; a coronary thrombosis (blood clot); or heart dis­ease, particularly when it affects the heart muscle, as in cardiomyopathy and myocarditis. Heart stoppage may also result from an irregular heart rhythm (arrhythmia) or Stokes-Adams syndrome. During heart surgery it is sometimes necessary to stop the heart deliberately. The heart is restarted by electrical stimulation (cardioversion).

See also arrhythmia; heart attack; heart disease; stokes-adams syn­drome.

Heart surgery is any surgical operation on the heart. There are two main forms of heart surgery, open and closed. Щ general procedure in an open technic⁸ is to cut open the chest cavity and WW expose the heart. The patient's blood supply is then connected to a heart. tion _{is a}i_So used to describe the ■tting ^of anesthesia. It may refer to b<travenous injection of a short-act- # !Lbiturate or the initial inhalation

*?„ anesthetic gas.

Щ^aD _ychology, induction is a logical ^{10 P}_{gs 0}f learning. The term also de- fl^jf feelings reflected in another

oir for example, grief in one per- P^ers ' induce sympathy in another. Oration (in du ra'shan) is an area of Eiual hardness or firmness in a body I -j-he term may refer to bruising, around a wound, or the hard- d tissue surrounding an abscess. Uustrial diseases are disorders Eased by exposure to industrial haz- Щ including toxic substances, tem- ⁸¹ ature extremes, mechanical hazards, I d biological hazards, such as micro- nanisms that are used in industrial orocesses.

See also occupational hazard. infantile paralysis. See poliomyelitis. wfarction (in fark'shan) is the death of body tissue caused by a blockage of the blood supply to that tissue. The seri­ousness of the condition depends on the location of the infarction. q: What causes an infarction? a: An infarction is caused by an arte­rial thrombosis (blood clot). The blood clot may be the result of ar- % teriosclerosis, damage to the blood

Vessel, or an embolism (a blood ? clot from another part of the body

that becomes trapped in the artery). Q: What are the symptoms of an in- || farction?

A:; The symptoms depend on which part of the body is affected. If the infarction is in the heart muscle ^myocardial infarction), the pa­tient's symptoms may range from a feeling of mild indigestion to se­vere pain that radiates from the left side of the chest to the left arm, neck, shoulders, back, and jaw. These symptoms are usually a sign (rf angina pectoris and are often the first warning of an impending heart attack.

|8 the infarction is in the brain, the patient suffers a stroke. In both - the brain and myocardial infarc­tions, there are no alternative blood supplies, and the tissues die. И the infarction is in the leg, the patient experiences acute cramp­ like pain, and the leg becomes white and cold. If the patient does not receive immediate surgery, gangrene (death of tissue) rapidly sets in. An infarction in the kidney produces blood in the urine (hema­turia).

Q: Can an infarction be treated? A: No. Once the tissue has died, it can not be replaced. It can gradu­ally heal and form scar tissue. Treatment is aimed at preventing another embolism or thrombosis from developing and causing a fur­ther infarction. Emergency surgery can replace part of the femoral ar­tery with a graft or plastic tubing, but if the tissues have already died, amputation is the only treat­ment.

See also gangrene; heart disease,

Coronary; stroke.

Infection (in fek'shan) is the invasion of the body by disease-producing organ­isms. There are six main types of infec­tive organisms: viruses, bacteria, fungi, protozoa, worms, and rickettsia. An in­fection may enter the body through air that is breathed, in food or liquid that is ingested, directly through the skin, or from another part of the body.

See also bacteria; communicable disease; fungal infection; infectious disease; protozoa; Rickettsia; virus. Infectious disease is an illness caused by the growth of disease-producing mi­croorganisms in the body; the infec­tious disease may be contagious.

The table on page 488 lists many common infectious diseases, each of which also has a separate entry in this encyclopedia. Other infectious diseases include amebic dysentery; brucellosis; cholera; epidemic pleurodynia; en­cephalitis; hand-foot-and-mouth dis­ease; hepatitis; rabies; sexually trans­mitted diseases; smallpox; toxoplasmosis; tuberculosis; typhoid fever; typhus; yaws; and yellow fever. Each of these diseases also has a sepa­rate entry in this encyclopedia, infectious mononucleosis. See mono­nucleosis.

Inferiority complex is a repressed state of mind in which a person believes himself or herself to be inferior to others.

See also complex.

Treatment with chemotherapy, corticosteroids, and radiotherapy may greatly prolong the patient's life, but the disease is eventually fatal. Treatment of secondary infec­tion with antibiotics and blood transfusion for severe anemia im­prove the patient's general health and vitality. See also chemo­therapy; corticosteroid; radio­therapy.

i Myocardial infarction. See heart at-

1 TACK.

Myocarditis (mi | kar di tis) is inflam­mation of the heart muscle. The symp­toms at first are often vague and mild. Fatigue, shortness of breath, and some­times palpitations (rapid, irregular I heart beat) occur. Heart failure may de­velop, and sometimes blood clots form in the heart. Pieces of the clots (emboli) may travel in the blood circulation to other parts of the body and cause strokes or sudden obstruction of an ar­tery to a limb, resulting in gangrene, the decay and death of tissue. Q: What causes myocarditis? A: Various infections can affect the heart muscle, either directly or by producing toxins that affect it, such as those from diphtheria. Many other conditions, such as disseminated lupus erythematosus and rheumatic fever, can also in­volve the heart. See also diphthe­ria; lupus erythematosus; rheu­matic fever.