Page:The New International Encyclopædia 1st ed. v. 09.djvu/741

* HEART. 681 HEART OF ENGLAND. exist as a complication of one of the infectious diseases. The valves of the heart may be covered Avitli vegetations, or there may be suppuration or necrosis with destruction of tissue. The vege- tations consist of granulation tissue covered with fibrin and containing many micro-oiganisms. It is most common on the mitral and aortic valves. More rarely, instead of occurring on the valves, iv involves the walls of the heart, when it may lead to perforation either of a septimi or of the external wall itself. Detachment of bits of the vegetations or necrotic tissue is not uncommon. Entering the circulation, they form infectious emboli, setting up foci of infection in distant parts of the body. Chronic endocarditis, the usual forerunner of valvular diseases of the heart, consists in sclerosis of one or more of the valves of the heart. The sclerosis may be primary, but is usually secondary, to the acute form of the disease. In this again, the cause is primarily in most eases rheumatism ; gout, syphilis, al- coholism, and Bright's disease are also important etiological factors. A common cause, especially in the case of the aortic valve, is constant and excessive muscular exertion. There may be small vegetations on the valves representing re- mains of acute inflammation. The valves are thickened, opaque, and shrunken. This shrinkage produces deformity; the edges become curled so that the valve is incapable of perfect closure. In this way the valve may become insufficient without any degree of stenosis (narrowing of the opening), or, as the process goes on and the thick- ening becomes greater, the stenosis may be marked. In the later stages of the disease lime salts are frequently deposited in the new con- nective tissue of the valves, forming a dense mass of calcareous tissue. Chronic endocarditis may aflfect the walls of the heart, forming patches of fibrous tissue. Tuberculous endocarditis some- times occurs. Endocarditis, whether due to rheumatic in- flammation (and the heart complication is said to occur in over 40 per cent, of the cases of rheumatism ). or whether due to other causes, produces difficulty with the action of the valves of the heart. The thickening of the cusps or flaps of the valves, due to deposits between the •ayers of endocardium which cover them, makes them clumsy and unyielding. They may obstruct the flow of blood through them, causing slenosis. The valve-flaps may become shortened from con- traction of the fibrous structure newly developed, and allow the blood to flow back through the valves when they are shut as tightly as possible, causing rcrnirgitation. Alteration of the normal heart sounds reveals to the trained ear informa- tion which will determine the condition. (See Sounds of the Heart, in the article Heart.) A rough surface on the valve-flaps may lead to a deposit of fibrin from the blood, and the formation of a thrombus (q.v. ). A thrombus, or a vegetation (a fringe or small lump of granulation tissue), may become broken off and be carried up into an artery of the brain, plug- ging it, with dire results. Such a plug is called an embolus, and the occurrence is termed emholisrn (q.v.). The result of embolism of a cerebral artery may be immediate death, pa- ralysis, convulsions, or secondary softening, with consequent mental deterioration in course of time. Chronic endocarditis may exist for a con- siderable length of time without causing any symptoms; the heart becoming hypertrophied in one or another of its parts, and being thus en- abled to meet the extra amount of work that is thrown upon it by the valvular stenosis or in- sufficiency. Sooner or later, however, the disease causes the appearance of symptoms, of which the most characteristic are: Shortness of breath, liemorrliage from the lungs, bluencss of the lips and finger-nails, dropsy of the hands and feet, dyspepsia, headaches, vertigo, and fainting spells. The prognosis depends upon the partiouhir valve afl'ected, the existence or non-existence of com- pensatory hypertrophv, the age of the patient, etc. Hypertrophy of the He.rt. This consists in thickening of the heart walls, the cavity of the heart remaining of normal size {simple hyper- trophy), contracting (concentric hypertrophy), or dilating (eccentric hypertrophy) . The muscle tissue in hypertrophy of the heart is enlarged, probably both by increase in the number of fibres and by increase in size of the individual fibres. The hypertrophied muscle is dense, firm, and dark in color. If the hypertrophy afi'ects both ven- tricles, there is an increase in both length and breadth of the heart. If the left ventricle alone is aiTected, there is an increase in the length of the heart, while hj'pertropliy of the right ventri- cle broadens the heart on the right side. Hyper- trophied hearts may weigh from two to three pounds or more. Dilatation of the heart may, as already mentioned, be associated with hyper- tiophy. This is known as active dilatation. Or dilatation may occur with thinning of the heart walls, which is known as passive dilatation. The dilatation may affect any one or all of the cavi- ties. The right side of the heart is more fre- quently affected than the left side. Dilatation with compensating hypertrophy, if the valves of the heart are competent, is of little moment. The heart is the stronger for the hyper- trophy. Jlountain-climbing may cause it, as well as mental emotion with oft-repeated increase of the heart's action, or obstacle to the circulation. When the heart has become enlarged as a sequel of kidney disease, it is the latter that causes death when it comes. The ventricles are far more often dilated than the auricles, though all four cavities may be dilated. Should the hyper- trophied heart become fatty, a grave danger arises; progressive cardiac failure may occur, with weakening of the circulation and dropsy of the lower extremities. In the main, heart diseases are rare, and they are an infrequent cause of death. One with val- vular trouble of a mild degree may fulfill the ordinary expectation of life, if he is content to live on a level, avoiding violent exercise, running or lifting, and avoiding anger, grief, and general emotional conditions. Cases of sudden death, called death from heart disease, are often due to cerebral embolism. Aneiieism of the Heart is very rare. It is al- ways fatal. Consult: Striimpell. Text-Book of Medicine (New York, 1901) ; Osier, Practice of Medicine (New York, 1901). HEART-BURIAL. See Burial. HEART-LYMPH. See Circi-latory Sys- tem. Evolution of. HEART OF ENGLAND. A name applied to Warwickshire, as the middle county of England.