Page:The New International Encyclopædia 1st ed. v. 09.djvu/740

* HEART. G80 HEART. disease, or it may be due to emotional disturbance (as fright or embarrassment), or to excessive pliysical strain, or to indigestion, with a produc- tion of gas and toxins, or to nervous disorder such as neurasthenia, or to tobacco, tea, cofTee, alcohol, or certain drugs, or to hemorrhage, or to certain diseases, such as Basedow's disease (q.v. ). Generally nervous excitability, appre- hension, shortness of breath, increased perspira- tion, and flushing of the face accompany palpita- tion. Acute pain in the heart is experienced by some patients during attacks of hysteria, for example; neuralgia of that organ also occurs. Cardiac pain also accompanies fermentative dys- pepsia. Disease of the coronary arteries causes, it is believed, the exquisitely painful angina pectoris (q.v.). ORGANIC DISEASES. Besides angina pectoris, these include peri- carditis, endocarditis, myocarditis, hypertrophy, dilatation, embolism, aneurism, and degenerative changes without inflammation. More than one disease may be foimd co-existing, and both func- tional and organic diseases may be present to- gether. Pericarditis is an inflammatory disease in which the pericardium is thickened and rough- ened. The pericardium is a loose sac in which the heart lies, and its lining membrane is re- flected over the external surface of the heart. The disease often coexists with gout or articular rheumatism, and is due to the same cause ; or it accompanies Bright's disease. It may also be caused by injuries, exposure to cold and damp- ness, infectious diseases, etc. The normal serous fluid which should exist in the pericardium dis- appears and a sero-fibrinous fluid exudes from the blood-vessels, sometimes greatly distending the pericardial sac, generally causing adhesions be- tween the two layers of the pericardium. If the amount of pericardial distention be great, the patient suffers with rapid pulse, oppressed breathing, and faintness. Occasionally the fluid must be drawn ofi' by tapping. The attacks are always serious; and, if recurring, are generally fatal. There is pain felt, from the rubbing of the roughened surfaces as the organ beats, ac- companied by what is called a friction sound. The area of heart dullness, as shown by percus- sion, increases with the production of fluid. In favorable cases the fluid is absorbed, and the sac regains, in great part, its normal condition. In very bad cases the inflammatory exudate con- sists of pus ; such cases usually terminate fatal- ly; evacuation of the pus affords the only hope of recovery. Degenerative Changes in the Heart Mus- cle. Parench natous degeneration, or cloudy swelling, as it is often called, is the form of de- generation which usually accompanies the infec- tious diseases such as diphtheria or typhoid fever. The heart walls are somewhat softer than nor- mally, and rather paler in color. The changes in the heart muscle cells are quite similar to the changes of parenchymatous degeneration in the cells of other organs. (See Degeneration.) The heart cells become gradually more granular, and in proportion to the extent of the granulation lose part or all of their normal striated appear- ance. 'Hyalin,' 'amyloid,' and 'calcareous' de- generation may occur in heart muscle. Fatty degeneration of the heart muscle is a quite com- mon lesion. Its causes are: auiemia, old age, wasting diseases, prolonged infectious fevers, cer- tain poisons, such as phosphorus, etc. It consists in the replacement of the heart muscle cell proto- plasm by, or its transformation into, fat, to a greater or lesser extent. The degeneration is often not distributed uniformly throughout the heart muscle, but occurs in patches. The degenerated muscle looks pale in color and is softer than normally. The fat droplets within the cells may be large or small, may be few in number, or in such numbers as to entirely destroy the normal appearance of the tissue. What is known as 'fatty infiltration of the heart' is not a lesion of the heart muscle itself, but consists in an accumulation of fat beneath the pericardium and in the connective tissue between the muscle-fibres. The amount of fat may be veiy large, causing atrophy of the muscle-tissue and interfering with the functions of the organ. Myocarditis. This is an inflammation occur- ring in the middle or muscular layer of the heart walls and involving also the blood-vessels and interstitial connective tissue. The acute form is frequently suppurative in character, and occurs as an extension from an ulcerative endo- carditis or pericarditis, or as a complication of one of the infectious diseases. It may be diffuse, or, as is more commonly the case, circumscribed with the formation of abscesses. In the chronic form of myocarditis the lesion consists in an in- crease in the connective tissue elements of the heart, with more or less atrophy of the muscular elements. The condition is usually associated with lesions of the coronary arteries. Opinions differ as to the primarj' lesion, some holding that the atrophy of the heart muscle is dependent upon the increase in connective tissue, a true pro- ductive inflammation; others that the degenera- tion of the heart muscle occurs first, the connec- tive tissue proliferation being of the nature of a replacement hyperplasia. Syphilitic myocarditis and tubercular myocarditis sometimes occur. Myocarditis may give rise to few or no symptoms. Endocarditis. The lesion in endocarditis is an inflammation of the endocardium, or lining mem- brane of the heart. While any portion of this membrane may be involved, it is common for the inflammation to be confined to that part of it whieh covers the valves of the heart and to result in an impairment of their efficiency. For this reason it is often referred to as 'valvular heart disease' or 'valvular endocarditis.' Simple acute endocardHis is a frequent complication of rheu- matism. It may also be caused by some of the acute infectious diseases, especially scarlet fever and pneumonia. There may be simply thickening of the valves of the heart, their surfaces remain- ing smooth ; or the valves may be rougli .and either eroded or studded with new growths, called vegetations, which give them a warty appear- ance. Microscopically the vegetations are seen to be made up of granulation tissue, covered on the surface with a layer of fibrin. There is usu- ally more or less proliferation of the cells in the subendothelial connective tissue. Malignant or ulcerative endocarditis is due to the action of bacteria. The streptococcus and staphylococcus pyogenes arc the most common incitants. ]Iore rarely the pneuraococcus. the gonococcus. or the bacilli of anthrax, tuberculosis, or typhoid fever are present. Tlie condition may be either pri- mary or, as is more frequently the case, it may