CASCS.
The mynearilitis may involve the entire cardiac muscle, including the papillary muscles. Peter (La Sem. Mrs1., Mar. 14, '91).
Cystic degeneration of the muscular fibres a number of eases. This condi tion found most marked in tlie fibres of the papillary muscles of the left ventricle, t' :twul in all other parts of the -rf rhe degree of rile exenva t... 11 „LI It 4 \ The destructive r • - i 11 11, 1110,t CA rt`1111: re1110VeS t. e ' the mustular substance from ,,tre bf the fibre. no part of which, tnt ‘.1111illed NN t lie microscope, ill 1.1, • t e 11,11.11 appearance, 1111d eve» t_ tr.1) ,11% 1110 cross-markings r;stiL of heart-muscle only in places.
I • e mu,tle nuclei often lies loosely in II e eat ith s. A. V. Meig.s (Amer. Jour. Ski_ May. '921.
In a srvere ease of gonorthrea the ptritardium was universally thickened sic] sw tiled and contained numerous i It ly-dilated blood-vessels with thin walls TI e blood found in the pericardial cavity came from the rupture of these vessels. In some places, the lesions of the n yocardiurn, although most intense near the endoeardium, appeared to ex tend from the pericardium and could be traced directly to this. The muscular fibres showed various degrees of degen eratir n. In the slightest change they ap peared slightly swelled. diffusely stained, their nuclei had disappeared. and they fr. quently contained vacuoles. There v‘;„ every degree of change from this up to a total necrosis of the muscular fibres, an I an entire substitution of areas of rurulLtit infiltration and necrosis for the rmal tissue of the heart. Some of the areas of degeneration involved almost the entire thiekness of the wall of the ven tricle and auricle. Extensive hremorrhage was found in some of the necrotic foci. Grnocceei were found in the sections in considerable numbers. IV. T. Council man Amer. Jour. Med. Sciences, Sept., 'ft3 .
The Tre,ent prevailing conception of thi- a.,..te infectious myocarditis is that tlic ;n.i.;ry to the muscular fibre is the prin ary condition, and that the intersti tial :I anfres are a reactive inflammation, sPet ndary to the di.sorg.anization of the
m II. The curtoxir FORM of myocarditis is generally regarded as merely a degener vire. and not an inflammatory, process.
Other names for it are chronic interstitial mvocarditis; fibroid inyocarditis; and fibroid infiltration, or cirrhosis, of the mvocardium. Its most frequent causes are lesions of the corollary arteries. It may also be associated with chronic peri carditis and chronic endocarditis. Occa sionally it is seen where none of these diseases exist. It may be comparatively diffuse or circumscribed, the parts most conunonly affected being the left ven tricle and the septum between the ven tricles. and in these portions of the heart it is more marked near the apex than near the base.
It consists in a growth of new con nective tissue between the muscular fibres,. which latter atrophy and degener ate. The process may be one of very slow development, corresponding with slow diminntion in the lumen of the corre sponding artery, or it may begin abruptly as the result of embolism, or more fre quently thrombosis, of the coronary ar tery or one of its branches. The ante rior or left coronary artery is the one most apt to be diseased; hence the fre quency of the chanae in the left ven tricle.
When the lumen of the artery is sud denly closed, the portion of the heart de pendent upon that artery for nutrition becomes necrotic.
The muscular fihre breaks down into granular detritus, and the connective tis sue undergoes a retrograde metamor phosis; so that the affected portion be comes yellow-ish white or gray and of soft consistency. It may be also of a dark-red color from the blood and present the ap pearances of an hmmorrhag,ic infarction. This softened area of nayomalacia may occasion rnpture of the heart or acute in flammation; or it may be gradually ab sorbed and superseded by new connective tissue, which finally shrinks into a scar.