The portion of the heart affected by interstitial degeneration is thinner than normal. The remainder of the heart may become hypertrophied to a certain ex tent; finally, it is almost certain, if life is prolonged, to become dilated. The fibroid spot may be so situated as to make no great difference in the contour of the heart-wall, but, if situated toward the apex of the heart, it may yield to the tension of the contained blood and give rise to a cardiac aneurism. Such an aneurism may be found after death in cases where it has not greatly affected the health of the patient. Or, again, it may finally rupture and cause sudden death, or it may become so large as fatally to impede the activity of the heart. Fur thermore, on the internal surfaces of car diac aneurisms thrombi are apt to form, and these may give rise to embolic proc esses. In some cases the fibroid parts of the heart exhibit a calcareous deposit.
When chronic myocarditis is the result of pericarditis or endocarditis, the proc ess is a diffuse one and superficial, in volving the fibres adjacent to the in flamed membrane. As already stated, valvular disease of chronic pulmonary obstruction, in their terminal results of cardiac dilatation and venous stasis, may give rise to fibroid changes in the heart muscle. These are more or less diffuse. They may demand careful microscopical examination in order to be detected. and their symptoms merge with and aggra vate the effects of the original disorder.
Results of extensive studies upon the subject of fibroid degeneration and allied lesions, as relating to the heart and cor onary arteries 11101T particularly. A very sharp distinction must always be drawn between true atrophic fibroid degenera tion and interstitial myocarditis; al though similar in their results, they differ very markedly in their mode of 1 production, and the former is the much more common lesion than the latter.
The influence of a morbid state of the coronary arteries must be taken into ac count in considering all diseases of the heart, but especially those of the myocar dium, and no examination of the heart can be regarded as complete which does not include a careful investigation of the state of these vessels. Steven (T,ancet, Dec. 24, '87).
In those cases of myocarditis charac terized by cedema and dyspncea the inyo carditis is principally localized in the auricles. Arteriosclerosis is not by any means confined to the later years of life, and it is in these youthful cases of ar terial disease that myocarditis is espe cially noted. This arteriosclerosis is sometimes noticed shortly after puberty, chiefly in males. It is commonly the result of various toxcemias, the most notable of which is, perhaps, that result ing from the use of tobacco. Then there are cases of hereditary myocarditis with out any toxic element, occurring almost wholly in young males. J. Adler (Med. Record, Jan. 27, 1900).
Prognosis.—I. ACUTE MYOCARDITIS.— Diffuse suppuration or abscess-formation is almost invariably fatal. The paren chymatous changes associated with in fectious diseases aggravate the patient's malady and lessen his resistant powers, but they are of compara,ively favorable prognosis. l'"ndoubtedly very many more of such cases recover than die. As in many other conditions, recognition of the danger is of great advantage to the patient. The avoidance of undue exer tion and the careful nursing and feeding of the sufferer contribute much to his safety.
The prognosis of aeule rheumatic. inyo. carditis is much more favorable than in case of endocarditis, for complvte re covery follows, except in cases that are immediately fatal. En the acute condi tion death may occur in syncope. Peter (La Sem. MM., Mar. 11, '91).