Space will not permit any detailed description of the symptoms and signs of endo- or pericarditis: these will be found in their proper places in this work, but a few observations are needed upon myocarditis, which occasionally occurs in combination with rheumatic pericarditis, and is a source of much more danger than the latter is, per se. Dr. Maclagan63 is almost the only authority who recognizes the occurrence of rheumatic myocarditis independently of inflammation of the membranes of the heart. He maintains that the rheumatic poison probably and not infrequently acts directly on the cardiac muscle; in which case the resulting inflammation is apt to be diffused over the left ventricle and to produce grave symptoms, while in other instances the inflammatory process begins in the fibrous rings which surround the orifices of the heart (especially the mitral), extends to the substance at the base of the heart, and is there localized. As in this latter form the inflammation usually extends also to the valves, "any symptoms to which the myocarditis gives rise are lost in the more obvious indications of the valvulitis." However, this limited inflammation of the myocardium is not dangerous. Dr. Maclagan asserts that the more diffused and dangerous inflammation of the walls of the left ventricle, while always difficult, and sometimes impossible, of diagnosis, can be determined with tolerable certainty in some cases. In this view, however, he has been preceded by Dr. Hayden,64 who states that the diagnosis of myocarditis is quite practicable irrespective of the accompanying inflammation of the membranes of the heart.
63 Rheumatism: its Nature, Pathology, and Successful Treatment, 1881.
64 Diseases of the Heart and Aorta, 1875, 746.
From the observations of the author just named, as well as of many others, it may be inferred that acute diffused myocarditis of the left ventricle exists in rheumatic fever when either with or without coexisting pericarditis there are marked smallness, weakness, and frequency of pulse, anguish or pain or great oppression at the præcordia, severe dyspnoea, the respiration being gasping and suspirious, feeble, rapid, and irregular action of the heart, great weakness of the cardiac sounds, and almost extinction of the impulse, evidence of deficient aëration of the blood combined with coldness of surface, tendency to deliquium, and when these symptoms and signs cannot be fairly attributed to extensive pericardial effusion or to pulmonary disease, or to obstructed circulation in the heart consequent upon endocarditis with intra-cardiac thrombosis or upon rupture of a valve. It might, however, be impossible to exclude endocarditis complicated with thrombosis, conditions which do occur in rheumatic endocarditis, or a ruptured valve, which, although rarely, has been occasionally observed. Grave cerebral symptoms, delirium, convulsions, coma, though frequently present, are not peculiar to acute myocarditis.65 Hence, even with the above group of clinical facts, the diagnosis at best can be but probable. The disease, too, may be latent, or, like Stanley's66 celebrated case, produce disturbances of the cerebral system rather than of the circulatory.
65 In illustration see case by Southey in which the symptoms and signs agree very well with the above description, and yet, although the heart's substance was of dirty-brown color and the striation of its fibre lost, Southey did not believe these appearances due to carditis. (Clin. Trans., xiii. p. 29.)
66 Med.-Chir. Trans., vol. vii.
Dr. Maclagan has advanced the opinion that a subacute myocarditis is not of uncommon occurrence in acute articular rheumatism, and may be unattended by endo- or pericarditis. Such a condition, he says, may be diagnosed when early in the course of the case the heart's sounds quickly become muffled rather than feeble. As he quotes but one case67 in which an autopsy revealed alterations in the walls of the heart, and as endocarditis and a little effusion in the pericardium coexisted, it is premature to accept the evidence as final, and the great importance of the subject demands further investigation.
67 Lib. cit., p. 175.
Admitting with Fuller the occasional deposition of fibrin upon the valves and endocardium in rheumatic fever independently of endocarditis, the murmur resulting therefrom could not be reliably distinguished from that of inflammatory origin. It remains to speak briefly of temporary incompetence of the mitral and tricuspid valves and their dynamic murmurs, and of hæmic murmurs. Occasionally, in severe cases of rheumatic fever, more especially in the advanced stage, there may be heard a systolic murmur of maximum intensity either in the mitral area or over the body of the left ventricle, unaccompanied by accentuation of the second sound, or, as a general rule, by evidence of pulmonary obstruction. Such murmurs are apt to be intermittent, and as they disappear on the return of health, they have been satisfactorily referred to temporary weakness of the walls of the heart, so that the auriculo-ventricular orifices are not sufficiently contracted during the ventricular systole for their valves to close them, and regurgitation follows. Yet, inasmuch as Stokes distinctly mentions the absence of murmur in many cases of softening of the heart in typhus, it is probable that an excessive weakness of the ventricular wall is incompatible with the production of murmur, and that the presence of murmur in such circumstances is evidence of some remaining power in the heart.
Dr. D. West68 has published some cases of acute dilatation of the heart in rheumatic fever which strongly corroborate these views. The murmur in one of them became appreciable only as the heart's sounds increased in loudness and the dilatation lessened. One ended fatally, and acute fatty degeneration of the heart's fibres was found in patches.69 I believe that some of these temporary mitral murmurs in acute rheumatism depend upon a moderate degree of valvulitis quite capable of complete resolution. Sibson70 has lately stated that he has met with the murmur of tricuspid regurgitation without a mitral murmur in 13 out of 107 cases of rheumatic endocarditis, and with a recent mitral murmur in 27 out of 50 cases. "The tricuspid murmur generally comes into play about the tenth or twelfth day of the primary attack, along with symptoms of great general illness;" it appears earlier, as a rule, in those cases in which it is associated with mitral regurgitation than when it exists alone; it is of variable duration, but usually short—from one to nineteen days or more. He regards it as of non-inflammatory origin, and dependent upon regurgitation due to the so-called safety-valve function of the tricuspid valve; and when limited to the region of the right ventricle he infers that it is usually the effect and the evidence of endocarditis affecting the left side of the heart. These novel statements are confirmed by the observations of Parrot, Balfour, and William Russell,71 which go to prove that tricuspid regurgitation occurs frequently in the more advanced stages of debility. No other authority than Sibson, however, insists upon its frequent occurrence in acute rheumatism.