Endocarditis By Its Proximate, no less than its secondary results, and therefore by a twofold local cause, may give rise to Dilatations of the Heart. As we have already observed in treating of these diseases, the form of dilatation thus occasioned is of a passive character, and depends on paralysis of the muscular substance of the heart, which is implicated in the inflammation. The dilatation is moreover mechanically increased in the more remote sequelae of extensive endocarditis by the continuance of a morbid condition of the valves, which are almost invariably implicated; and in these cases a moderate degree of hypertrophy is gradually associated with the dilatation. The dilatation must also, as is evident, be more considerable from its very origin, and must be of a more decided passive character, where endocarditis has been combined with pericarditis and carditis; and where the latter affection is of a very intense and deep-seated character, endocarditis may give rise to true aneurism of the heart.

Endocarditis occurs with a preponderating degree of frequency in the left side of the heart, where it is also generally present in the very rare cases in which it attacks the right side. In the case of the former, both the ventricle and the auricle are affected, while in the case of the right side of the heart, the ventricle is the special seat of the disease. The auriculo-ventricular valves of the left side are more frequently diseased than those of the right, whilst many morbid conditions of the aortic valves cannot be actually referred to an endocarditic origin.

An interesting exception to these relations is presented in the foetus, where endocarditis is much more frequent in the right side; and many of the cases of contraction of the openings of the right side, which are met with, in childhood and youth, are undoubtedly congenital and of foetal origin. There are, moreover, many anomalies of the arterial opening, especially of the right side of the heart and of its valves, which are commonly regarded as malformations (as, for instance, contraction and occlusion of this opening, and an abnormal condition of the trunk of the pulmonary artery), which are most probably the results of endocarditis already existing in an early period of foetal life, and which give rise to many arrests of structure within the heart. We may undoubtedly explain in a similar manner the many endocarditic metamorphoses observed in the hearts of persons suffering from cyanosis.

From what has been already stated, it will appear, that endocarditis occurs in the foetal condition as well as after birth. Youth and adolescence are the periods in which this affection is most frequently manifested.

The most important diseases with which it is associated, are its primary combination with pericarditis, and, whether this be present or not, with inflammations of serous membranes, namely, those of the synovial membranes - rheumatic inflammations of the joints. Valvular endocarditis, implicating tendinous insertion of the mitral valve, when combined with pericarditis, is extremely important, owing to the peculiar formation of the consecutive metamorphoses. Thus, for instance, we observe that the calcareous band developed at the tumefied point of insertion, not unfrequently expands into an osseous mass seated in the pseudo-membranous agglutinating medium between the pericardium and the heart. Endocarditis is also occasionally combined with carditis - inflammation of the muscular substance, - and this combination is then the common occasion inducing aneurism of the heart; while in some cases endocarditis may be merely an incidental combination, arising from some centre of inflammation in the muscular substance adjoining the endocardium.

To this class belong the combinations with croupous pneumonia, acute inflammation of the periosteum, acute ostitis, etc.

Endocarditis and its sequelae are not unfrequently met with in combination with Bright's disease, which is probably to be explained by the fact that this heart-disease becomes associated with disease of the kidneys in consequence of the abnormal condition of the blood.

Many of the anomalies already partially considered occur as the remote and indirect sequelae of endocarditis. Foetal endocarditis, at an early period, obstructs the completion of the inner structure of the heart, by means of the results to which it gives rise, and especially by contracting the openings of the heart; when it occurs at a later period and after birth, it obstructs the involution (closure) of the foetal passages. In subsequent periods of extra-uterine existence, many of the diseases of the different systems and organs considered under the head of dilatation and hypertrophy, may still be traced to the dilatations of the cavities of the heart and the anomalies of the valves (contraction and insufficiency), which have their origin in foetal endocarditis.