DISEASE OF THE MYOCARDIUM.

MANY large volumes have been written on the subject. of valvular disease of the heart, and much discussion has taken place as to the possibility of an accurate differential diagnosis and as to the exact pathologic condition which is the cause of a certain murmur. All text-books contain many

chapters on this branch of heart disease. On the other hand, diseases of the myocardium are dismissed with a short account of the rare forms of new growth which may be found in the muscular substance of the heart, and often by a rather confused account of dilatation and hypertrophy of the heart.

Practically we cannot with our present knowledge successfully apply treatment to chronic valvular diseases, or rather we cannot at any rate cure the deformities of the valves produced by chronic valvular endocarditis. In heart disease, individuals suffer only when and in proportion as the myocardium becomes involved as the result of a failure of the valves to carry on their work. This is certainly true of the cases of disease dependent upon valvular trouble, but such cases represent only a small proportion of the individuals who suffer from disturbance of the heart.

A very large number of individuals who are affected with "heart disease" have no valvular lesion. The nomenclature of non-valvular diseases of the heart is at present chaotic, and an exact diagnosis is most difficult to make, in many cases impossible. We are confronted by two possibilities in choosing the proper name for a given case; we

case.

may choose a name according to the most prominent clinical symptom as dilatation, or mitral regurgitation, or we may choose a name based on the probable pathologic condition. The former method is certainly faulty; as to the second suggestion we are rarely in a position to decide with accuracy as to the exact pathologic lesion present in a given In many cases we may be reasonably sure as to the ultimate cause of the trouble, as in cases of arterio-sclerosis, yet quite in the dark as to the exact pathologic condition of the heart. A glaring proof of the futility of attempting to define the disease on the basis of the pathologic condition is found in the continued use of the term "fatty heart," though we know that fatty degeneration of the heart is rarely found to be the cause of serious chronic myocardial disease. Until further light is thrown upon the subject the name myocardial disease, or disease of the myocardium, seems open to as little objection as any other term. Myocarditis is objectionable as it signifies a condition seldom present; degeneration of the myocardium is far more common than any inflammatory process.

It seems wise to choose a generic name rather than a definite name based on pathologic findings, as the changes found are manifold. Diseases of the myocardium may be classed as acute and chronic. In most septic diseases, using the word in the wide sense of including all diseases of acute course dependent upon bacteria, we find at autopsy more or less fatty or granular degeneration of the muscle of the heart. During life this process is suggested by rapid action or by irregularity and intermittent action. I have seen in diphtheria and scarlet fever weakness of the heart so marked that only a portion of the beats were transmitted to the pulse at the wrist, a condition that I have elsewhere described as the "acme of cardiac weakness." It is probable that in a large number of cases such a condition. is absolutely curable, though the recent investigations of

Thayer suggest that the more marked affections of the heart in typhoid may lead to subsequent disease appreciable by physical examination.

Aside from the irregularity of the heart and the increased rate, other phenomena may be noted. As a rule, dilatation of the heart cannot be or certainly is not diagnosed by percussion; but it is not unusual in the hospital, where careful measurements of the heart area are frequently made, to find in acute disease that the left border may extend some distance to the left of the nipple line. In children and young adults I have frequently seen such a dilatation come on rapidly, and as quickly subside with the improvement in the course of the disease. As the state of the patients in which I have found this condition has not always been serious, I am inclined to the opinion that dilatation might be found more often if its existence were sought for with care. In certain infectious diseases, especially in diphtheria, the affection of the heart is more common than in many others. Doubt has been raised whether the chief disturbing factor in producing incompetency of the heart in acute disease was to be sought for in the nerves or in the muscle of the heart. Until proof to the contrary is forthcoming, the fact that pathologic changes in the myocardium are common seems to weigh in favor of the assumption that the chief trouble is to be sought for in the degeneration of the muscular substance of the heart.

In the course of an acute disease the condition of the heart described above is not usually so marked as in itself to demand attention, aside from that given as routine practice in the care of the case, but in convalescence I have frequently seen irregularity of the heart persist after the main symptoms of the primary disease had entirely subsided. A slow action of the heart is frequently described as a symptom of heart weakness, especially in so-called "fatty heart"; this condition I consider rare, in fact very seldom seen; whereas in disease of the myocardium, as evidenced by weak

ness subsequent to acute infectious disease, a slow irregular pulse, often intermittent, is a common occurrence. If the patient survive the acute disease, the immediate prognosis of the cardiac condition is certainly good, as sudden death is rare except in diphtheria. From analogy it is more probable that sudden death in diphtheria is due to a disturbance of the nerves than to the pathologic condition of the myocardium.

Aside from acute degeneration of the myocardium already spoken of, other processes may be found. Abscesses in the course of general septicemia may be found. In gonorrhoea I have seen acute purulent myocarditis ending in sudden death. Acute malignant myocarditis of the same nature as acute malignant endocarditis is not very rare; in an analysis that I made of 59 cases of malignant endocarditis, in three the process was myocardial, and I have recently seen other cases. In none of the cases was the diagnosis made definitely, and probably such a diagnosis could not be absolutely established during life, unless by exclusion. In all the cases the heart was rapid, weak, and the symptoms suggested some serious heart disturbance.

The acute forms of myocardial disease described do not, except in the case of acute abscess, present a picture suggestive of heart disease, but are simply physical conditions that may account for the varying grades of the severity of an illness dependent upon the primary disease which gives rise to the cardiac condition.

In chronic disease of the myocardium we find an entirely different process. A patient consults us for symptoms suggestive of heart disease, shortness of breath, palpitation, precordial distress, cough, and having determined that the essential lesions causative of the disturbance are situated in the heart, we have to decide whether the case under consideration is suffering from valvular disease or from disease of the myocardium.

In approaching the consideration of such a case, determine as accurately as possible the size of the heart by palpation and percussion; the latter method is to my mind more accurate than palpation, and in most cases gives accurate data as to the size of the heart. Frequent comparison of the post mortem findings with the data determined by percussion gives me a good deal of confidence in drawing conclusions from percussion. This opinion is based largely on examination made by house pupils in the hospital, therefore I feel at liberty to make this statement as to the accuracy of percussion. The character of the pulse, the regularity of the beats, and the presence or absence of signs suggestive of chronic passive congestion, determine whether the enlargement be due mainly to dilatation or hypertrophy of the muscular substance. But we may with much certainty assert that where there is enlargement readily appreciable by percussion, a certain amount of dilatation is present. Frentzel makes the statement that in all cases where enlargement of the cardiac area is appreciable by percussion dilatation is present.

In

In the vast majority of cases the presence of an aortic murmur determines that the trouble is dependent upon degeneration of the aortic valves, and certainly the opposite conclusion can only be decided by post mortem evidence. This is not the case with a murmur in the mitral area. a large number of cases of myocardial disease there is a regurgitation through the mitral valve, not to be distinguished by its situation, quality or transmission from a murmur produced by endocarditis of the mitral valve. This murmur is certainly not even distantly related to the so-called "hæmic murmur," but is caused by a leak in the mitral valve as shown by the characteristics of the murmur, by the results dependent upon the leak evidenced in chronic passive congestion of remote organs, and associated with great enlargement of the mitral orifice often demonstrated post mor

tem.