Chronic Myocarditis.

Synonyms.—Fibroid Heart; Cardio-Sclerosis; Chronic Interstitial Myocarditis.

Definition.—A chronic inflammation of the heart muscle, resulting in induration, due to fibroid degeneration.

Etiology.—Sclerosis of the coronary arteries, Bright's disease, diabetes, rheumatism, gout, and the excessive use of tobacco and alcohol, are the most frequent causes of fibroid degeneration.

Sclerosis of the coronary arteries may be due to chemical irritants or syphilis, or may follow as a result of the infectious diseases. Each of these may be said to act as a causal agent. It may be an extension of chronic endocarditis and pericarditis; it may also follow acute .diffused myocarditis. Chronic valvular lesions may so impair the nutrition of the heart as to give rise to myocarditis, or it may be due to a direct extension of the inflammation along the chordae tendineas, or valves, to their muscular attachments.

Age and sex predispose somewhat, as sclerotic changes occur more frequently in elderly people, and more males than females suffer from this lesion. When the disease occurs during fetal life, the right heart is the seat of the disease.

Pathology.—While the anatomical changes may be diffuse, they are usually circumscribed, the wall of the left ventricle, the septum, and the papillary muscles being, even in the diffuse form, more extensively involved. In fetal myocarditis the apex of the right ventricle is the favorite site.

The muscular fibril is replaced by fibrous tissue, which is dense, hard, and of a grayish-white appearance. The weight of the heart is increased, both by the degenerative changes and the hypertrophy and dilatation that so frequently accompanies it. There may be a narrowing of the pulmonary and the aortic orifices due to contraction of the changed tissue.

The branches of the coronary arteries may be occluded, either by circumscribed areas or by emboli. These sclerotic changes in the coronary arteries are frequently due to syphilis, resulting in obliterating endocarditis. When aneurism of the heart occurs, it is usually due to anteriosclerosis. In advanced stages, fatty degeneration may replace the fibroid or be associated with it.

Symptoms.—The symptoms are not at all characteristic; in fact, they are so indefinite in many cases as not to cause a suspicion of the true difficulty, and the true nature is only revealed during an autopsy. The hypertrophy, that usually attends, so compensates that the patient is unaware of his condition.

Generally, however, there is evidence of enfeeblement, and this is accompanied by dyspnea and more or less palpitation. A sense of constriction is often present, and attacks of angina become quite frequent and distressing. The pulse is slow and often irregular, the pulse-rate being reduced to fifty, forty, or even less, per minute.

When there is a sudden failure of the cerebral circulation, or after unusual exertion, the patient may be attacked with syncope. Pseudo-apopleptic attacks may terminate in sudden death.

Physical Signs.—Where hypertrophy exists, the apex-beat is displaced downward and to the left, the dullness being in the same direction. Although the heart-sounds may be clear and strong early in the disease, they soon become feeble and indistinct.

Diagnosis.—The recognition of this disease before death is extremely difficult, and though cardiac weakness may be easily determined, it is often indistinguishable from hypertrophy with dilatation or the many valvular lesions. Generally the absence of murmurs enables us to differentiate it from valvular lesions. To distinguish it from fatty degeneration is quite impossible. Frequent attacks of angina would excite suspicion more than any other symptom, and if the pulse were reduced to fifty or forty per minute, additional reason would exist for believing in chronic myocarditis.

Prognosis.—The prognosis is usually unfavorable as to a cure, though favorable as to life. The disease comes so insidiously in the majority of cases, and degenerative changes have so far advanced, that a complete cure is out of the question. If, however, the patient can refrain from severe mental or physical exertion, can live in an equable climate, and be much in the open air, the life may be prolonged to its allotted period. Where frequent attacks of angina occur and the cerebral circulation suddenly fails, death may occur quite suddenly.

Treatment.—The habits and methods of living should be thoroughly impressed upon the patient. No severe mental or physical exertion should be allowed, no tobacco permitted, while coffee and tea should be taken sparingly or not at all. Gentle exercise in the open air is advisable. The diet should be nutritious, and, as a rule, fluids should be restricted.

In the way of medication, strychnia as a stimulant, when there is great debility, will be found useful. In case of syncope, a hypodermic injection of camphor and ether will give good results.

Cactus and crataegus are agents that will improve the innervation and nutrition of the heart, and should be administered for a long time.

If syphilis exists, the anti-syphilitics will be used.

The Eclectic Practice of Medicine, 1907, was written by Rolla L. Thomas, M. S., M. D.