MYOCARDITIS. 



147 



primarily from pneumonia. You have also seen that it m.a}- assume a 

 chronic form, and, after a varying period, render the animal useless. 



As in most other heart diseases, treatment is of doubtful efficacy. 

 We cannot stop the processes going on in the heart muscle by admin- 

 istering drugs. Moreover, the practitioner's attention is often exclu- 

 sively confined to the primary disease. If myocarditis is recognised or 

 suspected, treatment must be directed towards combating the ^\•cakness 

 of the heart, and supporting the animal's strength. 



The food should be fluid, consisting of mashes, gruel, hav tea, or 

 milk. If the patient will eat nothing, beef tea ma}- be given by the 

 rectum. The drugs indicated comprise stimulants like alcohol, wine, 

 and coffee given by the mouth ; caffeine, str}-chnine, and ether h\poder- 

 mically ; and, if myocarditis is secondary to pneumonia, digitalis. 

 Counter-irritation by means of a mustard plaster applied to both 

 sides of the chest, or refrigeration of the precordial region, may also be 

 tried. 



In contrast with the acute form, chronic myocarditis often occurs as 

 an isolated affection, apart from any other existing disease, or only 

 associated with lesions of the cardiac serous membranes ; and inasmuch 

 as it only produces vague functional disturbance, and very imperfectly 

 recognised local S3'mptoms, it often escapes notice altogether. No 

 hesitation is felt in affirming the existence of cardiac disease when a 

 murmur exists, but it is quite otherwise when the symptoms, though 

 apparently due to heart trouble, are unaccompanied by any abnormal 

 sound. When, however, the constitutional symptoms are supple- 

 mented by modifications in the action of the heart — irregularities, 

 momentary arrests, or intermittencies — the patient in the majorit}^ of 

 cases is suffering from a condition which, though insidious and of slow 

 progress, is nevertheless extremely- grave. Most frequenth' these 

 symptoms are due to chronic inflammation of the cardiac muscle. 



As a general rule, chronic myocarditis follows the acute form. 

 Inflammation of the myocardium continues in a less degree, slowly 

 producing degenerative changes, and later, functional disturbance. In 

 certain cases this inflammation occurs spontaneously and indirectly, 

 in consequence of cardiac or pulmonary lesions, which produce passive 

 permanent congestion of the heart muscle. It is described as being 

 produced directly by excessive functional activity of the heart, i. c. by 

 over-exertion. Now in draught animals, and especiall}- in horses, 

 nothing is commoner than over-exertion, but the usual result is simply 

 to produce hypertrophy of the heart, with or without dilatation of its 

 cavities. Myocarditis due to this cause alone is very rare, if indeed it 

 ever occurs. The cases seen are usually the consequence either of the 



