76 DISEASES OF THE HEART 



cussion: The area of cardiac dulness is increased, extending 

 back as far as the 7th rib; it may extend upwardly to the 

 height of the shoulder-joint. Auscultation: The heart 

 beat is stronger and louder than normal. In some cases it , 

 may shake the whole body (palpitation). In the last stages 

 general dropsy usually sets in. 



Course. — Acute cases of dilatation often recover if properly 

 treated. ' As a rule, however, the condition, coexisting with 

 hypertrophy, becomes chronic leading to general dropsy and 

 death. In advanced cases any unusual exertion (hard 

 pulling, racing) may result in the patient falling dead in 

 harness. 



Diagnosis. — Increase in extent of cardiac dulness, abnor- 

 mally loud systolic tone, weak arhythmic pulse and tendency 

 to dropsical swellings are indicative of dilatation. A hard, 

 full pulse with increased area of cardiac dulness on percus- 

 sion, speaks for hypertrophy. From pericarditis the con- 

 dition may be' differentiated by the weakness of the heart 

 tone and the frictional bruit in this disease. From hydro- 

 pericardium by the absence of the gurgling or metallic tinkling 

 sounds on auscultation. - v 



Treatment. — Healing only possible in acute, cases of 

 dilatation. Allowing the patient absolute rest and giving 

 cardiac tonics, especially digitalis fluidextract (§ss) to 

 which strychnin nitrate (gr. j) may be added are helpful. 

 The patient should be well cared for and fed highly nutritious 

 food. 



MYOCARDITIS. 



Definition. — An inflammation of the heart muscle. 



Etiology. — Myocarditis in animals is usually of infectious 

 origin. In practice it is seen to accompany influenza, 

 septicemia and foot-and-mouth disease. Cases occasionally 

 occur in azoturia or may follow overexertion or heatstroke. 

 In cattle foreign bodies penetrating the heart muscle form 

 a cause. Myocarditis may further be secondary to endocar- 

 ditis and pericarditis. In man myocarditis commonly results 

 from arteriosclerosis which in animals is extremely rare. 



From a pathological standpoint three forms of myocar- 



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