HYPERTROPHY OF THE HEART. 



Simple, eccentric, concentric. Ventricles chiefly afifected. Causes, in- 

 creased functional activity, from obstruction to the circulation, or con- 

 tinued extra exertion. Right ventricular hypertrophy-obstruction in the 

 pulmonary circulation ; left ventricular hypertrophy-obstruction in the 

 systemic. Auricular hypertrophy-insufiiciency of the anriculo-ventricular 

 valves. Pericarditis as a cause. Abnormal weights. Symptoms, beats 

 more forcible and prolonged, ist sound low, prolonged, 2nd sound clear, 

 often doubled, increased dulness on percussion, diagnostic signs of hyper- 

 trophy, dilatation and a combination of the two. Simple hypertrophy 

 rarelj' dangerous, with dilatation grave, threatens congestions and apoplex- 

 ies. Treatment, rest, laxatives, sedatives, in irregular heart action digitalis. 



An enlargement of the heart from increase of its muscular sub- 

 stance is by no means uncommon in the horse. It may exist 

 without any change in the capacity of the cavities of the heart 

 (simple hypertrophy) or it may be associated with dilatation of 

 one or more of these cavities (hypertrophy with dilatation ; — ex- 

 centric hypertrophy). A third variety has been described in 

 which the capacity of the cavities is decreased but Cruveilhier 

 and Budd have satisfactorily shown the nonexistence of this con- 

 dition except as a congenital deformity. 



It is in the ventricles that the increase is chiefly observed, the 

 reason of which is to be found in the causes of the malady. These 

 usually consist in some obstruction to the circulation such as 

 chronic congestions in the lungs or elsewhere, rupture of air cells 

 in the lungs, tuberculous and other abnormal deposits in the chest 

 and elsewhere, tumors which by their position interfere with the 

 circulation through the larger vessels, and the like. Where by 

 some such cause the blood is impeded in its outward course, one 

 or both ventricles are called upon to contract more vigorously to 

 force a sufficient amount of blood onward and in accordance with 

 the inherent adaptability of the animal economy, there takes place 

 an increase of the muscular walls of the ventricle proportionate 

 to the required energy of the contractions. The condition then 

 is essentially due to a more active nutrition and growth of the 

 muscular substance and finds its exact parallels in the well-de- 



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