r/6 Disease of tJic Heart 



culty in pumping blood through the lungs, as when the capillary a 

 is diminished by dilatation of the air-cells, as in emphysema and in 

 chronic phthisis, or by the compression of a pleuritic effusion. Ob- 

 struction at the pulmonary valve causes dilatation and hypertrophy 

 of the right ventricle, and so especially does incompetence of the 

 mitral valve, for the left ventricle then pumps blood back into the 

 left auricle, and the pulmonary veins cannot empty themselves ; the 

 pulmonary capillaries being overloaded, the right ventricle struggles 

 in vain to pass its blood onwards. 



In these circumstances, the right ventricle may grow so large as 

 entirely to cover the left ventricle and to hide the apex-beat. The 

 impulse is felt over a large area, even up to the third left cartilage, 

 and down in the epigastrium. But when the heart is working with a 

 tremendous bustle, and the radial pulse is, nevertheless, poor, it is 

 evident that the right ventricle, not the left, is hypertrophied. 



The left ventricle is dilated and hypertrophied when, Sisyphus- 

 like, it is struggling to force upwards its contents which are ever rolling 

 backwards though an incompetent aortic valve ; but these conditions 

 sometimes occur independently of valvular disease, as in the case of 

 athletes and others who are suddenly called upon for violent exertion. 



In the case of severe aortic disease the left auricle remains over- 

 full, the pulmonary circulation is delayed, and the right ventricle be- 

 comes hypertrophied as well as the left. The grave lung-complication 

 does not occur so long as the left ventricle remains strong enough for 

 its extra work, but it comes on as soon as the walls begin to^ yield. 



Delayed pulmonary circulation eventually causes hypertrophy of the 

 left ventricle as well as the right, as in emphysema ; the lungs being 

 full, the right heart is full, as are also the venous capillaries throughout 

 the body, and thus the left ventricle is obstructed in its work. 



Hypertrophy of the left ventricle without dilatation occurs in 

 the case of simple narrowness of the aortic opening, and also in Bright's 

 disease, when there is an increasing difficulty in forcing blood through 

 the narrowed and rigid capillaries. In such circumstances hyper- 

 trophy must not be regarded as disease. It is, rather, Nature's remedy 

 for disease. It is ' compensatory,' and of excellent omen. How peri- 

 lous, on the other hand, is the state of the feeble individual who, with 

 aortic obstruction, has a dilating ventricle with walls so thin as scarce 

 to supply a perceptible apex-beat ! So long as the ventricle is equal 

 to its extra work all goes well ; but when it begins to fail the left auricle 

 becomes distended and the case becomes as serious as one of mitral re- 

 gurgitation, venous congestion occurring, as already described. 



With aortic regurgitation (p. 1 73), dilatation precedes hypertrophy 

 and is inevitable ; in aortic narrowness there need be no dilatation of 

 the slowly thickening ventricle. 



When the left ventricle alone is hypertrophied the impulse may be 

 found in the sixth, seventh, or eighth space, and outwards towards the 





