336 DISEASES OF THE HEART. 



oulation ceases to be compensated for by the hypertrophy of the right 

 heart.) But the fact that all derangement of the circulation is averted 

 in valvular disease or emphysema, as long as the portion of the heart 

 involved is hypertrophied, instead of being dilated, warrants the con- 

 clusion, whenever there is much embarrassment of circulation, that 

 either the original dilatation has not been followed by any great de- 

 gree of hypertrophy, or else that the hypertrophy has turned into a 

 dilatation through degeneration of the substance of the heart. Of 

 course the extent of the disorders which arise in the circulatory system 

 varies with the seat of the dilatation. In treating of valvular disease, 

 we propose to describe more fully the conditions which result from dil- 

 atation of the various parts of the heart, just as we have made a de- 

 tailed description of the effect which the state of the right ventricle 

 exerts upon emphysema, in treating of that disease. There is but one 

 symptom (palpitation of the heart) to which we shall draw attention at 

 present, since its occurrence is quite as common in partial dilatation 

 as in the complete dilatation. This distressing subjective symptom, 

 consisting of a painful sense of pulsation in the region of the heart, 

 often ceases when the dilated heart becomes hypertrophied, and re- 

 turns when the hypertrophy begins to undergo degeneration. It is 

 not the beat of a hypertrophied heart which, though it often jars the 

 chest like the blow of a hammer, is nevertheless performed without 

 effort which gives rise to the sense of palpitation. This sensation is 

 rather the result of the laborious contractions of an unhypertrophied 

 organ. Thin-blooded and chlorotic persons complain much more of 

 palpitation than those whose heart is actually diseased ; and, of all the 

 varied disorders of the organ, dilatation, inflammation, and degenera- 

 tion of the cardiac substance, are the ones which are most generally 

 accompanied by palpitation. 



In the total dilatation which generally is due to a morbid flaccidity 

 of a degenerate heart-wall, it is often difficult to say how much of the 

 derangement of the circulation depends upon the degeneration and 

 how much upon the dilatation. The latter, however, plays an im- 

 portant part in their production, as it is found that degeneration of the 

 heart, without dilatation (which is common enough in anaemic persons), 

 is much better borne, and deranges the circulation much less, than 

 when it is accompanied by dilatation. 



The first symptoms which are observed in this form of dilatation 

 consist, as we have said, of a complaint of palpitation of the heart, 

 which form a striking contrast with the faintness of its objective and 

 visible pulsation, and which soon is accompanied by a slight dyspnoea. 

 The cause of the dyspnoea is easily traceable to the overloading of the 

 pulmonary veins and capillaries, and to the retardation of the circula- 



