HYPERTROPHY AND DILATATION OF THE HEART 79 



together are dropped. Occasionally, two beats occur in 

 rapid succession followed by a long pause. In some cases 

 exercise emphasizes the condition, in others it temporarily 

 relieves it. 



Course. — If due to some acute disease which it accompanies, 

 it will disappear with the healing of the disease. In some 

 cases it remains during the life of the patient, but never 

 causes disorder. 



Treatment. — If secondary the disease which it accompanies 

 must first be eradicated (gastric disorders). Usually no 

 treatment is demanded in idiopathic cases. 



HYPERTROPHY AND DILATATION OF THE HEART. 



Definition. — Hypertrophy is an enlargement of the heart 

 due to a thickening of its musculature. Dilatation is an 

 enlargement of the heart due to an increase in the size of its 

 cavities. The two conditions usually coexist. 



Etiology. — A pathological hypertrophy of the heart may 

 be due to anything which interferes with the heart action 

 from without: As an adhesion of the pericardium to the 

 heart; chronic lung, liver and kidney diseases, in that they 

 increase the heart's work by resisting the free flow of blood;, 

 or from within, as a valvular lesion. Generally the hyper- 

 trophy is confined to one chamber, although all may be 

 involved. When the heart has increased sufficiently in size 

 and strength to overcome the obstacle, the free circulation 

 is restored and the hypertrophy is spoken of as compensatory. 

 In case the hypertrophy cannot overcome the obstacle, dila- 

 tation will result. 



Symptoms. — ^A compensatory hypertrophy may not cause 

 any symptoms. In hypertrophy with dilatation the symp- 

 toms are as follows : The owner is attracted by the dyspnea 

 which develops durmg work. In some instances the patient 

 may have occasional attacks of vertigo or palpitations 

 ("thumps") when exercised. Undulation of the jugulars is 

 sometimes noted. In the latter stages edema appears 

 under the chest. The pulse^ is weak and arhythmic. Per- 



' In hypertrophy without dilatation, the pulse is full and quite strong. 



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