Treatment. 



1061 



be worked only with great care. If the arhythmia depends upon 

 organic diseases of the heart muscle, cardiac remedies are some- 

 times of value. 



Literature. Cadiot, Bull., 1894. 188. — Caroni, Ree., 1894. 607 — Herin? 

 D. 111. W., 1906. 929. — Siedamgrotzky, S. B., 1886. 20. — Wenckebach. Die 

 Arhythmie d. Herzens, 1903. 



4. Hypertrophy of the Heart. Hypertrophia Cordis. 



Hypertrophy of the heart consists in an increase in the 

 heart muscle ^vhich arises from thickening and possibly from 

 multipKcation of the muscular fibers under the influence of 

 an increase in function persisting for at least four weeks. 



Etiology. During severe w^ork the normal, or usually in- 

 creased blood is forced against the normal or increased re- 

 sistance at greatly shortened intervals, and if this is repeated 

 time and again it is followed by hypertrophy of the heart 

 muscle. In horses used for rapid motion, in hunting dogs, and 

 exceptionally in pack-horses and draught-oxen, the relatively 

 great size of the heart stands in relation to the increased 

 muscular exertion. A comparatively large heart may be said 

 to be a constant finding in some species of these animals, and 

 it is not improbable that heredity may be of influence upon 

 the dimensions of the heart. This physiological hypertrophy 

 is always in proportion to the development of the muscles of 

 the body and does not require any treatment. 



On the other hand a pathological hypertrophy of the heart 

 does not stand in direct relation to the development of the 

 skeletal muscles or is limited to some portions of the heart. 

 In persistent disturbances of the circulation the part of the 

 heart which is connected with the place of the disturbance is 

 forced to continuously increased exertion and this is eventually 

 followed by hypertrophy of this portion of the heart; in dis- 

 eases of the left venous ostium, however, the right ventricle 

 also hypertrophies owing to increased work done. Pathological 

 processes in the heart muscle itself, such as chronic myocarditis, 

 tumors, echinococcic cysts, etc., also lead to an increase in 

 the muscular tissue in those parts of the heart which are not 

 immediately affected. A similar result is produced by ad- 

 hesions of the layers of the pericardium because it necessitates 

 an increased amount of work on the part of the heart. Acute 

 cardiac dilatation may also form a basis for the development 

 of hypertrophy if the heart muscle is comparatively unimpaired. 

 (In chronic myocarditis the hypertrophy may at times be only 

 apparent being simulated by the fact that the wall of some 

 portion of the heart has become thicker owing to cellular in- 

 filtration or to simultaneous new-formation of connective tissue 

 [E. Albrecht]). Finally hypertrophy of the heart often de- 



