VALVULAR DEFECTS 161 



We often see cases where defects of the fiorta become equalized by a hy- 

 pertrophy of the left ventricle. In valvular defects of the mitrals the 

 stagnation of the blood occurs in the veins, capillaries, and arteries of the 

 lungs, and as far back as the right ventricle, which becomes dilated and 

 hypertrophied while trying to take up the extra work thrown on it. 

 In course of time we also see hypertrophy and dilatation of the left 

 ventricle; during diastole the stagnated blood runs in great quantities 

 into it out of the dilated auricle. 



These compensating processes of the heart are apt to prevent for a 

 long time any great functional disturbance provided the heart receives 

 its proportional nutrition. If this is not the case, for instance, in anaemic 

 and cachectic feverish animals, the compensating heart hypertrophy is not 

 present or is only developed to a slight degree, and also in cases of insufh- 

 cient nutrition, due to some alteration in the coronary artery, the heart 

 is no longer able to satisfy the demands claimed from it and tires out, 

 and all the effects of lilood-stagnation rapidly show themselves. 



Etiology of Deficient Valvular Action of the Heart. — The most com- 

 mon causes of valvular defects are endocarditic processes, which are de- 

 veloped on the valves and take an acute course, according to the amount 

 of the irritation, and cause a fibrinous, rigid thickening of the valves. 

 Sooner or later we find an imperfect closure of the valvular openings 

 through cicatricial contractions and adhesions to the lobula of the valves 

 or in their neighl)orhood. This condition is quite common in old 

 dogs, and may appear as a result of great nervous excitement, cold, 

 articular rheumatism, distemper, and other infectious diseases. Car- 

 diac valvular changes are frequently seen as a result of chronic nephri- 

 tis. The mitral valves are most frequently affected. Cadiot and Ries 

 found out of thirteen cases, five of the mitral, four of mitral and tricus- 

 pid, two of the tricuspid alone, and one of the valve of the aorta and one 

 mitral and aorta. AVe may also see deposits of lime salts and a con- 

 traction of the opening belonging to the alTected valve. In rare cases 

 there is heart weakness and imperfect valvular action, which may be 

 caused by a dilatation of the opening, and, thus becoming abnormally 

 distended, the valves cannot meet and make a complete closure. Ath- 

 eromatous processes may also produce this condition. . 



General Symptoms of Deficient Valvular Action of the Heart. — The 

 symptoms which a})pear at a certain time in all valvular troubles are 

 as follows: Increase of heart and pulse action (after slight exertion it is 

 al)normally increased); palpitation of the heart; difficulty in respiration; 

 vertigo after any exertion; cyanosis of the visible mucous meml)ranes, 

 especially of the head; venous pulse; dropsical effusions, such as oedema of 

 the legs, abdomen, or testicles; hydrothorax; hydropericartlium; ascites; 

 allDuniinuria, with lessening of the amount of urine; complications of the 

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