80 DISEASES OF THE HEART 



Necropsy.— It has been found that the mitral and aortic 

 valves are the ones most commonly affected in the dog. In 

 the early stages the edges of the valves are slightly thickened 

 and invaded with small nodules. Later are found, as the 

 sclerotic changes increase, contractions of the fibrinous 

 tissue, producing thickening and deformity of the segments 

 of the valves, the edges of which become round, curled and 

 cannot be closed perfectly. In some severe cases the valves 

 become very much thickened, with numerous hard nodules 

 (which may be calcareous), giving them a marked uneven 

 surface. The chordae tendinese are often found thickened 

 and contracted. The apices of the papillary muscles fre- 

 quently show fibrated or calcareous change. 



Symptoms.— In small animals the general symptoms of 

 valvular deficiency are of greatest importance from a clinical 

 standpoint, as it is very difficult during the life of the animal 

 to distinguish with any degree of accuracy the separate 

 valvular insufficiencies. However, some of them present 

 some symptoms which are rather characteristic, and there- 

 fore, a brief description of the most common ones will be 

 given. 



As general symptoms, the following are the principal ones 

 observed which are common to all valvular defects at some 

 period in their course: Increased heart action; rapid and 

 irregular pulse; palpitation of the heart; venous pulse 

 (observed in the jugular at its entrance to the thorax); 

 dyspnea; cyanosis of mucous membranes; hydrothorax; 

 ascites; edema along abdomen, pectoral region, extremities; 

 general emaciation, partial or complete loss of appetite with 

 marked digestive disturbance. The condition gradually 

 becomes aggravated until there is a general, nutritive dis- 

 turbance, weakness, and death from exhaustion. Careful 

 auscultation will reveal the valvular insufficiency. Palpation 

 over the cardiac region will determine the irregular and 

 rapid pulse, and often a distinct fremitus. The temperature 

 in the early stages is usually elevated (103°-104° F.); it 

 later becomes normal or even subnormal as the disease 

 progresses. 



Symptoms of insufficiency of the mitral valves: This is of 



