1096 Valvular Diseases. 



therefore become smaller. In consequence of tlie diminished 

 pressure in the right ventricle and in the pulmonary artery 

 thrombi easily form in them which may lead to embolism in the 

 blood vessels of the lungs. 



The heart beat is weak, a cardiac dullness can either not 

 be demonstrated at all or it is diminished in extent. The first 

 heart sound is clear, the second is accompanied by a presystolic 

 or diastolic murmur (for similar reasons as in mitral stenosis) 

 which is heard most strongly in the right 3d-4th intercostal 

 spaces in the middle of the lower third of the chest. The pulse 

 is feeble and small. The veins are filled strongly and a pre- 

 systolic (negative) venous pulsation, as well as undulation, may 

 be observed. The characteristic signs of severe blood-stasis, 

 especially marked dyspnea, possibly attacks of asphyxia, occur 

 already early in the disease. 



(i) Congenital Heart Lesions. 



Clinical manifestations of congenital heart lesions have 

 been described only rarely. The most decided symptom usually 

 consists in considerable weakness. The newborn animals are 

 not capable of looking for their mothers. They stand with 

 hardly a movement or cannot even keep their feet. Sometimes 

 at rest, more often on motion, severe dyspnea and cyanosis are 

 observed. Congenital valvular lesions give rise to the same' 

 local symptoms as the acquired forms, but murmurs are mostly 

 absent in cardiac lesions which are due to faulty development, 

 or they appear only in those cases in which there is a difference 

 in the pressure in two communicating heart portions, provided 

 the abnormal opening is not too large. In two cattle with per- 

 sistent interventricular openings Huynen observed a systolic 

 murmur in the left heart region and an accentuated diastolic 

 heart sound. 



The newborn animals usually die after a short time or are 

 killed, as they are not fit to be raised. In rare cases they de- 

 velop normally and may even live a fairly long time. 



(k) Combined Valvular Lesionsi 



The clinical pictures of valvular and ostial affections are 

 not always found as well marked as they have been described ; 

 in reality the forms which have been discussed separately often 

 occur in combinations. The most frequent ' combinations are 

 those in which a stenosis of the related ostium coexists with 

 insufficiency of a certain valve. Since valvular insufficiency is, 

 in a way, the opposite of stenosis, the individual components 

 of the clinical picture lessen each other ; an exception occurring 

 only in the accentuation of the second pulmonic sound in com- 

 bined disease of the left auriculo-ventricular opening. On. this 



