Diagnosis.—The pathognomic symptoms of Endocarditis are frequently very obscure, being like those of Pericarditis; but it is of very little consequence, as the treatment must be similar. However, the bellows-sound in the former, and the friction sound in the latter, are sufficient in the majority of cases to point out the nature of the disease when taken in connection with other symptoms which have been mentioned.
Prognosis.—Owing to the various terminations of Endocarditis, nearly all of a serious character, our opinion as to the ultimate result must be unfavorable, although in the majority of cases the animal appears to recover; but he is found afterwards not as good in his wind as formerly, easily distressed, and when going at an ordinary pace with hounds, will probably fall down and expire suddenly. A.A. will be our best resource.
Hypertrophy—Enlargement of the Heart
Definition.—An abnormal growth of the muscular tissue of the heart by thickening of the walls.
Varieties.—There are three. Simple Hypertrophy is the thickening of the walls without any change in the capacity of the cavities. Eccentric Hypertrophy is the thickening of the walls with dilatation of the cavities. Concentric Hypertrophy is the thickening of the walls with diminution of the cavities. The lesion is usually associated with other diseases, and especially with affections of the lungs.
The disorder is slow in its progress, though it soon interferes with the working capacity of the animal. It predisposes to other lesions, such as congestion of the lungs, hemorrhage, etc.
Causes.—Excessive effort of the heart to overcome obstruction to its action; constriction of the vessels and of the openings between the different cavities of the heart; deposits on the semi lunar valves; Aneurism of the aorta or the pulmonary artery; excessive physical exertion and consequent exhaustion of the heart. Mr. Pritchard remarks that “horses, particularly those employed in quick draught, are commonly called on to perform arduous tasks with full stomachs, by which the free action of the lungs is considerably impeded; thus, obstruction being given to the circulation through the pulmonary vessels, corresponding increase of force in the action of the heart is the consequence.” Hypertrophy has been often observed in broken winded horses.
Symptoms.—Strong, impulsive movement of the heart, which remains constant; intensity of sound, with a loud, hollow thumping beat; a metallic bruit or “clack”; irregularity of rhythm; dullness on percussion. The horse is easily distressed, palpitation comes on with ordinary quick work, and there is an anxious expression in his eye on these occasions, which leads us to suspect that there is something amiss with the animal. These symptoms are attended with languor, coldness of legs and ears, dyspnœa, giddiness or Megrims, loss of appetite, and, in a later stage of the disease, with œdematous swelling of the chest, abdomen, and extremities.
Pathology.—The thickening of the walls of the heart may be regarded as a beautiful provision of nature to strengthen the organ and enable it to overcome the obstacle which exists to the free circulation of blood through it. The thickening of the muscle depends upon excess of nutrition consequent on increased action; similar to the change in the biceps muscle of the blacksmith’s arm from hard work.
It may be an idiopathic disease not dependent on obstruction; but such cases are very rare. The obstruction will usually be found to depend on disease of some of the valves, or constriction of the aorta or pulmonary artery at its origin. The Hypertrophy may be general, or we may find only one auricle or ventricle (generally the latter) whose walls are thickened.