CARDITIS. MYOCARDITIS.
Definition. Rare. Complicates pericarditis and endocarditis, wounds of the heart, and tubercular and other deposits. Symptoms. Treatment.
Definition. Inflammation of the muscular substance of the heart.
This is a rare affection and is necessarily limited to a small portion of the heart’s substance, otherwise, the cardiac contractions must cease in obedience to the general law that the normal function of an inflamed organ is for the time abolished. It is mainly seen as a concomitant of endocarditis or pericarditis, and extends only to the superficial muscular layers; or it results from a wound as in the penetration of the heart by a needle or other sharp pointed body and is then equally circumscribed. It has been seen as a complication in infectious diseases—aphthous fever, pyæmia, septicæmia, pneumonia and tuberculosis.
The evidences of the existence of carditis are chiefly the lesions met with after death. 1st, The existence of abscesses in the heart’s substance associated with polypus (Gowing, Leblanc, etc.,) or otherwise (Reynal). Also diffuse suppuration in the heart’s substance (Puze, etc.) 2nd, Softening of the muscular substance, a state occasionally met with when an animal has died of ruptured heart. 3d, Ulceration of the walls of the heart as reported by Mercier in a case of endocarditis. 4th, Transformation, and induration of the heart’s substance whether into fibrous tissue, cartilage or bone. This last condition of the walls of the right auricle and ventricle has been repeatedly seen in old horses, the change being in certain cases so extensive that one is left in wonder as to how circulation could have been carried on. Three specimens of this kind were preserved in the museum of the Alfort Veterinary College, Paris, and the Royal Veterinary College, London. Lafosse records two cases of gangrene of the internal layers of muscle in endocarditis.
The symptoms are those of acute heart disease generally modified somewhat by the precise location of the inflamed spot, and treatment need not differ materially from that applied for inflammation of the investing membranes, inner and outer, and for the infectious disease which it complicates.