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.