Laceration of the wall of the heart is usually associated with fatty infiltration or degeneration, most frequently the latter. It is doubtful if in any instance the healthy muscle has broken. Rare causes are—acute softening, in consequence of embolism of a branch of a coronary artery; abscess from pyæmia; or an acute ulcer of the endocardium. Cysts simple or hydatid are mentioned, but the extreme rarity of causes other than fatty changes may be inferred from the statistics of Quain,32 who states that of 100 cases of rupture collected by him, fatty degeneration was noted (microscopically) in 77, and in the others there was softening in all but 2, or no mention was made of the condition of the wall.
32 Loc. cit.
Males are more frequently the subject of this accident than females, and the great majority of cases occur in persons over sixty years of age—two-thirds of the eases tabulated by Quain.33
33 Loc. cit.
The rent may occur in any of the chambers, but the most frequent site is the left ventricle on the anterior wall, not far from the septum. Statistics give, for 55 cases,34 43 in left ventricle, 7 in right ventricle, and 3 in right auricle and 2 in the left auricle.
34 Elleaumé, Essai sur les Ruptures du Coeur, Paris, 1857.
The break is generally a ragged, irregular rent in the course of the fibres, and the trajét may be oblique and crossed by strands of muscle. The internal orifice may be larger than the external; the opposite is rarely the case. Two or more rents have been found. Usually the fissure is not very long—from a quarter of an inch to an inch—but there are cases of long rents extending from base to apex. Clots usually block the orifices, and the pericardium also contains large coagula. Evidence is sometimes found to indicate that the tear has occurred slowly, as attempts at repair may be present.
The wall in the vicinity of the break has usually been found in a state of degeneration, and we can readily understand how sudden and violent contractions might strain a weak part and tear the substance. Perhaps irregularity in the contractions may be an important factor, such as we may suppose occurs when a wave of contraction reaches a patch of advanced fatty change or softening from embolism.
The accident usually takes place during exertion or excitement. Many cases are reported during straining at stool, others while lifting weights, running, or during coitus. Cases are mentioned as occurring during sleep or while at rest.
There may be no preliminary symptoms, and without warning the patient falls, and with a few gasps or a cry is dead. This occurred in 71 of the 100 cases collected by Quain. In other instances there is great pain in the præcordial region, a sense of suffocation and anguish, with vomiting, and life may be prolonged several hours. In one instance the patient lived eleven days.35 Probably in such cases there is a small rent at first which gets blocked with clots, and only a small amount of blood oozes into the pericardium with each systole. The symptoms may be those of simple heart failure, as in a case I examined for Burland of Montreal, in which the patient lived thirteen hours after the onset of the symptoms, and was able, though with difficulty, to continue his walk up a rather steep hill.36 Death appears to occur from shock or syncope, sometimes from compression of the heart by the extravasated blood. In the case just mentioned the amount of blood in the pericardium was very much less than I have seen in cases of rupture of an aneurism into this sac.