An examination of the minute struct ure of the myocardium in dilatation may show either interstitial myocarditis or fatty degeneration, or there may he no change in the heart-fibres appreciable even with the microscope. In certain of these cases it would seem probable that the nervous ganglia connected with the heart may be at fault. In marked dilata tion the pectinate muscles themselves are flattened into mere tendinous cords.
[The accompanying illustrations are from photographs of specimens in the Warren Museum in the Harvard Med ical School, for advice and assistance in obtaining which I am indebted to the courtesy of Dr. William F. Whitney, Curator. IIEnmAN VickEnr.1 Prognosis.—It will be seen from what has gone before that dilatation of the heart is a condition which it is not proper to generalize when considering any individual case. The state might be said to bear the same relation to heart conditions that jaundice holds to the liver and digestive tract. Each case should, therefore, be carefully consid ered on its own merits or demerits.
The most acute transitory form of dilatation is probably that which occurs in athletes and others under great or long-continued effort. The majority of these persons, if in good health and well trained, seem to escape permanent injury. It will be found, however, that a certain important proportion of those who engage in violent and desperate competitive physical exertions, as for in stance, a long boat-race, stiffer for years thereafter from discomfort in the cardiac region, with some tendency to irregu larity of the pulse.
Those who train athletes should ap preciate this possibility. The first de gree of dilatation and consequent venous stasis is shown by pallor, for this reason: as the left ventricle becomes tired, blood accumulates in the right side of the heart and the systemic veins in more than normal amount, yet not exceeding the capacity of the venous system. As a consequence of this increase of blood in the venous channels, there is less blood than- normal in the arteries, caus ing a pallor which does not advance to cyanosis until a much greater amount of blood is present in the veins. If, then, a person engaged. in vigorous exer cise changes from the ordinary pink flush of countenance to a decided pallor, the limit of safe exertion has been reached. Cyanosis conveys a still more
imperative warning: -With regard to the more common and usually slowly-developing forms of dila tation, it should be said that there may be many degrees of the disease in dif ferent persons. Here, too, sudden prog ress in the wrong direction may- occur, as the result of overstrain,—changing a moderate into a severe case. In gen eral, it may be said that the patient does not often survive a well-marked condi tion of cardiac dilatation for more than twelve or eighteen months.
The factors upon which we should lay weight in determining the reserve power of a dilated heart are of two kinds: ra tional and physical. If the disease has come on in one whose habits can be g-reatly changed for the better, with re gard either to overindulgence in alco hol, tobacco, the pleasures of the table, and such like, or sorrow, anxiety, over work, and long hours of sustained effort, then the chances are somewhat more favorable than if the subject has led a physiologically blameless life. The judiciousness or unsuitableness of the treatment heretofore adopted should also be considered. And those who have previously undergone one or two attacks of cardiac failure are to be regarded in a more dangerous condition than dur ing their previous illnesses.
Irregularity in the pulse is not neces sarily of evil import, but a great fre quency of the pulse-rate is discouraging. Of course, any degree of vigor in the cardiac impulse is a -welcome discoyery, as is also a sharp and decided quality in the second sounds at the base of the heart. The case may be considerably affected in its course by our ability to obtain for the patient a fair degree of sleep and maintain a sufficient nutrition of the body.
It is oftener possible to produce a cer tain degree of improvement than to maintain it, to say nothing of complet ing the recovery.
A fatal termination may be preceded by attacks of syncope, often most alarm ing; but death is more apt to come at the end of a comatose condition than with extreme suddenness. Embolism and thrombosis may also prove terminal factors.