DISTURBANCES OF THE CIRCULATION.
Influence of Pregnanry on Diseases of the Heart.—By reference to the previous remarks concerning the modifications in the circulatory system produced by pregnancy, the reader will see that, aside from the hypertrophy of the uterine vessels, the changes in the circulation may consist in: 1st. Increase of the total quantity of the blood. 2d. Alter ation of the constituent parts of the blood, as shown by the increase of water, white corpuscles, and by the diminution in the number of red discs, albumin, and iron, as well as the fibrin (at least early in preg nancy). There exists in the pregnant woman, therefore, a peculiar condition, neither plethora nor anwmia, characterized by cardiac hyper trophy and murmurs, dyspncea, oppression, and a tendency to congestion of the viscera, especially the lungs. Peter believes that the amount of blood increases during pregnancy, simply because of the existence of this condition, and the needs of the fcetus, so that the hemorrhage after delivery is physiologically necessary, in order to relieve the woman of the extra quantity of blood. Hypertrophy- of the left side of the heart is a purely mechanical result of the increased work, caused by the high aortic tension, from the direct pressure of the uterus (Raynaud), or the additional fcetal circulation. This hypertrophy is only temporary. disappearing rapidly and completely after delivery. But it may persist in some instances, and become permanent, increasing with each subse quent pregnancy, and culminate in a true cardiac affection, which, in its turn, under the influence of pregnancy, becomes the starting-point for a group of symptoms, now known as the cardiac symptoms of pregnancy (accidents gravido-cardiaques).
Pregnancy is only one of the causes which hasten the progress of heart-disease, the phenomena of which develop more or less rapidly during pregnancy and under its influence. This influence may be transient, when the valvular lesion or myocarditis is not aggravated, but repeated pregnancies do cause aggravation of them. Porak shows that on the whole, cardiac lesions, although not infrequent after delivery and during the puerperium, are rare during pregnancy. Opinions
differ regarding the presence of cardiac hypertrophy in pregnancy, some authorities believing in the existence of hypertrophy, others in dilatation, while others affirm the co-existence of both conditions. Lettille arrives at the following conclusions: Physiological hyTertrophy of the heart during pregnancy is not constant, the apparent enlargement of the organ being sometimes due to its elevation by the diaphragm. The presence of temporary dilatation is proved by the jugular reflux, cardiac and venous murmurs, and anaemia; some of these symptoms disappear after delivery. The dilatation is to be referred to the increased tension in the right ventricle, as well as to obstruction from pulmonary trouble; in this case, hypertrophy and dilatation may co-exist, when errors of diagnosis are easy, especially if the heart is elevated by the diaphragm. Porak found that the weight of the heart in women dying soon after _delivery varied from 8 to 10.9 ounces, while Letulle states that the weight varies from 8 to 10 ounces, the normal organ varying from 6.9 to 7.2 ounces. Cohnstein found hypertrophy of the left ventricle in ten cases out of twenty, dilatation in eight. myocarditis in eight and aortic stenosis in five. We do not see how Porak can arrive at this con clusion. Idiopathic hypertrophy of the heart must be rare, but it is not so in regard to actual cardiac lesions, and the persistence of the hypertrophy after repeated pregnancies is intimately related to sueii lesions. Degeneration of the myocardinm, leading to rapture of the heart, has been observed, especially during the puerperal state.
Endoeardial Lesions.—Endocarditis often occurs during pregnancy, and may be acute, sub-acute, or chronic. The acute form 'nay be of the typhoid or pytemic variety, and is marked by the presence of exuberant vegetations on the endocardium, resulting in emboli (due to coagulation or the detachment of bits of vegetations), the plugging of vessels and hemiplegia. However, acute endocarditis during pregnancy is rare.