A system of practical medicine. By American authors. Vol. 3

by Unknown

The compensatory alterations which commonly are held to indicate a congenital origin of stenosis of the pulmonary artery are patulousness of the auricular septum and of the ductus arteriosus Botalli. When both of these remain open there cannot be much doubt that the date of origin is from the foetal state or in the first weeks of life. If only one of the foetal passages remains open, the ductus gives a greater surety of a foetal date than the foramen ovale. The closure of both foetal passages does not exclude a congenital origin if the obstruction of the pulmonary orifice is moderate. The patulousness of both foetal passages indicates that the defect arose at least shortly after birth, because these openings close within four or five weeks of this event. The foramen ovale alone open indicates very little with certainty, as it is so often found with one or more small openings without any probable cause. Bézot found it partially unprotected in 44 cases out of 155; Klob, 224 in 500; Wallmann, 130 in 300. Rokitansky has indicated that a strong blood-pressure not unfrequently may press the fibrous valve of the foramen strongly toward one auricle or the other, and thus lead to its atrophy in part, forming larger or smaller openings of communication between the two cavities. In doubtful cases of stenosis of the pulmonary artery such small openings are not signs of much value in determining the congenital origin of the stenosis. Unless there is a marked defect in the septum atriorum, the congenital origin of the pulmonary atresia or stenosis cannot be predicated on this ground.

Patency of the ductus arteriosus Botalli has been very rarely observed as a primary malformation. A coincidence of this as primary defect with post-natal stenosis of the pulmonary artery must necessarily be extremely rare. In persistence of the ductus art. Botalli the current passes from the aorta toward the pulmonary artery; the obstruction of the pulmonary artery conditions a dilatation with hypertrophy of the right ventricle. Reopening of the closed ductus is impossible.

The condition of the pulmonary valves as well as the diameter of the pulmonary artery itself and its branches often afford valuable points for the determination of the congenital origin of stenosis of this orifice. The greater the narrowing, or the more extreme the thinning of the wall, the earlier the coming of the obstruction.

Morgagni reported the first case of stenosis of the pulmonary orifice—in fact, the first case of congenital malformation of the heart—in a girl aged sixteen. He recognized the relationship of the open foramen ovale and the dilatation of the right ventricle as mechanical effects of the pulmonary stenosis.

2. Obstruction of the conus arteriosus dexter, with open ventricular septum.

A. The separation of the conus in the form of a so-called supernumerary third ventricle has been reported by Peacock in ten cases, and ten others have been added by Kussmaul from various sources. The degree of separation varies very greatly in individual cases: in some it is so slight that the designation becomes doubtful, while in others it is so great that the word stricture might with propriety be employed. In two cases a goosequill-sized opening existed between the sinus of the right ventricle and the conus; in others the communication between the two was multiple. The size of the supernumerary ventricle varies greatly; in one case of a girl of twelve years it would only contain a hazelnut.

In most of the cases the partitioning probably commences by hypertrophy of the muscular bands which are more or less marked in normal hearts in this situation: to this, as the result of endo-myocarditis, is added cicatricial contraction of the inflammatory products, whereby the original partitioning becomes greatly increased. The preponderating frequency of the seat of the stenosis directly at the transition of the conus to the sinus increases the likelihood of this explanation of its causation.

Alteration of the valves of the pulmonary artery, probably of foetal inflammatory origin, is of very frequent occurrence with supernumerary ventricle and conus stenosis; sometimes only two cusps are found, though four cusps have been noted; they may be absent or be replaced by a ring mass formed from their union. Normal valves have been observed unaltered by inflammatory changes. The conus appears always to suffer diminution, and the pulmonary artery is found more or less narrowed according to the degree of obstruction. The sinus of the ventricle is dilated and its walls hypertrophied. The aorta, mostly widened, springs in all cases from both the ventricles, unless wholly from the right one. The foramen ovale is generally more or less widely open, although it has been found closed; the ductus art. Botalli is mostly closed. The duration of life may be long; Kussmaul reports the oldest case at thirty-eight years.

B. Of primary uniform narrowing or shrinkage of the right conus art. dext. Kussmaul reports eight cases from various sources. The conus was shortened, and formed a ring-shaped fissure, gradually reduced in size toward the orifice of the pulmonary artery. The pulmonary valves were variously changed, mostly by union of one or more of the cusps, though sometimes remaining normal in shape, though very delicate. The pulmonary artery was generally narrowed to about the width of the calibre of the conus itself, unless further change came to it from its special involvement by endarteritis.

In all cases the aorta arose from both ventricles. The right side of heart was dilated, and the right ventricular wall hypertrophied. The foramen ovale remained open. The ductus arteriosus Botalli has been found absent or closed, and the collateral circulation effected by anomalous communications, oftentimes duplicate or manifold; in most cases the ductus remains open. The oldest patient in which this form of heart has been found was twenty-five years.