Book - Congenital Cardiac Disease 9
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Abbott ME. Congenital Cardiac Disease (1915) Osler & Mccrae's Modern Medicine 6, 2nd Edition.
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- 1915 Congenital Cardiac: Congenital Cardiac Disease | Heart Development | Literature | Etiology | Cyanosis | Classification | Pericardium | Heart Displacement | Whole Heart | Anomalous Septa | Interauricular Septum | Interventricular Septum | Absence of Cardiac Septa | Aortic Septum | Pulmonary Stenosis and Atresia | Pulmonary Artery Dilatation | Aortic Stenosis or Atresia | Primary Patency and Ductus Arteriosus | Aorta Coarctation | Aorta Hypoplasia | Diagnosis Prognosis and Treatment | Figures | Embryology History | Historic Disclaimer
Defects of the Aortic Septum
When the aortic septum fails to develop, a single large thick-walled trunk {persistent truncus arteriosus) results, which arches upward in the course and gives off the branches of the normal aorta, the pulmonary artery arising therefrom. This abnormality is very uncommon. Partial defect of the aortic septum is even less frequent than is its complete absence. It may result in a common trunk with early division into aorta and pulmonary artery and rudimentary septum within it, or, when the defect is still smaller, in an abnormal communication between the aorta and the pulmonary artery or the conus of the right ventricle.
1 Jour. Anat. and Physiol., 1907, xli, 190.
2 Trans. Path. Soc, London, 1854, vi, 177.
3 Verh. d. XII Deut. path. Gesell, 1908, p. 174.
- Jour. Anat. and Physiol., 1894, xxviii, 305.
• 5 Trans. Path. Soc, 1846, i, 21. s Ihid., p. 21.
' Trans. Path. Soc, London, 1859, x, 49. « Ziegler's Beitr., 1889, vi, 485.
Persistent Truncus Arteriosus
(Common Arterial Trunk, Complete Defect of the Aortic Septum). This abnormality is very uncommon, only 22 cases are available in the literature and from other sources of study. The cardiac septa are frequently rudimentary or absent, a biloculate or triloculate heart existing. When, however, these are well developed and the heart is four-chambered and otherwise normal, a localized defect at the base of the interventricular septum always remains. The common trunk either rides above it, receiving the blood equally from both ventricles, or arises more or less entirely from the right ventricle, the blood entering it from the left through the defect.
Fig. 31 Persistent truncus arteriosus. Heart of a child, aged five years, in whom cyanosis developed at one and one-half years. A, common arterial trunk arising entirely from right ventricle, and communicating with the left ventricle through the right auricle; B, right auricle laid open; C, defect at base of interventricular septum; D, heavy muscular column from wall of right ventricle to base of defect; E, interauricular septum seen from right auricle showing multiple defects. Heart is wider than high. (From a specimen in the McGill Pathological Museum presented by Dr. Mackenzie Forbes.)
This recalls the early stage at which the arrest of growth has occurred, when the primitive aorta is given off entirely from the right side of the common ventricle (Fig. 16). A typical specimen of this kind is shown in Fig. 31 from a specimen in the McGill Museum. The large common arterial trunk springs entirely from the right ventricle, and has three strong semilunar cusps, behind two of which the coronaries arise. Below the anterior and right posterior cusps there lies a circular defect in the septum, admitting the little finger, with rounded edges, by which the left ventricle communicated with the aorta and with the right ventricle, which is much hypertrophied; a heavy muscular column runs from the anterior wall of this ventricle to the lower border of the defect. The left auricle and ventricle are perfectly formed, but are much smaller than the right chambers. There are multiple defects in the inter auricular septum. The blood supply to the lungs is unknown.
The pulmonary circulation in these cases is of the greatest interest.
Two large branches, one to either lung, may arise from the wall of the
common trunk some distance above its origin, as in the cases of Heath^
and Ramsbotham. Quite commonly one pulmonary branch arises from
the aorta soon after its origin, and supplies either the right or the left
lung, and a second branch passes to the lung of the opposite side from
the descending aorta, the first vessel evidently representing the pulmonary
portion of the truncus (sixth aortic arch) and the second the patent
arterial duct. This occurred in Dickson's^ and Wirth's^ cases, and also
in that by Preisz.* In the latter, distinct traces of a partial development
of the aortic septum were apparent. A common trunk provided with
four semilunar cusps, 14 mm. in diameter, arose from the right ventricle
above a large septal defect, and widened rapidly to 3 cm., becoming
grooved externally to indicate the right and left portions of its lumen,
that part on the right giving off the vessels of the arch, and thus representing the aorta, while that on the left yielded the vessels to the right
lung and represented the pulmonary artery. An additional pulmonary
artery was here also sent to the lungs from the descending aorta in the
position of the ductus arteriosus.
In a few instances in which the defect in the aortic septum appears to be only partial, the common trunk divides immediately after its origin from the heart, two-thirds of its lumen on the right forming the aorta, and one-third on the left forming the pulmonary artery, which takes its normal course.
This early division occurs in both of Rokitansky's cases, and in them the partial character of the defect is also proved by the presence of a delicate sickle-shaped septum within the undivided portion of the trunk, joining its wall between the left and posterior semilunar cusps behind, and left and right cusps in front. In Clarke's^ case the trunk divided early, but there was no sign of a rudimentary septum within.
The above are examples of true persistent truncus arteriosus. Under this title is also reported a series of cases in which the single trunk passing from the heart, represents the greatly dilated aorta or pulmonary artery, as the case may be, and an atresic cord attached to the external surface of the heart represents the obliterated origin of the other vessel. In one of Farre's cases, for instance, and in one by Forster, the single large trunk represented the pulmonary artery, and "a single coronary vessel which descended from the concavity of the arch to the base of the heart where it divided into two coronary arteries" was evidently the aorta, which was atresic at its origin, and was connected with the pulmonary by a large patent ductus. In Crisp's case, on the other hand, the pulmonary artery was rudimentary, and the large trunk represented the aorta.
1 Trans. Path. Soc, London, 1864, xii, 62.
2 Jour. Anat. and Physiol., 1914, xlviii, p. 210.
3 Giessen Thesis, 1912. ^ Ziegler's Beitrage, 1890, vii, 247. ^ Trans. Path. Soc, London, 1885, xxvi, 178.
As pointed out by Gierke, and also by Wirth, such cases should be clearly distinguished from the true persistent truncus due to complete absence of the aortic septum. Where the interventricular septum is defective at its base, as it is in all these cases, there is a tendency for the aortic septum to develop irregularly, thus cutting off a narrow aorta or pulmonary artery, as the case may be, and the calibre of the smaller vessel is likely to become still further reduced in size by the passage of the bulk of the circulation into the larger trunk. For this reason obliteration of one trunk in biloculate heart where no interventricular septum is present, is a comparatively common event, and the cases should be sharply distinguished from a true defect of the aortic septum. Gierke suggests that the presence of four semilunar cusps such as occurred in Preisz's case is positive proof of an undivided primitive arterial trunk, while the presence of three semilunar cusps such as occurred in the McGill specimen, his own, Dickon's, and Wirth's argues that development of the aortic septum had occurred and that obliteration of one or other of the vessels had taken place as a secondary event.
Symptoms and Physical Signs
Much the same remarks apply to persistent truncus as to bilocular heart, for symptoms and signs are not always commensurate with the seriousness of the lesion. But here the condition is a still graver one and the average duration of life is much shorter. Crisp's patient, a girl dumb from birth, with only slight cyanosis and clubbing, lived to twelve years, Forbes' to five years, Peacock's to thirteen months, and Buchanan's, who had a four-chambered heart with defect at the base of the septum, giving ph}'sical signs but no cyanosis, to six and a half months; all the others were marked cases of morbus coeruleus and died at birth or in early infancy. Vierordt quoted one dying at sixteen and another at nineteen years.
Communication between the Aorta and Pulmonary Artery
(Partial Defect of the Aortic Septum) A few cases have been described in which a circular or oval hole with perfectly smooth edges, and evidently not of inflammatory origin lies in the anterior wall of the aorta a short distance above the semilunar cusps, and leads directly into the pulmonary artery shortly above its origin. A. valuable developmental study was made by Hektoen,^ who gives a case of much interest and collected 9 others from the literature.
The effect produced upon the circulation by the abnormal communication between the two great vessels is the same as in a patent ductus
arteriosus, but the two conditions are quite distinct and have an entirely
different etiology. This lesion is not a patent ductus abnormally shOTtened so that aorta and pulmonary artery have been approximated, with
an apparent hole as a result. It is a true defect, as is proved both by
its situation, which is much nearer to the origin of both arteries than is
the ductus, and by the fact that in several of the cases reported the ductus
has been present as well. Neither is the defect of an inflammatory
nature, as is well seen in the smooth condition of its edges in the cases of
Girard, Wilks, and Rickards, and from the character of the combined
defects in the latter and in Fraentzel's case.
The abnormal opening is clearly a partial defect of the aortic septum,
not at its junction with the interventricular septum, but higher up in its own substance, probably at the point where the distal bulbar swellings
meet the aortic septum proper in the embryo.
1 Trans. Chicago Path. Soc, 1905.
In all the recorded cases but one, the hole lay in the aortic wall a
short distance above the semilunar cusps. In that of Richards the
aortic valve was bicuspid, and its segments congenitally fused. A funnelshaped opening communicated with the pulmonary artery and lay behind
the larger (fused) cusp. A triangular defect in the interventricular septum
existed also in this case.
Instead of opening into the pulmonary artery, the hole may lead from
the aorta into the right ventricle as in the cases of Livingstone^ and
Cayla. In one of Hektoen's cases the anomalous opening led from the
aorta into the right ventricle through a defect at the base of one of the
semilunar valves. This, also, is a most interesting example of a defect
of the lower (bulbar) part of the aortic septum.
A communication between the aorta and pulmonary artery of an acquired nature may occur in much the same situation as in the congenital form in aneurism of the base of the aorta. There is quite a large series of cases, especially in the earlier literature, which is reviewed by Brocq.^ The congenital cases are to be distinguished from those due to perforation of an aneurismal sac by the smooth appearance of the edges of the opening and the healthy arterial wall. The physical signs produced are the same and are often of remarkable intensity. Gairdner^ reported a typical case, characterized by a continuous murmur.
The pulmonary artery was larger than the aorta in Wilks' and Richard's cases, a little smaller in Fraentzel's and Girard's cases. Marked hypertrophy and dilatation of all the chambers of the heart, especially of the
right ventricle, constantly results. In Girard's and Richards' cases, in which there was no other cardiac lesion, the hearts weighed, respectively, 670 gms. and 23 oz. (651.8 gm.).
Symptoms and Physical Signs
Cyanosis is not, as a rule, present, and there is no characteristic picture, excepting that obstruction to the circulation is clearly manifest. All the cases recorded died before middle life with anasarca and other sjTiiptoms of chronic heart disease; those of Girard, Richards, and Fraentzel reached thirty-seven, thirty, and twenty-five years respectively. Wilks' infant died at eight months, Hektoen's and Lebederber's at birth. Precordial discomfort, amounting often to actual distress, was present since childhood in Richards' patient, as also in Fraentzel's and Girard's, and in the two latter there was dyspnoea on exertion and slight cyanosis. Physical signs may be absent or may be very marked, and they may vary, being sometimes quite atypical, or sometimes those usually associated with a patent ductus arteriosus. Owing to the great hypertrophy of the heart the cardiac dulness is usually much increased, especially to the right, and there is precordial bulging. Girard's case was characterized by a slight thrill and systolic murmur at the apex, which latter gave place later to reduplication" of the first sound and distinct gallop rhythm.
1 New York Med. Rec, 1883, p. 249.
2 Reuue de med., 1885, v, 1046 and 1886; vi, 786. ^ Glasgow Hospital Reports, 1899.
A diastolic murmur is common. In Rickards' case the cardiac dulness
was enormously increased, and there was an intense purring double
thrill over the cardia, and mm-murs, systolic and diastolic, running into
each other, were heard over the whole front and back of the chest, so loud
as to be audible even through the bedclothes. In Fraentzel's patient,
in whom there was a gaping opening 12 mm. across between the two
vessels, and the right pulmonary artery arose from the ascending aorta,
the heart was found to be greatly enlarged; both sounds were heard at
all the ostia, and a systolic murmur was heard at the apex; in the fourth
left space near the sternal border was a loud systolic and a long diastolic
murmur, the latter heard with equal intensity over the base of the xiphoid
cartilage. Both sounds and a diastolic murmur were audible in both
second spaces, the mm-mur being louder and rougher in the second right
space than in the left. Both sounds as well as systolic and diastolic
murmurs were audible in the carotids.
Deviation of the Aortic Septum
According to the teaching of Rokitansky, transposition of the arterial trunks, Rechtslage or deviation to the right of the aorta, as well as certain developmental forms of pulmonary and aortic stenosis, are due to irregularities in the development of the septum within the aortic bulb, or to its malunion with the interventricular septum. As this theory with certain modifications still finds general acceptance, the cases embraced by it will be considered here.
Transposition of the Arterial Trunks
This may be defined as an alteration in the position of the two great vessels relative to the ventricles of the heart or to each other at their origin, so that they either spring from reversed ventricles, the aorta from the right and the pulmonary from the left chamber (complete transposition), or from the ventricle to which they normally belong, but in a reversed relationship (" corrected" transposition) .
The condition was first described by Baillie in 1797, and early cases were reported by Farre in 1814, Ward^ in 1851, Peacock^ in 18.54, Buchanan^ and Meyer^ in 1857, Cockle^ in 1863, and Kelle/ in 1870. As a result of systematic observation of the autopsy material of infants at the St. Petersburg Foundling Hospital, Theremin found 26 cases of transposition among 106 cardiac defects. In his summary of the literature in 1898, Vierordt mentions (p. 47) 76 cases of transposition among 383 cardiac defects analyzed. Some thirty additional cases have been reported since. Among 270 cardiac defects in the London ]\Iuseimis examined by Keith, transposition occm-red in twenty-five. In our series of defects it was present seventy times.
1 Trans. Path. Soc, London, 1851, v, 67.
2 Ibid., 1854, vi, 117. ^ jud., 1857, viii, 149.
- Virchows Arch., 1857, xii, 364. ^ Medico-Chir. Trails., 1863, xlvi, 193.
^ Trans. Path. Soc, London, 1871, xxii, 92.
Pathogenesis
Peacock and others ascribed this anomaly to an irregularity in the development of the aortic septum, but until Rokitansky's work appeared in 1875, it remained a little understood phenomenon. In some minor particulars the observations of Rokitansky upon development do not coincide with those of later observers, but it is in the elucidation of the complex and hitherto obscure subject of transposition of the arterial trunks that the value of his great achievement may be said chiefly to lie. Rokitansky's explanation of transposition is one of those revelations, astonishing by its simplicity, and, as Vierordt remarks, he had the singular triumph of having supplied a working hypothesis that has not only explained the facts of his own experience, but has outlined and foreseen other pathological possibilities which have since been realized. He described and figured sixteen different forms of transposition, due, he believed, to different degrees and combinations of deviation or malunion of the aortic and interventricular septa, some of which he himself observed, and others have since been recorded by later workers. Even if the advance of comparative embryology should unfold some other explanation of this subject, the verification of Rokitansky's brilliant hypothesis by the subsequent observation of different forms of transposition showm by it to be possible, indicates that, so far as it goes, his theory is true, and that growing knowledge will amplify rather than supersede his solution of this difficult problem.
Since the above statement was written for the first edition of this
work, a remarkably clear exposition of Rokitansky's theory in the light
of recent investigations upon the normal anatomy of the bulbus cordis
in the dipnoan and reptilian heart and in the mammalian embryo, has
been published by Jane Robertson.^ The following is a brief statement
of Rokitansky's doctrine of transposition, as corroborated and amplified
by the result of these researches.
As may be seen by a glance at the normal adult heart, the great trunks
normally undergo a distinct torsion upon each other just above their
origin, so that the pulmonary artery, w^hich arises in front and to the
left, passes back behind the ascending aorta to the lungs, while the aorta,
although coming to lie ventral to the pulmonary artery, springs from the
heart behind it and to the right. This torsion of the vessels is
represented in the bulbus cordis of the early embryo and in the dipnoan
fish by a spiral arrangement of the valvular endocardial folds of the bulbus
cordis, which results from a kinking upon itself of the bulbus, which structure was at an earlier stage a straight tube. The aortic septum is formed
in its proximal portion by fusion of the spirally placed endocardial ridges
of the bulbus cordis, and in its distal part by a growth downward of a
septum in the common arterial trunk. If for any reason this normal
kinking does not occur and the bulbus remains a straight tube, the aortic
septum will not assume its spiral form, and the normal torsion of the
great trunks upon each other cannot take place. The result is an aorta
arising anteriorly and passing directly upward to the arch, and a pulmonary artery arising posteriorly and passing directly backward to the
lungs, i. e., transposition. In other words, transposition of the arterial
trunks is due to a lack of development of the torsion that normally occurs. The transposed vessels may be placed in their proper ventricles
in spite of their relative displacement, by the sympathetic adjustment
of the aortic in its union with the interventricular septum. In this case
the transposition is "corrected" (Rokitansky's Scheme A). Or the
transposed vessels may be placed in the reversed ventricles by the union
of the interventricular with the proximal portion of the malposed aortic
septum, when "uncorrected" (anomalous) transposition results (Rokitansky's Scheme B).
^ Jour. Path, and Bacleriol., 1913, xviii, 191.
Fig 32 Fig. 33 Fig. 34 True complete transposition, vessels in reversed ventricles. A, aorta; P, pulmonary artery; T, tricuspid valve; B, bicuspid valve; pm, pars membranacea: p, posterior cusp; a, anterior cusp; Ir, left, right cusps (the small circles indicate the situation of the coronary article.) (Republished from Vierordt, Nothnagel's System, 1898, xv, 1, 2.)
Rokitansky recognized this spiral disposition of the aortic septum and taught that these two factors, a deviation of the septum within the aortic bulb and its faulty union with the interventricular septum, might occur in all degrees and combinations, giving rise to a corresponding number of different forms of displacement of the arterial trunks or of "corrections" of such displacements. He distinguished two main classes (according as the transposition is "corrected" or otherwise by the interventricular septum), with eight sub-varieties in each. Of these his "Scheme A" has as its type or starting point the normal relation, in which the concavity of the septum looks backward and to the right. The different subvarieties are constituted by the different degrees of deviation of the aortic septum rotating in an imaginary circle from right to left. The characteristic of the group as a whole is that the interventricular unites with the aortic septum in such a way that, although the trunks are altered in their relation to each other, they remain placed in their respective ventricles: that is to say, the transposition is "corrected."
In his second group, or "Schema B," on the other hand, the arteries arise throughout from the "reversed" ventricles; that is to say, the transposition is "uncorrected" in the union of the interventricular septum. The type, or fundamental form from which the series starts, is the so-called transpositio vera, in which the septum has rotated through 180 degrees, so that its concavity looks downward and to the left, and the arteries lie in reversed cavities in the exact opposite of the normal position, the aorta to the left and anteriorly, the pulmonary to the right and posteriorly (Fig. 34) . Another explanation of transposition has been offered recently by Keith, namely, that it is due to an atrophy of the bulbus cordis around the pulmonary artery, and its great muscular development about the origin of the aorta, where it normally undergoes involution. The effect would be the pulling round of the aorta at its orifice to the position normally occupied by the pulmonary artery, so that the relation of the two vessels to the auricular canal becomes reversed.
A similar result would be attained by supposing a reversal of the normal right to left bulboventricular bend, so that this undergoes a left to right twist, which would bring the vessel lying posteriorly into relation with the right side of the auricular canal. Such a reversal of the bulboventricular bend has been suggested to me by Dr. Lewis as a probable explanation of those cases of transposition in which the transposed aorta is cut off by an anomalous septum from a common ventricle,, and has also been mentioned in this connection by Keith.
From a consideration of the above theories, and from the study of two models made by Dr. Frederic Lewis and myself, the series of events occurring in transposition appears to us to be as follows: (1) A reversal of the bulboventricular bend, so that the two great trunks resulting from division of its distal aortic portion come to occupy a reversed relation to the auricular canal; (2) a reversal of the normal kinking of the aortic bulb so that it remains a straight tube or assumes a curve complementary to the reversed bulboventricular twist below; (3) a consequent reversal of the normal spiral arrangement of the bulbar endocardial ridges; and (4) a resulting malposition of the aortic septum so that its spiral twisting either does not take place, or takes place in a reversed direction, leading to a lack of the normal torsion of the great arterial trunks, that is, transposition.
The interdependence of the first and second of the above events is evident from a glance at the compensatory curves of the normal embryonic bulbus (Plate V), but the question as to which of these two is of primary occurrence is not altogether clear. The reversal of the bulboventricular twist may be of the nature of a localized situs inversus and the causative factor of the whole proceeding. Or it may be secondary to a primary arrest of the kinking that normally takes place in the aortic bulbus, and of the consequent lack of spiral disposition of its valves.
That the second of these two alternatives, namely, a primary arrest of development, may be the correct solution is suggested in a striking way by two remarkable cases reported by Wenner/ and Birmingham^ of " piire"dextrocardia, in which the transposed vessels arose from the extreme right side of a common (in Birmingham's case of a right) ventricle, and both auricular appendages lay entirely on their left side, just as in the very early embryo, the common auricle lies to the left of the common
trunk. In both cases the dextrocardia was not a true situs inversus, but the apex of the heart was formed by the right ventricle, again evidencing a persistence of an early embryonic state, and a true primary arrest of development.
Fig. 35
A, Wenner's case of cor biatriatrum triloculare with transposed aorta and pulmonary artery passing up to the right, and both right and left auricular appendages displaced to the lett side. A, Superior vena cava; B, right pulmonary artery; C, right auricle; D, ductus botalli; E, left pulmonary artery; F, right auricular appendix; G, left auricular appendix.
B, figure of normal embryonic heart showing the position which the truncus comes to occupy between the auricular appendages after the normal shunting to the left of this structure has taken place. A, common arterial trunk; B, B, auricular appendages.
C, figure of embryonic heart in which the normal shunting to the left of the common arterial trunk has not occurred, so that this structure still comes off entirely from the right side of the heart (as in the very early stages), and both auricular appendages still lie on the left (as in Wenner's case). A, common arterial trunk; B, auricular appendages. From Beitrdge zur Lehre der Herzmisshiidungen, Case 9. Otto Wennej-, Virch. Arch., 1909, 196, pp 140, 155,
Pathology
It is impossible to follow Rokitansky's minute classification in a statistical study of recorded cases, for the relation of the vessels to each other is often indefinitely stated. For practical purposes the classification into complete, corrected, and partial transposition, suggested by Vierordt, may be used.
(a) In complete transposition, the vessels arise from reversed ventricles. This occurred in 43 of our 70 cases. In 18 of these the aorta arose from the right ventricle to the right and in front, and the pulmonary artery to the left and behind. The so-called transpositio vera, in which the aorta arises in exactly reversed relation to the left and anteriorly, and the pulmonary artery from the left ventricle to the right and posteriorly, is illustrated by the cases of Pye-Smith^ and Thiele. The pulmonary rose above a defect in the septum and the aorta from the infundibulum of the right ventricle in three of Theremin's cases, and in those of Lees and Rheiner. The aorta rose from both ventricles above the defect, the pulmonary from the left ventricle, in that by Buchanan.^
(6) In corrected transposition (see Fig. 33 Scheme A), the relation of the vessels to each other is altered, but they are placed in their proper ventricles by the union of the interventricular septum. Minor degrees of displacement probably often pass unnoticed, for the "correction" prevents pathological results. More extreme grades can be at once recognized. Six almost identical cases are described by Rokitansky (two cases), Rauchfuss, Tonnies,^ and Theremin (two cases), in which the aorta and pulmonary artery are completely reversed in relation to each other, but arise each from their own ventricle. In all there was a defect in the interventricular septum at the base, and in all the auriculoventricidar orifices were also transposed, the mitral lying in the right, the tricuspid in the left ventricle, and thus the "correction" of the transposition of the arteries by the septum was seemingly nullified; the aorta arises from a ventricle of venous form (in that it has a tricuspid valve), the pulmonary from an arterially constructed one. Rokitansky suggests that in these cases "the ventricle in which the septum arises anteriorly forms as the arterial one." Fingerhuth described a case of corrected transposition with situs inversus of the viscera, and no transposition of the ventricles.
1 Virchoivs. Arch., 1909, cxcvi, 127.
2 Jour. Anat. and Physiol., 1893, xxvii, 139. ^ Trans. Path. Soc, London, 1873, xxiii, 80. 4 Ibid., 1857, viii, 149.
^ GoUingen Thesis, 1884.
(c) Partial transposition, in which both vessels arise from the same
ventricle or from a common ventricle in reversed relations, is relatively
infrequent. Both vessels may arise from the right ventricle, as in Theremin's
forty-first observation and in Tooth's case/ in which a large thick-walled
aorta arose from the usual origin of the pulmonary artery, which was
itself small, thin-walled, bicuspid, and was given off from the right
ventricle directly behind the aorta. Both vessels may spring from the
left ventricle. Thus, Crocker reported a girl, aged thirteen years, in
whom the pulmonary artery, small and constricted, arose from a small,
thick-walled, left ventricle to the right and anteriorly, while the aorta
arose from the same cavity posteriorly, and communicated with the right
ventricle through a defect in the septum. Both vessels may arise transposed
from a covimon ventricle, as in two examples of cor biatriatrum triloculare
with pulmonary atresia and transposition, and in the biloculate heart
reported by Rudolf. The remarkable cases of displacement of both
auricular appendages to the left of the transposed vessels fall in this
category. Finally, the transposed vessels may arise from a rudimentary
cavity cut off by an anomalous septum from the common ventricle.
The condition of the semilunar cusps in transposition is of interest. In one or other of the vessels, more commonly in the pulmonary, they are frequently deformed, of unequal length, bicuspid, or, as in Bokay's case, markedly increased in depth. Their position varies with the degree of displacement, and should therefore be carefully observed, as the degree of deviation may be thus detected. In true transposition, for instance, the non-coronary cusp in the aorta lies anteriorly instead of posteriorly.
Changes in the relative size and thickness of the tivo great trunks are usually present, and are of importance as supporting Rokitansky's view that an altered position of the aortic septum is a fundamental part of the condition. In spite of the fact that the pulmonary arises from the left ventricle, which is anatomically constructed as the strongest of the two chambers, this vessel is usually thin-walled and narrowed and its orifice is stenosed or atresic, while the aorta is dilated. Among Rokitansky's 18 cases of transposition, pulmonary stenosis or atresia occurred 11 times, and it was present in 17 out of the 25 cases of Keith's series. In a few instances the reverse holds good and a large thick-walled pulmonary may be combined with a short, narrow aorta. Theremin's series of 14 cases in infants, 10 of which were of complete and 4 of partial transposition, forms a remarkable exception to the above statement. In 3 of his cases the pulmonary was dilated, and in the remainder it was equal in size to the aorta. In our own series, which includes these 14 of Theremin's, among 70 cases, in 43 of which the transposition was complete, in 22 partial, and in 5 "corrected," the pulmonary was stenosed or atresic in 23 cases.
1 Trans. Path. Soc, London, 1879, xxxi, 92. VOL. IV — 25
The Fetal Passages
In complete transposition the venous blood from the right heart is distributed to the arterial system through the aorta, while the aerated blood entering the left auricle is returned again to the lungs by the pulmonary artery. The conditions of the circulation are thus of the poorest, and unless one or other of the fetal passages remains open, life cannot be sustained. The interventricular septum is frequently entire, but a widely patent foramen ovale is nearly always present and combines with a patent ductus or with a septal defect to allow of the passage into the aorta of the aerated blood. Very rarely does one of these conditions exist singly. In our series, among 37 cases of complete transposition the foramen ovale was patent 32 and the ductus arteriosus 22 times. A patent foramen was the only communication between the two sides of the heart in 8 cases, namely, those by Emanuel, Doming,^ Kelly, Cockle, Bokay, and in three of Theremin's cases. It was combined with a patent ductus in 14 cases, with a defect of the interventricular septum in 6, and with patency of both of these openings in 4 cases. The ventricular septum was completely closed in 25 cases and was defective in 12, in one of which, that by Heuyer and Campergne,^ the septal defect was the only communication, and in another by Guttmann^ the ductus arteriosus was also patent. In Theremin's thirtyseventh observation and in Ramm's case, a large patent ductus was the only communication between the right and left heart. In a few cases the bronchial arteries were markedly dilated.
Bokay* has made an analysis of 43 cases of complete transposition, with regard to the condition of the fetal passages, and there are 33 additional cases in our series from the literature. The following table shows the condition of the fetal passages in these 76 cases.
F. 0. Patent. D. A. Patent. V S. Defect.
F. O. patent 16 36 7
D. A. patent 36 3 3
V. S. defect 7 3 5
Patent F. O., defect V. S., patent D. A. ... 4 4 4
Total 63 46 19
The abbreviations are as follows: F. 0., foramen ovale; D. A., ductus arteriosus; V. S., interventricular septum.
Hypertrophy and Dilatation of the Heart
Under the altered conditions of the circulation the aorta is required to supply blood, not only to the systemic circulation, but through one or other of the persistent fetal passages to the lung. The right heart is practically invariably hypertrophied and dilated, sometimes to an enormous extent, and the right auricle likewise. The left chambers usually share in these changes though to a less degree.
1 Trans. Am. Fed. Soc, 1891, ii, 46.
2 Bull, de la Soc. Anat., April, 1913, p. 209.
3 Deut. med Woch., 1893, xc, 74.
4 Arch.f. Kinderheilk., 1911, Iv, 321.
Symptoms and Physical Signs
During the period of fetal circulation, transposition of the vessels is of little pathological significance, so that, unless associated anomalies exist, the subjects are born at full term, well developed, and apparently normal. In complete transposition, marked cyanosis is almost always a prominent feature, but it may not be present at birth, appearing usually after some days or weeks, and perhaps developing, as Theremin suggests, as the ductus becomes obliterated. On account of the extreme degree of the cyanosis, clubbing of the fingers and toes usually develops in infants which have survived the first six months of life. In partial transposition, on the other hand, or in complete transposition with large septal defects, cyanosis may be quite moderate in degree. In Theremin's patient, dying at three and a half years, there was no cyanosis until the last illness, but large defects of interauricular and interventricular septa combined to relieve the situation. In a remarkable case of partial transposition, recorded by Lebert,^ death occurred from failing compensation, at the age of twenty, without any sign of cyanosis having developed during life. The patient was a young man in good health until three years previously, when cardiac symptoms developed suddenly after lifting a heavy weight. The aorta arose in front of the pulmonary from the right ventricle, the pulmonary was stenosed and a large septal defect admitted the index finger.
In uncomplicated cases, and where a ventricular septal defect is either not present or is of small size, physical examination may yield no evidence of the defect, except a sharply accentuated second sound over the pulmonary (aortic) area. The combination of marked cyanosis with signs of hypertrophy of the right heart and an entire absence of adventitious sounds, or precordial thrill, in an infant or young child, is strongly suggestive of transposition, and a successful diagnosis has frequently been made on these features. In Theremin's thirtieth observation this was based upon "cyanosis increasing when the infant cried, hypertrophy of the heart both in vertical and transverse diameter, the heart sounds loud and accentuated but pure, the aortic and pulmonary sounds distinct." In Ramm's case, aged fifty-six days, a probable diagnosis was made. Here also there was cyanosis from birth, no murmur, no accentuation or reduplication of the heart sounds, but dulness extending beyond the right sternal border and upward to the second rib, of so marked a character that a mediastinal tumor was at first suspected. In Theremin's thirtieth, thirty-first, thirty-eight, and thirty-ninth observations the heart sounds were free from murmurs, although muffied, and cardiac dulness was increased to the right. On the other hand, a loud systolic murmur with maximum intensity at the apex was heard in Kelley's case, the same at the base and at the back in Pye-Smith's, and was probably produced by the patent foramen ovale present.
The patent ductus, patent foramen, or septal defect present, may produce their characteristic physical signs, and thus obscure the negative character of the auscultatory phenomena, which is significant of the clinical picture of an uncomplicated transposition.
Prognosis
The duration of life varies in the three groups distinguished. In complete transposition it is usually very short. In 32 of the 40 cases in our series it varied between eleven months and a few days. When a septal defect is present, life may be considerably prolonged; the age of sixteen years was attained by Keith's patient, eleven by Emanuel's, and four by Buchanan's. In partial or corrected transposition on the other hand, early adult life is usually reached. Birmingham's patient was twenty, Tonnies' twenty-one, Elliott's^ nineteen. Young's thirty six, and Geipel's forty-six years. Vierordt gives the following analysis of the duration of life in 75 cases. To this is added that of the 70 in our series, of which there were 57 classified as the primary lesion, and 13 complicating other defects.
^ Virchows Arch., 1863, Ixxxii, 405.
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Abbott ME. Congenital Cardiac Disease (1915) Osler & Mccrae's Modern Medicine 6, 2nd Edition.
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- 1915 Congenital Cardiac: Congenital Cardiac Disease | Heart Development | Literature | Etiology | Cyanosis | Classification | Pericardium | Heart Displacement | Whole Heart | Anomalous Septa | Interauricular Septum | Interventricular Septum | Absence of Cardiac Septa | Aortic Septum | Pulmonary Stenosis and Atresia | Pulmonary Artery Dilatation | Aortic Stenosis or Atresia | Primary Patency and Ductus Arteriosus | Aorta Coarctation | Aorta Hypoplasia | Diagnosis Prognosis and Treatment | Figures | Embryology History | Historic Disclaimer
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Cite this page: Hill, M.A. (2024, April 24) Embryology Book - Congenital Cardiac Disease 9. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Book_-_Congenital_Cardiac_Disease_9
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