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.
C. Ring-formed narrowing of the conus, due to a muscular band. Peacock
reports this defect from a girl æt. nineteen, cyanotic from birth; the
constriction was situated at the bases of the valves, and was formed by
a muscular band covered by fibrous tissue, and the edges of the opening
were studded with warty vegetations. The pulmonary valves were two in
number, probably resulting from fusion of two of the cusps; were
thickened and opaque, but smooth. The index finger could be passed
between the valves. The artery was of small size, but much wider than
the constriction. The aorta was dilated, and arose from both ventricles
through a perforation of the septum ventriculorum. The foramen ovale
was closed. The ductus art. Botalli gave free passage to a crowquill.
The right side of heart showed dilatation and hypertrophy of both its
cavities, and the tricuspid valve was thickened and had vegetations on
its auricular aspect.
3. Simple stenosis and atresia of the pulmonary artery, with open
septum ventriculorum.
This class includes malformations, with stenosis or atresia of the
pulmonary artery, in which the defects occur before the completion of
the ventricular septum, as the result of engorgement already described,
but in which no other primary congenital defect exists; thus the
separation of the pulmonary artery from the truncus arteriosus communis
is completed; the auricles and ventricles are marked out by their
septa, though not completely divided; {705} the position of the aorta
in relation to the pulmonary artery is either normal or more to its
right; and there are no primary defects of any consequence in the other
orifices of the heart. The simple stenosis or atresia of the pulmonary
artery as thus defined is by far the most frequent malformation of the
heart. Kussmaul has found about 90 described; among these are 26 cases
of atresia.
As a rule, in partial obstruction the entire length of the artery, as
far as the bifurcation, shows narrowing, but the greatest narrowing
exists at the orifice of the pulmonary artery; only rarely are the
orifice and the tube equally narrowed. Exceptionally, the tube has been
found narrower just without the orifice, and later resumed its normal
circumference. The walls are very often thin, like those of veins, and
at times the vessel is shrunken. The valves are variously altered,
often to a greater or less degree united, thickened, and opaque.
In complete closure two different conditions are seen; in some the
artery itself to its bifurcation changes to a firm cord or thread; in
others the tube is more or less narrowed and the orifice alone is
closed.
As a rule, in stenosis and atresia of the pulmonary artery the conus is
only moderately narrowed and its walls hypertrophied, while the sinus
of the right ventricle is dilated and hypertrophied. The right auricle
is dilated and hypertrophied. The tricuspid leaflets are clouded and
thickened. The left ventricle is commonly small, and the wall not
thicker than the dilated right ventricle. Sometimes the aortic and
mitral valves suffer alterations of an inflammatory sort, probably of
foetal origin. The shape and position of the heart are changed, but the
size, as a whole, may not be much altered. The aorta may be widened,
often to double the normal size. As to the origin of the aorta, it is
often difficult to speak with certainty; its relative position to the
pulmonary artery and to the body and axis of the heart is, as a rule,
unchanged. Whether it is to be described as arising from one or both
ventricles, or from the right one alone, depends on the posture which
the septum ventriculorum assumes beneath its orifice. As a matter of
fact, this relationship makes little difference to the flow of blood
from the right ventricle, whose normal orifice is obstructed; provided
the septal opening is sufficient, the flow of blood is secured and the
hindrance to the circulation precluded. The opening in the septum
ventriculorum may be only at the membranous portion, or it may also
involve the adjacent muscular septum; the defect may be round or
triangular, with its apex above and with smooth margins.
The foramen ovale has been found open in 39 cases out of 53. Its
condition in this respect shows very great proportional variation in
the different collections of cases. The open or closed condition of the
foramen does not seem to depend on the degree of stenosis of the
pulmonary artery itself. It depends, probably, more on the freedom of
escape for the blood from both the ventricles through the
aorta--probably also on the condition of the ductus arteriosus Botalli.
The foramen ovale and ductus art. Bot. have been found closed much more
frequently in stenosis than in atresia of the pulmonary artery, and the
ductus is deficient or absent oftener in stenosis than in atresia. This
absence of the ductus occurs in 13 per cent. of the cases, and tends to
support Peacock's theory that narrowing of the pulmonary artery is the
consequence of the defective development of that branchial arch out of
which the ductus art. Botalli is formed.
It is of great interest to note the collateral circulation by which
blood reaches the lungs when the pulmonary artery is closed. When the
ductus arteriosus is open, the blood passes from the aorta into the
ductus and the branches of the pulmonary artery become branches from
it. When the ductus arteriosus is closed or very narrow, the bronchial
arteries become {706} the means of supply for the lungs, and through
them the blood passes to be aërated. Branches from the coronary
arteries have been found supplying a partial channel for the blood to
the lungs, as well as the oesophageal, pericardial, internal mammary,
and intercostal arteries.
The duration of life is often very considerable. Thirty-seven years
have been attained.
4. Combined Stenosis and Atresia of the Pulmonary Artery.--Under this
division are arranged other primary defects of the heart, which are
found combined with stenosis and atresia of the pulmonary artery. It is
very striking how frequently this artery is narrowed or closed in
defects of the heart which date from the early period of foetal life,
before the division of the truncus art. comm. and of the ventricles has
occurred. It is only very rarely that defects from this early period
show a normal width in this vessel; in the great majority it is
narrowed or closed. The aorta is rarely affected in this manner.
Changes in the aorta may come also, but a complete failure or great
narrowness of this circulation is so difficult to overcome by a
collateral circulation--more difficult than the pulmonary
circulation--that life must cease in the foetus, or at least the
conditions are incompatible with extra-uterine existence.
A. Combination with partial persistence of the truncus arteriosus
communis. The defects coming under this head show usually very great
deficiency of the organ and its great vessels, although the heart
itself in rare instances shows the proper arrangement of the cavities
and their valves. The persistence of the truncus art. comm. may be
complete or partial; the defect consists in the total absence or arrest
of growth of the septum of the truncus, which partitions it into two
portions. Normally, the two septa grow simultaneously and meet at the
base of the heart. In cases of persistence of the truncus art. comm.
the upper septum fails to develop. In incomplete division of the
truncus the pulmonary artery suffers more than the aorta, and the
former is always narrower than its fellow-vessel. This difference
varies greatly. The valves of the pulmonary artery often fail entirely,
and the ductus art. Botalli is many times absent.
B. Combination with cor biloculare.--Here we have a heart consisting of
two cavities--one auricle and one ventricle--where no partitioning has
taken effect. The defect results from the failure of the septum
ventriculorum to grow; and with this, as in the former division, comes
also a more or less complete failure of the septum trunci art. comm.
C. Combination with single ventricle and divided auricles (cor
triloculare biatriatum).--In the cases of single ventricle with more or
less complete division of the auricles the pulmonary artery generally
shows narrowing to a greater or less degree; it may still be pervious,
although its orifice is closed, or it may be throughout entirely
obliterated. The valves may be entirely wanting. The duration of life
is very short, though in a very few with effective compensatory changes
it may be prolonged very considerably.
D. Combination with divided ventricle and a single auricle (cor
triloculare biventriculare).--In strictness, this defect is nothing
more than an open foramen ovale with some deficiency of the pulmonary
artery; but, in reality, the heart is much more malformed. The whole
septum atriorum is wanting; the superior or descending vena cava is
doubled--one entering the left part of the common auricle, the other
opening more to the right. The ventricular septum shows a greater or
less defection, the pulmonary artery is narrowed, and the aorta arises
from both ventricles or wholly from the right one.
E. Combination with special anomalies in the position of both the great
arterial trunks.--Here come a variety of anomalies in the arrangement
of the aorta and the pulmonary artery in relation to their respective
ventricles and to themselves.
{707} _a_. In transposition of the great arteries, the aorta arising
from the right ventricle and the pulmonary artery from the left cavity,
either there comes a general transposition of all the viscera or the
heart alone is reversed. Very rarely in transposition of the vessels
the septum ventriculorum is closed, commonly open, and although the
size of the vessels may be normal, usually their relation and position
continue reversed throughout their course. In cases where the pulmonary
artery is narrowed the duration of life is short. _b_. The pulmonary
artery may arise from the left ventricle and the aorta from both
ventricles; or, _c_, the aorta may come wholly from the right
ventricle, and the pulmonary artery from both cavities; the latter
vessel may be narrowed or show its normal width or even be considerably
dilated. _d_. Both the great vessels may arise from the left ventricle,
very much dilated, with the aorta in front of the pulmonary artery and
the latter narrowed. _e_. The relation of the great arteries may be
found reversed--_i.e._ the aorta in front and the pulmonary artery
behind, and the aorta spring from both ventricles and the pulmonary
from the right alone.
F. Combination with primary defects of other valvular orifices of the
heart.
_a_. The tricuspid valve may be quite rudimentary, producing by the
regurgitation thus allowed, especially when combined with pulmonary
stenosis, great dilatation of the right auricle. When the pulmonary
artery is narrowed the septum ventriculorum remains open; the aorta
carries the blood, distributing it to the lungs by an open ductus
arteriosus Botalli or a collateral circulation. The collateral
circulation is less developed the greater the width of the pulmonary
artery. The foramen ovale may close in such a case, but when it remains
open the relief to the over-distended right auricle is very great.
_b_. Many cases of congenital stenosis and atresia of the right
auriculo-ventricular orifice are reported in which the condition of the
pulmonary artery is not described. In fact, it is a difficult matter to
determine if the auriculo-ventricular narrowing is a primary one. Its
defective size may be merely, as it were, a rudimentary condition, a
failure to enlarge through disuse. When the pulmonary orifice is closed
and the right ventricular cavity remains small, the tricuspid orifice
is naturally small in size. There are, however, undoubted cases of
tricuspid narrowing with or without stenosis of the pulmonary artery;
the defect consists in a primary contraction of the fibrous ring or in
the union by partial adhesions of the leaflets.
Malformations affecting primarily the Left Side of the Heart.
Primary defects of the systemic side of the heart are, for the reasons
already given, very much more rarely seen than those of the pulmonary
heart. In such cases the aortic conus and its orifice are found more
frequently affected than the mitral orifice; both of these orifices,
however, may be congenitally altered without foetal malformations at
other parts of the heart being present; such cases are on record,
though only sparsely scattered through the literature of cardiac
diseases. Dilg[8] has recently made an important addition to this
subject. He proposes a classification on a new basis for all forms of
cardiac malformation; to these classes he makes conform the
malformations of the left side of the heart. In the first class he
places all cases dependent on an inflammatory process occurring in the
foetal heart after its normal development is completed; in the second,
those cases of malformation in which the deviation from the normal
consists in defects of formation; in the third, those which present a
combination of endo-myocarditis with defective development.
[Footnote 8: _Virch. Arch._, Bd. xci., S. 193-259, 1883: "Ein Beitrag
zur Kenntniss seltener Herzanomalien in Anschluss an einem Fall von
angeborner linksseitiger Conusstenose."]
{708} Among the many cases of malformation of the heart which he
presents there are reports of 15 cases of stenosis of the conus, which
are to be divided into two categories, in accordance with his
classification. In the first group, in 7 cases the stenosis is due to
an inflammatory process, and is conditioned by the results of the
endo-myocarditis localized in the aortic conus. These cases must have
originated at a late period of foetal life, and they correspond closely
to the conditions arising in the adult organs from similar processes.
In all the specimens the mitral orifice was involved, and contributed a
share in the production of the conus stenosis; in all the cases the
aortic valves also had suffered inflammatory changes. Here Dilg also
speaks of a band-like hypertrophy of muscular fibres, marking the
outlines of the aortic conus, similar to the condition described by
Peacock in the right ventricle; in this condition there was no evidence
of endocarditis, and the condition may have been due to cadaveric
rigidity. The left ventricle presented varying conditions according to
the state of the aortic and mitral valves; in some cases there was
concentric hypertrophy, or, more strictly speaking, narrowing or
shrivelling of the cavity with hypertrophied walls; in others
dilatation existed. The other cavities of the heart were influenced by
the competency of the mitral orifice, but almost always showed
considerable hypertrophy and dilatation. The valvular apparatus of the
right heart was not free from evidences of old inflammation, but this
condition was not very marked. The ages of the reported cases reached
from thirty to seventy-five years.
In the second group there are eight cases in which the defective
condition of the aortic conus caused malformation of other parts of the
heart. Here the conus stenosis occurred at an early period of foetal
development, before the permanent structures of the heart were fully
formed. The conus stenosis is to be considered as primary, the other
defects as secondary. As we have already seen, the left side of the
heart is much less liable to deforming causes, and when such do occur
the secondary defects are less conspicuous. Thus, in only four of these
cases were there such malformations of other parts of the heart as
openings in the septa of the ventricles or auricles, patency of the
ductus arteriosus Botalli. The defects consist more usually in what
were formerly called excesses of development, such as the formation of
bands below the aortic orifice; or of deficiencies of development, such
as only two aortic valves. These conditions are very doubtfully due to
formative excesses or deficiencies, but rather to intense inflammatory
processes or other morbid conditions which have resulted in the
formation of excessive cicatrices or the removal of normal parts.
Another division of cases shows narrowing of the aortic trunk itself.
This condition is probably always a true defect of development; so far
as these cases, collected by Dilg, show, it is unquestionably so. In
narrowing or closure of the pulmonary artery trunk it is found that in
some instances this condition was dependent on an endarteritis
resulting in a partial occlusion of the lumen of the vessel; here,
however, the aortic trunk furnishes no evidences of such a process. It
must therefore be due to an unequal division of the truncus arteriosus
communis. The cause and the mechanism of this unequal division of the
common trunk, resulting in a reduction of the size of the aorta, are
probably similar to what Rokitansky indicated for the reduction in the
size of the pulmonary artery trunk.
In the specimens of aortic narrowing (no cases of complete closure are
reported) from this cause and mechanism the pulmonary artery has been
found unusually wide, but this condition of the pulmonary trunk is not
very conspicuous, and does not necessarily result from the narrowed
state of the aorta. The compensatory or secondary defect of open septum
ventriculorum, or even of the auricular septum, is, in these cases,
neither invariable nor necessary to a proper maintenance of the foetal
or adult circulation. In fact, {709} the open ventricular septum is
rare; the condition of the auricular septum is, in the reports, often
not stated. The left ventricular walls commonly show a preponderance of
hypertrophy over dilatation of this cavity, but in some cases the
distension of the cavity is marked.
* * * * *
SYMPTOMS.--The most striking symptom which occurs in malformation of
the heart is the cyanosis, but the appearance of this peculiar symptom
may be postponed until some time, even a long period, after birth. In
the newly-born infant presenting a blue color the diagnosis rests
between the not infrequent temporary failure of respiration from many
causes and a defective development of the circulatory organs. In most
cases the doubt is promptly solved by the voluntary or artificial
efforts of breathing, whereby the cyanosis disappears. If the dark hue
persists after the respiratory movements have been developed, the
cyanosis may be found to depend either on cardiac malformation or an
imperfect expansion of the lungs (atelectasis). The distinction between
these two conditions can usually be made by a study of the respiratory
movements, by the state of the heart's action and of the pulse, aided
sometimes by an inspection of the outlines of the chest. In cardiac
malformation respiration seems to be well performed and full, though
often hurried or labored; in atelectasis this function is often found
characteristically altered by being short, high, and imperfect, with
imperfect distension; the ribs, instead of moving upward and outward,
fall toward the median line, and the chest fails to expand
transversely. In malformation the heart's action and the pulse are
rapid, and a murmur can often be heard. The thoracic outline may
deviate from the usual antero-posterior flattening by the sternum being
prominent in cases where the heart, instead of its usual position to
the left, is placed more centrally, as comes in certain defects of
development. Both of these conditions may be present, and then the
symptoms are mixed in character.
Cases of atelectasis, sufficiently marked to give rise to persistent
cyanosis, if not relieved too frequently show a pretty rapid increase
of color, becoming deeply livid, with convulsive movement, ending
shortly in death. The diagnosis in such cases between a cardiac
malformation and a non-expanded lung is almost impossible unless the
respiration shows characteristic features. It is probable that the
treatment proper for the latter would aggravate the condition of the
circulation in malformation. In a majority of cases a post-mortem
examination is necessary to determine whether the cyanosis is of
cardiac or of pulmonary origin. In the atelectatic condition, if death
comes within a few days of birth, the ductus arteriosus Botalli and the
foramen ovale may both be found open, especially the latter, their time
of normal closure not having arrived; in cases dying at a later period,
if the foetal openings are still found patulous, the open state must be
considered as dependent on the condition of the lung-tissue, since in
malformation of the heart the patulous state of these foetal openings
is, as has already been shown, rare as a primary defect, and, except in
connection with defects of development resulting in obstruction, which
operate at other points of the foetal circulation, is almost never
found. In other words, an open foramen or ductus is a secondary defect,
dependent, on the one hand, on a primary obstruction of the cardiac
ostia, or, on the other hand, it may be on a primary atelectasis or
malformation of the lungs.
If the child passes beyond the first weeks of life without exhibiting
cyanosis, the subsequent occurrence of the condition becomes almost a
pathognomonic symptom of cardiac or vascular malformation, unless it
can be shown that the coloration is dependent on some acute disease,
especially acquired valvular disease: in this connection collapse of
the lung (post-natal atelectasis), too, must be remembered.