appearance in the great majority of cases of malformation of the heart,
in the proportion of more than two to one of the cases. The coloration,
once developed, may remain permanent and of equal intensity until
death, but as less than 8 per cent. of infants with malformation die
within the first week, and only 36 per cent. within the first year,
this symptom usually remits. It may wholly disappear, to return on very
slight provocation, such as excitement, or on exertion, on the advent
of acute disease, or without apparent cause. Probably about one-fourth
of those who die in infancy perish in paroxysms of dyspnoea, another
quarter of acute disease, and the remaining half of convulsions; and
toward death the cyanosis generally becomes very intense.
If the malformation is not of character or degree to develop cyanosis
early in life, the child grows and passes through the usual stage of
development, usually, however, feeble, poorly nourished, incapable of
common exertion, but often without any special phenomena to attract
attention, and the vice of formation is undetected unless by a special
examination. There are several other symptoms frequently present in
connection with malformation, but not of a pathognomonic character.
Dyspnoea, though rarely occurring without cyanosis, may attract
attention, and, if frequently brought on by active exercise, increases
in violence, to be later accompanied with the cyanosis originally
absent. Palpitation is not uncommon, especially in cases of great
hypertrophy with dilatation, in hearts struggling to overcome an
obstruction; in other cases it is absent or only occurs on exertion in
connection with dyspnoea and cyanosis. The degree of animal heat varies
greatly, judging by the various opinions expressed by writers. The
sensation of patients able to express their feeling is often that of
chilliness, and in some cases the surfaces of the body feel cold,
although the indications of the thermometer show no great variation
from the normal temperature. It is obvious that no very great variation
from this standard is compatible with the long duration of life,
although a depression may exist during or immediately after paroxysms
of dyspnoea or cyanosis. Cough is also frequent, but is probably always
due to some acquired pulmonary disease.
The physical signs offer increased facilities for the recognition of
defects of development. In the early reported cases there are of course
no records of these conditions, and there is therefore a lessened
number of instances from which to collate the physical signs. In the
early days of life it has been shown wherein the presence of a cardiac
murmur may lead to the distinction between malformation and
atelectasis. In later periods of life the physical signs cannot be
regarded as characteristic. There are no signs by which a malformation
can be distinguished accurately from an acquired cardiac disease, so
that without the clinical history and a grouping of symptoms the
diagnosis cannot be made from the physical examination.
Inspection and palpation of the chest often show the heart to be in an
unusual position, placed more centrally under the sternum. It must be
remembered that transposition of the heart to the right side is not
unfrequently unaccompanied with any malformation of its ostia giving
rise to symptoms; and this organ may be even more markedly displaced
without being malformed, although under both these conditions
irregularities of the principal trunks are usually found.
Percussion frequently shows enlargement of the area of cardiac dulness,
but, on the other hand, at the post-mortem examination the heart is
often found markedly defective without externally showing variation of
its size or shape, or of its position within the thorax; hence in such
cases no deviation from the normal will be revealed on percussion or
inspection of the chest. It is probable that cardiac murmurs are not
always to be detected in cases of even marked defects of development,
but when present it is recorded most {711} frequently that a single
murmur is heard over the base of the heart, blowing in character and
systolic in time. Such a sound is probably produced by the passage of
the blood through an abnormal opening between the ventricles or through
the foramen ovale. Other murmurs may also be present; if the arterial
ostia are defective from narrowing, roughness, or insufficiency of
their valvular apparatus, abnormal sounds of different characters,
diastolic or systolic in time, may be heard. Too few observations as
yet exist for a general diagnostic scheme to be formulated.
Auscultation of the intra-uterine heart may in the future become
sufficiently accurate to enable us to prognosticate a congenital
cardiac malformation or disease; there is one case on record in which a
correct diagnosis was made in this way.
The ends of the fingers and toes are frequently described as bulbous.
This rounding and retraction of the nails, frequently spoken of as
clubbing, does undoubtedly exist in many cases, but the condition
cannot be regarded as characteristic of malformation of the heart,
since it comes with even more frequency in tubercular disease of the
lungs, in chronic pleurisy, and in other chronic pulmonary maladies.
Lebert has recently insisted on the connection between stenosis of the
pulmonary artery and tuberculosis, not merely as a coincidence, but as
the cause of the development of the tubercles in the lungs. Many others
have spoken of this connection, and very many are the cases
recorded--perhaps nearly one-quarter of the whole number. In some cases
large or small single cheesy masses exist; in others cavities form, and
in rare cases a miliary tuberculosis exists, still more rarely
affecting other organs than the lungs. In view of the recent dogmas of
tuberculosis it is doubtful if many of these authors would at present
insist on the connection between malformation of the heart and
tuberculosis being other than a coincidence, since it is not apparent
why such patients are more likely to be invaded by a bacillus of
tuberculosis than other persons, and this organism is known to grow so
readily wherever the spores chance to fall.
* * * * *
DURATION OF LIFE.--In connection with certain malformations some
indications have already been given in respect to the duration of life
in such defects. It is, however, apparent that the degree of the
obstruction to an orifice or vessel, and still more the completeness of
the secondary compensatory alterations, exert a greater influence than
the seat of the malformation on the continuance of life. The occasional
slight isolated malformations, such as open septa without obstruction
of the orifices, in themselves often entail no symptoms, and, unless
combined with acquired valvular disease, exercise no influence on the
duration of life; here, however, the prognosis merges entirely into the
acquired malady.
Of the other conditions of malformation, narrowing of the aorta and of
the aortic conus seems to be, on the whole, compatible with a longer
duration of life than any other condition, and these defects cause
death in the early days or months in fewer cases than similar
obstructions on the right side of the heart. This result apparently
comes from the fact that the left ventricle seems to possess unlimited
capacity for hypertrophy, and hence is able to overcome the
obstruction; when the aortic valves allow of regurgitation the
compensation fails and death comes sooner. When the main branches of
the aorta are defective or when the descending aorta is derived from
the pulmonary artery, the duration of life is much shortened.
In cases of pulmonary narrowing in general it may be stated that the
greater the obstruction the shorter the life. This rule is subject to
many exceptions; so frequent are the exceptions that the rule is almost
valueless for determining the life in any given case. Complete closure
of the pulmonary trunk has permitted of the continuance of life for
sixteen years, {712} and then ended from an intercurrent acute disease.
When the septa are maintained open--when, therefore, the communications
between the pulmonic and systemic sides of the heart are free--a
greater age is attained than when these openings have become closed.
This condition of the pulmonary artery in order to permit of a long
duration of life must be coincident with a considerable development of
the collateral circulation by which the blood freely enters the lungs
for aëration; otherwise the compensation fails very soon.
In transposition of the main trunk relatively to the ventricles, with
closure of the septum ventriculorum (very rare), life ends not many
weeks after birth; if the septa remain open, which is not common, life
may be prolonged for a year or two.
Cyanosis.
There are two views to be found, set in opposition to each other, to
account for the peculiar blue coloration of the skin and mucous
membranes in cases of malformation of the heart. The first explanation
attributes the phenomenon to a general congestion of the venous system,
due to the obstruction of the pulmonary artery. This view was proposed
by Morgagni in connection with his, the first described, case of
malformation of the heart. The other view considers that the
intermingling of venous and arterial blood through any channel, but
especially by means of abnormal openings in the septa, produces the
blue coloration. Numerous writers have defended each of these theories
of causation; from most of their observations darkness rather than
light has resulted through the attempt to defend one or the other
theory exclusively.
Gintrac defended the admixture theory for cyanosis, and his views
became so well known that a large majority of persons conformed their
belief to his teachings. This author distinguished four varieties of
blue coloration: first, that due to some malformation of the heart or
great vessels, by which the blood of the right side of the heart enters
the systemic arterial circulation; second, likewise due to intermixture
of the blood, but produced by conditions developed after birth through
the re-establishment of the passages of communication or other changes
in the circulation; third, where the coloration appears without direct
admixture of the blood, but from organic disease of the heart; fourth,
cases without malformation, from a suppression of the menses. Before
the time of Gintrac, cyanosis had a very indefinite signification, and
the condition was looked upon, and was classed by very many, as one of
the cachexiæ, and was often spoken of as a form of icterus. He,
however, held that the organic lesions of the heart and great vessels
were the necessary conditions of its production, and that the mixture
of the red and black blood, and the distribution of the mixed fluid by
means of the arteries to all parts of the body, determined its
essential character. He showed, too, that all communications between
the right and left heart were not followed by cyanosis; the explanation
of the absence of the blue color was that from the simultaneous
contraction of the auricles and ventricles of the two sides of the
heart an equilibrium was produced, and the blood did not deviate from
its normal course. This result followed only when the normal exits of
the blood were unobstructed. This supposition, as is apparent, is not
in accord with the facts. During the filling of the ventricles, before
the muscular contraction of the walls occurs, the blood has the
opportunity of freely mingling if the opening between the cavities is
sufficiently large: that the blood will not thus mingle when the
muscular contraction acts remains to be proved. Cases of open septum
ventriculorum, as an isolated defect, without obstruction of the great
vascular trunks (a rare condition), are not attended with cyanosis: the
absence of this symptom, as will be shown later, is readily to {713} be
explained on other grounds than those supposed by Gintrac. The normal
outlets of the blood are, however, almost always obstructed to a
greater or less degree; and here the explanation of the absence of the
cyanosis fails. In the delayed appearance of cyanosis Gintrac
considered the reason to be that the venous blood differed less from
the arterial in the young subject than in those of more advanced age,
because, on the one hand, the aëration was more active, and, on the
other hand, the deterioration of arterial blood was less marked. In
other cases he points to an increase of the obstruction, through
inflammatory changes, as the probable reason for the delayed appearance
of the blue color; in still other cases it was supposed to be due to a
disturbance of the equilibrium of the pulmonary and systemic
circulation from an increase in the blood-mass. In cases of unilocular
and bilocular hearts, of which the author speaks, his explanation
completely fails, for here the admixture of the blood within the heart
is very marked; yet such cases have been reported without cyanosis. He
further believed that openings in the ventricular septum, as well as
between the auricles, were effected after birth as the results of
acquired cardiac disease.
Gintrac, in speaking of the causes of cyanosis, says that the condition
shows no hereditary tendency; that the pregnancy during which the
defective infant is developed is without noticeable phenomena; and that
the confinement is normal. It is on some of these points that we are in
want of accurate information. It has been pointed out that many
congenital defects of the heart result from morbid processes affecting
the organ during its developmental stage. These lesions are the same in
kind as those which produce cardiac and vascular disease in the adult,
and are likewise of a sort capable of communication from the parent to
the foetus. Such diseases are found acting oftentimes temporarily in
the parent; and if they acted during pregnancy, or even if present only
at the time of conception, their results would rationally be expected
to be displayed in the foetus. Such diseases as rheumatism and
syphilis, which may be regarded as temporarily-acting maladies, would
come under this class, and doubtless many others might be added to the
list. The work of collecting the histories of pregnancies or the
condition of the parents at or before the time of conception would be
painfully tedious: such records do not exist at present, and they could
be made sufficiently full only in exceptional cases; but their value in
determining the causes which operate in the production of defective
development of the heart cannot be too highly estimated.
The conclusions stated by Moreton Stillé[9] seem to be the first which
justly cover the ground from a comparison of large numbers of cases of
malformation of the heart. The first conclusion by him is that cyanosis
may exist without admixture of the blood; by this was meant that no
abnormal communication between the right and left sides of the heart,
and no channels between the principal vascular trunks, are present. He
mentions five cases of cyanosis occurring in which no means of
admixture existed. The second conclusion is that there exists no
proportion between cyanosis and the degree in which the blood is mixed;
for this he cites four cases, some with the aorta arising from the
right ventricle, others of hearts with only two cavities and the common
trunk undivided, in which the cyanosis was only partial or transient.
The third conclusion, the converse of the first, and reinforcing the
preceding one, is that complete admixture of the blood may take place
without cyanosis. The fourth, that the variation in the extent, depth,
and duration of the discoloration is inexplicable by the doctrine of
the mixture of the blood.
[Footnote 9: "Inaug. Thesis." _Amer. Journ. Med. Sci._, N. S., vol.
viii., 1844.]
Having shown that commingling of arterial and venous blood cannot be
the cause in itself of cyanosis, Stillé proceeds to the study of the
other {714} theory--viz. that it is due to congestion of the general
venous system resulting from some obstruction in the right side of the
heart or in the pulmonary artery, impeding the passage of the blood
through the heart. These structural lesions must fulfil the three
following indications: 1st, that they shall be sufficient in degree to
account for the symptom; 2d, that they be present in every case of
cyanosis, or in their place some other cause acting on similar
principles; 3d, that they shall never exist without cyanosis or without
a satisfactory explanation of the exceptional occurrence. He holds that
contraction of the pulmonary artery is to be taken as the type of all
the lesions that may produce cyanosis, and that this type fulfils the
indications given above.
Most writers since Stillé have coincided with him, or have regarded
cyanosis as partly due to venous congestion and partly to commingling
of arterial and venous blood. Some writers, however, have pointed to
the abnormal communications between the right and left side of the
heart, and asked why, if admixture of the venous and arterial blood is
not the cause of cyanosis, should the admixture through such openings
be found in such a large proportion of cases. Such writers have failed
to distinguish between the primary and secondary defects of
development. They have failed to see that the pulmonary obstruction
which prevents the blood during extra-uterine life from passing to the
lungs for aëration, and consequently produced the cyanosis, prevented
the closure of the ventricular septum during intra-uterine life, or of
the auricular septum within a few days of birth. In reply to the above
question it may be pointed out, as Peacock has done, that such
communications between the two sides of the heart are all important for
the continuance of life, even for the shortest period, when the
pulmonary artery is occluded.
It is evident, as Peacock has shown, that if Stillé's first and third
conclusions are true, as the cases undoubtedly show, the theory of
intermixture of the blood does not account for the condition of
cyanosis. It is probable in many of these cases with abnormal openings
in the septa that the intermixture of the blood is but slight, since if
the pressure on the two sides of the heart is equal--and it may become
equal through the establishment of a collateral circulation, although
primarily it was unequal--no intermixture takes place through the
defective septa. Neither does the admixture theory account for cases of
intermittent or delayed cyanosis. Such cases can only be supposed to be
due to a varying propulsive power or to a subsequent increase of the
pulmonary obstruction. Neither does admixture account for localized
cyanosis; for example, in the face or in one extremity: this condition,
rare as it is, must be due to other causes. Peacock, while combating
the admixture theory, considers that Stillé's conclusions in favor of
the congestion theory as dependent on obstruction of the pulmonary
artery are too exclusive. He discusses also the relationship of
congenital cyanosis due to malformation, to cyanosis acquired through
pulmonary and cardiac disease as seen in the adult, and shows why the
latter condition is rarely ever as intense as the former, and also why
acquired obstruction of the pulmonary artery is not necessarily
productive of cyanosis. The reason of the difference he believes
consists in the compensatory hypertrophy of the right ventricle, with
perhaps a gradual diminution of the blood-mass, as seen in some cases.
On the whole, Peacock subscribes to the congestive theory, but thinks
that the intensity of the cyanosis is modified by the capacity of the
capillaries, by the period of development or duration of the
obstruction, by the natural coloration of the skin, and by the color of
the blood itself.
Under these two theories, and the arguments offered in support of them,
there seems to be no other explanation possible of the condition of
blueness, and yet the whole story of the mechanism of cyanosis does not
seem clear. Partly, this is due to the incomplete knowledge of the
physiology of the aëration of the blood which obtained during the most
active period of the {715} discussion of cyanosis and its causation.
Let us consider briefly the simplest case of cyanosis. Every child born
has in one sense a temporary malformation of the heart--an open foramen
ovale which does not close for several days after birth. Every child is
born partially cyanotic, owing to compression of the uterine sinuses or
pressure on the umbilical cord; it is completely cyanotic if there
occurs premature separation of the placenta. The cyanosis continues
until the child breathes. The cause of this cyanosis must be looked
for, not in the temporary malformation, but in the imperfect expansion
of the lungs. As soon as the respiratory function is assumed--as soon
as, in other words, the pulmonary-artery branches carry a full amount
of blood which becomes aërated in the lungs--the cyanosis ceases,
although the foramen ovale is not yet closed.
The closure of the foramen by a trapdoor valve is, as has already been
pointed out, not in accordance with the anatomical facts: turning the
newly-born infant on its right side does not favor, as it is commonly
supposed, the closure by gravity of a preformed swinging lid, which
when it has dropped down for ever partitions the right from the left
auricle. The right-sided position may favor the expansion of lungs or
in other ways promote the pulmonary circulation, but in itself it does
not tend to close the foramen. In fact, cyanosis does not here depend
on the defective development, but on want of aëration of the blood.
Again, looking to the skin or mucous membrane, what is the condition of
the blood and of the circulation which renders the parts of a blue
color, and in what do they differ from the normal? In the normal state
of the blood and circulation the capillaries of a given area are
filled, one half with arterial blood, and the other half with venous
blood; that is to say, the capillaries at the point of their origin
from the arterioles contain pure arterial blood: as the blood-current
proceeds outward the blood becomes progressively less and less red and
more and more blue or black; when the venous radicle is reached the
blood-current is of as dark a hue as it ever becomes. In general terms,
therefore, it may be said, taking the average, that in a given area
half the blood is venous, half arterial. Here, then, we see, with an
equal mixture of the red and blue blood, nothing resembling cyanosis.
It is evident, therefore, that to produce a cyanotic hue the blood must
be wholly venous; the intensity of the blueness will vary with the
amount of non-aërated blood present in the capillaries. But let us
suppose an equal admixture of right- and left-sided blood to take
place--for example, when the aorta arises from both ventricles, the
pulmonary artery obstructed. It cannot be supposed that the venous
blood would retain its dark hue. The contact of the two bloods within
the aorta on their way to the capillaries would result in arterializing
the venous blood at least one-half, so that when it arrives at the
capillary network the intensely blue color of a marked case of cyanosis
would have disappeared.