Ectopia Cordis. Cyanosis, pervious foramen ovale. Symptoms, blue
mucosæ, coldness, staring coat, unthriftiness. Unequal to exertion,
palpitations, murmur before the first heart sound. Obstructed
circulation in the lungs as a cause of cyanosis, cyanosis as a cause
of lung disease.
These have been much less frequently observed in the lower animals than
in man. The anomalies observed in mammals include the following: The
displacement of the heart to the right side of the chest; displacement
entirely out of the chest (ectopia cordis); permanent communication
between the right and left auricles (cyanosis); entire absence of heart;
two hearts; one common ventricle communicating with two auricles as in
reptiles; three ventricles; only one auricle; absence of one or several
valves; absence of the pericardium; variations in the mode of connection
of the heart and large vessels, etc.
=Displacements of the heart= have been especially studied by Hering on
calves. The breast bone remained as originally developed in two lateral
halves, and the heart remained outside connected with the interior of
the chest only by its large vessels. The heart thus exposed and covered
only by its investing membrane (pericardium) afforded an excellent
opportunity to study its action, of which Hering freely availed himself.
Animals affected in this way survived their birth but a very short time.
An approach to this condition was thirty years ago made familiar to the
medical world in the person of M. Gouz, a German mechanic, the movements
of whose heart could be easily watched through a fissure in the breast
bone.
=Permanent communication between the two auricles.= =Pervious foramen
ovale.= =Cyanosis.= Previous to birth there is an opening between the
right and left auricle, allowing the blood to flow from the former into
the latter in place of, as in after life, descending into the right
ventricle and thence circulating through the lungs. At birth this is
contracted, and in a few days is completely closed in accordance with
the new life, which demands that all blood must circulate through the
lungs in order to its æration. Sometimes this fails to be effected, and
venous blood from the right side of the heart continues to mix with
arterial in the left, deteriorating it in quality and unfitting it for
nutrition, secretion, calorification, and other essential processes. The
semi-venous blood circulating in the arteries gives a bluish hue to the
visible mucous membrane, hence the name of _the blue disease_. This
blood is unfit for sustaining the vital changes essential to the
production of animal heat, so that the animal suffers from coldness of
the surface and extremities, staring coat and general unthrifty
appearance. Such subjects grow badly, and refuse to lay on flesh, but
are said to arrive at maturity in some instances and to have their
imperfection recognized only because of the short breathing, and
irregular heart’s action when subjected to exertion. A heart murmur
preceding the first sound of health is usually present, as in anæmia.
Drs. Abernethy and Wardrop draw attention to the frequency of previous
_foramen ovale_ in the human subject in connection with pulmonary
consumption, and opine that it is reopened as a consequence of this
disease. The coincidence has not been observed in the lower animals,
though if it were found to exist the question would arise whether the
deterioration of the blood and general health in open _foramen ovale_
did not also favor the deposit of tubercle in the lungs. When from
deficient ventilation the atmosphere and blood become impregnated with
carbonic dioxide the production of tubercle in man or in animals is
correspondingly frequent.
The subjects of previous foramen ovale die young or prove worthless when
they arrive at maturity. Nothing can be done to ameliorate the
condition.