=Hypertrophy= of the heart is an enlargement of the heart, due to
an increase in the muscular tissue. It is usually associated with
dilatation. The ventricles are more often involved than the auricles,
and the left ventricle is more likely to be affected.
=Etiology.=—Valvular disease of the heart causing an obstruction to
the outflow of blood, as mitral insufficiency, diseases of the aortic
valve; increased intra-vascular pressure, caused by sclerotic changes
in the walls of the vessels; contraction of smaller arteries, due to
irritation of toxic substances in the blood, as in Bright’s disease.
Overeating or drinking and excessive physical exercise would also
induce hypertrophy of the left ventricle. Hypertrophy of the right
ventricle is caused by valvular lesions on the right side. Lesions
of the mitral valve causing an increased resistance in the pulmonary
vessels are etiologic factors; also diseases of the pulmonary vessels
in the lungs, as in cirrhosis and emphysema. There are conditions
affecting the heart, as the use of tea, alcohol and tobacco.
Disturbed innervation, as in exophthalmic goiter; derangements of the
vertebræ, and ribs corresponding to the upper five dorsals; downward
displacements of the floating ribs, causing a prolapse of the diaphragm
and a consequent retardation of blood through it to and from the heart,
will affect the heart’s action. Simple hypertrophy never occurs in
the auricles; it is always accompanied with dilatation. The condition
develops in the left auricle in mitral lesions; in the right auricle
when there are disturbances of the pulmonary circulation. The tricuspid
is rarely affected primarily.
=Pathologically=, the left side of the heart is more commonly enlarged
than the right; the ventricles than the auricles. The shape of the
heart varies when the left ventricle is hypertrophied, the conical
shape being more or less lost; it lies more horizontally and is
elongated. When both ventricles are enlarged the heart is round. When
the right ventricle is affected, it occupies the largest part of the
apex. The increase in the size of the heart is probably due to a
numerical increase in the muscle cells. The muscle is firm, of deep red
color and cuts with considerable resistance. Normally, the heart weighs
from eight to nine ounces. In general hypertrophy it may weigh from
fifteen to thirty ounces.
=Symptoms.=—Hypertrophy, being a conservative process or an act of
=compensation=, does not necessarily present any symptoms at first.
At the beginning there is rarely any pain, but a sense of fullness
and discomfort is present. As the hypertrophy increases, the arteries
become fuller, the veins less full and the circulation accelerated.
In hypertrophy associated with arteriosclerosis the blood pressure is
increased, and the pulse full and firm. Epistaxis may be of frequent
occurrence and the face congested. Pains occur in the precordial
region. There are nervousness, headache, hot flushes, palpitation,
cough and vertigo. In hypertrophy of the =left ventricle=, the apex
is lower and to the left. The carotids pulsate visibly and the radial
pulse is strong and tense. Percussion reveals enlargement to the left
and downward. The first sound is louder and prolonged. The aortic
second sound is intensified. In hypertrophy of the =right ventricle=
the enlargement is to the right edge of the sternum. The second
sound in the pulmonary area is increased. The apex-beat is displaced
outward. The pulse at the wrist is usually small. Hypertrophy of the
=auricles= always occurs with dilatation, which is most common in the
left auricle. The physical signs are characteristic. They are caused by
diseases of the mitral and tricuspid valves and diseases of the lungs,
as emphysema and cirrhosis.
=Diagnosis.=—If a careful examination is made, hypertrophy can hardly
be mistaken for any other condition. There may be a resemblance to
pericardial effusion, pleuritic effusion, aneurism or mediastinal
tumor, when near the heart. The X-ray will be of assistance.
=Prognosis.=—Depends largely upon the cause producing the hypertrophy.
Remember that hypertrophy is a compensatory act. The prognosis is more
or less unfavorable if resulting from emphysema, Bright’s disease or
in old age; also in degeneration of the vessels. In most cases of
functional overaction, persistent treatment can usually accomplish
considerable.
=Treatment.=—The treatment must be according to the cause of the
hypertrophy. There are many etiological factors, consequently the
treatment depends upon the influence of these factors. The principal
treatment will be found under endocarditis, as valvular diseases are
usually caused by endocarditis, and hypertrophy of the heart is a
conservative process of nature—an act of compensation secondary to
valvular and arterial lesions. The indications are to lessen the force
and number of pulsations of the heart and remove the cause if possible.