Mitral Stenosis: Mitral Narrowing


Categories: Uncategorized
Sources: Disturbances Of The Heart

This particular valvular defect occurs more frequently in women than

in men, and between the ages of 10 and 30, and is generally the

result of rheumatic endocarditis or chorea, perhaps 60 percent of

mitral stenosis having this origin. Other causes are various

infections or chronic disease, such as nephritis. Of course, like

any valvular lesion, it may be associated with other lesions, and

sooner or later in many instances, when the left ventricle becomes

dilated or weakened, mitral insufficiency also occurs.



It has sometimes seemed that high blood pressure has caused the left

ventricle to act with such force as to irritate this mitral valve,

and later develop from such irritation a sclerosis or narrowing, and

stenosis occurs. It has been suggested that, though lime may be of

advantage in heart weakness, as will be stated later, if the blood

is overfull of calcium ions the valvular irritations may more

readily have deposits of calcium, in other words, become calcareous,

and therefore cause more obstruction. It is quite likely, however,

that this sort of deposit is only a piece of the general

calcification of tissue in arteriosclerosis and old age, and could

not be caused by the administration of calcium to a younger patient,

and might then occur in older patients even if substances containing

much calcium were kept out of the dict. Calcium metabolisim in

arteriosclerosis and in softening of the bones is not well

understood.



Patients with this lesion are seriously handicapped when any

congestion of the lungs occurs, such as pneumonia, pleurisy, or even

bronchitis. Asthma is especially serious in these cases, and these

patients rarely live to old age.



The pulse is generally slow, unless broken compensation occurs;

dyspnea on exertion is a prominent symptom; the increased secretion

of mucus in the bronchial tubes and throat is often troublesome, and

there is liable to be considerable cough. If these patients have an

acute heart attack, a feeling of suffocation is their worst symptom

and the dyspnea may be great, although there may be no tachycardia,

these hearts often acting slowly even when there is serious

discomfort. When compensation fails, there is an occurrence of all

the usual symptoms, as previously described.



The distinctive diagnostic physical sign of this lesion is the

diastolic and perhaps presystolic murmur heard over the left

ventricle, accentuated at the apex and transmitted some distance to

the left of the heart. There is also an accentuated pulmonary

closure. To palpation this lesion often gives a characteristic

presystolic thrill at and around the apex.



The first symptoms of weakening of the compensation are irregularity

in the beat and venous congestion of the head and face, causing

bluing of the lips, often nosebleed, and sometimes hemoptysis and

insomnia. Later the usual series of disturbances from dilatation of

the right ventricle occurs. As previously stated, with the absence

of good coronary circulation and the consequent impaired nutrition,

the left ventricle may also dilate and the mitral valve may become

insufficient. Sudden death from heart failure may occur with this

lesion more frequently than with mitral insufficiency but less

frequently than with aortic insufficiency.



A particularly dangerous period for women with this lesion is when

the blood pressure rises after the menopause and the patients become

full-blooded and begin to put on weight. Also, these patients always

suffer more or less from cold extremities. In most cases they sleep

best and with least disturbance with the head higher than one

pillow.



Besides the usual treatment for broken compensation in patients with

this lesion, digitalis is of the greatest value, and the slowing of

the heart by it, allowing the left ventricle to be more completely

filled with the blood coming through the narrowed mitral opening

during the diastole, is the object desired. This drug acts similarly

on both the right and left ventricles, and though there is no real

occasion for stimulation of the left ventricle, and it is the right

ventricle that is in trouble, dilated and failing, still a greater

force of left ventricle contraction helps the peripheral

circulation. The action on the right ventricle contributes greatly

to the relief of the patient by sending the blood through the lungs

and into the left auricle more forcibly. and the left ventricle

receives an increased amount of blood, the congestion in the lungs

is relieved, and the dyspnea improves. Perhaps there is no class of

cardiac diseases in which more frequent striking relief can be

obtained than in these cases of mitral stenosis.



If the congestion of the lungs is very great, and death seems

imminent from cardiac paralysis, if cyanosis is serious, and bloody.

frothy mucus is being expectorated, venesection and an intramuscular

injection of aseptic ergot may be indicated. Digitalis should also

be given, hypodermically perhaps, but its action would be too late

if it was not aided by other more quickly acting drugs. The

physician may often save life by such radical measures.





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