Aortic Stenosis Aortic Obstruction


Categories: Uncategorized
Sources: Disturbances Of The Heart

Valvular disease at the aortic orifice is much less common than at

the mitral orifice, and while stenosis or obstruction is less common

from rheumatism or acute inflammatory endocarditis than is

insufficiency of this valve, a narrowing or at least the clinical

sign of narrowing, denoted by a systolic blow at the base of the

heart over the aortic opening, is in arteriosclerosis and old age of

frequent occurrence. If such narrowing occurs without aortic

insufficiency at the age at which it usually occurs, it may not

seriously affect the heart. It may follow acute endocarditis, but it

most frequently follows chronic endocarditis or atheroma, in which

the aortic valves become thickened and more or less rigid; this

condition most frequently occurs in men.



Anything that tends to increase arterial tension, as tobacco, lead

or hard work, or anything that tends to cause arterial disease, as

alcohol or syphilis, is often the cause of this lesion.



At times the edges of the valves may grow together from ulcerative

inflammation, and the lumen thus be diminished in size; or

projecting vegetations may interfere with the opening of the valve

and with the flow of blood. With such narrowing the left ventricle

more or less rapidly hypertrophies to overcome its increased work.



The murmur caused by this lesion is a systolic one, either

accentuated in the second intercostal space at the right of the

sternum, or perhaps heard loudest just to the left of the sternum in

this region. The murmur is also transmitted up the arteries into the

neck, and may at times be heard in the subclavian arteries. It may

also be transmitted downward over the heart. The pulse is slow, the

apex of the rise of the sphymographic arterial tracing is more or

less sustained and rounded, and the rise is much less than normal.



If this lesion occurs in old age, there is general arterial disease

present, and the tension and compressibility of the arteries vary,

depending on how much they are hardened. The disturbed circulation

is evidenced by imperfect peripheral circulation and capillary

sluggishly, with at times pendent edema of the feet and ankles, but,

perhaps, little congestion of the lungs. The left ventricle being

sufficient, there is no damming back through the left auricle to the

lungs. The left ventricle may, however, become weakened, either by

some sudden strain or by a chronic myocarditis, and relative

insufficiency of the mitral valve may occur. The subsequent symptoms

are typically those of loss of compensation.



This lesion may allow a patient to live for years, provided no other

serious disturbance of the heart occurs, such as myocarditis or

coronary disease; but sooner or later, with the failing force of the

blood flow and the lessened aortic pressure, slight attacks of

anemia of the brain occur, causing syncope or fainting. Also, sooner

or later these patients have little cardiac pains. They begin to

"sense" their hearts. There may not be actual anginas, but a little

feeling of discomfort, with perhaps pains shooting up into the neck,

or a feeling of pressure under the sternum. Little excitements or

overexertions are likely to make the heart attempt to contract more

rapidly than it is able to drive the blood through the narrowed

orifice, and this alone causes cardiac discomfort and the feeling of

cardiac oppression.



It is essential, then, that these patients should not hasten and

should not become excited; and any drug or stimulant which would

cause cardiac excitement is bad for them. On the other hand, these

are the very patients in whom, sometimes, alcohol in small doses may

be advisable, especially if the patient is old; and a dose of

alcohol used medicinally when an attack of cardiac disturbance is

present is good treatment. The quick dilatation is valuable.

Nitroglycerin will also do good work in these cases, and with high

blood tension may be the only safe drug for the patient to have on

hand. As soon as his attack occurs, with or without real angina

pectoris, let him dissolve in his mouth a nitroglycerin tablet. If

he feels faint, he will feel better the moment he lies down, and in

this instance he may be improved by a cup of coffee, or a dose of

caffein or camphor.



If the left ventricle becomes still weaker and shows signs of

serious weakness, or if there is actual dilatation, the question of

whether or not digitalis should be used is a subject for careful

decision. The left ventricle should not be forced to act too

sturdily against this aortic resistance. Consequently the dose of

digitalis must be small. On the other hand, it frequently happens,

especially in old age, that myocarditis or fatty degeneration has

already occurred before this cardiac weakness develops in the

presence of aortic narrowing, and digitalis may not be indicated at

all. We cannot tell how far degeneration may have gone, however, and

small doses of digitalis used tentatively and carefully, perhaps 5

drops of an active tincture two or three times a day, and then the

drug carefully increased to a little larger dose to see whether

improvement takes place, is the only way to ascertain whether or not

digitalis can be used with advantage. If it increases the cardiac

pain and distress, it should not be used. Strychnin is then the drug

relied on, with such other general medication as is needed, combined

with the coincident administration of nitroglycerin, which may also

be given in conjunction with digitalis, if deemed advisable.

Generally, however, if a heart with aortic stenosis needs

stimulation, the blood pressure is generally none too high, although

there may be arteriosclerosis present. Therefore when nitroglycerin

is indicated to lower blood pressure, digitalis is not usually

indicated; when digitalis is indicated to aid the heart,

nitroglycerin is generally not indicated. These patients must have

high blood pressure to sustain perfect circulation at the base of

the brain.



Patients who have this lesion should not use tobacco in large

amounts, or sometimes even small amounts, as tobacco raises the

blood pressure and thus puts more work on the left ventricle; in the

second place, if the left ventricle is failing, much tobacco may

hasten its debility. On the other hand, with a failing left

ventricle and a long previous use of tobacco, it is no time to

prohibit its use absolutely. A failing heart and the sudden stoppage

of tobacco may prove a serious combination.





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