Mitral valve

“ It may, I think, be safely affirmed that a larger number of persons with mitral valve disease live in blissful ignorance of the existence of serious heart lesion than any other group of cardiac cases. ”

“ The degree of hypertrophy of the left or right ventricle is thus, up to a certain point, a measure of the extent of the lesion of the aortic or mitral valve respectively. When the effects of the valvular lesion are so neutralized by these structural changes in the heart that the circulation is equably maintained, “compensation” is said to be efficient. ”

“ The prolonged diastole allows the ventricle time to completely fill, and the more forcible contraction causes the mitral valve to close more thoroughly and at the same time increases pressure in the coronary arteries, serving thereby the double purpose of relieving pulmonary engorgement and increasing heart nutrition. ”

“ The soft and friable vegetations may be torn into long shreds by a forcible blood-current, and subsequently may excite endocardial inflammation where they come in contact with the walls of the heart-cavity, or they may break off and form emboli. A fibrinous string upon a flap of the aortic valve is not infrequently driven down and back by a regurgitant current, so as to excite endocarditis in the mitral valve. ”

“ DECOMPENSATION To understand the physiology, pathology and the best treatment for broken compensation, it is necessary to study the physics of the circulation under the different conditions. With the mitral valve insufficient, a greater or less amount of blood is regurgitated into the left auricle, which soon becomes dilated. Distention of any hollow muscular organ, if the distention is not to the point of paralysis, means a greater inherent or reflex attempt of that organ to evacuate itself ”

“ Weight in the male ten to twelve ounces; in the female eight to ten. It increases up to an advanced period of life. The tricuspid valve (three segments) closes the opening between the right auricle and right ventricle. Pulmonary semilunar valves guard the orifice of the pulmonary artery, keeping the blood from flowing back into the right ventricle. The mitral valve guards the opening to the left ventricle from the left auricle. The semilunar valves surround the opening from the left ventricle into the aorta and keep the blood from flowing back. ”

“ In disease of the mitral valve, in cardiac dilatation and in simple feebleness of the heart, such as is seen in old age and after debilitating fevers, especially typhoid, there is commonly developed a venous congestion of the bases of the lungs, forming the so-called hypo static congestion of those organs, and to this is frequently added pneumonia. ”

“ Before the heart muscle actually weakens, the blood pressure has been increased more or less constantly, perhaps permanently, until such time as the left ventricle fails. The left ventricle from tobacco alone, without any other assignable cause, may become dilated and the mitral valve become insufficient. Before the heart has been injured to this extent the patient learns that he cannot lie on his left side at night without discomfort, that exertion causes palpitation, and that he frequently has an irregularly acting heart and an irregular pulse. ”

“ Valvular lesions on the right side are rare causes of hypertrophy in the adult, but during foetal life, when endocarditis is more prevalent in the pulmonary and tricuspid valve, stenosis or insufficiency at these orifices leads to great enlargement of the ventricle. Pulmonary stenosis is the most common lesion; incompetence is not often met with. Lesions of the tricuspid valves in the adult are almost always associated with mitral disease. When the dilated hypertrophy of the right ventricle reaches a certain grade in cases of mitral disease or pulmonary lesion, tricuspid incompetence develops. ”

“ Murmurs very frequently obscure the sounds; they are produced by incompetency of the valves due to the great dilatation, or are associated with the chronic valve disease on which the condition depends. The aortic second sound is replaced by a murmur in aortic regurgitation; the pulmonary is accentuated in mitral regurgitation and pulmonary congestion, but with extreme dilatation it may be much weakened. The heart's action is irregular and intermittent, and the pulse is small, weak, and quick. ”

“ Here the process may be more local, affecting, for example, the left ventricle chiefly, as in the hypertrophy from aortic valve disease or in association with contracted kidneys, or the right ventricle in chronic lung affections and mitral stenosis. More rarely we find the process confined chiefly to the auricles, but there may be advanced changes of this nature in the hypertrophied left auricle in mitral stenosis. The fatty degeneration of an hypertrophied heart may be induced by any of the general causes above referred to, but there are also special ones to which it is liable. ”

“ AORTIC OBSTRUCTION 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. ”

“ In some rare cases the tricuspid orifice has become slightly insufficient.
ETIOLOGY.—Mitral disease is especially met with in the young, and in the child it is almost invariably a stenosis. The average age is about thirty-one; it is very rare to find it occurring after the fiftieth year of life. It seems from statistics that it is nearly twice as frequent in females as in males.
It is not infrequently of congenital origin. Acute rheumatic endocarditis is its most frequent cause. The mitral valves are more frequently affected in chorea than the aortic. ”

“ The first step in the treatment of a serious lesion at the mitral valves is to make the patient clearly understand his exact condition, that he may see the reasonableness of the advice given, for his treatment for the most part must be carried on by himself. A patient must be fully persuaded of its necessity before he will regulate his habits and mode of life in accordance with the requirements of his case. The rules as to nutrition are the same as those to be observed in aortic stenosis and reflux. ”

“ Warty excrescences, which deposit generally upon the surfaces or margins of the aortic or mitral valves, although they may be found adherent to other portions of the endocardium. These warty growths or vegetations are only so in appearance, for their real structure is mainly that of fibrin. Rarely do we find them in the right heart. They have a jagged mulberry or cauliflower aspect, and adhere to an otherwise healthy endocardial lining or to points where an alteration or fissure already exists. ”

“ When the mitral valves become involved, the combined lesions render the prognosis unfavorable.
Death may result from cerebral complications, pulmonary oedema, or cardiac degeneration.
Aortic insufficiency is a much graver form of valvular disease than aortic stenosis. It is difficult to estimate the probable duration of life in aortic [p. 682] insufficiency, for it frequently gives rise to no symptom that would lead to its diagnosis until it is far advanced. Twenty-one days and five years are the extreme limits that have been recorded. ”

“ MITRAL NARROWING 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. ”

“ While it remains full it is feeble and always compressible. When the heart's action is excited, it has a certain tremulousness: these last-named characteristics are to be regarded more as the result of the failure of the left ventricle than of changes in the valvular insufficiency. If a mitral regurgitant pulse has any distinctive peculiarity, it is its diminution in volume.
Coincident mitral or aortic stenosis may render the pulse regular even in extensive mitral regurgitation. ”

“ In very many instances it is unnecessary to tell a patient with mitral reflux that he has an incurable heart disease, for with no other valvular lesion the individual may live to advanced life. But when it is combined with mitral stenosis it must be regarded as a very serious form of valvular lesion. As soon as symptoms occur that show failure of the right heart, the prognosis becomes unfavorable. Oedema of the extremities or fluid in any of the serous cavities, cyanosis, dyspnoea, and hæmoptysis, are indications of such failure. ”

“ The later in life mitral stenosis occurs, the more unfavorable the prognosis.
Mitral regurgitation uncomplicated by any other valvular lesion gives rise to very little disturbance of the systemic or capillary circulation. It is more often fully compensated for than any other valvular lesion. The changes which lead to it are of slow growth and their tendency is to remain stationary. Patients with a moderate regurgitation at the mitral orifice suffer very little except during or after violent physical exercise, and, were it not for the slight dizziness which attends it, it would pass unnoticed. ”

“ The reserve strength of the heart muscle, as has been previously stated, is much less in valvular compensation than that of the normal heart, and this reserve force is easily overcome by the pregnancy, and loss of compensation occurs with all of its usual symptoms.
The most serious lesion a woman may have, as far as pregnancy is concerned, is mitral stenosis. An increased abdnominal pressure interferes with her lung capacity, and her lungs are already overcongested. The left ventricle may be small with mitral stenosis, and therefore her general systemic circulation poor. ”

“ The murmur of mitral stenosis is very rarely, if ever, conveyed to the left of the apex-beat, and it is rarely heard more than two inches to the right of the apex. The second sound of the heart is intensified over the pulmonary valves. When mitral reflux and mitral obstruction coexist, the two murmurs run into each other, constituting a single murmur that may be mistaken for a systolic murmur. The harsh character of the presystolic element of the murmur can always be recognized. ”

“ It most frequently comes with acute rheumatism, chorea, tonsilitis, scarlet fever, and pneumonia. The valves in the left heart are most often affected, the mitral simply swollen or bearing small growths. ”