A diseased valve can never be restored to its normal functions, and the shorter and more gushing the murmur the more extensive the regurgitation. The effects of the regurgitation must be carefully estimated before a prognosis can be given in any case. When one aortic flap is puckered and shrunken, the other two may elongate and compensate for the patency. But this occurs only in very young subjects.
Aortic regurgitation is, however, more serious in the very young than in adults. In children the valvular changes are less atrophic and more inflammatory in character.
Where the disease is met with in middle life, in those who daily undergo severe mental or bodily strain, the prognosis is unfavorable. And when in such patients there are the evidences of arterial degeneration or a tendency to it, the dangers are greatly increased, for the hypertrophied ventricle drives out the blood from its dilated cavity with greater than the normal force, and the vessels being weakened there is great danger of their rupture; hence the frequent occurrence of apoplexy and infarctions. In the very old I have seen aortic incompetence last a long time and cause little inconvenience.
Again, the prognosis is bad when cyanosis and dropsy result from the failure of a dilated and hypertrophied left ventricle to empty itself. This weakness is the result of that interference with the coronary circulation which brings about impaired nutrition, and therefore degeneration of the heart-walls.
When mitral insufficiency is secondarily induced, then obstruction to the systemic circulation leads to induration of the liver and kidneys, which interferes with the performance of their functions and hastens the fatal issue.
Sudden rupture of a valve or valvular disease that has developed very rapidly is more dangerous than when the valvular insufficiency is slowly developed. The flap or flaps involved can sometimes be determined during life, and then the prognosis will be more or less favorable according as the anterior or posterior are incompetent. In all cases the prognosis depends more upon the condition of the heart-walls and on the general nutrition than upon any other element.
When aortic regurgitation is complicated by aortic stenosis, mitral regurgitation, or by the vascular and visceral conditions resulting from the derangement of the circulation, the prognosis is exceedingly unfavorable. Death may result from embolism, apoplexy, dropsy, pulmonary oedema, from sudden cardiac insufficiency, or from visceral complications. When the radial impulse is felt a little after the apex-beat, it is always important to determine whether the action of the heart remains regular under mental excitement or violent physical exertion: if it does, the prognosis is far better than when it becomes irregular.
Mitral stenosis admits of but slight compensation; if extensive, it is always a grave disease. The prognosis in any case can be estimated by the severity of the thoracic symptoms. When physical exertion greatly exacerbates the thoracic symptoms, the prognosis is especially bad; for during violent exercise such patients are not only liable to pulmonary congestion and oedema, but to pulmonary infarctions and pulmonary apoplexy with large extravasations.
Where mitral stenosis is extensive it ranks next to aortic regurgitation in its danger of sudden death. The statistics furnished by Bellevue Hospital show sudden death to occur as often in mitral stenosis as in aortic reflux.
Congenital mitral stenosis is not dangerous, and does not cause much embarrassment, for it is invariably associated with hyperplasia of the pulmonary arterial system. The later in life mitral stenosis occurs, the more unfavorable the prognosis.