History
Patients with mild mitral stenosis (MS) may deny all symptoms. They may provide a history consistent with acute rheumatic fever; however, in a given patient, an inverse relationship between the severity of rheumatic heart disease and the severity of rheumatic arthritis is often observed.
The most prominent symptom of severe MS is dyspnea. This results from pulmonary congestion. Patients with severe MS may also experience orthopnea as well as significant exercise limitation.
MS due to rheumatic heart disease rarely occurs in childhood in the United States. When it does occur, the history generally reveals the insidious onset of exercise limitation. These patients may present with certain signs.
Pulmonary congestion is evidenced by increasing severity of dyspnea (depending on the degree of MS), ranging from dyspnea only during exercise to paroxysmal nocturnal dyspnea, orthopnea, or even symptoms related to frank pulmonary edema.
Dyspnea may be precipitated or worsened by an increase in blood flow across the stenotic mitral valve (eg, pregnancy, exercise) or a reduction in diastolic filling time because of increased heart rate (eg, emotional stress, fever, respiratory infection, atrial fibrillation with rapid ventricular rate).
Signs of right heart failure, including peripheral edema and fatigue, may appear late.
Approximately 30-40% of patients with MS eventually develop atrial fibrillation. This rarely occurs in the pediatric age group. Atrial fibrillation may cause the following:
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Loss of the atrial kick to the LV filling that may further diminish cardiac output
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Thromboembolic events, occurring in 10-20% of patients with MS, approximately 75% of which cause stroke
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Infective endocarditis, which should be suspected if embolization occurs during sinus rhythm
Hemoptysis may be caused by rupture of dilated bronchial veins, and pink frothy sputum may be a manifestation of pulmonary edema. Both are associated with endstage and severe MS.
Chest pain, possibly related to RV hypertension, occurs in approximately 15% of patients with MS.
Rarely, dysphagia may occur from compression of the esophagus by an enlarged left atrium. Hoarseness may occur if the enlarged left atrium impinges on the recurrent laryngeal nerve.
Physical Examination
Physical examination findings vary according to the severity of the mitral stenosis (MS}.
Mild-to-moderate MS signs include the following:
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Normal peripheral pulses and good perfusion
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Loud S1 because of abrupt closure of a stenotic, but still pliable, mitral valve
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Long A2 to opening snap interval: In mild MS, left atrial pressure is mildly increased; as a result, the mitral valve opens at a more normal interval after closure of the aortic valve (A2).
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Diastolic murmur: The diastolic murmur of MS begins at the time of mitral valve opening and accentuates following atrial contraction (presystolic accentuation) as long as the patient is in sinus rhythm. The murmur is low frequency and rumbling in quality. In mild MS, the mid diastolic murmur may be difficult to hear. As MS becomes more severe, murmur duration increases, and, to some extent, intensity also increases.
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No S3
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Pulmonic component of S2: The pulmonic component of the second heart sound increases in intensity in direct proportion to elevation of left atrial (and, consequently, pulmonary artery) pressure. Similarly, the A2 -P2 splitting interval narrows as pulmonary artery pressure increases.
Severe MS signs include the following:
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Diminished peripheral perfusion and pulses because of decreased cardiac output
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Palpation of an RV impulse (enlarged RV) because of pulmonary hypertension
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Soft S1 because of decreased mobility of the mitral leaflets as they become more thickened and/or calcified: Decreased cardiac output with severe stenosis also decreases the intensity of the S1, particularly with a faster heart rate.
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Shorter A2 to opening snap interval: As left atrial pressure increases, the mitral valve opens earlier in relation to aortic valve closure (S2).
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Diastolic rumble: A long, low-frequency diastolic rumble with presystolic accentuation is best heard at the apex. Murmur intensity decreases as cardiac output decreases.
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Increased intensity of pulmonic component of S2 (P2) secondary to pulmonary hypertension
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RV S3 or RV S4: RV S3 or RV S4 may occur; however, an RV S3 is rare in the presence of tricuspid valve regurgitation.
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Systolic murmur: A systolic murmur of tricuspid regurgitation may occur as right ventricular function deteriorates. This murmur is best heard at the lower left sternal edge. It accentuates with inspiration.
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Diastolic murmur: A high-frequency early diastolic murmur of pulmonic valve regurgitation may be heard immediately following an accentuated P2. Eponymously called the Graham Steell murmur, this finding reflects severe pulmonary hypertension.
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Acquired Mitral Stenosis. Hemodynamic changes in severe mitral valve stenosis (MS). MS causes an obstruction (in diastole) to blood flow from the left atrium (LA) to the left ventricle (LV). Increased LA pressures are transmitted retrograde to pulmonary veins and pulmonary capillaries, resulting in capillary leak with subsequent development of pulmonary edema. To overcome pulmonary edema, the arterioles constrict, increasing pulmonary pressures. Over time, capillaries develop intimal thickening, causing fixed (permanent) pulmonary hypertension. The right ventricle (RV) hypertrophies to generate enough pressure to overcome the increased afterload. Eventually, the RV fails, which manifests as hepatomegaly and/or ascites, edema of the extremities, and cardiomegaly on radiography.
