History
Congenital mitral stenosis (MS) in infancy
Patients with severe MS may present with respiratory distress from pulmonary edema shortly after birth if a significant atrial septal communication is not present. The presence of an atrial septal defect decompresses the left atrium, resulting in a clinical picture of pulmonary overcirculation and decreased systemic cardiac output.
Patients with mild-to-moderate MS present after the neonatal period with signs of low cardiac output and RV failure such as pulmonary infections, failure to gain weight, exhaustion and diaphoresis with feeding, tachypnea, and chronic cough.
Congenital MS in older children
Children with MS may present with the insidious onset of exercise limitation and other clinical signs.
Pulmonary congestion evidenced by increasing severity of dyspnea (depending on degree of MS) that may range from dyspnea during exercise to paroxysmal nocturnal dyspnea, orthopnea, or even frank pulmonary edema. Dyspnea may be precipitated or worsened by an increase in blood flow across the stenotic mitral valve (eg, pregnancy, exercise) or by a reduction in diastolic filling time achieved by increasing the 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 be present.
Patients with MS, including those previously without symptoms may develop atrial fibrillation, although this is an uncommon event in childhood. It results from chronic distension of the left atrium. Atrial fibrillation may cause the following:
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Loss of the atrial kick to LV filling reduces systemic output; this may precipitate or exacerbate congestive heart failure.
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Thromboembolic events (seeding of systemic emboli) occur in 10-20% of patients with MS. Many of these emboli lodge in the brain, causing a stroke.
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Infective endocarditis (a rare event) should be suspected when embolization occurs during sinus rhythm.
Hemoptysis may be caused by rupture of dilated bronchial veins. Pink frothy sputum may be a manifestation of frank pulmonary edema. Both are associated with end-stage severe MS but rarely occur in pediatric patients.
Chest pain occurs in approximately 15% of patients with MS.
Dysphagia can be produced by compression of the esophagus as a result of a dilated left atrium. It rarely occurs in children.
Hoarseness can occur if the dilated left atrium impinges on the recurrent laryngeal nerve. It is a rare manifestation of severe MS.
Physical Examination
Physical examination findings vary according to the severity of mitral stenosis (MS).
Mild-to-moderate MS
Features of mild-to-moderate MS include the following:
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Normal peripheral pulses and good perfusion
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Loud S1 caused by abrupt closure of the stenotic mitral valve
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Increased intensity of the pulmonic component of the second heart sound in proportion to elevation of pulmonary arterial pressure
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A long low-frequency diastolic murmur beginning shortly after S2 best heard at the apex, with late diastolic accentuation (as long as sinus rhythm is present) (Intensity and length of the murmur are in proportion to severity of the obstruction.)
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Possible demonstration of S4 at the apex in older children
Severe MS
Features of severe MS include the following:
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Diminished peripheral perfusion and pulses
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Palpation of an RV impulse (enlarged RV) when pulmonary hypertension is present
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Soft S1 in the presence of heart failure and diminished left ventricular filling
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Accentuation of the pulmonic component of S2 with minimal respiratory splitting of S2
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Holodiastolic murmur with presystolic accentuation best heard at apex (The diastolic murmur may diminish secondary to low cardiac output from heart failure.)
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With severe pulmonary hypertension, possible occurrence of a high-frequency early diastolic murmur of pulmonic valve regurgitation in the pulmonic listening area
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RV S3 or S4
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Congenital Mitral Stenosis. Hemodynamic changes in severe congenital 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. With 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.
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Congenital Mitral Stenosis. Two-dimensional echocardiograph, parasternal long axis view of a 5-month-old boy with congenital mitral valve stenosis. A small mitral valve annulus (star) is appreciated when compared with the normal-sized tricuspid valve annulus. Mitral valve stenosis has caused left atrial (LA) enlargement. AoV = Aorta; LA = Left atrium; LV = Left ventricle; RA = Right atrium; RV = Right ventricle.
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Congenital Mitral Stenosis. Two-dimensional echocardiograph, parasternal long axis view of a patient who required mitral valve replacement with a St. Jude's prosthetic mitral valve (star). He developed a stroke one month after mitral valve replacement despite anticoagulation with warfarin and required re-replacement of the prosthetic mitral valve. He will eventually outgrow this new prosthetic mitral valve and require subsequent mitral valve replacements with a larger mitral valve prosthesis. AoV = Aorta; LA = Left atrium; LV = Left ventricle; RA = Right atrium; RV = Right ventricle.
