Daniel Bernstein
Pulmonary valvular insufficiency most often accompanies other cardiovascular diseases or may be secondary to severe pulmonary hypertension . Incompetence of the valve is an expected result after surgery for right ventricular outflow tract (RVOT) obstruction, including pulmonary valvotomy in patients with valvular pulmonic stenosis or valvotomy with infundibular resection in patients with tetralogy of Fallot . Isolated congenital insufficiency of the pulmonary valve is rare. These patients are usually asymptomatic because the insufficiency is generally mild.
The prominent physical sign is a decrescendo diastolic murmur at the upper and mid-left sternal border, which has a lower pitch than the murmur of aortic insufficiency because of the lower pressure involved. Radiographs of the chest show prominence of the main pulmonary artery and, if the insufficiency is severe, right ventricular (RV) enlargement. The electrocardiogram (ECG) is normal or shows an rSR′ pattern in the right precordial leads (V1 , V2 ) and minimal RV hypertrophy. Pulsed and color Doppler studies demonstrate retrograde flow from the pulmonary artery to the right ventricle during diastole. Cardiac magnetic resonance angiography (MRA) is the best method for quantifying both RV volume and the regurgitant fraction, as well as RV systolic function (ejection fraction). Isolated pulmonary valvular insufficiency is generally well tolerated and does not require surgical treatment. When pulmonary insufficiency is severe, especially if significant tricuspid insufficiency has begun to develop, replacement with a homograft valve or transcatheter stent valve may become necessary to preserve RV function.
Congenital absence of the pulmonary valve is usually associated with a ventricular septal defect (VSD), often in the context of tetralogy of Fallot (see Chapter 457.1 ). In many of these neonates, the pulmonary arteries become widely dilated and compress the bronchi, with subsequent recurrent episodes of wheezing, pulmonary collapse, and pneumonitis. The presence and degree of cyanosis are variable. Florid pulmonary valvular incompetence may not be well tolerated, and death may occur from a combination of bronchial compression, hypoxemia, and heart failure. Correction involves plication of the massively dilated pulmonary arteries, closure of the VSD, and placement of a homograft across the RVOT.
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Daniel Bernstein
Congenital mitral insufficiency is rare as an isolated lesion and is more often associated with other anomalies. It is most frequently encountered in combination with an atrioventricular septal defect , either an ostium primum defect or a complete atrioventricular septal defect (see Chapter 453.5 ). Mitral insufficiency is also seen in patients with dilated cardiomyopathy (see Chapter 466.1 ) as their left ventricular (LV) function deteriorates, secondary to dilation of the valve ring. Mitral insufficiency may also be encountered in conjunction with coarctation of the aorta, VSD, corrected transposition of the great vessels, anomalous origin of the left coronary artery from the pulmonary artery, or Marfan syndrome. In the absence of other congenital heart disease, endocarditis or rheumatic fever should be suspected in a patient with isolated severe mitral insufficiency (Table 455.1 ).
Table 455.1
Causes and Mechanisms of Mitral Regurgitation
| ORGANIC | FUNCTIONAL | |||
|---|---|---|---|---|
| Type I* | Type II † | Type IIIa ‡ | Type I* /TYPE IIIb ‡ | |
| Nonischemic | Endocarditis (perforation); degenerative (annular calcification); congenital (cleft leaflet) | Degenerative (billowing/flail leaflets); endocarditis (ruptured chordae); traumatic (ruptured chord/PM); rheumatic (acute RF) | Rheumatic (chronic RF); iatrogenic (radiation/drug); inflammatory (lupus/anticardiolipin), eosinophilic (endocardial disease, endomyocardial fibrosis) | Cardiomyopathy; myocarditis; left-ventricular dysfunction (any cause) |
| Ischemic | — | Ruptured PM | — | Functional ischemic |
* Mechanism involves normal leaflet movement.
† Mechanism involves excessive valve movement.
‡ Restricted valve movement, IIIa in diastole, IIIb in systole.
PM, Papillary muscle; RF, rheumatic fever.
Adapted from Sarano ME, Akins CW, Vahanian A: Mitral regurgitation, Lancet 373:1382–1394, 2009, Table 1.
In isolated mitral insufficiency, the mitral valve annulus is usually dilated, the chordae tendineae are short and may insert anomalously, and the valve leaflets are deformed. When mitral insufficiency is severe enough to cause clinical symptoms, the left atrium enlarges as a result of the regurgitant flow, and the left ventricle becomes hypertrophied and dilated. Pulmonary venous pressure is increased, and the increased pressure ultimately results in pulmonary hypertension and RV hypertrophy and dilation. Mild lesions produce no symptoms; the only abnormal sign is the apical holosystolic murmur of mitral regurgitation. Severe regurgitation results in symptoms that can appear at any age, including poor physical development, frequent respiratory infections, fatigue on exertion, and episodes of pulmonary edema or congestive heart failure. Often, a diagnosis of reactive airways disease will have been made because of the similarity in pulmonary symptoms, including wheezing, which may be a dominant finding in infants and young children.
The typical murmur of mitral insufficiency is a moderately high-pitched, apical blowing holosystolic murmur. If the insufficiency is moderate to severe, it is usually associated with a low-pitched, apical mid-diastolic rumbling murmur indicative of increased diastolic flow across the mitral valve. The pulmonic component of the second heart sound will be accentuated in the presence of pulmonary hypertension. The ECG usually shows bifid P waves consistent with left atrial enlargement, signs of LV hypertrophy, and sometimes signs of RV hypertrophy. Radiographic examination shows enlargement of the left atrium, which at times is massive. The left ventricle is prominent, and pulmonary vascularity is normal or prominent. The echocardiogram demonstrates the enlarged left atrium and ventricle. Color Doppler demonstrates the extent of the insufficiency, and pulsed Doppler of the pulmonary veins detects retrograde flow when mitral insufficiency is severe. Cardiac catheterization shows elevated left atrial pressure. Pulmonary artery hypertension of varying severity may be present. Selective left ventriculography reveals the severity of mitral regurgitation.
Mitral valvuloplasty can result in striking improvement in symptoms and heart size, but in some patients, installation of a prosthetic mechanical mitral valve may be necessary. Before surgery, associated anomalies must be identified. Clinical studies using stent-valves in the mitral position show early encouraging results in selected patients.
Daniel Bernstein
Mitral valve prolapse results from an abnormal mitral valve mechanism that causes billowing of 1 or both mitral leaflets, especially the posterior cusp, into the left atrium toward the end of systole. The abnormality is predominantly congenital but may not be recognized until adolescence or adulthood. Mitral valve prolapse is usually sporadic, is more common in girls, and may be inherited as an autosomal dominant trait with variable expression. It is common in patients with Marfan syndrome, straight back syndrome, pectus excavatum, scoliosis, Ehlers-Danlos syndrome, osteogenesis imperfecta, and pseudoxanthoma elasticum. The dominant abnormal signs are auscultatory, although occasional patients may have chest pain or palpitations. The apical murmur is late systolic and may be preceded by a click, but these signs may vary in the same patient, and at times, only the click is audible. In the standing or sitting position the click may occur earlier in systole, and the murmur may be more prominent in late systole. Arrhythmias may occur and are primarily unifocal or multifocal premature ventricular contractions.
The ECG is usually normal but may show biphasic T waves, especially in leads II, III, aVF, and V6 ; the T-wave abnormalities may vary at different times in the same patient. The chest radiograph is normal. The echocardiogram shows a characteristic posterior movement of the posterior mitral leaflet during mid- or late systole or demonstrates pansystolic prolapse of both the anterior and posterior mitral leaflets. These echocardiographic findings must be interpreted cautiously because the appearance of minimal mitral prolapse may be a normal variant. Prolapse is more precisely defined by single or bileaflet prolapse of >2 mm beyond the long axis annular plane with or without leaflet thickening. Prolapse with valve thickening >5 mm is “classic”; a lesser degree is “nonclassic.” Two-dimensional real-time echocardiography shows that both the free edge and the body of the mitral leaflets move posteriorly in systole toward the left atrium. Doppler can assess the presence and severity of mitral regurgitation.
This lesion is not progressive in childhood, and specific therapy is not indicated. Antibiotic prophylaxis is no longer recommended during surgery and dental procedures (see Chapter 464 ).
Adults (men more often than women) with mitral valve prolapse are at increased risk for cardiovascular complications (sudden death, arrhythmia, cerebrovascular accident, progressive valve dilation, heart failure, and endocarditis) in the presence of thickened (>5 mm) and redundant mitral valve leaflets. Risk factors for morbidity also include poor LV function, moderate to severe mitral regurgitation, and left atrial enlargement.
Often, confusion exists concerning the diagnosis of mitral valve prolapse. The high frequency of mild prolapse on the echocardiogram in the absence of clinical findings suggests that, in these cases, true mitral valve prolapse syndrome is not present. These patients and their parents should be reassured of this fact, and no special recommendations should be made regarding management or frequent laboratory studies.
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Maron BJ, Ackerman MJ, Nishimura RA, et al. Task Force 4: HCM and other cardiomyopathies, mitral valve prolapse, myocarditis, and Marfan syndrome. J Am Coll Cardiol . 2005;45:1340–1345.
Padang R, Bagnall RD, Semsarian C. Genetic basis of familial valvular heart disease. Circ Cardiovasc Genet . 2012;5:569–580.
Daniel Bernstein
Isolated tricuspid regurgitation is most often associated with Ebstein anomaly of the tricuspid valve . Ebstein anomaly may occur either without cyanosis or with varying degrees of cyanosis, depending on the severity of the tricuspid regurgitation and the presence of an atrial-level communication (patent foramen ovale or atrial septal defect). Older children tend to have the acyanotic form, whereas if detected in the newborn period, Ebstein anomaly is usually associated with severe cyanosis (see Chapter 457.7 ).
Tricuspid regurgitation often accompanies RV dysfunction. When the right ventricle becomes dilated because of volume overload or intrinsic myocardial disease, or both, the tricuspid annulus also enlarges, with resultant valve insufficiency. This form of regurgitation may improve if the cause of the RV dilation is corrected, or it may require surgical plication of the valve annulus. Tricuspid regurgitation is also encountered in newborns with perinatal asphyxia. The cause may be related to an increased susceptibility of the papillary muscles to ischemic damage and subsequent transient papillary muscle dysfunction. Lastly, tricuspid regurgitation is seen in up to 30% of children after heart transplantation, which can be a risk factor for graft dysfunction, but is also seen as a result of valve injury caused by endomyocardial biopsy.
Ben Sivarajan V, Chrisant MR, Ittenbach RF, et al. Prevalence and risk factors for tricuspid valve regurgitation after pediatric heart transplantation. J Heart Lung Transplant . 2008;27:494–500.
Hetzer R, Javier M, Delmo Walter EM. The double-orifice valve technique to treat tricuspid valve incompetence. J Heart Valve Dis . 2016;25(1):66–71.
Sachdeva R, Fiser RT, Morrow WR, et al. Ruptured tricuspid valve papillary muscle: a treatable cause of neonatal cyanosis. Ann Thorac Surg . 2007;83:680–682.