(See also Overview of Congenital Cardiovascular Anomalies Overview of Congenital Cardiovascular Anomalies Congenital heart disease is the most common congenital anomaly, occurring in almost 1% of live births ( 1). Among birth defects, congenital heart disease is the leading cause of infant mortality... read more .)
Pathophysiology of Ebstein Anomaly
The primary abnormality in Ebstein anomaly is adherence of variable portions of the septal and inferior tricuspid valve leaflets to the endocardial surface of the right ventricle. The adherence of the valve leaflets results in displacement of the effective tricuspid valve orifice distally, compromising the functional size of the right ventricle with an atrialized portion of the right ventricle that is proximal to the valve opening. This anomaly has been associated with maternal use of lithium during pregnancy and is frequently part of the spectrum of abnormalities with congenitally corrected transposition of the great arteries Congenitally Corrected Transposition of the Great Arteries In congenitally corrected transposition of the great arteries (CCTGA), the right atrium enters a right-sided morphologic left ventricle, which gives rise to the pulmonary artery, and the left... read more .
Ebstein anomaly is associated with abnormalities that commonly include severe dysplasia and variable dysfunction of the tricuspid valve leaflets, atrial septal defect Atrial Septal Defect (ASD) An atrial septal defect (ASD) is an opening in the interatrial septum, causing a left-to-right shunt and volume overload of the right atrium and right ventricle. Children are rarely symptomatic... read more , pulmonic stenosis Pulmonic Stenosis Pulmonic stenosis (PS) is narrowing of the pulmonary outflow tract causing obstruction of blood flow from the right ventricle to the pulmonary artery during systole. Most cases are congenital... read more , and Wolff-Parkinson-White syndrome Wolff-Parkinson-White (WPW) syndrome Reentrant supraventricular tachycardias (SVT) involve reentrant pathways with a component above the bifurcation of the His bundle. Patients have sudden episodes of palpitations that begin and... read more . Multiple factors may lead to enlargement of the right atrium and elevated right atrial pressure, such as "atrialized ventricle," tricuspid regurgitation and/or stenosis, abnormal diastolic function, and limited capacity of the effective right ventricle distal to the tricuspid valve origin. Right atrial pressure will often exceed pressure in the left atrium and lead to right-to-left shunting through a patent foramen ovale or atrial septal defect and subsequent cyanosis. In very severe forms of the anomaly, during the newborn period, the right ventricle might not be able to generate a systolic pressure greater than the elevated pulmonary artery pressure, leading to "functional pulmonary atresia" (failure of a normal pulmonary valve to open in systole).
Symptoms and Signs of Ebstein Anomaly
There is a remarkably wide spectrum of manifestations, ranging from severe cyanosis in neonates, cardiomegaly, mild cyanosis in childhood, exercise intolerance in adolescents, to atrial arrhythmias or paroxysmal supraventricular tachycardia Reentrant Supraventricular Tachycardias (SVT) Including Wolff-Parkinson-White Syndrome Reentrant supraventricular tachycardias (SVT) involve reentrant pathways with a component above the bifurcation of the His bundle. Patients have sudden episodes of palpitations that begin and... read more in a previously asymptomatic adult.
The onset of symptoms depends on the degree of tricuspid valve anatomic and functional derangement and presence of accessory pathways (eg, Wolff-Parkinson-White syndrome Wolff-Parkinson-White (WPW) syndrome Reentrant supraventricular tachycardias (SVT) involve reentrant pathways with a component above the bifurcation of the His bundle. Patients have sudden episodes of palpitations that begin and... read more ).
Clinical signs include a widely split first heart sound (S1) due to delayed closure of the anterior leaflet of the tricuspid valve producing a "sail sound" (a complex closing sound which includes a sudden stopping sound after the anterior and/or other tricuspid leaflets balloon out at systole). Multiple other auscultatory findings are often present, such as a systolic murmur due to tricuspid regurgitation, a diastolic murmur due to tricuspid stenosis, and third or fourth heart sounds due to abnormal right ventricular diastolic compliance. Patients may have elevated jugular venous pressure, chronic cyanosis, and clubbing.
Diagnosis of Ebstein Anomaly
Chest x-ray and ECG
The ECG is usually abnormal with right axis deviation, low voltage right bundle branch block, and first-degree atrioventricular block. Wolff-Parkinson-White (WPW) syndrome is present in 20% of patients.
Chest x-ray findings include a variable degree of cardiomegaly with prominent right atrial borders. A subset of infants with severe Ebstein anomaly have massive cardiomegaly, referred to as a wall-to-wall heart shadow.
Echocardiography clearly delineates the anatomic and functional abnormalities of the tricuspid valve and any associated defects.
MRI provides valuable additional detail regarding the tricuspid valve, which is helpful in planning surgical intervention.
Treatment of Ebstein Anomaly
Medications play a role in managing neonates who are severely cyanotic and have inadequate pulmonary blood flow. Maintaining ductal patency with prostaglandins allows time for the pulmonary vascular resistance to drop. The decrease in pulmonary artery pressure allows the compromised right ventricle to provide adequate pulmonary blood flow. Some neonates with very severe Ebstein anomaly and functional compromise of the right ventricle require more prolonged palliation with a Blalock–Thomas–Taussig (BTT) shunt or other complex surgical interventions.
After the first several months of age, surgical repair of the tricuspid valve should be considered when any symptoms are present or there is evidence of progressive tricuspid valve dysfunction or enlargement of the right heart chambers. Surgical treatment of this anomaly has evolved over the years with developments such as the cone procedure (1 Treatment reference Ebstein anomaly is a rare congenital cardiac defect that consists of variable apical displacement from the annulus and dysplasia of the septal and inferior leaflets of the tricuspid valve. The... read more ). This approach to repair of the tricuspid vale involves delamination and mobilization of the tricuspid valve leaflets, plicating the atrialized portion of the right ventricle and the annulus and reattaching newly created "leaflet cone" to the true tricuspid annulus. These advances have greatly enhanced the surgeon's ability to achieve an excellent functional repair of even the most deformed tricuspid valves. Any atrial defect is closed at the same time.
Interventional catheterization techniques may be used to close an atrial communication when cyanosis is present, but the tricuspid valve dysfunction is only modest.
1. da Silva JP, Baumgratz JF, da Fonseca L, et al: The cone reconstruction of the tricuspid valve in Ebstein's anomaly. The operation: early and midterm results. J Thorac Cardiovasc Surg133(1):215–223, 2007. doi:10.1016/j.jtcvs.2006.09.018
The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
American Heart Association: Common Heart Defects: Provides overview of common congenital heart defects for parents and caregivers
American Heart Association: Infective Endocarditis: Provides an overview of infective endocarditis, including summarizing prophylactic antibiotic use, for patients and caregivers
Drugs Mentioned In This Article
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|Eskalith, Eskalith CR, Lithobid|