Ebstein Anomaly

Practice Essentials

Ebstein anomaly is a congenital malformation of the heart that is characterized by apical displacement of the septal and posterior tricuspid valve leaflets, leading to atrialization of the right ventricle with a variable degree of malformation and displacement of the anterior leaflet.

Essential update: Associations of QRS duration and fractionation in Ebstein anomaly

In a study of 63 adult patients with Ebstein anomaly (mean age, 22 +/- 13 y), QRS duration and QRS fractionation on surface electrocardiogram were markers of right ventricular dysfunction and atrialization.[1] The QRS duration was correlated with anatomic RV diastolic volume but inversely correlated with right ventricular ejection fraction. Moreover, QRS fractionation was a predictor for greater atrialized right ventricular volume. The investigators suggested that a preserved surface electrocardiogram may help to identify a subset of patients with a better clinical profile and mild morphologic and functional abnormalities than that in the general population of patients with Ebstein anomaly.[1]

Signs and symptoms

Patients can have a variety of symptoms related to the anatomic abnormalities of Ebstein anomaly and their hemodynamic effects or associated structural and conduction system disease, including the following:

CyanosisFatigue and dyspneaPalpitations and sudden cardiac deathSymptoms of right heart failure, such as edema and ascites

Other less common presenting symptoms include the following:

Brain abscess due to right-to-left shuntBacterial endocarditisParadoxical embolism, stroke, and transient ischemic attacks

See Clinical Presentation for more detail.

Diagnosis

Physical findings in patients with Ebstein anomaly span a spectrum from subtle to dramatic. They may include the following:

Cyanosis and clubbingPrecordial asymmetryJugular venous pulseArterial pulses: Usually normal but are diminished late in the disease courseHeart sounds: Widely split first heart sound with loud tricuspid component and soft/absent mitral component in the presence of prolonged PR interval; usually normal second heart sound but may be widely split when pulmonary component delayed due to right bundle-branch block; third and fourth heart sounds commonly present, even in the absence of congestive heart failure

Testing

A 12-lead electrocardiogram may demonstrate the following findings in patients with Ebstein anomaly:

Normal sinus rhythmIntermittent/paroxysmal supraventricular tachycardia, atrial flutter/fibrillation, ventricular tachycardiaAbnormal P waves consistent with right atrial enlargementProlonged PR interval; may be normal/short in patients with Wolff-Parkinson-White syndromeRight bundle branch block and/or low voltage QRS complexImaging studies

The following imaging studies may be used to assess patients with suspected Ebstein anomaly:

Chest radiographyEchocardiography: Includes M- mode, 2-dimensional, and Doppler studiesCine magnetic resonance imaging: In selected patients; not used routinely

See Workup for more detail.

Management

Treatment of Ebstein anomaly is complex and dictated mainly by the severity of the disease itself and the effect of accompanying congenital structural and electrical abnormalities. Treatment options include medical therapy, radiofrequency ablation, and surgical therapy.

Pharmacotherapy

Ebstein anomaly requires drug treatment for cardiovascular consequences resulting from tricuspid atrialization of the right ventricle, valvular regurgitation, and septal defects. Patients may require antibiotic prophylaxis for bacterial endocarditis.

The following medications are used in patients with Ebstein anomaly:

Diuretics (eg, furosemide)Cardiac glycosides (eg, digoxin)Angiotensin-converting enzyme inhibitors (eg, enalapril)

Nonpharmacotherapy

Radiofrequency ablation of the accessory pathways is an alternative to medication for treatment of arrhythmias. Curative therapy of supraventricular tachycardia with radiofrequency ablation is the treatment of choice. However, in patients without significant structural heart disease, the success rate of this procedure is lower.

Surgical option

Surgical intervention includes the following:

Correction of the underlying tricuspid valve and right ventricular abnormalitiesCorrection of any associated intracardiac defectsPalliative procedures in early days of life as a bridge to more definitive surgical treatment laterSurgical treatment of associated arrhythmias (eg, ablation of the accessory pathways; maze procedure for atrial arrhythmias)Cardiac transplantation in selected patients

See Treatment and Medication for more detail.

NextBackground

Ebstein anomaly is a congenital malformation of the heart that is characterized by apical displacement of the septal and posterior tricuspid valve leaflets, leading to atrialization of the right ventricle with a variable degree of malformation and displacement of the anterior leaflet.

Wilhelm Ebstein first described a patient with cardiac defects typical of Ebstein anomaly in 1866. In 1927, Alfred Arnstein suggested the name Ebstein's anomaly for these defects. In 1937, Yates and Shapiro described the first case of the anomaly with associated radiographic and electrocardiographic data.

PreviousNextPathophysiology

The embryological development of tricuspid valve leaflets and chordae involves undermining of the right ventricular free wall. This process continues to the level of the atrioventricular (AV) junction. In Ebstein anomaly, this process of undermining is incomplete and falls short of reaching the level of the AV junction. In addition, the apical portions of the valve tissue, which normally undergo resorption, fail to resorb completely. This results in distortion and displacement of the tricuspid valve leaflets, and a part of the right ventricle becomes atrialized. In one study involving 50 hearts with the anomaly, the entire right ventricle was found to be morphologically abnormal.[2]

Ebstein anomaly is commonly associated with other congenital, structural, or conduction system disease, including intracardiac shunts, valvular lesions, and accessory conduction pathways (eg, Wolff-Parkinson-White [WPW] syndrome).

The hemodynamic consequences of Ebstein anomaly result from displaced and malformed tricuspid leaflets and atrialization of the right ventricle. The leaflet anomaly leads to tricuspid regurgitation. The severity of regurgitation depends on the extent of leaflet displacement, ranging from mild regurgitation with minimally displaced tricuspid leaflets to severe regurgitation with extreme displacement.

The atrialized portion of the right ventricle, although anatomically part of the right atrium, contracts and relaxes with the right ventricle. This discordant contraction leads to stagnation of blood in the right atrium. During ventricular systole, the atrialized part of the right ventricle contracts with the rest of the right ventricle, which causes a backward flow of blood into the right atrium, accentuating the effects of tricuspid regurgitation.

PreviousNextFrequencyUnited States

True prevalence is unknown because mild forms frequently are undiagnosed. Currently, with wide application of echocardiography, more cases are being diagnosed. Ebstein anomaly probably accounts for 0.5% of cases of congenital heart diseases.

PreviousNextMortality/Morbidity

The natural course of the disease varies according to the severity of tricuspid valve displacement.

Patients presenting in infancy generally have severe disease and unfavorable prognosis.[3, 4] Mean age of presentation is in the middle teenage years. According to older observational data, approximately 5% of these patients survive beyond age 50 years. The oldest recorded patient lived to age 85 years. Race

Ebstein anomaly is more common in children of white females.

Sex

No specific sex predominance exists.

Age

Ebstein anomaly can present at various stages of life.

Fetal life: Ebstein anomaly is usually diagnosed incidentally by echocardiography.Neonatal life and infancy: Ebstein anomaly presents with cyanosis and/or severe heart failure; typically, symptoms present in infancy improve as pulmonary vascular resistance decreases. Adult life: Ebstein anomaly presents with fatigue, exertional dyspnea, cyanosis, tricuspid regurgitation and/or right heart failure, and palpitations; arrhythmias are common. PreviousProceed to Clinical Presentation , Ebstein Anomaly