AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Background

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.

Pathophysiology

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. 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.

Frequency

United 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.

Mortality/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.
• 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.

CLINICAL

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

History

Patients can have a variety of symptoms related to the anatomical abnormalities of Ebstein anomaly and their hemodynamic effects or associated structural and conduction system disease.

• Cyanosis
• • Fairly common and frequently due to right-to-left shunt at the atrial level and/or severe heart failure
  • Transient in neonatal life with recurrence in adult life
  • May appear for the first time in adult life
  • Transient appearance/worsening of cyanosis in adult life due to paroxysmal arrhythmias
  • Once apparent, progressively worsens
• Fatigue and dyspnea: These are due to poor cardiac output secondary to right ventricular failure and decreased left ventricular ejection fraction.
• Palpitations and sudden cardiac death
• • Due to paroxysmal supraventricular tachycardia (SVT) in as many as one third of patients
  • Fatal ventricular arrhythmias, which may be due to the presence of accessory pathways
• Symptoms of right heart failure: These include ankle edema and ascites.
• Other less common presenting symptoms
• • Brain abscess due to right-to-left shunt
  • Bacterial endocarditis
  • Paradoxical embolism, stroke, and transient ischemic attacks

Physical

Physical findings, like the symptoms, span a spectrum from subtle to dramatic.

• Cyanosis and clubbing - Varying degrees of cyanosis at various times in life and transient worsening with arrhythmias
• Precordial asymmetry
• • Usually left parasternal prominence and occasionally right parasternal prominence
  • Absent left parasternal (ie, right ventricular) lift an important negative sign
• Jugular venous pulse
• • May be normal owing to a large, thin-walled right atrium, which can absorb the volume and pressure transmitted from the right ventricle through an incompetent tricuspid valve
  • Large a and v waves late in the course of the disease, with development of right heart failure
• Arterial pulses
• • Usually normal
  • Diminished volume late in the course of the disease due to severe right heart failure and decreased left ventricular stroke volume
• Heart sounds
• • First heart sound is widely split with loud tricuspid component secondary to delayed closure of the elongated anterior tricuspid leaflet, which has an increased excursion. Mitral component may be soft or absent in the presence of prolonged PR interval.
  • Second heart sound usually is normal but may be widely split when the pulmonary component is delayed due to right bundle-branch block (RBBB).
• Additional heart sounds and murmurs
• • Third and fourth heart sounds are commonly present, even in the absence of congestive heart failure (CHF). Summation of third and fourth heart sounds, especially with prolonged PR interval, can mimic an early diastolic murmur.
  • The holosystolic murmur of tricuspid regurgitation is heard maximally at the lower left parasternal area and sometimes at the apex owing to the displaced location of the tricuspid valve; murmur intensity and duration increase during inspiration.

Causes

• Ebstein anomaly is a congenital disease of often uncertain cause.
• Environmental factors implicated in etiology include the following:
• • Maternal ingestion of lithium in first trimester of pregnancy
  • Maternal benzodiazepine use
  • Maternal exposure to varnishing substances
  • Maternal history of previous fetal loss
• Risk is higher in whites than in other races.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Other Problems to be Considered

Rule out Ebstein anomaly in patients with the following:

• Accessory pathway-mediated WPW syndrome and SVT
• Cyanotic congenital heart diseases
• Atrial septal defect (ASD)
• Cases of severe right heart failure
• Isolated severe tricuspid regurgitation
• L-transposition of the great vessels

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Imaging Studies

• Chest radiographs can reveal the following:
• • Normal findings
  • Cardiomegaly
  • Small aortic root and main pulmonary artery shadow
  • Decreased pulmonary vasculature
  • Large right atrium
• Echocardiogram is the criterion standard for diagnosis.
• • M-mode
    • Paradoxical septal motion
    • Dilated right ventricle
    • Delayed closure of tricuspid valve leaflets more than 65 milliseconds after mitral valve closure
  • Two-dimensional
    • Apical displacement of the septal leaflet of tricuspid leaflet of greater than 8 mm/m² - Most specific sign
    • Abnormalities in morphology and septal attachment of the septal and anterior tricuspid leaflets
    • Eccentric leaflet coaptation
    • Dilated right atrium
    • Dilated right ventricle with decreased contractile performance
    • Various left heart structural abnormalities (described recently in up to 39% of patients with Ebstein abnormality)
  • Doppler studies
    • Varying degrees of tricuspid regurgitation
    • Excludes associated shunts
  • Assessment of severity and surgical options by echocardiography
    • Functional right ventricular area less than 35% of total right ventricular area or an atrialized to functional right ventricular ratio greater than 0.5 associated with unfavorable prognosis
    • Functional right ventricular size
    • Degree of septal leaflet displacement
    • Amount of leaflet tethering
    • Magnitude of leaflet deformity and dysplasia
    • Aneurysmal dilatation of right ventricular outflow tract (right ventricular outflow tract-to-aortic root ratio of >2:1 on parasternal short axis view)
    • Moderate-to-severe tricuspid regurgitation
• Cine MRI is currently not used routinely; it may become a useful noninvasive modality in the future.

Other Tests

• Twelve-lead ECG
• • Rhythm
    • Usually normal sinus findings
    • Intermittently SVT, paroxysmal SVT, atrial flutter, atrial fibrillation, ventricular tachycardia
  • Abnormal P waves consistent with right atrial enlargement
  • PR interval
    • Most commonly prolonged
    • May be normal or short in patients with WPW syndrome
  • QRS complex
    • RBBB
    • Low voltage in many patients

Procedures

• Cardiac catheterization
• • Rarely performed today
  • Confirms echocardiographic findings
  • Can reveal right ventricular electrical activity on the intracardiac ECG with simultaneous right atrial pressure and waveform when the catheter is withdrawn from the right ventricle, back across the tricuspid valve into the right atrium
• Electrophysiologic studies
• • Of patients with Ebstein anomaly, 25-30% have accessory pathways, and 5-25% have evidence of preexcitation on the surface ECG.
  • Electrophysiologic (EP) studies in patients with tachyarrhythmias can delineate accessory conduction pathways and guide ablative therapy.
  • Right-sided pathways are more common.
  • Fifty percent of the patients have multiple pathways.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical Care

Ebstein anomaly presents with a spectrum of congenital abnormalities of the tricuspid valve and the right ventricle. The age of presentation with symptoms is variable, and a wide range of treatment options is available. 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.

• Antibiotic prophylaxis for infective endocarditis
• Medical therapy for heart failure - Angiotensin-converting enzyme (ACE) inhibitors, diuretics, and digoxin
• Arrhythmia treatment - Medical treatments such as anti-arrhythmic drugs or radiofrequency ablation of the accessory pathways
• • Curative therapy of SVT with radiofrequency ablation is currently the treatment of choice.
  • The success rate is lower than that in patients without significant structural heart disease.
  • Factors associated with lower likelihood of success include the following:
    • Accessory pathways located along the atrialized right ventricle
    • Multiple accessory pathways
    • Complex geometry of the pathways
    • Abnormal morphology of the endocardial action potentials in this region

Surgical Care

Surgical care includes correction of the underlying tricuspid valve and right ventricular abnormalities, correction of any associated intracardiac defects, palliative procedures in early days of life as a bridge to more definitive surgical treatment later, and surgical treatment of associated arrhythmias.

• Indications for surgery are generally as follows:
• • New York Heart Association (NYHA) class I-II heart failure with worsening symptoms or with a cardiothoracic ratio of 0.65 or greater
  • NYHA class III-IV heart failure
  • History of paradoxical embolism
  • Significant cyanosis with arterial O₂ saturation of 80% or less and/or polycythemia with hemoglobin of 16 g/dL or more
  • Arrhythmias refractory to medical and radiofrequency ablation
• Generally, the trend is to perform surgery earlier rather later in the course of heart failure.
• Various approaches are available to treat structural abnormalities.
• • Tricuspid valve repair is preferred over valve replacement, and bioprosthetic valves are preferred over mechanical prosthetic valves.
  • The atrialized portion of the right ventricle can be resected surgically, and the markedly dilated, thin-walled right atrium can be resected.
  • Associated septal defects may be closed.
• Palliative procedures include creation of atrial septal defect, closure of tricuspid valve with plication of the right atrium, and maintenance of pulmonary blood flow through aortopulmonary shunt. Palliative procedures usually are reserved for severely ill infants with otherwise dire prognosis.
• Surgical treatments of arrhythmias include the following:
• • Ablation of the accessory pathways
  • Maze procedure for atrial arrhythmias
• Cardiac transplantation is appropriate in selected patients.

Consultations

• Electrophysiologist
• Cardiac surgeon

Diet

A low-sodium diet is recommended for symptomatic relief from fluid overload.

Activity

Activity may be allowed as tolerated.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

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. Treatment of SVT is typically by radiofrequency ablation rather than drug therapy. CHF is treated with ACE inhibitors, diuretics, and digoxin.

Drug Category: Diuretics

These agents promote excretion of water and electrolytes by the kidneys. They are used in treatment of hypertension, heart failure, and hepatic, renal, or pulmonary disease when salt and water retention has resulted in edema or ascites.

Drug Category: Cardiac glycosides

These agents possess positive inotropic activity, which is mediated by inhibition of sodium-potassium adenosine triphosphatase (Na⁺/K⁺ ATPase). Also, cardiac glycosides reduce conductivity in the heart, particularly through the atrioventricular node, and therefore have a negative chronotropic effect. The cardiac glycosides have very similar pharmacological effects but differ considerably in their speed of onset and duration of action. They are used to slow the heart rate in supraventricular arrhythmias, especially atrial fibrillation, and also are administered in chronic heart failure.

Drug Category: Angiotensin-converting enzyme inhibitors

ACE inhibitors are beneficial in all stages of chronic heart failure. Dyspnea and exercise tolerance are improved. Unlike diuretics, studies demonstrate improvement of survival and reduced progression of mild or moderate heart failure to more severe stages. They have benefit in asymptomatic left ventricular dysfunction.

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Further Outpatient Care

• Outpatient follow-up is directed toward the following:
• • Assessment of general symptoms (eg, fatigue, lassitude)
  • Assessment for development of bacterial endocarditis with careful history and examination for signs of bacterial endocarditis, such as fever, weight loss, anorexia, night sweats, splinter hemorrhages, clubbing, Roth spots, Janeway lesions, Osler nodes, splenomegaly, and hematuria
  • Assessment of signs of worsening heart failure, such as weight gain, ankle edema, and rales
  • Assessment for arrhythmias by history of symptoms, such as faintness or syncope
  • Periodic chest radiographs to assess for worsening cardiomegaly
  • Evaluation and adjustment of medications

Transfer

• Transfer to a cardiothoracic surgery unit if necessary.

Complications

• Congestive heart failure
• Sudden cardiac death
• Bacterial endocarditis
• Brain abscess
• Paradoxical embolism
• Transient ischemic attacks
• Stroke

Prognosis

• Prognosis depends on the severity of the disease and treatment options available.
• Poor prognostic signs include the following:
• • Male sex
  • Earlier age at presentation
  • Cardiothoracic ratio of more than 0.65 on chest radiographs
  • Septal leaflet attachment ratio (ie, ratio of distance between AV ring and distal attachment of septal leaflet to length of septal leaflet) of more than 0.45
  • Increasing ratio of combined area of right atrium and atrialized right ventricle to that of the functional right ventricle—grade 1, which is less than 0.5, to grade 4, which is more than 1.5 (increase in the relative risk of 2.7 for each increment in the grade)
  • NYHA class - Also has been linked with mortality rate in some studies

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• Failure to diagnose Ebstein anomaly in patients with tricuspid regurgitation and right heart failure is a potential pitfall.
• Failure to identify and treat various arrhythmias associated with Ebstein anomaly may cause problems.
• Failure to refer the patient for electrophysiological studies is a potential pitfall.
• Failure to provide endocarditis prophylaxis advice is a potential pitfall.
• Failure to refer the patient to a cardiothoracic surgeon in a timely fashion is a potential pitfall.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

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• Kaneko Y, Okabe H, Nagata N, Yasui S, Yamada S, Kobayashi J. Repair of septal and posterior tricuspid leaflets in Ebstein's anomaly. J Card Surg. Jul 1998;13(4):229-35. [Medline].
• Khositseth A, Khowsathit P. Factors affecting mortality in Ebstein's anomaly of the tricuspid valve. J Med Assoc Thai. Nov 1999;82 Suppl 1:S10-5. [Medline].
• MacLellan-Tobert SG, Driscoll DJ, Mottram CD, Mahoney DW, Wollan PC, Danielson GK. Exercise tolerance in patients with Ebstein's anomaly. J Am Coll Cardiol. Jun 1997;29(7):1615-22. [Medline].
• Perloff JK. Ebstein's anomaly of the tricuspid valve. In: Perloff JK, ed. The Clinical Recognition of Congenital Heart Disease. 3^rd ed. Philadelphia, Pa: WB Saunders Company; 1991:235-251.
• Ronan Jr JA. Congenital heart disease. In: Chizner MA, ed. Classic Teachings in Clinical Cardiology. 2. First ed. Cedar Grove, NJ: Laennec; 1996:1242-44.
• Shaughnessy R. Ebstein's anomaly. In: Crawford MH, DiMarco JP, eds. Cardiology. London: Mosby International; 2001:6.13.1-6.
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Article Last Updated: Feb 6, 2008