Ebstein Anomaly

An Ebstein anomaly is an uncommon congenital cardiac anomaly characterised by a variable developmental anomaly of the tricuspid valve 1.

Epidemiology

The anomaly accounts for only approximately 0.5% of congenital cardiac defects 6-7. There is no recognised gender predilection and almost all cases seem to be sporadic, although an association with maternal lithium carbonate injection has been postulated 6. A few familial cases have been reported 6-7.

Clinical presentation

Presentation is often antenatally with development of hydrops foetalis and tachyarrhythmias 6, or in less severe cases at birth. Depending on the degree of atrial right to left shunting, the infant may or may not be cyanosed.

Associations

* maternal lithium carbonate ingestion : possible
* trisomy 13
* Down syndrome (trisomy 21)
* multiple other congenital heart lesions (e.g with an ASD being quite common)
* conduction abnormalities leading to arrhythmias (common) : e.g Wolf-Parkinson-White syndrome

Pathology

The main abnormality is an abnormal tricuspid valve (particularly anterior leaflet), which is displaced downwards into the right ventricle resulting in atrialisation of the parts of the ventricle above the valve. This results from the tricuspid valve leaflets inadequately separating from each other or from the chorda tendinae from the inferior portion of the ventricle during embryologic development.

Radiographic features

Plain film

Findings largely depend on the severity of the abnormality and the degree to which the tricuspid valve is displaced downwards.

There is often severe right sided cardiomegaly due to an elongated and enlarged right atrium which may result in an elevated apex. Classically, the heart is described as having a "box shape" on a frontal chest radiograph.

Echocardiography / Ultrasound

Typically shows right heart enlargement. Colour doppler may show tricuspid regurgitation, and an abnormally downward displaced tricuspid valve and small right ventricle.

CT / MRI

Allows direct visualisation of anatomical detail. Cine CT or MRI can be used akin to echocardiagrphy for functional assessment.

Treatment and prognosis

As the anomaly is of variable severity, so is the prognosis. Symptomatic cases however, especially those that present in utero have a poorer prognosis 6-7. Even in initially asymptomatic cases, life expectancy is usually limited to a few decades 7.

A number of surgical procedures have been performed with mixed results.

Etymology

Named after Wilhelm Ebstein : German physician (1836 - 1912) 4

Differential diagnoses

The differential on a chest radiograph is extremely broad, especially as the findings in Ebstein anomaly are so variable. With echocardiography and MRI, the diagnosis is usually self evident, once the downwardly displaced tricuspid valve in identified.

Differential on a chest radiograph includes:

* other congenital heart anomalies
o left to right shunts : enlarging right atrium
o pulmonary stenosis : right heart enlargement
o tetralogy of Fallot
o Uhl anomaly 3
* large pericardial effusion
* selective fatty infiltration of right ventricular myocardium 3

Ebstein's Anomaly Chest X-rays

ea1.jpg
ea2.jpg
ea3.jpg

Article & X-rays Source : Dr Yuranga Weerakkody, Radiopaedia

References

  1. 1. Choi YH, Park JH, Choe YH et-al. MR imaging of Ebstein's anomaly of the tricuspid valve. AJR Am J Roentgenol. 1994;163 (3): 539-43. AJR Am J Roentgenol (abstract) - Pubmed citation
  2. 2. Ferguson EC, Krishnamurthy R, Oldham SA. Classic imaging signs of congenital cardiovascular abnormalities. Radiographics. 27 (5): 1323-34. doi:10.1148/rg.275065148 - Pubmed citation
  3. 3. Cook AL, Hurwitz LM, Valente AM et-al. Right heart dilatation in adults: congenital causes. AJR Am J Roentgenol. 2007;189 (3): 592-601. doi:10.2214/AJR.07.2420 - Pubmed citation
  4. 4. Wilhelm Ebstein from whonamedit.com, the dictionary of medical eponyms. Wilhelm Ebstein
  5. 5. Brant WE, Helms CA. Fundamentals of diagnostic radiology. Lippincott Williams & Wilkins. (2007) ISBN:0781761352. Read it at Google Books - Find it at Amazon
  6. 6. Drose JA. Fetal Echocardiography. W B Saunders Co. (2009) ISBN:1416056696. Read it at Google Books - Find it at Amazon
  7. 7. Moss AJ, Allen HD, Driscoll DJ et-al. Moss and Adams' heart disease in infants, children, and adolescents, including the fetus and young adult. Lippincott Williams & Wilkins. (2007) ISBN:0781786843. Read it at Google Books - Find it at Amazon
Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License