Ebstein's anomaly

Ebstein's anomaly
Classification and external resources
Pathological specimen and ultrasound image of a heart with Ebstein's anomaly. Abbreviations: RA: Right atrium; ARV: Atrialized right ventricle; FRV: Functional right ventricle; AL: Anterior leaflet; SL: Septal leaflet; LA: Left atrium; LV: Left ventricle; asterisk: grade II tethering of the tricuspid septal leaflet.
ICD-10	Q22.5
ICD-9	746.2
OMIM	224700
DiseasesDB	4039
eMedicine	med/627
MeSH	D004437

Ebstein's anomaly is a congenital heart defect in which the opening of the tricuspid valve is displaced towards the apex of the right ventricle of the heart.

Presentation

The annulus of the valve is still in the normal position. The valve leaflets, however, are to a varying degree, attached to the walls and septum of the right ventricle. There is subsequent 'atrialization' of a portion of the morphologic right ventricle (which is then contiguous with the right atrium). This causes the right atrium to be large and the anatomic right ventricle to be small in size.

Risk factors

There may be an increased risk of this abnormality in infants of women taking lithium during the first trimester of pregnancy, (though some have questioned this)^[1] and in those with Wolff-Parkinson-White syndrome.

History

Ebstein's anomaly was named after Wilhelm Ebstein.^[2][3]

Related abnormalities

While Ebstein's anomaly is defined as the congenital displacement of the tricuspid valve towards the apex of the right ventricle, it is often associated with other abnormalities.

Anatomic abnormalities

Typically, there are anatomic abnormalities of the tricuspid valve, with enlargement of the anterior leaflet of the valve.

About 50% of individuals with Ebstein's anomaly have an associated shunt between the right and left atria, either an atrial septal defect or a patent foramen ovale.

Electrophysiologic abnormalities

About 50% of individuals with Ebstein's anomaly have evidence of Wolff-Parkinson-White syndrome, secondary to the atrialized right ventricular tissue.

10-lead ECG of a woman with Ebstein's anomaly. The ECG shows signs of right atrial enlargement, best seen in V1. Other P waves are broad and tall, these are termed "Himalayan" P waves. There is also a right bundle branch block pattern and a first degree atrioventricular block (prolonged PR-interval) due to intra-atrial conduction delay. There is no evidence of a Kent-bundle in this patient. There is T wave inversion in V1-4 and a marked Q wave in III; these changes are characteristic for Ebstein's anomaly and do not reflect ischemic ECG changes in this patient.

Other abnormalities that can be seen on the ECG include (1) signs of right atrial enlargement or tall and broad 'Himalayan' P waves, (2) first degree atrioventricular block manifesting as a prolonged PR-interval, (3) low amplitude QRS complexes in the right precordial leads, (4) atypical right bundle branch block, (5) T wave inversion in V1-V4 and Q waves in V1-V4 and II, III and aVF.^[4]

Management

Pharmacological

Ebstein's cardiophysiology typically presents as an (antidromic) AV nodal reentrant tachycardia with associated pre-excitation. In this setting, the preferred pharmacological treatment agent is procainamide. Since AV-blockade may promote conduction over the accessory pathway, drugs like beta blockers, calcium channel blockers and digoxin are contraindicated.

If there is atrial fibrillation with pre-excitation, treatment options include procainamide, flecainide, propafenone, dofetilide and ibutilide since these medications slow conduction in the accessory pathway causing the tachycardia and should be administered before considering electrical cardioversion. Intravenous amiodarone may also convert atrial fibrillation and/or slow the ventricular response.

References

1. ^ Yacobi S, Ornoy A (2008). "Is lithium a real teratogen? What can we conclude from the prospective versus retrospective studies? A review". Isr J Psychiatry Relat Sci 45 (2): 95–106. PMID 18982835. http://www.psychiatry.org.il/presentation_sender.asp?info_id=53760. 
2. ^ synd/435 at Who Named It?
3. ^ W. Ebstein. Über einen sehr seltenen Fall von Insufficienz der Valvula tricuspidalis, bedingt durch eine angeborene hochgradige Missbildung derselben. Archiv für Anatomie, Physiologie und wissenschaftliche Medicin, Leipzig, 1866, 238-254.
4. ^ Khairy P, Marelli AJ (December 2007). "Clinical use of electrocardiography in adults with congenital heart disease". Circulation 116 (23): 2734–46. doi:10.1161/CIRCULATIONAHA.107.691568. PMID 18056539. http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=18056539. 

External links

Wikimedia Commons has media related to: Ebstein's anomaly

• Ebstein's Malformation information from Seattle Children's Hospital Heart Center
• Overview and diagram at Mayo Clinic
• Information and support for those affected by Ebstein's anomaly
• Resource for Adults living with Ebstein's Anomaly