Ebsteins anomaly
Comments Ebstein's malformation of the tricuspid valve is characterized by displacement of
the septal and posterior leaflets of the tricuspid valve downward into the right ventricle
(RV) to varying degrees. The portion of the RV proximal to the valve is called 'atrialized
RV'. The anterior leaflet of the valve is usually normal but can be affected. The valve's
annulus is normally located. The anatomy of the leaflets is variable and the chordal
attachments are abnormal.
CLINICAL CONSIDERATIONS Ebstein's malformation
Prevalence of Ebstein's malformation of the tricuspid valve is 0.5% of all congenital heart
disease. There is an equal distribution among males and females and most cases occur
sporadically. An association with lithium ingestion during pregnancy has not been
confirmed.
Ebstein's malformation of the tricuspid valve is characterized by displacement of the
septal and posterior leaflets of the tricuspid valve into the RV to varying degrees; the
portion of the RV below the valve is called 'atrialized RV'. The anterior leaflet of the
valve is usually normal but can be affected. The valve's annulus is normally located. The
anatomy of the leaflets is variable and chordal attachment is abnormal. Associated lesions
include interatrial communications in most cases, VSD's, pulmonary stenosis or atresia, and
more rarely tetralogy of Fallot or coarctation of the aorta may also occur. Physiology
depends on the degree of anatomical deformity. With mild degrees of displacement there is
almost no regurgitation. If there is severe insufficiency, the presence or abscence of an
atrial communication is determinant. If there is an atrial level communication there may be
cyanosis due to right to left shunting; if there is not an atrial level communication right
atrial pressures rise and the symptoms are secondary to systemic venous congestion. The RV
size is also important and in extreme cases the RV may be unable to pump blood into the
lungs, especially in the newborn period, causing functional pulmonary atresia.
Clinical features depend on the degree of malformation and dysfunction of the valve.
Manifestations include cyanosis, dyspnea on exertion, arrhythmias (SVT, atrial flutter or
fibrillation, wandering pacemaker or ventricular ectopy).
Physical exam is characterized by cyanosis, jugular venous distention, diffuse heart
impulse, systolic thrill at left sternal border, normal or decreased S1, split S2,
prominent S3, S4, and mid-diastolic murmur secondary to true or relative tricuspid
stenosis. ECG shows right atrial enlargement, WPW in 20-30% of the patients, RBBB in
patients with no WPW, or RVH. The chest x-ray can be normal in mild cases, but it usually
shows severe cardiomegaly with prominent RA border, straight or convex left heart border
secondary to dilated or displaced RVOT and decreased pulmonary vascular markings.
Echocardiography allows visualization of the lesion showing the abnormally displaced
tricuspid valve and assessment of the degree of insufficiency or stenosis.
Cardiac catheterization is usually not needed because of diagnostic non-invasive methods.
Treatment can be categorized into medical and surgical. The former includes the use of
prostaglandins to maintain ductal patency to assure pulmonary blood flow, management of
congestive heart failure and pharmacologic management of arrhythmias. Frequently, neonatal
symptoms of cyanosis improve as the pulmonary vascular resistance falls, and their is
better forward flow from the right ventricle into the pulmonary artery. Nitric xide might
improve pulmonary blood flow in patients with Ebstein's by reducing pulmonary vascular
resistance. Surgical treatment includes paliative procedures (systemic to pulmonary artery
shunts). or correction with valvuloplasty or valve replacement. Ablation of accessory
pathways can be achieved in the catheterization laboratory or intraoperativley. Prognosis
depends on the degree of valve displacement and presence of associated lesions.
Long axis view shows the enlarged, 'atrialized' RV with a downward
displaced tricuspid valve.
Short axis view shows the enlarged RV with a 'D'-shaped
interventricular septum.
4 chamber view shows the enlarged, 'atrialized' RV with a downward
displaced tricuspid valve.
4 chamber color doppler shows the incompetence of the downward
displaced tricuspid valve.
Long axis view shows the enlarged, 'atrialized' RV with a downward displaced
tricuspid valve.
Short axis view shows the enlarged RV with a 'D'-shaped interventricular
septum.
4 chamber view shows the enlarged, 'atrialized' RV with a downward displaced
tricuspid valve.
Aside from needing a pacemaker, this patient's xray shows little obvious right cardiac
border enlargement and there are normal pulmonary vessels.
