Ebstein’s Anomaly - Review

NEERAJ VARYANI

HistoryWilhelm Ebstein – German

physician(1866) presented account titled “On a Very Rare Case of Insufficiency of the Tricuspid Valve Caused by a Severe Congenital Malformation of the Same”.

By 1950 only 3 case reports had been published.

Figure from Ebstein’s case report

Prevalence1 in 200,000 live births. 1% of all

cases of CHD.

40% of congenital malformations of tricuspid valve.

Pathologic Anatomy

Normally 3 leaflets : anterior, inferior(posterior) and septal.

Anterior : semicircular or quadrangular and

Posterior: scallopedSeptal : attaches ventricular septum

and posterior wall of right ventricle. Apical displacement of basal attachment compared to mitral valve : 15mm in children, and 20mm in adults.Normally < 8mm/m2.

Contd…Leaflets develop equally from

endocardial cushion and myocardium.

Leaflets and tensile apparatus develop from delamination of the inner layer of inlet zone of ventricles.

Ebstein ‘s anomaly : DELAMINATION FAILURE.

Mechanism unknown probably TV leaflets displacement.

Ebstein’s characteristicsAdherence of septal and inferior

leaflets to myocardium.Apical displacement of functional

annulus(septal>inferior>anterior).Dilatation of “atrialized” RV

(ARV).Devoid of muscular tissue.Redundancy,fenestrations, and

tethering of the anterior leaflet.Dilation of the right AV junction.

CARDIOMEGALY CAUSED BY RIGHT SIDED CHAMBER DILATATION

Tricuspid ValveTV morphology in ebstein’s is variable.Tricuspid orifice is typically

incompetent,occasionally stenotic and rarely imperforate.

Anterior Leaflet: In ebstein’s redundant and may contain several fenestrations and chordae tendineae are short and malformed.Anterior leaflet mobile tissue may get displaced into RVOT.

Inferior and septal leaflet development is variable.

Apical displacement is maximal at inferior and septal leaflets commisure.TV annulus is dilated but not displaced.

RCA demarcates true annulus and is vulnerable to kinking during RV plication,annuloplasty or TV replacement.

THE RANGE OF VARIABILITY IS INFINITE.

Ebstein’s malformation of TV

TRICUSPID VALVE WITH LEAFLETS IN ONE PLANE

Right VentricleRV in ebstein’s divided into 2 regions:1. Inlet portion : involved in malformation2. Trabecular and outlet portions: not

involved ARV dilated > half RV volume instead

of usual < one- third. >2/3 of ebstein’s heart have RV

dilatation involving both portions leading in some cases to D shaped or crescent shaped LV.

Classifications Difficult as no two hearts are alike. Echocardiographic appearance:

mild, moderate and severe according to : Extent of apical displacement, degree of TR, degree of RV dilatation and dysfunction.

Four types based on anatomic findings during surgery.

1988 Carpentier et al. 4 types:

Type A : true RV volume adequate

Type B: large ARV but mobile anterior leaflet

Type C: anterior leaflet movement restricted causing RVOT obstruction.

Type D: complete atrialization

Celermajer et al.ECHO GRADING

For neonates with ebstein’s anomaly the Great Ormond Street Echocardiography (GOSE)score

Ratio of combined area of the RA and ARV is compared to the functional RV and left heart.

o Grade 1 : ratio < 0.5o Grade 2 : ratio of 0.5 to 0.99o Grade 3 : ratio of 1.0 to 1.49o Grade 4 : ratio ≥ 1.5

Genetic FactorsMost cases are sporadic hence males

and females are equally affected; familial ebstein’s anomaly is rare.

Cardiac transcription factors: NKX2.5 mutation, 10p13-p14 deletion and 1p34.3-p36.11 deletion.

MYH 7 mutation in subset with LV noncompaction and this warrants genetic testing and family evaluation.

Environmental and reproductive factors

More common in twins

Family history of congenital heart disease

Maternal exposure to lithium( 28 fold increased risk) and benzodiazepines.

Associated Cardiac Defects

Interatrial septal defects: patent PFO or ASD mostly secundum type present in 80% to 94%

VSD with or without pulmonary atresia.RVOT obstruction: pulmonary valve

stenosis or pulmonary atresia, branch pulmonary artery stenosis and rarely displaced TV.

Patent ductus arteriosusCoarctation of aorta

Accessory pathways:15% to 20% patients.Majority around orifice of malformed TV.

Left side heart lesions: 39% patientso Diastolic and systolic dysfunctiono Mitral valve prolapseo Subaortic stenosiso Bicuspid or atretic aortic valveo Muscle bands of LVo Myocardial changes resembling LV

noncompaction

Congenitally corrected transposition of the great arteries(cc-TGA):

o 15% to 50% of cc-TGA have ebstenoid displacement of morphologic TV but lack ARV and dilated morphologic RV unlike right sided ebstein anomaly.

Pathophysiology

Functional impairement of RV and TR retard forward flow.

ARV acts as a passive reservoir during atrial systole and ballons out decreasing volume of ejected blood.

RA dilates increasing size of interatrial communication.TR increases with annular dilatation.

Symptomatic neonates have massive cardiomegaly with lung hypoplasia.

Contd…Decreased forward flow leads to

physiologic pulmonary atresia and child is duct dependent.

LV output is compromised in sick neonates with severe cyanosis and acidosis.

Mild cyanosis may not be noted till adult life .

Clinical Presentation

Varies widely Symptoms are related to anatomic

severityMost common presentation varies with

age at presentationo Fetuses- abnormal routine prenatal

scan(86%). Ebstein’s anomaly is common lesion referred for fetal echocardiography because severe forms lead to cardiomegaly,hydrops and tachyarrhythmias.

Contd..

o Neonates- cyanosis(74%)

o Infants-heart failure(43%)

o Children- incidental murmur(63%)

o Adolescents and adults- arrhythmia(42%),decrease exercise tolerance , fatigue or right sided heart failure

Symptoms

o Cyanosis and Heart failureFrom TRTRANSIENT NEONATAL CYANOSIS:

appears soon after birth due to high pulmonary vascular resistance and improves as pulmonary vascular resistance decreases.

May appear first during pregnancy

o Exertional Dyspnea, Fatigue,Cyanosis(50% cases), AND Palpitations

May occur at a later ageMay recur and may be insidious in

onseto PalpitationsDue to atrial tachyarrhythmiasPresent in 20%-30% casesSome may be due to WPW

Paradoxical Embolization:leading to brain abscesses and sudden death

Chest pain – enigma.Retrosternal,sharp,shooting suggesting serous origin (fibrinous pericardium over ARV.

Physical Examinationo Vary with severity of pathology

and magnitude of right to left shunting.

Precordial asymmetry usually left parasternal prominence occasionally right anterior chest wall because of enlarged RA

Murmur and clickCyanosis: digital clubbing will

depend on degree of cyanosis

JVP: prominent “a” wave but large V wave is rare despite severe TR because large RA engulfs increased volume ,thin walled toneless ARV and as TR is low pressure and hypokinetic.

Hepatomegaly:passive hepatic congestion and is pulsatile .

Palpable prominent diffuse apical impulse

Systolic thrill at the left lower sternal border

First heart sound: widely split due to RBBB,hypokinetic RV,large size and increased excursion of anterior leaflet requiring longer time to reach fully tensed closed position.Single S1 (T1) due to prolonged PR and preexcited RV.Loud T1 (sail sound) sign of anterior leaflet mobility.

Second heart sound: widely split due to RBBB. Single S2 (A2) due to low pressure in pulmonary trunk.Paradoxical split due to preexcited RV

Prominent S3 and/or a loud S4 give the impression of multiple heart sounds (triple or quadruple gallop)

Systolic murmur: from TR ,decresendo,grade 2/6 to 3/6 ,prominent in leftward location towards apex, intensity increases with inspiration . Mid-diastolic murmur due to high diastolic flow volume.Soft or absent in adults because of low velocity to- and –fro flow and rapid equalization of pressure across TV

Diagnostic Evaluation

Chest Radiography: normal to globe shaped with narrow waist(pulmonary trunk is not border forming and ascending aorta is small or absent.

CT ratio > 0.65 indicates poor prognosis.Infundibulum straightens the left cardiac

border or forms a convex borderLungs fields may be normal or decreased

due to hypoplasiaMOST CONSISTENT FEATURE IS

ENLARGED RA SILHOUETTE

CHEST RADIOGRAPH OF EBSTEIN’S ANOMALY

Electrocardiography

Ebstein’s anomaly may be diagnosed using ECG

Rarely normal even with a mild anomaly.

Rarely and oddly ECG may be normal even when the anomaly is severe

Major findings are: Intraatrial conduction disturbance: right

atrial P wave(Himalayan)and prolonged PRAtrioventricular nodal conduction:

prolonged PR Infranodal conductionIntra-His or infra-His conduction

abnormalityRBBBBizarre second QRS attached to preceding

normal QRS

ECG OF EBSTEIN’S ANOMALY

WPW preexcitationSupraventricular tachycardiaAtrial fibrillation or flutterArrhythmogenic ARVDeep Q waves in leads V1-V4 and

inferior leadsComplete heart block is rare but

first degree AV block occurs in 42% patients.

Echocardiography

2D echocardiography is the diagnostic test of choice

3D echocardiography provides additional details of TV anatomy and size and function of different cardiac chambers.

Apical displacement of septal leaflet by at least 8mm/m2 body surface area is the diagnostic feature

ECHOCARDIOGRAM OF PATIENT WITH EBSTEIN’S ANOMALY

Presence of at least three accessory attachments of leaflets to the ventricular wall confirms tethering.

Marked enlargement of RA and ARV is present when combined area of RA and ARV is larger than combined area of functional RV ,LA and LV in apical 4 chamber view in end diastole.

Helps assess site and degree of TR and feasibility of its repair.

Ebstein’s anomaly can be diagnosed in utero as early as 18th week of pregnancy.

Patency of RVOT and GOSE score can predict outcome in neonatal ebstein’s anomaly

Cardiac CatheterizationRarely required apart from

preoperative coronary angiography in older patients

Required in patients with LV dysfunction and suspected elevated pulmonary artery pressure and elevated LVEDP. Important if bidirectional cavopulmonary anastomosis is being considered.

Magnetic Resonance ImagingQuantitative measurement of RA

and ventricular size and function in presence of distorted RV anatomy.

Axial imaging provides new expressions of disease severity such as atrialized RV volume.

3D images provide greater dilineation of disease severity

MANAGEMENT

Neonatal EbsteinPoor prognosis: 2o% to 40% do not

survive 1 month and less than 50% survive to 5 years.

Surgery required in presence of heart failure or cyanosis. Options include: (a)biventricular repair(Knott-Craig approach), (b) single ventricle pathway with right ventricular exclusion ( Starnes’ approach), and , rarely, (c) cardiac transplantation

Biventricular repair( Knott-Craig approach):TV repaired and atrial septum partially closed along with routine right atrial reduction.High early mortality (25%) intermediate outcome is promising.

Right ventricular exclusion Starnes approach: useful with RVOT

obstruction (a) fenestrated patch closure of the TV orifice, (b) enlarging the interatrial communication, (c) right atrial reduction, (d) placing systemic to pulmonary artery shunt

Modified Starnes Repair( Total Ventricular Exclusion): RV free wall is resected and closed primarily.

Cardiac Transplantation:rarely performed in current era.Option in patients with significant LV dysfunction.

Management in Children and AdultsMedicalBacterial endocarditis prophylaxisThose not candidates for surgery

managed with ACEI’s and heart failure regimes.

Arrhythmias managed medically with operative or catheter based interventions

Catheter Ablation: success rate is lower.Atrial fibrillation and flutter are treated surgically at the time of operation.

SurgeryIndications:symptoms ,cyanosis and

paradoxical embolization, decreased exercise performance, progressive increase in cardiothoracic ratio, progressive right ventricular dilatation and dysfunction, onset and progression of arrhythmias,NYHA class III or IV symptoms and echocardiographic probability of successful valve repair.

Principles of surgeryClosure of intracardiac

communicationsTV repair or replacementAblation of arrhythmiasPlication of ARVReduction right atrioplastyRepair of associated defects

TV RepairMayo Clinic Experienceo Danielson Repairo Modified Danielson repairBRAZIL Experience(da Silva

Approach):cone repair;most anatomic repair.

FRENCH EXPERIENCE (BROUSSAIS Approach)

Ventriculization procedure

Tricuspid Valve Replacement

If TV repair not feasible Porcine bioprosthetic valve is

good alternative over mechanical valve due to good durability and lack of need for anticoagulation.

TV REPLACEMENT TECHNIQUE

oOne and Half Ventricle repair BDCPA: reduces venous return to

dysfunctional enlarged RV and provides preload to LV.

Indications for BDCPA:Severe RV enlargementD shaped LVModerate TS(mean gradient

>6mmHg)RA/LA pressure ratio > 1.5 Preoperative cyanosis at rest or with

exercise

o Disadvantages of BDCPA:Pulsations of head and neck veinsFacial swellingDevelopment of pulmonary AV

fistulaeCompromised access to the heart

using internal jugular vein approach

o Plication of ARV ADVANTAGES: (a) decreases size

of nonfunctioning RV, (b) minimizes pancake effect of RV on LV.

Potential risk of RCA injury o Right reduction atrioplasty:

performed routinely. Avoid suture in crista terminalis.

Surgical Treatment of ArrhythmiasIn atrial fibrillation right sided cut

and sew lesions of Cox-maze III procedure

Bilateral maze done in chronic AF, LA dilation and MR.

In atrial flutter right atrial isthmus lesion is added.

AVNRT unsuccessful ablation in preoperative EP laboratory treated by perinodal cryoablation

Heart Transplantationo In presence of severe

biventricular failure ( LV Ejection Fraction < 25%), severe LV dilatation and severe MR with LV dysfunction.