Ebstein’s anomaly

Ebstein's anomaly

• Ebstein’s anomaly was named after Wilhelm Ebstein, who in 1864 described the heart of the 19 year old Joseph Prescher.

Incidence/prevalence

• 2.4 per 10,000 live births.

• Accounts for 0.3% to 0.7% of all cases of congenital heart disease.

• It represents about 40% of congenital malformations of the Tricuspid valve.

Normal TV• The semicircular or quadrangular anterior leaflet is the

largest of the three.

• The posterior leaflet is scalloped.

• The septal leaflet attaches chiefly to the ventricular septum.

• The septal leaflet normally exhibits a slight but distinct apical displacement of its basal attachment compared with the mitral valve: 15 mm in children, and 20 mm in adults.

Basic anatomic anomaly?

Pathological Anatomy• EA is a malformation of the tricuspid valve and

right ventricle characterized by

(1) Adherence of the septal and posterior leaflets to the underlying myocardium

(2) Downward(apical) displacement of the functional annulus (septal>posterior>anterior)

Pathological Anatomy

(3) Dilation of the “atrialized” portion of the right ventricle, with various degrees of hypertrophy and thinning of the wall

(4) Redundancy, fenestrations, and tethering of the anterior leaflet; and

(5) Dilation of the right atrioventricular junction (true tricuspid annulus)

DELAMINATION

• Normal myocardial development – Delamination begins at tips of leaflets and reaches toward the AV junction

• A normal, completely delaminated leaflet wil have hinge point at or near the anatomic tricuspid valve

• Failure of delamination (namely splitting of the tissue by detachment of the inner layer during embryologic development) results in leaflets that variably adhere to the underlying myocardium

Downward Displacement

• Functional orifice gets shifted towards RV apex or into RV outflow tract

• Not just linear shift it is rotational or spiral in nature

• Adhered portions have little or no motion• Large coaptation defect – severe TR• Septal hinge point is inferior to attachment

point of anterior mitral leaflet

Displacement Index

• Distance between the two septal hinges in the four chamber view is divided by patients body surface area to caluculate a “Displacement Index “

• Index values >8 mm/m2 - distinguish EA from others

• Downward displacement of STL is associated with discontinuity of central fibrous body and septal AV ring - potential substrate for accessory pathways and preexcitation

• Associated with WPW type B – rt sided pathways are more common

RT Heart – 3 components

• RA Proper

• Inlet portion of RV [Atrialized]

• Trabecular and outlet portion[Functional RV]

• The greater the apical displacement of the posterior and septal leaflets, the larger the atrialized RV and the smaller the functional RV.

Atrialized RV

• Thin walled

• Devoid of muscle tissue

• Dilated often aneurysmally[1/2 of RV volume]

• Paradoxical expansion in systole –passive reservoir

Functional RV

• An absolute decrease in the number of myocytes .

• An increase in fibrosis

• Both responsible for infundibular dilation

Communication between atrialised RV and functional RV?

• Free communication

• Slits or perforations in the ATL

• Separated by a muscular partition or shelf that restricts flow

• Anteromedial commissure is fused and the ATL is intact, the tricuspid orifice is imperforate.

• Two thirds of hearts - show dilated right ventricles.

• Dilatation involves not only the atrialized inlet portion of the right ventricle but also the functional right ventricular apex and outflow tract.

• Right ventricular dilatation is so marked that the ventricular septum bulges leftward, compressing the left ventricular chamber.

• In extreme cases, episodic left ventricular outflow tract obstruction can occur.

• Most patients have RV dysfunction (both atrialized and functional ventricle)

• More than a valve disease – a cardiomyopathy

Anterior leaflet

• Redundant

• Contains muscular strands

• Mobility is impaired – thickening, nodularity, fibrosis and multiple short chordae

• Described as SAIL – LIKE

Abnormalities of Left heart

• Seen in 39% cases

1. Derangements in left ventricular geometry2. Impairment of systolic and diastolic function3. Noncompaction4. MVP5. Accessory MV Tissue6. Bicuspid / atretic AV7. Subaortic stenosis

Associated cardiac defects

• ASD or PFO• VSD with or without PA• RVOTO• PDA• COA• AP 15-20% cases around malformed TVO• CCTGA Lt sided Ebstenoid TV.

ClassificationAttenhofer Jost CH et al: Based on

mild/moderate/severe apical displacement,TR and RV size

Carpentier classification(on surgery table finding):A,B,C,D

Danielson GK(Based on Carpentier classification):I,II,III &IV

Carpentier et al classification • Type A – volume of rt ventricle is adequate

• Type B – large atrialised component of the right ventricle. Anterior leaflet moves freely

• Type C – anterior leaflet is severely restricted and causes significant obstruction to RVOT

• Type D – complete atrialisation of the ventricle with the exception of small infundibular component

Carpentier et al

Danielson GKI II III IV

The ATL is larger and mobile but the posterior and STL are apically displaced, dysplastic, or absent. The ARV size varies from relatively small to large.

The anterior, posterior, and often septal leaflets are present, but are relatively small and displaced in a spiral fashion toward the apex. The atrialized ventricular chamber is moderately large.

The ATL is restricted motion with shortened, fused, and tethered chordae. Direct insertion of papillary muscles into the anterior leaflet is frequently present. The posterior and septal leaflets are displaced, dysplastic, and usually not reconstructable. The ARV is large.

The ARV is severely deformed and displaced into the RV outflow tract. PTL is typically dysplastic or absent, and the septal leaflet is represented by a ridge of fibrous material descending apically from the membranous septum. TV displaced into the RVOT and may cause obstruction of blood flow (functional tricuspid stenosis). RV=ARV

Physiological consequences- determinants

• Morphologic derangement of the tricuspid leaflets

• Hemodynamic burden imposed on an inherently flawed right ventricle

• Left ventricular function

• Atrial rhythm

• The tricuspid orifice is typically incompetent, occasionally stenotic, and rarely imperforate.

• The thin-walled atrialized RV is either passive or functions as an aneurysm –expands paradoxically in systole.

• Functional impairment of the RV depends on the severity of TR , size of the RA and atrialized RV relative to the size of the functional RV.

• Atrial tachyarrhythmias have serious physiologic implications with Accessory pathways.

Rt to Lt shunt

• Neonates [ high PVR]

• Old age - RV Filling pressure ↑

• Stenotic/imperforate - T.orifice

EM Properties –basis for clinical diagnosis

Mechanical stimulation of ARV- PVT

• Clusters of ventricular cardiomyocytes are isolated within a fibrous matrix .

• It prevents spiral/scroll reentrant waves from anchoring.

• When spiral/scroll waves do not anchor, they meander erratically as polymorphic ventricular tachycardia.

LV function affected

• Geometric distortion of the ventricle

• Reduced end-diastolic volume

• Paradoxical motion of the ventricular septum

• An increase in fibrous tissue, and a decrease in cardiomyocytes in the free wall and septum.

History

• Males and females are equally affected

• Familial Ebstein’s anomaly has been reported( more common in twins and in those with family history of CHD

• Relative risk of Ebstein’s anomaly is increased by 28fold in offspring exposed to in utero lithium carbonate.

• Maternal exposure to benzodiazepines

Genetic factors

• NKX 2.5 mutations

• 10 p13-p14 deletion

• 1p34.3-p36.11 deletion

• MYH7 gene mutation

Clinical presentation

• Most common age related presentations1 - Detection of anomaly in a routine fetal ECHO2 - Neonatal cyanosis3 - Heart failure in infancy4 - Murmur in childhood5 - Arrhythmias in adolescents and adults

Clinical Presentation

• Foetus – poor prognosis – cardiomegaly, hydrops, pulmonary parenchymal hypoplasia,tachyarrhythmias

• Neonates –congestive heart failure due to tricuspid valve regurgitation, cyanosis, and marked cardiomegaly caused by right heart dilation.

• Neonates – 20 to 40% donot survive 1 month , <50% survive – upto 5 years.

• Symptomatic children with Ebstein’s anomaly may have progressive rightsided heart failure, but most will reach adolescence and adulthood

• In subjects <2 years old at presentation, a haemodynamic problem is more common than in older patients (72% versus 29%, p <0.01).

• In subjects >10 years old at presentation, an electrophysiological problem is more common than in younger patients

Clinical Presentation

• Adults - arrhythmias , progressive cyanosis, decreasing exercise tolerance, fatigue, or right-sided heart failure

• Exercise tolerance depends on – Oxygen saturation and heart size

SCD• Threat regardless of severity of the anomaly

• Responsible for the decline in survival rate in the fifth decade

• WPW - Atrial flutter or fibrillation with accelerated conduction -major increase in the risk of SCD.

• Arrhythmogenic ARV - Spontaneous VT/fibrillation looms as a threat.

• The onset of chronic AF prefigures death within 5 years.

Chestpain • Is an enigma.

• The pain is retrosternal, epigastric or in the right or left anterior chest.

• It is sharp, stabbing, or shooting, features that suggest serous surface origin.

• A fibrinous pericardium has been found at necropsy over the atrialized RV.

Paradoxical Embolisation

• In the presence of an interatrial communication, the risk of paradoxical embolisation, brain abscess and sudden death is increased

Pregnancy • Poorly tolerated

• Cyanosis may first become manifest.

• Hypoxemia increases the risk of fetal wastage.

• A right-to-left interatrial shunt incurs a puerperal risk of paradoxical embolization.

• PAT are potential hazards during pregnancy especially with AP.

Physical appearance • Growth and development are normal - in patients

asymptomatic as neonates and infants.

• Persistent cyanosis or intermittent exercise-induced cyanosis occurs in > 50% of cases.

• Clubbing

• Precordial asymmetry - usually left parasternal prominence, but occasionally the right anterior chest is prominent( enlarged Rt atrium ).

Pulse

• Pulse is normal

• Decreases when ventricular stroke volume falls

JVP

• Prominent C wave• Preserved X descent /normal V waves despite severe TR

– damping effect of rt atrium and atrialized ventricle ,TR is low pressure and hypokinetic

• Gaint A wave – stenotic/imperforate TV• Prominent A and V - RHF

Inspection and palpation

• Precordial asymmetry• LVI • Absent systolic impulse over inflow portion of

RV – negative sign • Systolic impulse –L3ICS-Infundibular dilation.• RVI ,Tricuspid systolic thrill – neonates.

Percussion

• Cardiac dullness beyond RT parasternal border by 2-3 cm where it merges with liver dullness due to RAE

AUSCULTATION• S1 – Wide split

• M1 – T1 ,Loud and delayed T1[Sail sound]

• Delayed T1 – Complete RBBB, Hypokinetic RV, Large and increased excursion and tension of ATL .

• PR prolongation – soft M1

• Preexcitation of RV – Early loud T1 /Buried M1

37 female acyanotic

S2

• Often Single – P2 inaudible –low pressure in PT

• Wide split S2 – complete RBBB• Little variation with respiration • Paradoxical split S2 – RV preexcitation

S3 /S4

• Produce a distinctive triple or quadruple rhythm

• Often summate because of PR interval prolongation

• May increase during inspiration• Sometimes sufficiently prolonged to produce

short diastolic murmurs

Opening sounds

• Early diastolic sounds with the timing of opening snaps have been described .

• Attributed to opening movements of the large mobile ATL.

Systolic murmur -TR

• Low pressure TR from hypokinetic low pressure RV

• Soft, decrescendo, medium frequency, grade 2 to 3/6 intensity, prominent leftward location towards apex, no increase with inspiration

17y old acyanotic /prominent murmur near apex.

• However, in neonates with Ebstein’s anomaly, the TR murmur is holosystolic because right ventricular systolic pressure is elevated.

• The timing and quality of systolic and diastolic murmurs occasionally create the impression of a pericardial friction rub.

• Hepatomegaly – uncommon

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