Aim: To present the various echocardiographic spectrum of Ebstein’s mal-formation in adolescence and adults. Introduction: Ebstein’s anomaly has different anatomic and hemodynamic variables with clinical manifestations of cyanosis, right-sided heart failure and arrhythmias. The leaflet tethering and dysplasia, together with dilatation of the tricuspid valve ring, constitute the anatomic cause of tricuspid regurgitation observed in this condition. Case Reports: The spectrum of leaflet tethering from mild to extreme with varying degrees of tricuspid regurgitation were documented by echocardiography in a 16-year-old cyanotic male with Ebstein’s anomaly associated with an atrial septal defect and mild low tricuspid regurgitation (TR), 22-year-old acyanotic male with right-sided heart failure due to severe tricuspid regurgitation and an intact atrial septum, 55-year-old asymptomatic female with moderate high tricuspid regurgitation. The extreme form was described as an “atretic” mem-brane in a 28-year-old cyanotic male and as a “blanket” of leaflet tissue in a 30-year-old cyanotic male. Conclusion: Ebstein’s anomaly has to be sus-pected clinically in presence of cyanosis with a WPW (Wolf-Parkinson-White) or atrioventricular (AV) block pattern of ECG and its management is complex and must be individualized. RV (right ventricular) exclusion procedures are preferred in advanced cases.
Ebstein’s anomaly is a disease of the entire right ventricle. It is a spectrum of abnormalities, characterized by apical displacement of the valve, anomalous distal attachment of the leaflets, size of the functional right ventricle and degree of tricuspid regurgitation, with alteration in the left ventricle as well. It occurs with a prevalence of about 0.3% to 0.7% among patients with congenital cardiac disease [
In 1988, Carpentier, et al. proposed a classification of Ebstein’s anomaly based on the morphology of right ventricle and tricuspid valve as shown in
The essence of the Ebstein’s malformation is the fact that the tricuspid valve leaflets do not attach normally at the tricuspid annulus [
1) Case 1 (16-year old cyanotic male with Ebstein’s anomaly)
A 16-year old male presented with cyanosis and he had features of an atrial septal defect such as wide, fixed splitting of second heart sound at left second intercostal space and a grade 2/6 systolic murmur at the lower left sternal border. 2D echocardiography revealed the features of Ebstein’s anomaly such as tethering of septal tricuspid leaflet (STL) to the ventricular wall associated with an ostium secundum type atrial septal defect (ASD) and low mild tricuspid regurgitation jet as shown in Figures 1-3.
The patient was advised definite repair with closure of the atrial septal defect.
2) Case 2 (22-year old acyanotic male with Ebstein’s anomaly)
A 22-year old acyanotic male was presented with features of right heart failure and a grade 3/6 systolic murmur at lower left sternal border. 2D echocardiography
Type | Right ventricle | Tricuspid valve |
---|---|---|
A | Small contractile atrialized right ventricle. Adequate-size right ventricle | Moderate displacement of septal and posterior leaflets. Normal anterior leaflet. |
B | Large noncontractile atrialized right ventricle. Small right ventricle | Marked displacement of septal and posterior leaflets. Hypoplastic adherent septal leaflet. Normal anterior leaflet. |
C | Large noncontractile atrialized right ventricle. Very small right ventricle | Marked displacement of septal and posterior leaflets. Hypolastic adherent septal and posterior leaflets. Restricted anterior leaflet motion. |
D | Almost completely noncontractile atrialized right ventricle (except for infundibulum) | Marked displacement of septal, posterior and anterior leaflets. Hypoplastic adherent septal and posterior leaflets. Anterior leaflet is adherent to ventricular wall. |
revealed a normally attached septal tricuspid leaflet (STL), but tethered to the ventricular wall suggesting an Ebstein’s anomaly with severe tricuspid regurgitation swirling around the lateral wall of right atrium and interatrial septum, and a dilated atrium and atrialized RV (right ventricle) as shown in Figures 4-8.
The patient was treated with antifailure measures such as digoxin and diuretics and advised definite repair (Tricuspid valve replacement with right atrial reduction atrioplasty along with plication of atrialized RV (right ventricle).
3) Case 3 (55-year old female with Ebstein’s anomaly)
A 55-year old asymptomatic, acyanotic female, given birth to three children, presented with grade 2/6 systolic murmur at the lower left sternal border. 2D echocardiography revealed a septal tricuspid leaflet tethering and a high moderate tricuspid regurgitation as shown in
The patient was advised periodic follow up since she was remaining asymptomatic.
4) Case 4 (28-year old male with Ebstein’s anomaly)
A 28-year old male presented with cyanosis and auscultation revealed a “sail sound” (loud tricuspid component of first heart sound due to increased tension developed by the large anterior leaflet as it reaches the limits of its systolic excursion―an important sign of anterior leaflet mobility), a “cadence” quality of quadruple rhythm due to wide splitting of first and second sounds (due to complete right bundle branch block), atrial and ventricular filling sounds (summation of these sounds due to prolonged PR interval). ECG revealed the features of Ebstein’s anomaly as shown in
The patient was advised Starnes’ procedure along with Kay annuloplasty and a pacemaker implantation onto left ventricular endocardium.
5) Case 5. (30-year old cyanotic male with Ebstein’s anomaly)
A 30-year old male was presented with marked cyanosis and no murmur and abnormal heart sounds on auscultation. 2D echocardiography revealed the features of Ebstein’s anomaly such as insertion of anterior leaflet into the trabeculated RV, forming a “blanket” of leaflet tissue across the inflow and trabecular parts and bulging of ventricular septum towards leftward due to marked dilatation of RV, and LV became “banana” shaped as shown in Figures 28-30.
The patient was palliated with bidirectional Glenn shunt and advised periodic follow up for an RV exclusion procedure.
6) Case 6. (12-year old male with inverted Ebstein’s anomaly)
A 12-year old, asymptomatic boy was presented with features of an inverted Ebstein’s anomaly on routine echocardiographic screening as shown in
7) Case 7. (Ebstein’s mitral valve in a 10-year old boy).
A 10-year old boy was presented with a grade 1/6 systolic murmur at the apex and blood chemistry revealed a positive ASO (antistreptolysin O) titer, suggesting a rheumatic involvement. 2D echocardiography revealed a displaced anterior mitral leaflet and it is thick, calcified and mildly regurgitant as shown in
The boy was advised penicillin prophylaxis (oral penicillin V 250 mg twice daily) and periodic follow up.
Ebstein’s anomaly was initially described by Wilhelm Ebstein at All-Saints Hospital in Breslau (now Wroclaw), Poland in the autopsy findings of a 19-year old cyanosed laborer, Joseph Prescher who died with a severe malformation of tricuspid valve in July 1864 [
The exact embryology of Ebstein’s anomaly is unknown since the normal tricuspid valve is believed to be formed by a process of either “delamination” of the inner layer of the inlet zone of right ventricle [
In Ebstein’s anomaly, “delamination” fails to occur, resulting in downward displacement of the origin of septal and inferior leaflets and the antero-superior leaflet is mostly “sail-like”, but still attached to its usual atrioventricular junction line and the mechanism for this is not entirely understood [
The leaflets of the tricuspid valve develop equally from the endocardial cushion tissue and myocardium. Endocardial cushion tissue lines the right atrioventricular junction and acts as an adhesive to maintain the integrity of that portion of the subjacent myocardium which forms the tricuspid valve apparatus. Expansion in the size of right ventricular inflow tract occurs by a process called “undermining”. The subendocardial portion of the ventricular free wall becomes fenestrated and spongy since the resorption of the myocardium progressively dissolves the wall and thereby enlarges the chamber size. Undermining and resorption produce a flap-like muscular skirt that is attached at the annulus and is anchored to the underlying ventricular wall by numerous branching pillars of myocardium. Progressive thinning and fibroblastic ingrowth result in the formation of tricuspid valve leaflets as anterior leaflet forms much earlier and it is not adherent to the right ventricular wall. The late forming septal and posterior leaflets remain adherent to the underlying myocardial wall and thus, Ebstein’s malformation is thought to occur as a result of incomplete undermining of the right ventricular myocardium [
Most cases of Ebstein’s anomaly are sporadic and familial incidence is rare [
The malformation documented by Ebstein at autopsy consists of an abnormal insertion of the tricuspid valve, the septal and posterior leaflets were adherent to the ventricular wall and the mobile free parts were displaced towards the apex of the right ventricle. The two anatomic features, i.e., valve displacement and leaflet morphology vary independently and its pathology is not uniform.
Apical displacement was determined as the distance between the anticipated normal basal attachments of the leaflets and the right ventricular apex. The degree of displacement was classified by Becker in 1971 as shown in
The intrinsic abnormality of the tricuspid valve leaflets is generally categorized as “dysplasia” and it usually affects all leaflets with varying degrees as shown in
Apical displacement always affects the septal leaflet and also involves the posterior leaflet. The leaflets are not displaced beyond the junction between the inlet and trabecular parts of the right ventricle and the point of maximum displacement is usually at the commissure between the two leaflets. The spectrum of leaflet tethering varies from mild to extreme. The degree of dysplasia is also categorized as I to III as shown in
When chordae are absent, the free leaflets insert directly into the ventricular wall. In some cases, the greater part of the affected leaflets is firmly adherent to the right ventricular wall, drape the apical trabeculations and completely blended with ventricular wall. The communication between the atrialized and functional right ventricle is confined to slits or perforations in the anterior leaflet as Ebstein originally described. When the anteromedial commissure is fused and the anterior leaflet is intact, the tricuspid orifice is “imperforate” [
Grade | Distance between atrioventricular junction and the apex |
---|---|
Grade 1 | Apical displacement of <10% (or <25%) (the normal septal attachment of the tricuspid valve dipped below the Expected annular attachments) |
Grade 2 | displaced between 10% and 50% (or 25% to 50%) |
Grade 3 | displaced > 50% |
Grade a | focal or diffuse thickening of the leaflets |
---|---|
Grade b | deficient development of chordae and papillary muscle |
Grade c | improper separation of the valve components from the ventricular wall |
Grade d | focal agenesis of valve tissue |
Dysplasia I | Fibromyxomatous thickening |
---|---|
II | Shortening and thickening of the chordate tendineae |
III | leaflet tethering, rudimentary or absent papillary muscles, Fibromuscular histology of anterior leaflet |
in part, so that the inner surface of the inflow part of the right ventricle is formed by a “blanket” of dysplastic valve tissue towards the apex. The leaflets are said to be “plastered” out of the right ventricular myocardium, so that the fibrous transformation of the leaflets from the muscular precursors remain incomplete. In severe cases, the leaflets are thickened, focally muscularized and attached to the underlying myocardium by numerous muscular stumps. In extreme cases, the fusion of leaflet tissue is so complete as a membrane-like continuum and the only identified remnants of leaflet tissue are nodular fibrous ridges at the level of the displaced functional annulus. In this setting, the entire inflow tract is atrialized and the functional right ventricle consists only of trabecular and outflow (infundibulum) components. The designation of “atretic“ Ebstein’s malformation was documented by Kumar [
Echocardiography is the diagnostic test of choice for Ebstein’s anomaly and the first echocardiographic diagnosis was reported by Lundstrom in 1969. The first diagnostic criteria for Ebstein’s anomaly using a multi-crystal two-dimensional system was defined by Hagan in 1974 [
The anterior tricuspid leaflet is not involved in the process of downward displacement, it may be abnormally inserted occasionally as in Figures 1-4 and Shiina, et al documented the apical displacement of anterior tricuspid leaflet in 14% of cases echocardiographically [
In severe cases, the inferior wall of the right ventricle may consists soley of thin fibrous tissue, devoid of myocytes and thereby represent an area of aneurysmal dilatation as in Cases 2 (
The tricuspid orifice is typically incompetent (primary tricuspid regurgitation as in
The functional impairement of right ventricle and regurgitation of tricuspid valve retard the forward flow and the overall effect is right atrial dilatation as shown in
An interatrial communication is present in 80% to 94% of patients with Ebstein’s anomaly [
GOSE score | Index (RA + RV): (RV + LA + LV) | Risk of mortality (%) | |
---|---|---|---|
Grade 1 | Ratio < 0.5 | 0 | |
Grade 2 | Ratio of 0.5 to 0.99 | 10 | |
Grade 3 | Ratio of 1 to 1.49 | 44 - 100 | |
Grade 4 | Ratio ≥ 1.5 | 100 | |
incidence of 4% in clinical series and 12% in autopsy studies. The hearts in which the opening is proximal to the displaced tricuspid valve, a left ventricular to right atrial shunt may occur as shown in
Ebstein’s anomaly of inverted tricuspid valve has been described in 15% - 50% of cases of congenitally corrected transposition of great arteries [
The treatment plan for Ebstein’s anomaly is individualized since the hemodynamic abnormality vary considerably with the extent of tricuspid valve displacement into the right ventricle.
In neonates, the disease process is much different and have a rapidly deteriorating course with severe heart failure, cyanosis and acidosis. If congestive cardiac failure is prominent, infants may require initial support with inotropic agents and long-term anticongestive measures with digoxin and diuretics. The efficacy of angiotensin-converting enzyme inhibitors in patients with Ebstein’s anomaly having right-sided heart failure is unproved and they are not recommended, including angiotensin-receptor blockers (ARBs) and β-blockers, because these drugs may increase pulmonary artery pressure, triggering further heart failure and pulmonary edema [
In newborn infants whose primary problem is that of cyanosis, treatment may be limited to careful observation awaiting its resolution when pulmonary vascular resistance decreases. In early neonatal period, maintanance of the patency of ductus arteriosus is necessary with prostaglandin E1 to ensure adequate pulmonary blood flow.
Occasionally, arrhythmias with or without associated Wolf-Parkinson-White syndrome will be dominant in infants. Treatment is directed primarily towards delaying conduction through the AV node with class I antiarrhythmic agents (quinidine, procainamide, flecainide).
Downward displacement of the septal tricuspid leaflet is associated with discontinuity of the central fibrous body and the septal atrioventricular ring, creating a potential substrate for accessory pathways and preexcitation. The atrialized right ventricle contains right ventricular muscle fibers, which can provoke polymorphic ventricular tachycardia [
“Electrical instability” due to ventricular preexcitation (5% to 25% [
Catheter ablation is difficult due to right atrial dilatation, atrioventricular ring distortion and large continuity of muscle in between the atrium and ventricle. Poor outcomes are mostly attributed to the presence of broad/multiple accessory pathways caused by faulty formation of the insulating tissues at the atrioventricular junction located around the orifice of the malformed tricuspid valves [
Selective right-sided cryo-ablation-Maze procedure may be done for patients with documented paroxysmal flutter or inducible atrial arrhythmias.
Surgical options in Ebstein’s anomaly depend on specific circumstances and the goal should be to palliate for optimum survival, accomplished with valvuloplasty, Valve repair or replacement and right ventricular (RV) exclusion procedures.
It is favoured if the anterior leaflet is suitable for use as a functional monocuspid valve. The leaflet must exhibit adequate excursion and be free of large fenestrations. If the leaflet is “sail-like” and free and when the tricuspid annulus is markedly dilated, an aggressive “Kay annuloplasty” is preferred as for case 4.
A large mobile anterior leaflet with a free leading edge is favourable for valve repair and valve reconstruction was possible in 34.4% of patients with Ebstein’s anomaly. The repair of tricuspid valve was reported in two patients in 1959 and both died [
If there is moderate to severe TR and an adequate sized functional RV, then a complete biventricular repair (Knott-Craig approach) may be considered as for case 2. In this method, the tricuspid valve is repaired and the atrial septal defect is partially closed. A RV to PA valve conduit is used along with tricuspid valve repair and currently, valve repair is preferred over valve replacement whenever feasible in Ebstein’s anomaly
For older patients with persistent cyanosis or congestive cardiac failure, definite repair can be considered. Tricuspid valve replacement along with plication of some part of the atrialized right ventricle and closure of the atrial septal defect is recommended mostly as for case 1. Valve replacement may be done either a bioprosthetic (preferred) as for case 2 or mechanical valve. A regurgitant tricuspid valve was successfully replaced in Ebstein’s anomaly as a first time in 1962 [
It is the reintegration of the atrialized chamber into the right ventricular cavity, which can be obtained by orthopic transposition of the detached septal and posterior leaflets of the tricuspid valve. The reimplanted septal leaflet serves as an opposing structure for the coaptation of the reconstructed atrioventricular valve [
When there is greater than 50% delamination of the anterior leaflet and a usable posterior leaflet, cone reconstruction is a preferred technique and it is closest to an “anatomic repair” [
The significant leaflet tethering, i.e., adherence of the edge or body of the leaflet to the underlying endocardium, makes the successful repair more difficult. The presence of a dilated right-sided pumping chamber (the functional RV) is also considered as an ominous sign, usually impairing the surgical results.
RV exclusion approach was first reported by Starnes and associates in 1991. The procedure included patching of the tricuspid valve and a modified Blalock-Taussig shunt. RV exclusion procedure should be indicated for the more severe end spectrum where there is diminutive true RV, highly laminated leaflet tissue and a marked dilatation of right ventricle impinging on the left ventricular function as in case 5. The RV exclusion technique decompresses the right side, allow the left ventricle to function more effectively and decrease the incidence of atrial arrhythmias by eliminating the right atrial enlargement. RV exclusion with a fenestrated tricuspid valve patch and a systemic-to-pulmonary shunt provide an effective palliation for neonates presenting with critical Ebstein’s anomaly who had a poor outcome, but with an adequate LV size. In patients with small RV and mild TR, A modified Blalock-Taussig shunt (mBTS) is preferred. If there is moderate to severe TR and the functional RV is small, then a fenestrated RV exclusion (Starnes’ procedure) should be performed. The Starnes’ procedure consists of a patch closure of the tricuspid valve orifice, enlarging the interatrial communication and placing a systemic-to-pulmonary artery shunt. This approach is particularly helpful in patients who also have an anatomic right ventricular outflow tract obstruction. The total RV exclusion is a modification to Starnes’ procedure, proposed by Sano and associates, in which the free wall of the right ventricle is resected and closed primarily with a polytetrafluro ethylene patch and it acts like a large RV plication.
Few patients may undergo a successful valve repair and also a potential for one and half ventricular repair after palliation by RV exclusion. The downside of RV exclusion procedure is a commitment to the single-ventricle Fontan pathway. In very severe cases, with massive right ventricular dilatation and dysfunction, the Fontan procedure may be applicable. Conversion to a single-ventricle approach for symptomatic neonates also had been advocated [
Chauvaud suggest that a paper thin right ventricular wall is an indication that a Glenn shunt might be needed [
For severe cases of Ebstein’s anomaly associated with left-sided obstructive lesions, transplantation should be considered. However, heart transplantation is rarely necessary in the current era because of improved results with Knott-Craig and Starnes’ approaches in the most severe forms of Ebstein’s anomaly [
The clinical course of Ebstein’s anomaly ranges from intrauterine death to asymptomatic survival into late adulthood. The outlook for fetal Ebstein’s anomaly has been aptly characterized as “appalling” [
Besides the fact that patients with milder form of the disease can live well into adulthood, woman become pregnant and deliver normal term infants in most cases [
Ebstein’s original case was an example of obstruction at the tricuspid orifice by a membrane dividing the right ventricle into two halves as shown in
On follow-up, cases 1 and 2 showed no further deterioration and cases 3, 6, 7 remain asymptomatic. Cases 4 and 5 are referred to surgical interventions.
Ebstein’s anomaly is a rare congenital heart defect occurring in 1 in 20,000 live births in general population. [
Muthiah, R. (2018) Ebstein’s Anomaly―An Overview. Case Reports in Clinical Medicine, 7, 90-125. https://doi.org/10.4236/crcm.2018.72009