(Circulation. 2007;115:277-285.)
© 2007 American Heart Association, Inc.
Congenital Heart Disease for the Adult Cardiologist |
From the Divisions of Cardiovascular Diseases (C.H.A.J., H.M.C.), Cardiovascular Surgery (J.A.D.), and Anatomic Pathology (W.D.E.), Mayo Clinic, Rochester, Minn.
Reprint requests to Heidi M. Connolly, MD, Division of Cardiovascular Diseases, Mayo Clinic, 200 First St SW, Rochester MN, 55905.
Key Words: atrium heart defects, congenital hemodynamics pathology pediatrics
| Introduction |
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1 per 200 000 live births and accounting for <1% of all cases of congenital heart disease.26 This anomaly was described by Wilhelm Ebstein in 1866 in a report titled, "Concerning a very rare case of insufficiency of the tricuspid valve caused by a congenital malformation."7,8 The patient was a 19-year-old cyanotic man with dyspnea, palpitations, jugular venous distension, and cardiomegaly.7,8 At autopsy, Ebstein described an enlarged and fenestrated anterior leaflet of the tricuspid valve. The posterior and septal leaflets were hypoplastic, thickened, and adherent to the right ventricle. There was also a thinned and dilated atrialized portion of the right ventricle, an enlarged right atrium, and a patent foramen ovale9 (Figure 1). By 1950, only 3 cases of this anomaly had been published.8,10,11
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| Pathological Anatomy |
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The apical displacement of the hinge point of the valve in Ebsteins anomaly from the atrioventricular ring is shown in Figure 2.12,1517 The point of maximal displacement is at the commissure between the posterior and septal leaflets of the tricuspid valve.16 In normal human hearts, the downward displacement of the septal and posterior leaflets in relation to the anterior mitral valve leaflet is <8 mm/m2 body surface area.6 The spectrum of the malformation in Ebsteins anomaly may range from only minimal displacement of the septal and posterior leaflets to an imperforate membrane or muscular shelf between the inlet and trabecular zones of the right ventricle.
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The anterior leaflet is generally redundant and may contain several fenestrations.6 Its chordae tendineae are generally short and poorly formed. Moreover, the anterior leaflet of the tricuspid valve may be severely deformed, so that the only mobile leaflet tissue is displaced into the right ventricular outflow tract, where it may cause obstruction or form a large sail-like intracavitary curtain. Typical autopsy examples of Ebsteins anomaly are shown in Figures 3 and 4
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In Ebsteins anomaly, the right ventricle is divided into 2 regions: the part directly involved with the malformation (ie, the inlet portion), which is functionally integrated with the right atrium, and the part that is not involved by the anomaly, which consists of the other 2 components of the right ventricle, namely the trabecular and outlet portions, that constitute the functional right ventricle. The "atrialized" portion of the right ventricle (ie, the inlet component) can become disproportionately dilated and may account for more than half of the right ventricular volume in extreme cases instead of the usual one third of the total right ventricular volume. There is often marked dilatation of the true tricuspid valve annulus, which is not displaced, and a large chamber separating this true annulus from the functional right ventricle (atrialized portion of the right ventricle)6,12 (Figure 2). The right coronary artery demarcates the level of the true annulus and may become kinked during plication annuloplasty procedures.
Two thirds of hearts with Ebsteins anomaly show dilated right ventricles. Dilatation often involves not only the atrialized inlet portion of the right ventricle but also the functional right ventricular apex and outflow tract. In some cases, right ventricular dilatation is so marked that the ventricular septum bulges leftward, compressing the left ventricular chamber.6 In such cases, the short-axis view demonstrates a circular right ventricle and a crescentic left ventricle. In extreme cases, episodic left ventricular outflow tract obstruction can occur.
| Nomenclature and Classification |
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In 1988, Carpentier et al18 proposed the following classification of Ebsteins anomaly: type A, the volume of the true right ventricle is adequate; type B, a large atrialized component of the right ventricle exists, but the anterior leaflet of the tricuspid valve moves freely; type C, the anterior leaflet is severely restricted in its movement and may cause significant obstruction of the right ventricular outflow tract; and type D, almost complete atrialization of the ventricle except for a small infundibular component.
Celermajer et al19 described an echocardiographic grading score for neonates with Ebsteins anomaly, extended Glasgow Outcome Scale, with grades 1 to 4.19 The ratio of the combined area of the right atrium and atrialized right ventricle is compared with that of the functional right ventricle and left heart (ratio <0.5, grade 1; ratio of 0.5 to 0.99, grade 2; ratio of 1.0 to 1.49, grade 3; ratio
1.5, grade 4).
| Prevalence and Genetic Factors |
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There are heterogeneous genetic factors in Ebsteins anomaly. Case-control studies suggest genetic, reproductive, and environmental risk factors (eg, the anomaly is more common in twins, in those with a family history of congenital heart disease, and in those with maternal exposure to benzodiazepines).4 Maternal lithium therapy can rarely lead to Ebsteins anomaly in the offspring.20 Most cases are sporadic; familial Ebsteins anomaly is rare.
In a genetic study of 26 families with Ebsteins anomaly, 93 of 120 first-degree relatives were evaluated.21 No case of the anomaly was found, but 2 first-degree relatives had ventricular septal defects, and another, who died at 7 months, was said to have had congenital heart disease. Rare cases of cardiac transcription factor NKX2.5 mutations, 10p13-p14 deletion, and 1p34.3-p36.11 deletion have been described in the anomaly.2224
| Associated Cardiac Malformations in Ebsteins Anomaly |
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Abnormalities of left ventricular morphology and function, as well as other left-sided heart lesions, also occur in Ebsteins anomaly.14,15,2730 We recently reported features resembling noncompaction in 3 patients with the anomaly.31 Since then, we have analyzed 106 consecutive patients who had Ebsteins anomaly and found left-sided heart abnormalities in 39%; 18% of these patients had left ventricular dysplasia resembling noncompaction.32
Most patients with congenitally corrected transposition of the great arteries have an abnormal systemic tricuspid valve, which fulfills the criteria for Ebsteins anomaly in 15% to 50% of cases.16,3335 It is unclear whether the fundamental nature of the anomaly is identical in concordant and discordant atrioventricular connections.36,37 The morphological right ventricle is rarely dilated in congenitally corrected transposition.14,36
| Physiology |
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| Clinical Features |
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On examination, the jugular venous pulse rarely shows a large V wave despite severe regurgitation of the tricuspid valve because the large right atrium engulfs the increased volume. A widely and persistently split second heart sound and several added sounds are typical.38 A systolic murmur may be audible. Digital clubbing depends on the degree of cyanosis.38
Ebsteins anomaly is a common lesion referred for fetal echocardiography because severe forms may lead to cardiomegaly, hydrops, and tachyarrhythmias.39,40
Neonates with Ebsteins anomaly may present with cyanosis, congestive heart failure caused by regurgitation of the tricuspid valve, and marked cardiomegaly.39 Symptomatic children with Ebsteins anomaly may have progressive right-sided heart failure, but most will reach adolescence and adulthood.
Children >10 years of age and adults often present with arrhythmias.19 Adults also present with progressive cyanosis, decreasing exercise tolerance, fatigue, or right-sided heart failure. In the presence of an interatrial communication, the risk of paradoxical embolization, brain abscess, and sudden death increases.19 Exercise tolerance is dependent on heart size and oxygen saturation.41,42
| Diagnostic Evaluation |
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The principal feature of Ebsteins anomaly is apical displacement of the septal leaflet of the tricuspid valve from the insertion of the anterior leaflet of the mitral valve by at least 8 mm/m2 body surface area.6 Tethering of the tricuspid valve is present if there are at least 3 accessory attachments of the leaflet to the ventricular wall, causing restricted motion of the leaflet.39 Marked enlargement of the right atrium and atrialized right ventricle is present when the combined area of the right atrium and atrialized right ventricle is larger than the combined area of the functional right ventricle, left atrium, and left ventricle measured in the apical 4-chamber view at end diastole.19 The site and degree of regurgitation of the tricuspid valve and the feasibility of valve repair also are assessed with echocardiography.14
Cine magnetic resonance imaging may be used to assess ventricular size and function when echocardiographic image quality is inadequate.44,45
Electrocardiography
The ECG is abnormal in most patients with Ebsteins anomaly. It may show tall and broad P waves as a result of right atrial enlargement, as well as complete or incomplete right bundle-branch block.38 The R waves in leads V1 and V2 are small. Bizarre morphologies of the terminal QRS pattern result from infra-Hisian conduction disturbance and abnormal activation of the atrialized right ventricle.46 A typical ECG is shown in Figure 6.
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Complete heart block is rare in Ebsteins anomaly, but first-degree atrioventricular block occurs in 42% of patients because of right atrial enlargement and structural abnormalities of the atrioventricular conduction system.38,47 The atrioventricular node may be compressed and the central fibrous body abnormally formed. The right bundle branch may be abnormal or show marked fibrosis (or both).15,16,48
The downward displacement of the septal leaflet of the tricuspid valve is associated with discontinuity of the central fibrous body and septal atrioventricular ring with direct muscular connections, thus creating a potential substrate for accessory atrioventricular connections and pre-excitation.5,6 From 6% to 36% of patients with Ebsteins anomaly have
1 accessory pathways,26,38,46,49,50 and most accessory pathways are located around the orifice of the malformed tricuspid valve.25,27,47 Correct identification and treatment of accessory pathways are essential and may help to prevent sudden cardiac death. Paroxysmal tachyarrhythmias in Ebsteins anomaly are based on typical, fast-conducting atrioventricular accessory pathways with both antegrade and retrograde conduction properties in most patients.46 In addition, wide QRS tachycardia over a septal accessory atrioventricular pathway, ventricular tachycardia, or flutter, as well as ectopic atrial tachycardia, atrial flutter, and atrial fibrillation, can occur.46,50 Atrial fibrillation and atrial flutter are most likely caused by secondary alterations of the right atrial myocardium from previous cardiac surgery or are postoperative as a result of incisional atrial tachycardia.46
Chest Radiography
The cardiac silhouette may vary from almost normal to the typical Ebsteins anomaly configuration consisting of a globe-shaped heart with a narrow waist similar to that seen with pericardial effusion (Figure 7). Vascularity of the pulmonary fields is either normal or decreased. A cardiothoracic ratio >0.65 carries a poor prognosis.
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Cardiac Catheterization
Diagnostic cardiac catheterization is rarely necessary in patients with Ebsteins anomaly, other than for preoperative coronary angiography. Right ventricular and pulmonary artery pressures are usually normal in patients with the anomaly, although the right ventricular end-diastolic pressure may be increased. Right atrial pressure may be normal despite severe regurgitation of the tricuspid valve, especially if the right atrium is markedly dilated. Oximetry may show systemic arterial desaturation in the presence of an interatrial communication and right-to-left shunting.
| Management |
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Physical activity recommendations are summarized by Task Force 1 on Congenital Heart Disease.51 Athletes with mild Ebsteins anomaly, nearly normal heart size, and no arrhythmias can participate in all sports. Athletes with severe Ebsteins anomaly are precluded from sports unless the anomaly has been optimally repaired, the heart size is nearly normal, and no history of arrhythmias exists.
Patients with Ebsteins anomaly and cardiac failure who are not candidates for surgery are treated with standard heart failure therapy, including diuretics and digoxin. The efficacy of angiotensin-converting enzyme inhibitors in patients with Ebsteins anomaly who have right-sided heart failure is unproved. Medical management of arrhythmias should be individualized and combined with operative or catheter-based intervention.
Catheter Ablation
Electrophysiological evaluation and radiofrequency ablation of symptomatic accessory pathway(s) should be performed when feasible in patients with Ebsteins anomaly who have tachyarrhythmias. Catheter ablation has a lower success rate in patients with the anomaly than in those with structurally normal hearts, and the risk of recurrence is increased.46,5254 Supraventricular tachyarrhythmia associated with Ebsteins anomaly also can be ablated at the time of operative repair.55,56
Surgical Options
In 1959, repair of the tricuspid valve was reported in 2 patients who had Ebsteins anomaly; both died.57 Successful operative intervention for regurgitation of the tricuspid valve in patients with the anomaly was first described in 1962; the valve was replaced.58 The initial publication on patients with Ebsteins anomaly undergoing tricuspid valve replacement reported a surgical mortality of 54%.49 Similar high early mortality and unsatisfactory late results for tricuspid valve repair by the methods available at that time were described.57,59
Between April 1972 and January 2005, 540 consecutive patients with Ebsteins anomaly were operated on at Mayo Clinic Rochester. The age at operation ranged from 2 months to 79.1 years (median, 20 years). Of those having a tricuspid valve procedure, valve reconstruction was possible in 34.4%, and valve replacement (usually bioprosthesis) was performed in 65.6%. There were 29 early deaths (5.4%). Late results of the first 323 operations have been reviewed.60 There were 23 late deaths (7.6%) during a follow-up extending to 25 years (mean, 7.1 years).
Our initial repair technique reported in 1979 consisted of plication of the free wall of the atrialized portion of the right ventricle, posterior tricuspid annuloplasty, and right reduction atrioplasty.61 The repair is based on the construction of a monocuspid valve using the anterior leaflet. Since the initial report, we have incorporated various modifications of tricuspid valve repair, depending on the numerous variants encountered with the anatomy of Ebsteins anomaly.14,62 Our current repair usually involves bringing the anterior papillary muscle(s) toward the ventricular septum, thus facilitating coaptation of the leading edge of the anterior leaflet with the ventricular septum (Figure 8). Generally, an anteroposterior tricuspid purse-string annuloplasty is used, and atrialized right ventricular plication or resection is performed selectively. This results in a tricuspid valve repair at the level of the functional annulus, in contrast to our original repair, which brought the functional annulus up to the true annulus. We believe the 2 most important features that enable a successful, durable repair are a free leading edge of the anterior leaflet and at least 50% delamination of the anterior leaflet.
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In 1988, Carpentier et al18 proposed a repair that used mobilization of the anterior leaflet of the tricuspid valve. For their types B and C, temporary detachment of the anterior leaflet and adjacent part of the posterior leaflet was followed by longitudinal plication of the atrialized ventricle and adjacent right atrium, repositioning of the anterior and posterior leaflets to cover the orifice area at the normal level, and remodeling and reinforcement of the tricuspid annulus with a prosthetic ring. This repair was reported in 191 patients (mean±SD age, 24±15 years).64 The early mortality rate was 9%, and the mean late survival rate at 20 years was 82%±5%. It is unclear whether late problems will develop because of devitalized tricuspid valve tissue related to reattachment.
Another repair technique is characterized by reintegration of the atrialized chamber into the right ventricular cavity (called ventricularization). Ventricularization can be obtained by orthotopic transposition of the detached septal and posterior leaflets of the tricuspid valve. The reimplanted septal leaflet serves as an opposing structure for coaptation of the reconstructed atrioventricular valve.65
Posterior annular plication without plication of the atrialized right ventricle and prophylactic cavopulmonary connection are additional surgical options for nonneonatal Ebsteins anomaly; however, no long-term follow-up data are available.66 The benefit of adding a bidirectional cavopulmonary shunt after tricuspid valve repair or replacement to reduce right ventricular volume load in selected patients with Ebsteins anomaly is unclear. We use the bidirectional cavopulmonary shunt when the right ventricle is markedly dilated and functioning poorly. This allows a reduced volume load on the right ventricle and improves preload to the left ventricle. Left atrial and pulmonary artery pressures must be low for the shunt to provide hemodynamic benefit. In our experience, a modified Fontan procedure is very rarely required for patients with Ebsteins anomaly who present after infancy.
It has not been shown whether tricuspid valve repair or replacement has the better long-term outcome, nor is it known whether bioprostheses are preferable to mechanical prostheses for tricuspid valve replacement in Ebsteins anomaly. One study has suggested that valve repair is less durable in adults than in children.67 It is known that tricuspid bioprostheses in Ebsteins anomaly have greater durability than in other cardiac positions, especially for pediatric patients; the mean rate of freedom from bioprosthesis replacement was 80.6±7.6% in a study with up to 17.8 years of follow-up (mean, 4.5 years).68 In a series of 294 patients with Ebsteins anomaly, the difference in freedom from reoperation at 12 years for tricuspid valve repair versus replacement and for bioprosthetic versus mechanical valve prostheses was not significant.68 Currently, we prefer valve repair, when feasible, over valve replacement because repair has the potential of being more durable and avoids the potential complications of valve prostheses. Some of our early patients are doing well, free of reoperation >20 years after valve repair. We generally prefer bioprostheses over mechanical prostheses for Ebsteins anomaly, reserving the latter for those who are already taking anticoagulants for another indication.14 The method we currently use for tricuspid valve replacement in Ebsteins anomaly is shown in Figure 9.
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Although a decrease in atrial tachyarrhythmias after standard repair of Ebsteins anomaly generally has been noted,69 we prefer to combine repair with directed antiarrhythmia procedures.14,53,56 This can be accomplished without an increase in operative mortality and with freedom from arrhythmia recurrence in 75% of patients with atrial flutter or fibrillation and in up to 100% of patients with accessory pathwaymediated tachycardia or atrioventricular nodal reentry tachycardia.55,70
Symptomatic neonates with Ebsteins anomaly have a poor prognosis. Marked cardiac enlargement, advanced echocardiographic severity score, cyanosis, and severe regurgitation of the tricuspid valve all predict neonatal death without surgery.19,71 Biventricular repairs in combination with correction of all associated cardiac defects are feasible, and midterm results are good.71 Conversion to a single-ventricle approach for symptomatic neonates also has been advocated.72 Results of tricuspid valve repair in young children have been reported and demonstrate low early mortality and good durability at late follow-up.73
Indications for Operation
Observation alone is advised for asymptomatic patients with no right-to-left shunting and only mild cardiomegaly. Children who have survived infancy generally do well for several years, and surgery can be postponed until symptoms appear, cyanosis becomes evident, or paradoxical emboli occur. Deliberations about an operation should begin if evidence of deterioration exists, such as progressive increase in right heart size, reduction in systolic function, or appearance of ventricular or atrial tachyarrhythmias. However, once symptoms progress to New York Heart Association functional class III or IV, medical management has little to offer, surgical risks increase, and operation is clearly indicated. A biventricular reconstruction is feasible for most patients. A 1.5 ventricle repair can be applied to the failing right ventricle. Heart transplantation is reserved for patients with severe biventricular dysfunction.
Some patients with cyanosis on exercise who have a shunt at the atrial level but only mild or moderate regurgitation of the tricuspid valve may benefit from device closure to alleviate cyanosis and to prevent paradoxical emboli. Some centers commonly perform such procedures either as a staged approach or for long-term palliation.74 The degree of tricuspid valve regurgitation must be assessed carefully, however, because closure of an atrial septal defect alone may worsen right ventricular dysfunction.
Pacing
Permanent pacing is required for 3.7% of patients with Ebsteins anomaly, most commonly for atrioventricular block and rarely for sinus node dysfunction.75 In the presence of a tricuspid valve prosthesis, the ventricular lead for permanent DDD pacing usually is placed epicardially or through the coronary sinus or a cardiac vein. Alternatively, a previously placed transvenous ventricular lead may be sutured outside the prosthesis sewing ring at the time of valve replacement. Placement of a transvenous ventricular lead through a bioprosthesis is effective but less desirable because of the possibility of propping open one of the valve cusps, thus creating regurgitation of the tricuspid valve. This complication can be minimized by use of transesophageal echocardiographic monitoring to ensure that the lead lies safely in a commissure between the valve cusps.
| Natural History and Long-Term Sequelae |
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Of all neonates with the diagnosis of Ebsteins anomaly, 20% to 40% do not survive 1 month, and <50% survive to 5 years.7982
Celermajer et al19 reviewed 220 cases of Ebsteins anomaly with 1 to 34 years of follow-up. Actuarial survival for all live-born patients was 67% at 1 year and 59% at 10 years. Predictors of death were echocardiographic grade of severity at presentation (relative risk increased by 2.7 for each increase in grade), fetal presentation, and right ventricular outflow tract obstruction.
In rare cases, patients with Ebsteins anomaly live >70 years, but 1 reported patient died at 85 years of age.38 A reassessment of the prognosis of Ebsteins anomaly is appropriate in the current era of refined cardiovascular intervention.
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| Acknowledgments |
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Disclosures
None.
| Footnotes |
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This article is based in part on a previously published manuscript.1 Used with permission.
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