Ebstein's Anomaly:

Cardiac imaging in Ebstein anomaly

Ebstein anomaly is a congenital disorder of right ventricular myocardial development, which affects the tricuspid valve in addition to the right ventricular myocardium. Cardiac imaging by transthoracic echocardiography and cardiac magnetic resonance imaging are the key modalities used to assess timing and type of surgery. In this article, we review the current standards of echocardiographic and magnetic resonance imaging in Ebstein anomaly.

Echocardiographic assessment of Ebstein's anomaly

Ebstein's anomaly is a complex congenital lesion which primarily involves the tricuspid valve. The tricuspid leaflets are tethered to varying degrees to the right ventricular free wall and the ventricular septum often resulting in significant tricuspid regurgitation and a small functioning right ventricular chamber. Although the septal leaflet originates normally at the right atrioventricular junction, the proximal portion is often completely tethered to the ventricular septum resulting in a misconception and erroneous statements in many publications that its attachment is apically displaced. Although two-dimensional echocardiography represents the primary modality for the diagnosis of this anomaly, three-dimensional echocardiography provides incremental value in characterizing the extent and severity of tethering of individual tricuspid valve leaflets. This information is useful in surgical decision making whether to repair or replace the tricuspid valve.

Unnatural history of the right ventricle in patients with congenitally malformed hearts

The long-term outcome of patients with congenitally malformed hearts involving abnormal right ventricular morphology and haemodynamics is variable. In most instances, the patients are at risk for right ventricular failure, in part due to morphological differences between the right and left ventricles and their response to chronic volume and pressure overload. In patients after repair of tetralogy of Fallot, and after balloon valvotomy for valvar pulmonary stenosis, pulmonary regurgitation is the most significant risk factor for right ventricular dysfunction. In patients with a dominant right ventricle after Fontan palliation, and in those with systemic right ventricles in association with surgically or congenitally corrected transposition, the right ventricle is not morphologically capable of dealing with chronic exposure to the high afterload of the systemic circulation. In patients with Ebstein's malformation of the tricuspid valve, the degree of atrialisation of the right ventricle determines how well the right ventricle will function as the pump for the pulmonary vascular bed.

Multiplanar review of three-dimensional echocardiography gives new insights into the morphology of Ebstein's malformation

INTRODUCTION

We aimed to assess the ability of the multiplanar review modality of three-dimensional echocardiography to examine the dynamic morphology and the functional characteristics of malformed tricuspid valves in patients previously identified as having Ebstein's malformation. Based on these characteristics, we attempted to differentiate Ebstein's malformation from tricuspid valvar dysplasia.

METHODS

Using three-dimensional multiplanar review, analysed with either Qlab 6.0 or Tomtech Image Arena 3.0, we studied 23 patients, aged from 1 day to 70 years, previously diagnosed using cross-sectional echocardiography as having Ebstein's malformation.

RESULTS

Using the features of rotational abnormality, and the orientation, of the effective tricuspid valvar orifice as diagnostic features of Ebstein's malformation, we reclassified 11 patients (48 per cent) as exhibiting tricuspid valvar dysplasia. In addition, we studied the dynamic morphology as well as the function of the tricuspid valve. Surgical treatment was undertaken on 10 patients, revealing good correlation with the findings obtained using three-dimensional multiplanar review. In those with Ebstein's malformation, we found varying degrees of rotation, with the effective valvar orifice always directed towards the right ventricular outflow tract. The opening of the orifice of dysplastic tricuspid valves, in contrast, was towards the apex of the right ventricle. The degree of delamination, and abnormalities of subcordal apparatus, were similar in the two groups.

DISCUSSION

Three-dimensional multiplanar review permits accurate definition of the dynamic morphology of Ebstein's malformation, permitting clear differentiation from tricuspid valvar dysplasia.

Defining Ebstein's malformation using three-dimensional echocardiography

Ebstein's malformation is difficult to visualise, for both the echocardiographer and the surgeon. The essence of the problem in Ebstein's malformation is the deviation of the hingepoints of the leaflets towards the junctions of the inlet and apical trabecular parts of the right ventricle. Three-dimensional echocardiography offers new insights into the morphology and function of malformed valves, and allows elucidation of all the features. It allows clear visualisation of the valve leaflets, showing the precise morphology of the valve leaflets, the extent of their formation, the level of their attachment, and their degree of coaptation. Visualisation of the mechanism of regurgitation or stenosis is possible, as is more accurate quantification of the regurgitant jet or jets. Subchordal apparatus may be seen more clearly using three-dimensional echocardiography, and their functional anatomy understood. The multiplanar review modality allows examination of the three-dimensional data set even in patients with sub-optimal echocardiographic imaging. Previously, much of this information could only be well-understood at the time of surgery or post mortem, meaning that the majority of the specimens fully examined were at the poorly functioning end of the spectrum. This information is of use in furthering our understanding of this complex lesion as it functions in vivo, and demonstrating which anatomical pathology is significant in producing functional and physiological consequences. It is also of use for the clinician in selecting which patients are amenable to surgical intervention, for either single or biventricular repair, and for the surgeon in planning how to approach the operation. Correlation between three-dimensional echocardiographic findings and surgical findings has already been established, but the effect of this enhanced anatomical knowledge on surgical planning and surgical outcome requires further investigation.

Anatomy and echocardiography of the normal and abnormal tricuspid valve

Perhaps because it guards the inlet to the lesser circulation, the morphologically tricuspid valve has received less attention in terms of its anatomy than the well-explored mitral valve, which will receive attention in a subsequent review in this supplement.1 As we will show in our initial review, nonetheless, the approach to morphological analysis is the same for both valves, irrespective of whether the specific morphology is displayed in the autopsy room or the echocardiographic laboratory. It is essential that the valve be analysed so as to reveal the precise structure of each if its components – the so-called valvar complex.2 Equally important, in the current era, with the burgeoning use of three-dimensional displays that place the heart firmly within the context of the body, it is essential that the components of the valve be described as seen relative to the bodily axis,3 rather than following the present custom of describing the heart as though it is removed from the body and positioned on its own apex.

Tricuspid Valve Repair for Ebstein’s Anomaly in Young Children: A 30-Year Experience

BACKGROUND

The purpose of this study was to examine early and late outcome of tricuspid valve repair for Ebstein's anomaly in young children.

METHODS

Between October 1974 and November 2003, 52 children (25 boys) underwent tricuspid valve repair and annuloplasty for Ebstein's anomaly. Mean age was 7.1 +/- 3.9 years (range, 5 months to 12 years). Concomitant procedures included atrial septal defect closure (n = 46), division of accessory conduction pathways (n = 4), ventricular septal defect closure (n = 3), and other (n = 7).

RESULTS

Early mortality was 5.8% (3 of 52 patients; no mortality since 1984, n = 31). Risk factors were age younger than 2.5 years (p = 0.03) and weight less than 10.7 kg (p = 0.03). Morbidity included transient atrial (n = 11) and ventricular arrhythmias (n = 5), and early reoperation in 3 patients. There was no need for a permanent pacemaker. Mean follow-up was 12.2 +/- 7.4 years (maximum, 24.3 years). Actuarial survival at 5, 10, and 15 years was 92.3% +/- 3.7%, 89.9% +/- 4.3%, and 89.9% +/- 4.3%, respectively. Freedom from all reoperations at 5, 10, and 15 years was 91.0% +/- 4.3%, 76.9% +/- 6.8%, and 61.4% +/- 8.8%, respectively. Moderate (grade II) or more tricuspid regurgitation on dismissal echocardiogram was the only risk factor for reoperation (p = 0.04). Tricuspid stenosis did not occur in any patient. At late follow-up, 89% of patients were in New York Heart Association class I or II.

CONCLUSIONS

Ebstein's anomaly in young children can now be repaired with low mortality and good tricuspid valve durability. Tricuspid regurgitation at the completion of operation should be mild or less to minimize need for reoperation. Tricuspid valve repair and annuloplasty did not result in stenosis despite somatic growth. Most patients enjoy an excellent quality of life.

Surgical Management of Ebstein’s Anomaly in the Adult

Ebstein's anomaly is a rare cardiac malformation that affects the tricuspid valve, right ventricle, and right atrioventricular junction. These anatomical and functional abnormalities cause important tricuspid regurgitation that results in right atrial and right ventricular dilatation and atrial and ventricular arrhythmias. Diagnosis is made by echocardiography. Operation includes tricuspid valve repair or replacement, closure of any interatrial communications, and appropriate antiarrhythmia procedures. Repair of Ebstein's anomaly eliminates right-to-left intracardiac shunting, improves exercise tolerance and functional class, and reduces supraventricular arrhythmias. In addition, quality of life and longevity are improved.

Supraventricular tachyarrhythmias in Ebstein anomaly: management and outcome

OBJECTIVE

This study was undertaken to review the role of electrophysiology testing and to determine the early and late results of medical and surgical management of supraventricular tachyarrhythmias in Ebstein anomaly.

METHODS

We reviewed 130 patients between 1990 and 2001 with Ebstein anomaly and history of tachyarrhythmia with a median age of 25 years (mean age 27.5 years); 106 underwent electrophysiologic testing and 24 had documented atrial flutter or fibrillation. We excluded 21 patients: negative results of testing (n = 18), ventricular tachycardia (n = 2), and junctional tachycardia (n = 1). The remaining 109 patients had more than one mechanism: accessory pathway-mediated tachycardia (n = 49), atrioventricular nodal reentrant tachycardia (n = 10), and atrial flutter/fibrillation (n = 70).

RESULTS

Eighty-three patients underwent at least one arrhythmia procedure combined with surgery for Ebstein anomaly. Early mortality was 4.8%. Forty-one patients underwent surgical ablation of an accessory pathway without recurrent accessory pathway-mediated tachycardia at a mean follow-up of 48 months. Seven patients underwent surgical perinodal cryoablation for atrioventricular nodal reentrant tachycardia without recurrence at a mean follow-up of 57 months. Forty-eight patients underwent surgical intervention for atrial flutter or fibrillation (right-sided maze procedure, n = 38, and cryoablation of the atrial isthmus, n = 10). Freedom from recurrent atrial flutter or fibrillation was 75% at a mean follow-up of 34 months.

CONCLUSION

Concomitant arrhythmia procedures can be performed without increase in early mortality and should be added to Ebstein repairs for all patients who have supraventricular tachyarrhythmias. Surgical procedures for accessory pathway-mediated tachycardia and atrioventricular nodal reentrant tachycardia give excellent (100%) freedom from recurrence of those arrhythmias. Surgical intervention for atrial flutter/fibrillation yields freedom from late recurrence in 75% of cases.

The clinical profile of Ebstein's malformation as seen from the fetus to the adult in 52 patients

Ebstein's malformation of the tricuspid valve is a rare but complex congenital cardiac lesion characterised by a variable degree of dysplasia and displacement of the proximal attachments of its inferior and septal leaflets from the true atrioventricular junction. The aim of our retrospective study is to report the risk factors for mortality, and to determine the clinical profile as seen in 52 cases diagnosed in our service between 1978 and 2002, concentrating in particular on the outcome for the neonatal patient. There were 26 females and 26 males, and the age at presentation ranged from 30 weeks gestational age to 46 years. We found 23 associated cardiac anomalies in 20 cases. Of the patients, 11 patients (21%) died. Actuarial survival at 30 years was 65%. Predictors of death included fetal or neonatal presentation, presence of associated defects, a grade within the Celermajer index of 3 or 4, and a cardiothoracic ratio equal to or greater than 65%. The diagnosis was made in the neonatal period in 24 patients, nine of whom died. Of the 15 survivors, only 4 are free of symptoms. Surgical treatment was undertaken in 9 patients, with a mortality rate of 33% without late deaths, with all the survivors being in good condition. The mean period of follow-up for the 41 living patients was 16.5 years. An arrhythmia of variable severity appeared during the evolution of 27 patients (66%). At present, only 7 cases are in the functional class III or IV of the grading system of the New York Heart Association, but 25 patients (61%) needed some medical treatment, meanly for arrhythmic events. Thus, fetal and neonatal presentation of Ebstein's malformation is associated with a poor outcome. Moreover, the echocardiographic appearance, marked cardiomegaly, and the presence of associated lesions are all risk factors for mortality. Arrhythmia and need of medical treatment are common in older children and adults. Survival after surgical treatment is associated with a good outcome.

Congenital Heart Surgery Nomenclature and Database Project: Ebstein's anomaly and tricuspid valve disease

Ebstein's anomaly is a rare congenital heart defect that is characterized by a spectrum of anatomical abnormalities of the tricuspid valve that also involve the right atrium and right ventricle. The extant nomenclature for Ebstein's anomaly and our approach to the description of the severity of Ebstein's anomaly are reviewed with the objective of establishing a unified reporting system. Although there are common features in Ebstein's anomaly, there is a wide spectrum of pathology with an infinite variety of combinations of severity of the involved structures. An effort was made to develop a classification system that would take into consideration the anatomic abnormalities that help direct the surgical management, particularly in regard to tricuspid valve repair or valve replacement. Isolated congenital tricuspid stenosis and regurgitation are also rare, and a simple classification system is presented. Acquired causes of tricuspid regurgitation and stenosis are more common and are included in the classification system. A comprehensive database set for these malformations is presented so that a comprehensive risk stratification analysis can be performed. A minimum database set is also presented that will allow for data sharing and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and risk factors are presented.

The adult patient with Ebstein anomaly. Outcome in 72 unoperated patients

Knowledge of the long-term outcome in unoperated adult patients with Ebstein anomaly is limited, and the therapeutic approach is still controversial. We studied unoperated adult patients with Ebstein anomaly to define the patterns of presentation, anatomic characteristics, outcome, and predictive factors for survival. Seventy-two unoperated survivors of Ebstein anomaly aged over 25 years attended from 1972 to 1997 were reviewed and followed-up from 1.6 to 22.0 years. Patients were classified in 3 groups of severity according to the echocardiographic appearance of the septal leaflet attachment of tricuspid valve. The mean age at diagnosis was 23.9 +/- 10.4 years, and the most common clinical presentation was an arrhythmic event (51.4%). There were 30 (42%) deaths, including 6 from arrhythmia, 12 related to heart failure, 7 sudden, 2 unrelated, and 3 unascertained. According to Cox regression analysis, predictors of cardiac-related death included age at diagnosis (hazard ratio 0.89 for each year of age, 95% confidence intervals CI[ 0.84-0.94), male sex (3.93, 95% CI, 1.50-10.29), degree of echocardiographic severity (3.34, 95% CI, 1.78-6.24), and cardiothoracic ratio > or = 0.65 (3.57, 95% CI, 1.15-11.03). During follow-up, morbidity was mainly related to arrhythmia and refractory late hemodynamic deterioration. The magnitude of tricuspid regurgitation, cyanosis, and the New York Heart Association (NYHA) functional class at time zero were significant risk factors according to the univariate analysis, but not after multivariable confrontation. The results of this study suggest that pattern of presentation, clinical course, and prognosis of unoperated adult patients with Ebstein anomaly are influenced by several factors. Although the initial symptoms are usually mild and commonly related to supraventricular arrhythmias, these are not associated with the long-term outcome. The severity of the morbid anatomy was the main determinant of survival only in extreme cases, but not in those with mild or moderate deformations, which are more common in adults. Other independent risk factors such as cardiothoracic ratio, sex, age at diagnosis, and the echocardiographic evaluation may help to determine the therapeutic approach. Adult patients with Ebstein anomaly should not be considered as a simple low-risk group.

Mimics of Ebstein's anomaly

The purpose of this study was to determine the most discriminating clinical and echocardiographic features that are most helpful in correctly identifying Ebstein's anomaly of the tricuspid valve from other causes of tricuspid regurgitation. Ebstein's anomaly is an uncommon malformation of the tricuspid valve with diagnostic echocardiographic features. Other cardiac disorders associated with tricuspid valve regurgitation and predominate right-sided heart chamber enlargement can be misdiagnosed as Ebstein's anomaly. All patients who were referred to our institution between 1982 and 1995 with the diagnosis of Ebstein's anomaly but were found to have other abnormalities of the tricuspid value or right ventricle were identified. Their clinical, echocardiographic, and surgical records were reviewed retrospectively. Twenty-two patients (12 males and 10 females), aged 7 to 68 years (mean 33 years), were referred to our institution with the diagnosis of Ebstein's anomaly but were found to have another abnormality that mimicked clinical and diagnostic features of Ebstein's anomaly. The most common initial symptom was exercise intolerance (13 [59%] patients) followed by atrial arrhythmia (seven [32%] patients). Two patients had cyanosis. Three patients had paroxysmal and six had chronic atrial fibrillation/flutter. Cardiomegaly on chest x-ray film was noted in 18 (82%) patients. Referral diagnosis of Ebstein's anomaly had been made by echocardiography (12 patients), cardiac catheterization (four patients), both techniques (five patients), and echocardiography and magnetic resonance imaging (one patient). All 22 patients had predominate right atrial and right ventricular enlargement, and 18 (82%) of 22 patients also had right ventricular dysfunction. However, Ebstein's anomaly was confidently ruled out with repeat comprehensive echocardiography at our institution by establishing (1) absence of significant apical displacement of the septal tricuspid valve leaflet (> or = 8 mm/m2) and (2) lack of a redundant, elongated, anterior tricuspid valve leaflet in all 22 patients (100%). All had significant tricuspid regurgitation caused by tricuspid valve dysplasia (nine patients), tricuspid valve prolapse (four patients), trauma (four patients), right ventricular dysplasia (three patients), endocarditis (one patient), and annular dilation caused by free pulmonary regurgitation (one patient). In all 15 patients who subsequently underwent surgery (tricuspid valve repair [seven patients] or replacement [eight patients]), the absence of Ebstein's anomaly was confirmed. Echocardiographic absence of the characteristic degree of displacement of the septal leaflet of the tricuspid valve (> or = 8 mm/m2) and the presence of a nonelongated, nonredundant anterior tricuspid valve leaflet consistently excluded the diagnosis of Ebstein's anomaly. Under such circumstances, other anomalies of the tricuspid valve or right ventricle were consistently identified. Recognition of the mimics of Ebstein's anomaly had important surgical implications.