Morphologic spectrum of Ebstein's malformation: revisitation relative to surgical repair

Neonatal repair of Ebstein's anomaly: indications, surgical technique, and medium-term follow-up

BACKGROUND

Ebstein's anomaly in the severely symptomatic neonate is usually fatal. Because the mortality for various surgical interventions has been prohibitively high, the indications for operation in these critically ill neonates are unclear.

METHODS

We reviewed our results with biventricular repair of three consecutive severely symptomatic neonates (2.8 to 3.2 kg) at our institution since 1994. Each had associated complex cardiac pathology, including multiple muscular ventricular septal defects (n = 1), pulmonary stenosis with functional pulmonary atresia (n = 1), and anatomic pulmonary atresia (n = 1). Preoperatively, all infants had severe tricuspid regurgitation, Great Ormond Street Ebstein echocardiogram scores greater than 1.3:1 (grade 3 or 4) and cardiothoracic ratio greater than 0.85. Two patients were severely cyanotic. Hepatic and renal insufficiency with diffuse coagulopathy was present preoperatively in two patients. Surgical repair consisted of (1) reconstruction of a competent monocuspid tricuspid valve, (2) right ventriculorrhaphy, (3) subtotal closure of atrial septal defect (ASD), (4) aggressive reduction atrioplasty, and (5) repair of all associated cardiac defects.

RESULTS

There were no early or late deaths. All patients are currently asymptomatic, without medications, and in sinus rhythm. At 5-year follow-up, trivial tricuspid regurgitation is present in 1 and mild regurgitation in 2 patients. On the basis of these results and review of the current literature, we propose new indications for surgical repair in the neonate with Ebstein's anomaly.

CONCLUSIONS

Biventricular repair of Ebstein's anomaly in the critically ill neonate is feasible and medium-term durability of the repair is excellent. Therefore, conventional management of these patients should be revised and early surgical repair encouraged.

The atrioventricular junctions in Ebstein malformation

OBJECTIVE

To review the anatomical structure of the right atrioventricular junction, including the specialised atrioventricular conduction system, in hearts with Ebstein's malformation, to identify potential substrates for the abnormalities in conduction.

METHODS

Five heart specimens representing the morphological spectrum of Ebstein malformation were examined grossly and histologically.

RESULTS

On the endocardial surface, the atrioventricular junction was marked by a faint line in two hearts, and by a small ridge in the other three. Analysis of the right parietal junction in four hearts revealed only two accessory muscular atrioventricular connections. A plane of fibrofatty tissue separated atrial from ventricular myocardium in the right parietal junction in all hearts. The compact atrioventricular node was closer to the coronary sinus than usual. Accessory nodoventricular connections were present in four hearts, while accessory fasciculo-ventricular connections were found in one. The right bundle branch was hypoplastic or absent in four hearts.

CONCLUSIONS

In this small series, the parietal atrioventricular junction was better developed than previously thought. Structural abnormalities of the atrioventricular conduction system, however, were present. These may account for some of the conduction abnormalities frequently observed with the Ebstein malformation.

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.

Ebstein's Malformation

Ebstein's malformation of the tricuspid valve is a complex and heterogeneous disorder that has diverse hemodynamic and arrhythmic manifestations. Hemodynamic dysfunction is due to valvar regurgitation and decreased pulmonary blood flow, varying in severity from mild tricuspid insufficiency to severe dysplasia of the right ventricle without forward flow. Atrioventricular reentrant tachycardia and atrial tachyarrhythmias are commonly associated with Ebstein's malformation. Treatment ranges from conservative medical management to the ablation of pathways by catheterization to complex surgical repair or palliation. All patients with Ebstein's malformation should be followed on a regular basis by a cardiologist familiar with congenital heart disease. The frequency of evaluations should depend on the severity of the disease and the presence of arrhythmias. A specialist in electrophysiology should also follow those patients with complex arrhythmias.