What is Ebstein's anomaly (congenital heart defect)?

From the Guidelines

Surgical repair of the tricuspid valve is recommended for patients with Ebstein's anomaly who have symptoms, deteriorating exercise capacity, or signs of worsening hemodynamics, as it can improve symptoms and functional ability, and prevent or delay worsening symptoms. Ebstein's anomaly is a rare congenital heart defect characterized by abnormal development of the tricuspid valve, which separates the right atrium from the right ventricle. In this condition, the tricuspid valve is positioned lower than normal in the right ventricle, causing part of the right ventricle to be incorporated into the right atrium. This leads to an enlarged right atrium, a smaller functional right ventricle, and often a leaky tricuspid valve. Symptoms vary widely depending on severity, ranging from no symptoms in mild cases to severe heart failure in infants with more serious defects. Common symptoms include heart rhythm abnormalities (particularly Wolff-Parkinson-White syndrome), shortness of breath, fatigue, cyanosis (bluish discoloration of the skin), and heart failure.

According to the 2019 AHA/ACC guideline for the management of adults with congenital heart disease 1, surgical repair generally consists of tricuspid valve repair (preferred when feasible) or replacement, selective plication of atrialized right ventricle, reduction atrioplasty, arrhythmia surgery, and/or closure of atrial level shunt. The guideline also recommends that surgery be performed before the development of heart failure or RV systolic dysfunction, as delay of surgery until these conditions ensue is associated with poorer outcomes.

Key considerations in the management of Ebstein's anomaly include:

• Assessment for arrhythmia substrates and proceeding with catheter ablation if identified, before surgery 1
• Surgical interruption of accessory pathways is largely reserved for patients who have failed attempts at catheter ablation 1
• The use of the bidirectional cavopulmonary shunt is usually reserved for patients with severe RV dysfunction with concern that the right ventricle will not tolerate supporting the entirety of stroke volume 1
• Heart transplantation is considered when significant LV dysfunction has occurred and important symptoms of heart failure are present 1

Overall, the management of Ebstein's anomaly requires a comprehensive approach that takes into account the individual patient's symptoms, hemodynamic status, and arrhythmia risk, with the goal of improving symptoms, functional ability, and preventing or delaying worsening symptoms.

From the Research

Definition and Prevalence of Ebstein's Anomaly

• Ebstein's anomaly is a rare congenital heart disorder accounting for less than 1% of all congenital heart defects 2, 3.
• It affects the development of the tricuspid valve with widely varying morphology and clinical presentation 4.
• The prevalence of Ebstein's anomaly is approximately 0.3-0.5% of congenital heart defects, representing 40% of congenital tricuspid valve abnormalities 4.

Clinical Presentation and Management

• Presentation can vary from a severe symptomatic form during the neonatal period to an incidental detection later in life due to the wide morphological variation of the condition 5, 4.
• Asymptomatic patients can be conservatively treated and kept under close follow-up, whereas surgical operation is indicated for those patients with evidence of right heart dilation and progressively impaired ventricular systolic function 6.
• Management options include catheter interventions, indication for operation, and surgical options such as tricuspid valve repair and replacement 2, 5.
• The da Silva Cone repair has become the valvuloplasty of choice, especially beyond the neonatal period, and can be applied to a wide morphological variation of the condition with good long-term durability 5.

Surgical Options and Outcomes

• Surgical options available for patients with Ebstein's anomaly include mono-leaflet repairs, cone repair, and its modifications 4.
• A biventricular repair consisting of the reconstruction of a competent monocuspid tricuspid valve, right ventriculorrhaphy, subtotal atrial septal defect closure, and aggressive reduction atrioplasty is suitable for most patients 6.
• Heart transplantation should be considered in patients with associated left ventricular dysfunction 5, 6.

Genetics and Associated Conditions

• Genetic bases of Ebstein's anomaly may be related to mutations in myosin heavy chain 7 and NKX2.5, among others 6.
• Associated congenital cardiac lesions tend to be found more often in younger patients and may even be the reason for presentation 4.