Ebstein anomaly

Disease Description (Causes and Symptoms)

• Definition summary: A congenital heart defect in which the leaflets of the tricuspid valve (the valve between the right atrium and right ventricle) are displaced downward toward the right ventricle from their normal position (the annulus), causing atrialization of the right ventricle, tricuspid regurgitation, and right ventricular dysfunction (English: Ebstein anomaly).
• Causes/pathophysiology: Due to an abnormality in heart valve formation during early embryonic development, the septal and posterior leaflets move downward from the annulus, causing enlargement of the right atrium and “atrialization” of part of the right ventricle → increased tricuspid regurgitation, right ventricular outflow tract obstruction (functional pulmonary atresia) or stenosis, and often a right-to-left shunt caused by an atrial septal defect (PFO/ASD).
• Main symptoms:
  • Heart murmur (tricuspid regurgitation murmur), shortness of breath, poor exercise tolerance/fatigue
  • Cyanosis (especially in newborns or when a right-to-left shunt is present)
  • Difficulty feeding and poor growth (infants)
  • Symptoms of heart failure (edema, rapid breathing)
  • Arrhythmias (especially supraventricular tachycardia such as WPW syndrome), fainting, or dizziness

Treatment Methods (Standard Treatment, Medications·Procedures·Surgery, Lifestyle Management and Precautions)

• Management of newborns and the acute phase
  • Mild cases: Observation while waiting for pulmonary vascular resistance to decrease naturally (oxygen support may be helpful).
  • Severe cases (severe cyanosis, inadequate pulmonary blood flow): Maintain ductus arteriosus patency with prostaglandin E1 (PDA) to secure pulmonary blood flow. If persistent, temporary shunt surgery (Blalock–Taussig shunt) may be considered.
• Medication treatment
  • Symptomatic treatment, including diuretics, to control heart failure symptoms.
  • Antiarrhythmic drugs when arrhythmias occur (the type depends on the type of arrhythmia). However, caution is needed when selecting medications in electrophysiological situations associated with WPW (AV nodal blockers are contraindicated in certain situations).
• Procedures/surgery
  • Tricuspid valve repair (valve preservation and repair are recommended whenever possible): Surgery to reduce regurgitation by performing plication to reduce the atrialized right ventricle or reconstructing the leaflets (in modern practice, cone repair, etc.).
  • Valve replacement: Replacement with a prosthetic valve when the defect is too severe for preservation.
  • In cases of single-ventricle physiology: Securing pulmonary blood flow and reconstructing the circulation through a staged approach (initial shunt followed later by the Fontan pathway).
  • Arrhythmia treatment: Catheter ablation (especially for WPW) — in WPW accompanying Ebstein anomaly, accessory pathways are often located at multiple sites along the annulus, so ablation may be more difficult and the success rate may be lower.
• Lifestyle management and preventive measures
  • Regular cardiac follow-up (echocardiography, ECG/Holter monitoring, and exercise capacity assessment).
  • Follow infectious endocarditis prevention guidelines (depending on the indication, check with the treating physician whether antibiotic prophylaxis is needed before dental procedures).
  • Consult in advance with an obstetrician and an adult congenital heart disease specialist when planning pregnancy and childbirth.
• Precautions and risk of complications
  • Increased risk of arrhythmias (especially WPW-related supraventricular tachycardia and atrial flutter/fibrillation) and cerebral thrombosis/brain abscess (when a right-to-left shunt is present).
  • When symptoms are severe during the neonatal or early infancy period, mortality is high, and approximately 30–40% of severe cases may die within 12 months after birth (the more severe the case, the poorer the prognosis).
  • Exercise caution regarding electrophysiological and medication selection when treating arrhythmias (for example, some AV nodal blockers may be dangerous in pre-excited AF).
  • The timing and method of surgery are determined according to each individual’s condition (symptoms, right ventricular function, and associated defects).

Checklist Before an Outpatient Visit (Materials to Bring and Information to Organize in Advance — Including Example Questions)

• Items to bring and prepare
  • A list of all currently used medications (dosages and dosing times)
  • Previous test materials: recent echocardiogram, ECG, Holter monitor results, chest X-ray, and surgical/procedure records (if any)
  • Growth records (for infants and young children: feeding and sleep patterns and weight-gain trends)
  • Symptom diary: record the time, duration, and triggering circumstances of episodes of cyanosis, fainting, dizziness, seizures, or tachycardia
  • Any recent infections, fever, or dental treatment
• Items to check in advance at the outpatient visit (to confirm personally)
  • Has shortness of breath or fatigue during exercise increased?
  • History of chest pain or fainting
  • Frequency and duration of episodes of paroxysmal tachycardia (palpitations)
  • Pregnancy plans (for women of childbearing age)
• Information useful to tell the doctor during the outpatient visit
  • When the symptoms first began and how they have changed
  • Daily life (exercise and any restrictions at school/work)
  • History of previous arrhythmia treatment (medications·ablation) and surgery

Examples of General Questions to Ask the Doctor

• “What tests and follow-up intervals are recommended for my (or my child’s) current condition?”
• “What are the main side effects and precautions of the medication being used?”
• “What emergency actions should be taken if symptoms of heart failure or arrhythmia worsen?”
• “What is the prognosis? As age increases, what problems should we mainly expect?”

Examples of Disease-Specific Questions

• “Based on my (or my child’s) tricuspid valve condition, which do you recommend—repair (valve-preserving surgery) or replacement—and why?”
• “If there is a risk of arrhythmia (such as WPW), do you recommend catheter ablation, and what are the success rate and risks of the procedure (especially when accompanied by Ebstein anomaly)?”