Ebstein’s Malformation

Introduction

  • Apical displacement of the septal and postero-lateral leaflets of the tricuspid valve resulting in:
    • “Atrialized” RV above the valve (ratio)
    • Small “functional” RV below the valve
    • Very large anterior leaflet (attaches the same location while other leaflets shift apically)
    • Severe RA enlargement
  • Can be cyanotic with an ASD or PFO (frequently associated)
  • 5.2 per 100,000 births
  • Classic Association: Maternal Lithium use
Ebstein's Anomaly Diagram (CDC Public Domain Image)

Associations

  1. ASD or PFO (50%)
  2. Accessory Pathway / WPW (25%)
  3. Pulmonary Stenosis (rare)

Physical Exam

  • Inspection:  Cool periphery ± cyanosis (poor cardiac output)
  • JVP – “V” wave unreliable
    • Can have torrential TR and no V-wave (RA is very large and absorbs the regurgitation jet)
  • RV Lift Subtle (RV wall is thin)
  • Auscultation
    • Loud T1 (anterior leaflet large, “flaps”, makes sound)
    • Holosystolic murmur worse with inspiration (TR)
    • Clicks (large valve clicks when opens)

Diagnosis

  • ECG
  • Chest Xray
  • Echo Doppler
  • Oximetry

Chest Xray

  • Large globular heart (massive RA)
  • Narrow vascular pedicle
    (due to low cardiac output)
    • NO increase pulmonary vascularity
    • PAs are small
    • No ascending or descending aorta visible
Ebstein's Anomaly Chest Xray

ECG

  • RBBB (90%)
  • Pre-Excitation
  • Tall P-waves (aka “Himalayan”)
  • Prolonged P-R Interval
  • Atrial fibrillation or flutter
Ebstein's Typical ECG Markup

Echocardiogram

  • ***See tricuspid valve in the parasternal long axis***
    • Tricuspid and mitral valves are never in the same plane in normal individuals
  • Sail-like large redundant anterior leaflet
  • Shiina et al. J Am Coll Cardiol 3(2 Pt 1):356–370, 1984
    Diagnostic Criteria
    Septal leaflet is 8mm/m2 displaced from the crux of the heart (defined by mitral valve insertion)
  • RV size and function correlates to disease severity and is prognostic
  • The more atrialized the RV, the less functional it is
  • Classic M-Mode: See tricuspid and mitral valves at the same time
Classic M-Mode of Ebstein's Anomaly

Management

  • Surgical Repair
    1. Tricuspid valve repair (if feasible) or replacement
    2. Selective plication of atrialized RV
    3. Reduction atrioplasty (reducing RA size)
    4. Arrhythmia Surgery
    5. Closure of ASD (if present and safe) 
  • Surgical Issues:
    • If RV is too small or severely dilated/dysfunctional such that cannot tolerate full stroke volume, need single-ventricle palliation measures (Glenn/Fontan etc)
      • Glenn/Fontan cannot be done if LA pressure or LVEDP are high or LV dysfunction is present (Class IIB – AHA)
    • EP study prior to surgery is often done (Class IIB – AHA)
      • 1/3 have multiple accessory pathways
      • Once valve is replaced, R-sided access for ablation is difficult
  • Timing of Surgery:
    • Children: Offer surgery early if cyanotic (main indication), otherwise wait until older (safer)
    • Risk of surgery increases if:
      • RV enlarges/fails
      • Right Heart Failure / Eisenmenger
      • Severe reduction in exercise capacity
Indications for Repair 2008 (Canadian)
CachNet Guidelines 2008
  • Worsening exercise capacity (NYHA > II)
  • Increasing heart rate (CTR > 60%)
  • Cyanosis (resting O2 sat < 90%)
  • Severe TR with symptoms
  • TIA / Stroke
  • Sustained AFL or AF
  • Accessory Pathway Atrial Arrhythmias
 
AHA 2018 Guidelines
AHA 2018 Guidelines (USA)
  • CMR useful to define anatomy (Class IIa)
  • EP study ± ablation if pre-excitation or pre-op (Class IIa)
    OR high risk pathway/multiple APs (Class I)
  • Surgical Repair Indications:
    • HF Symptoms
    • Objective worsening exercise capacity
    • Progressive RV dysfunction (echo/CMR)

Pregnancy

  • Pregnancy usually well tolerated
  • Contraindications to pregnancy
    • Cyanosis
    • R-sided HF
    • Arrhythmias

References