Ebstein's Anomaly

• Congenital defect of the tricuspid valve (TV) and the right ventricle (RV)
• TV septal and posterior leaflets are apically displaced resulting in "atrialization" of a portion of the right ventricle (ultimately a large right atrium and small right ventricle)
• ~40-50% of individuals with Ebstein anomaly have evidence of Wolf-Parkinson-White, secondary to the atrialized right ventricle
• ECG abnormalities include:
  • Right atrial enlargement or tall and broad P waves (Himalayan P waves) 
  • Prolonged PR interval
  • Right bundle branch block 
  • Low amplitude QRS complexes in the right precordial leads
  • T wave inversions V1-V4 and/or Q waves V1-V4

References

Osiro S, Tiwari K, Mathenge N, et al. When Lithum Hurts: A Look at Ebstein Anomaly. Cardiology in Review. Oct 2013, Vol 21(5); pgs 257-263.