Left atrial enlargement


Left atrial enlargement (LAE) may result from many conditions, either congenital or acquired.

As per echocardiography, using body surface area, an index LA volume is resulted, with a recommended upper limit of normal being an indexed left atrial volume of 34 mL per square meter.



  • mitral stenosis
  • mitral regurgitation
  • left ventricular failure
  • left atrial myxoma
  • atrial fibrillation


  • ventricular septal defect (VSD)
  • patent ductus arteriosus (PDA)

Clinical presentation

  • Ortner syndrome: left recurrent laryngeal nerve palsy secondary to compression from enlarged left atrium 
  • dysphagia megalatriensis: compression of esophagus between the enlarged left atrium and vertebral bodies 
  • atrial fibrillation
  • thromboembolic events (e.g. ischemic stroke) due to stasis of blood in the enlarged left atrium (especially the left atrial appendage) and/or atrial fibrillation

ECG presentation

  • broad, bifid P wave in lead II (P mitrale) and enlarges the terminal negative portion of the P wave in V1

  In lead II 

  • bifid P wave with > 40 ms between the two peaks 
  • Total P wave duration > 110 ms 

   In lead V1 

  • Biphasic P wave with terminal negative portion > 40 ms duration 
  • Biphasic P wave with terminal negative portion > 1mm deep

Picture 1 P mitrale 

Picture 2  Terminal negative portion of the P wave in V1


  1. Parajuli P, Ahmed AA. Left Atrial Enlargement. 2020 Aug 11. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan–. PMID: 31971736.
  2. https://litfl.com/left-atrial-enlargement-ecg-library/
  3. https://radiopaedia.org/articles/left-atrial-enlargement