Left atrial enlargement

Introduction

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.

Causes

Acquired

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

Congenital

  • 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



References

  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