Right Atrial Enlargement (RAE) ECG Review

When right atrial enlargement occurs, it does not take longer for cardiac action potentials to travel through the atrial myocardium (similar to left atrial enlargement). However, the amplitude of the P wave is exaggerated due to the close proximity of the hypertrophied right atrial myocardium to the SA node. This is referred to as p-pulmonale since lung disease can cause severe right heart strain and right atrial enlargement. Thus, the P wave height becomes larger. The ECG criteria for diagnosing right atrial enlargement (RAE) are as follows:

  1. The P wave amplitude in lead II > 2.5 mm, or
  2. The upward deflection of the P wave in lead V1 > 1.5 mm in amplitude.

ECG Examples:

References:

  1. Surawicz B, et al. Circulation. 2009;119:e235-240.
  2. Chou's Electrocardiography in Clinical Practice: Adult and Pediatric, Sixth Edition, Saunders, Philadelphia, 2008.