Right Atrial Enlargement

Atrial enlargement can be determined by analyzing the P waves in leads II and V1. The first half of the P wave represents right atrial depolarization, while the second half represents left atrial depolarization. In right atrial enlargement, a tall P wave in lead II (greater than 2.5mm) can be seen.


P wave morphologies for atrial enlargement in leads II and V1.



  1. Wagner GS, Strauss DG. Marriott’s Practical Electrocardiography. 12th ed. Lippincott Williams & Wilkins; 2014.