Conduction abnormality within the right and left atrium, which may be due to both right and left atrial enlargement (dilation), or right and left atrial hypertrophy (thickening).
-Combination of criterial for right atrial abnormality and left atrial abnormality.
-Right atrial abnormality:
-P wave 2 (inferior leads): >2.5 mm tall; >2 boxes wide; peaked.
-P waves V1: >1.5 mm tall.
-Left atrial abnormality:
-P wave V1: >1 box deep; >1 box wide.
-P wave 2: >0.12 sec (3 boxes); notched.