By Ken Grauer, MD, Professor, Department of Community Health and Family Medicine, University of Florida. Dr. Grauer is the sole proprietor of KG-EKG Press, and publisher of an ECG pocket brain book.
Scenario: The ECG above was obtained from a slender and previously healthy 27-year-old woman having atypical chest discomfort. Is there evidence of chamber enlargement?
Interpretation: The ECG shows sinus rhythm with slight variation in rate (sinus arrhythmia). The PR, QRS, and QT intervals are normal. The axis is vertical at +80 degrees. The P wave is tall and peaked in each of the inferior leads (II, III, aVF). It is > 2.5 mm tall in lead II, thereby satisfying criteria for right atrial abnormality (RAA). Given the patient's age, voltage criteria for LVH are not met (QRS amplitude is often increased in adults younger than age 35). There are small q waves in multiple leads; transition occurs normally (between V2-to-V3) and ST-T waves are normal. We are left with the impression of an essentially normal tracing for this 27-year-old woman, with the exception of RAA.
The reason we prefer the terms right and left atrial abnormality (RAA/LAA) instead of right and left atrial enlargement (RAE/LAE) is that altered P wave morpho-logy does not always imply pathology. In addition to true increased atrial chamber size, other causes of altered P wave morphology include atrial conduction defects, abnormal chamber pressure, and body habitus. Tall, peaked P waves in the inferior leads are commonly seen in slender young adults with a vertical QRS axis. Assuming the patient had a normal examination, it is most likely that RAA is a benign variant pattern in her case with no clinical implications.