Different names for of P waves in right atrial overload are P pulmonale, P congenitale and P tricuspidale. P pulmonale has a rightward axis of P wave so that P wave in lead III is taller than that in lead II, while in P congenitale, P wave is taller in lead II than in lead III. P tricuspidale is a tall and notched P wave with first peak taller than the second.
General features indicating right atrial overload are:
- Tall sharp P waves in lead II measuring 0.25 mV (2.5 mm) or more.
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Sharp initial deflection of P wave in V1 of 0.1 mV (1 mm) or more.
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Sharp intrinsicoid deflection of P wave (atrial intrinsicoid deflection) is suggestive of right atrial enlargement even in the presence of a prominent negative deflection in V1 (pseudo left atrial enlargement pattern, often seen in atrial septal defect).