| Condition | EKG Findings |
|---|---|
| Normal P-waves | – Upright in II, Biphasic in V1, and inverted in aVR with an axis of 0° to 75° and a duration < 120 msec (3 small squares) – II: < 2.5 mm tall and < 3 mm wide – V1: Positive component is < 1.5 mm tall and Negative component is < 1 mm wide and < 1mm deep. |
| Right Atrial Abnormality | – II: > 2.5 mm tall – V1: > Positive deflection is > 1.5 mm tall |
| Left Atrial Abnormality | – II: > 3mm wide ± notched p-wave – V1: > 1 mm wide or > 1 mm deep negative deflection |
| Ectopic beats not from SA node | – P-wave morphology changes based on origin. – PR interval is usually normal since the AV nodal delay is present. |
| Junctional beats, AVNRT | – P-waves are inverted – P-waves may be immediately before (so short PR), embedded within, or shortly after the QRS. |
| – Multifocal Atrial Tachycardia (HR≥100) – Wandering Atrial Pacemaker (HR < 100) | – ≥ 3 morphologies of P-waves |
| Atrial Flutter | – P-waves are replaced by F-waves, typically with a rate of around 300 beats per minute |
| Atrial Fibrillation | – No P-waves. Coarse Atrial fibrillation may show waves that are irregular with many different morphologies and a very high rate. |
| Tachycardia, PACs, severe first degree heart block | – P-waves may be embedded in T-waves and not be immediately obvious. |
| Supra-ventricular tachycardia | – P-waves may be embedded in QRS and not be immediately obvious. |
| – Sinus Arrest, 3rd degree Sinoatrial exit block – Atrial Flutter (has F-waves) – Atrial Fibrillation | – Absent P-waves |
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