II. Findings: Normal
- Upright: I, II, avF, V4, V5, V6
- Inverted: aVR
- Variable: III, avL, V1, V2, V3
III. Causes: P Wave Inversion (other than aVR)
- Ectopic atrial focus
- AV nodal rhythm
IV. Causes: High Amplitude - Atrial hypertrophy or atrial dilatation
- Mitral valve or tricuspid valve disease
- Hypertension
- Cor Pulmonale
- Congenital Heart Disease
V. Causes: Low Amplitude (short P Wave)
- Hyperkalemia (associated with a tall T Wave)
VI. Causes: Wide P Wave (over .11 sec)
- Left atrial enlargement
VII. Causes: Biphasic P Wave (second half negative in III or V1)
- Left Atrial Enlargement
VIII. Causes: M shaped or notched P Wave
- M-Mitral: Left atrial enlargement
- Findings
- Over 0.04 seconds between peaks
- Taller in I than in III
IX. Causes: Peaked P Wave
- P-Pulmonale: Right atrial enlargement
- Findings
- Tall and pointed
- Taller in Lead III than in I
X. Causes: P Waves absent
- Precaution
- Look closely for regularly spaced "artifact" on the ekg (e.g. low voltage P Waves)
- Atrial Fibrillation or Atrial Flutter
- Sinoatrial node block
- AV Nodal rhythm
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| Definition (NCI) | An electrocardiographic finding of the current of atrial contraction when they are depolarized. The initial portion of the P wave is largely a reflection of right atrial depolarization and the terminal portion reflects depolarization of the left atrium. |
| Concepts | Organism Attribute (T032) |
| SnomedCT | 142070006, 33405001 |
| LNC | MTHU024602 |
| English | p wave, p waves, P Wave, P wave (observable entity), P wave, P wave feature (observable entity), P wave feature |
| Spanish | onda P (entidad observable), onda P |
