P Wave (PPT) – Dr. Akif Baig

The P wave on an electrocardiogram (ECG) represents the depolarization of the atria, the heart’s upper chambers. It signifies the electrical impulse that originates in the sinoatrial (SA) node and spreads through the atria, causing them to contract and push blood into the ventricles. A normal P wave is smooth, rounded, and typically lasts about 0.08 to 0.10 seconds (80-100 ms).

Key Points about the P Wave:

• Duration: 0.08 to 0.10 seconds (80-100 ms).
• Amplitude: Usually less than 2.5 mm in height.
• Direction: Typically upright in leads I, II, and aVF, and inverted in lead aVR.
• Significance: Reflects normal atrial function. Abnormalities in the P wave can suggest atrial enlargement, atrial fibrillation, or other conduction disturbances.

Abnormal P Wave Patterns:

• P pulmonale: Tall, peaked P waves, often indicating right atrial enlargement (associated with pulmonary conditions).
• P mitrale: Notched or broad P waves, indicating left atrial enlargement.
• Absent P waves: Often seen in atrial fibrillation or junctional rhythms.