An electrocardiogram (ECG) is a graphical representation of the heart’s electrical activity. The key components of the ECG waveform are the P wave, QRS complex, ST segment, and T wave. Here’s a detailed assessment:
Components of the ECG Waveform
- P Wave:
- Location: The first upward deflection in the ECG.
- Start: At the beginning of atrial depolarization.
- Duration: Normally 0.08 to 0.10 seconds (80-100 ms).
- Significance: Represents atrial depolarization. Abnormalities in the P wave can indicate atrial enlargement or other atrial abnormalities.
- PR Interval:
- Location: From the beginning of the P wave to the start of the QRS complex.
- Start: Beginning of atrial depolarization.
- End: Beginning of ventricular depolarization.
- Duration: 0.12 to 0.20 seconds (120-200 ms).
- Significance: Represents the time taken for the electrical impulse to travel from the atria to the ventricles. Prolonged PR interval indicates first-degree heart block.
- QRS Complex:
- Location: The next set of waves after the PR interval, typically consisting of a small downward Q wave, a large upward R wave, and a downward S wave.
- Start: Beginning of ventricular depolarization.
- Duration: 0.06 to 0.10 seconds (60-100 ms).
- Significance: Represents ventricular depolarization. A widened QRS complex can indicate bundle branch block or ventricular rhythm.
- ST Segment:
- Location: From the end of the QRS complex to the start of the T wave.
- Start: End of ventricular depolarization.
- End: Beginning of ventricular repolarization.
- Duration: Typically isoelectric (flat), but can vary.
- Significance: Represents the period when the ventric