ECG depicts the depolarisation and repolarisation process during the cardiac cycle. In the ECG of a normal healthy individual one of the following waves is not represented.

Options

A. Depolarisation of atria
B. Repolarisation of atria
C. Depolarisation of ventricles
D. Repolarisation of ventricles

Answer

To solve the question regarding which wave is not represented in the ECG of a normal healthy individual, we will analyze the components of the ECG and the processes they represent.

### Step-by-Step Solution:

1. **Understanding ECG**: The ECG (electrocardiogram) records the electrical activity of the heart during the cardiac cycle. It consists of several waves that correspond to specific electrical events in the heart.

2. **Identifying the Waves**:
- **P Wave**: Represents the depolarization of the atria.
- **QRS Complex**: Represents the depolarization of the ventricles.
- **T Wave**: Represents the repolarization of the ventricles.
- **PR Interval**: Indicates the delay at the AV node but is not a wave itself.
- **ST Segment**: Represents the beginning of ventricular repolarization.

3. **Analyzing the Options**:
- **Depolarization of Atria**: This is represented by the P wave. Therefore, it is present in the ECG.
- **Repolarization of Atria**: This is not represented in the ECG. There is no distinct wave for atrial repolarization.
- **Depolarization of Ventricles**: This is represented by the QRS complex. Hence, it is present in the ECG.
- **Repolarization of Ventricles**: This is represented by the T wave. Thus, it is also present in the ECG.

4. **Conclusion**: The only wave that is not represented in the ECG of a normal healthy individual is the **repolarization of the atria**.

### Final Answer:
The wave not represented in the ECG of a normal healthy individual is the **repolarization of the atria**.

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