Which of the following is not represented in normal human ECG?

Options

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

Answer

To solve the question "Which of the following is not represented in normal human ECG?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the ECG**: The first step is to understand what an electrocardiogram (ECG) is. An ECG is a recording of the electrical activity of the heart over a period of time. It shows the heart's rhythm and can help identify various heart conditions.

2. **Identify the Components of ECG**: The ECG consists of several waves and intervals that represent different phases of the heart's electrical cycle:
- **P Wave**: Represents atrial depolarization.
- **QRS Complex**: Represents ventricular depolarization.
- **T Wave**: Represents ventricular repolarization.

3. **Analyze the Options**: Now, let's analyze the options given in the question:
- **Option A: Depolarization of atria**: This is represented by the P wave in the ECG.
- **Option B: Depolarization of ventricles**: This is represented by the QRS complex in the ECG.
- **Option C: Repolarization of atria**: This is not distinctly represented in the ECG. It is often obscured by the QRS complex.
- **Option D: Repolarization of ventricles**: This is represented by the T wave in the ECG.

4. **Determine the Correct Answer**: From the analysis, we see that the repolarization of the atria (Option C) is not represented in a normal human ECG. Therefore, the correct answer to the question is **Option C: Repolarization of atria**.

### Final Answer:
The correct answer is **Repolarization of atria**.