In all the leads of ECG, all the following are positive waves except

Options

A. P
B. Q
C. R
D. T

Answer

To answer the question "In all the leads of ECG, all the following are positive waves except," we need to analyze the components of an electrocardiogram (ECG) and understand the characteristics of the waves produced.

### Step-by-Step Solution:

1. **Understand the ECG Waves**: An ECG consists of several waves, primarily the P wave, QRS complex, and T wave. Each of these waves represents different electrical activities of the heart.

2. **Identify the Waves**:
- **P Wave**: Represents atrial depolarization and is typically a positive wave in most leads.
- **QRS Complex**: Represents ventricular depolarization. The Q wave can be negative, but the R and S waves can be positive or negative depending on the lead.
- **T Wave**: Represents ventricular repolarization and is usually positive in most leads.

3. **Analyze the Leads**: In standard ECG leads (I, II, III, aVR, aVL, aVF, V1-V6), we need to determine which wave is not positive in all leads.

4. **Identify the Exception**: The Q wave is often negative in many leads, particularly in lead aVR and sometimes in lead V1. Therefore, it is the wave that is not positive in all leads.

5. **Conclusion**: The correct answer to the question is the Q wave, as it is the only wave that can be negative in certain leads of the ECG.

### Final Answer:
In all the leads of ECG, all the following are positive waves except the Q wave.