Which correctly pairs an ECG phase with the cardiac event responsible ?

Options

A. P wave -Depolarization of the ventricles
B. P wave -Depolarization of the AV node
C. QRS wave-Depolarizatiion of the ventricles
D. T wave-Repolarization of the atria

Answer

To solve the question of which ECG phase correctly pairs with the cardiac event responsible, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the ECG Phases**: The ECG (electrocardiogram) consists of several phases: P wave, QRS complex, and T wave. Each of these phases corresponds to specific electrical events in the heart.

2. **Identify the Cardiac Events**:
- **P Wave**: Represents atrial depolarization (contraction of the atria).
- **QRS Complex**: Represents ventricular depolarization (contraction of the ventricles).
- **T Wave**: Represents ventricular repolarization (relaxation of the ventricles).

3. **Evaluate Each Option**:
- **Option A**: P wave corresponds to depolarization of ventricles. This is incorrect because the P wave represents atrial depolarization, not ventricular.
- **Option B**: P wave represents depolarization of the AV node. This is also incorrect; the AV node does not generate a wave in the ECG but rather conducts impulses.
- **Option C**: QRS wave causes depolarization of ventricles. This is correct because the QRS complex indeed represents the electrical activity that leads to ventricular contraction.
- **Option D**: T wave represents repolarization of atria. This is incorrect; the T wave represents ventricular repolarization, not atrial.

4. **Conclusion**: The only correct pairing is found in Option C, where the QRS wave corresponds to the depolarization of the ventricles.

### Final Answer:
**Option C: QRS wave causes the depolarization of ventricles.**