In a normal ECG recording, heart sound will occur

Options

A. On the P wave and at the end of QRS complex
B. On the QRS complex and at the end of T wave
C. At the end of P wave and on the T wave
D. At the end of QRS complex and on T wave

Answer

To answer the question about when heart sounds occur in a normal ECG recording, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understand the Components of an ECG**:
- An ECG (electrocardiogram) consists of several key components: the P wave, QRS complex, and T wave.
- The P wave represents atrial depolarization (contraction of the atria).
- The QRS complex represents ventricular depolarization (contraction of the ventricles).
- The T wave represents ventricular repolarization (relaxation of the ventricles).

2. **Identify Heart Sounds**:
- Heart sounds are produced by the closing of heart valves during the cardiac cycle.
- The first heart sound (S1), known as the "LUB" sound, occurs when the atrioventricular (AV) valves close at the beginning of ventricular contraction.
- The second heart sound (S2), known as the "DUB" sound, occurs when the semilunar valves close at the end of ventricular contraction.

3. **Correlate Heart Sounds with ECG Phases**:
- The S1 sound occurs during the QRS complex, which indicates that the ventricles are depolarizing and contracting.
- The S2 sound occurs at the end of the T wave, which indicates that the ventricles are repolarizing and relaxing.

4. **Conclusion**:
- Therefore, in a normal ECG recording, heart sounds will occur during the QRS complex (for S1) and at the end of the T wave (for S2).

### Final Answer:
In a normal ECG recording, heart sounds will occur during the QRS complex and at the end of the T wave.

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