The apex beat of heart is synchronous with

Options

A. First sound
B. Second sound
C. Third sound
D. Fourth sound

Answer

**Step-by-Step Solution:**

1. **Understanding Apex Beat**: The apex beat of the heart refers to the point of maximum impulse where the heart's contraction can be felt, typically located at the left fifth intercostal space. It is primarily caused by the contraction of the ventricles.

2. **Identifying Heart Sounds**: The heart produces sounds during the cardiac cycle, primarily the first heart sound (S1) and the second heart sound (S2). The first heart sound (S1) is often described as "lub," while the second heart sound (S2) is described as "dub."

3. **Mechanism of Heart Sounds**: The first heart sound (S1) occurs due to the closure of the atrioventricular (AV) valves, which include the tricuspid valve (right side) and the bicuspid or mitral valve (left side). This closure happens at the beginning of ventricular contraction (systole).

4. **Synchronous Events**: The apex beat, which is the result of ventricular contraction, occurs simultaneously with the closure of the AV valves. Therefore, the apex beat is synchronous with the first heart sound (S1).

5. **Conclusion**: Based on the above understanding, the apex beat of the heart is synchronous with the first heart sound (S1).

**Final Answer**: The apex beat of the heart is synchronous with the first sound (S1).

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