Following Is true regarding opening snap –
**Core Concept**
An opening snap is a clinical finding associated with mitral stenosis, a valvular heart disease characterized by the narrowing of the mitral valve orifice. It is a high-pitched sound heard during early diastole, representing the sudden opening of the stenotic mitral valve.
**Why the Correct Answer is Right**
The opening snap is caused by the sudden opening of the mitral valve, which is due to the increased pressure gradient between the left atrium and the left ventricle. This is a result of the mitral valve orifice being narrowed, leading to a higher pressure in the left atrium. The snap is generated by the sudden movement of the mitral valve leaflets, which is facilitated by the increased pressure gradient. This mechanism is similar to the way a spring snaps open when it is released from tension.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because an opening snap is not typically associated with aortic stenosis, which is a valvular disease affecting the aortic valve.
**Option B:** This option is incorrect because a mid-diastolic murmur is characteristic of mitral stenosis, but it is not the same as an opening snap.
**Option C:** This option is incorrect because a pericardial friction rub is a sound associated with pericarditis, which is an inflammation of the pericardium.
**Clinical Pearl / High-Yield Fact**
A key clinical correlation to remember is that an opening snap is often associated with a low-pitched diastolic murmur, which is the characteristic auscultatory finding in mitral stenosis.
**Correct Answer:** D