Murmur of Mitral Stenosis

Murmur of Mitral Stenosis

Classic Murmur of Mitral Stenosis

Murmur of Mitral Stenosis

Mid-diastolic low-pitched rumbling murmur of mitral stenosis with pre-systolic accentuation is best audible at the apex, in the left lateral position with the bell of the stethoscope.

Pre-systolic accentuation usually means the presence of atrial contraction and hence sinus rhythm, but it may persist in AF following short diastoles.

The duration of the murmur is directly proportional to the severity of mitral stenosis, but the intensity of the murmur is not.

The murmur can be heard provided the atrioventricular gradient remains above 3 mmHg.

Because diastolic mean gradient is directly related to heart rate, the manoeuvres that increase heart rate can help to detect an otherwise faint murmur.

Opening snap (OS) of the Mitral stenosis

High-pitched early diastolic sound due to sudden tensing of the valve leaflets and subvalvular apparatus at the end of the opening excursion.

  1. Opening snap is a high-pitched sound in early diastole
  2. Coincides with the opening of the mitral valve.

How to differentiate – Opening snap vs S3

  1. Opening snap -Because of its higher pitch, Opening snap can be heard over a wider area over the precordium than mid-diastolic rumble and S3
  2. Opening snap – is a much higher pitched sound than S3
  3. S3 – localised to the apex only
  4. Opening snap -can be heard at the left sternal border and even at the base of the heart.

How to differentiate – Opening snap vs P2

  1. Loud P2 may simulate the OS
  2. Normally P2 is not heard at the aortic area unless there is severe pulmonary hypertension.

A crisp OS suggests a pliable valve and hence is probably suitable for balloon mitral valvuloplasty.

Opening snap – occurs closer to S2 than the pericardial knock and the S3 gallop.

Opening snap – Best heard in the “supramammary area” – just above and slightly to the left of the nipple (or between the apex and the left sternal border).

  • The OS occurs 40-120 milliseconds after A2.
  • A2-OS interval is inversely proportional to the height of the left atrial (LA)-LV diastolic pressure gradient.

Mitral Stenosis severity – A2-OS interval varies inversely with the severity of mitral stenosis.

  • Mild MS – A2-OS interval of more than 100 milliseconds usually indicates mild MS
  • Moderate MS – A2-OS interval 70 -100 milliseconds usually suggests Moderate MS
  • Severe MS – A2-OS interval less than 70 milliseconds usually suggests severe MS

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