Mitral regurgitation physical examination
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The following are the key features of the physical examination in mitral regurgitation:
Palpation
Arterial Pulse: Watson's water hammer pulse or bounding pulse- brisk upstroke followed by rapid fall off of arterial pulse. However, the volume of the pulse may be decreased in the presence of heart failure.
Blood pressure: There is a wide pulse pressure.
Apical impulse: Brisk and hyperdynamic and may be displaced leftwards secondary to left ventricular enlargement.
Auscultation
Heart Sound:
- S1 is usually diminished due to failure of mitral valves to close properly.
- S2 is commonly widely split due to shorter time duration of left ventricular ejection and early A2.
- P2 is louder than A2 in presence of severe pulmonary hypertension.
- S3 may also be heard due to rapid filling of left ventricle. S3 in this case should not be interpreted as a feature of heart failure.
Murmur:
Quality: High pitched and blowing. Best heard with diaphragm of stethoscope with patient in left lateral dicubitus position.
Location: Usually best heard over the apical region with radiation to left axilla and left subscapular area.
- Posterior leaflet dysfunction murmur radiate to sternum or aortic area.
- Anterior leaflet dysfunction murmur radiate to back.
Duration:
- In the presence of an incompetent mitral valve, the pressure in the left ventricle becomes greater than that in the left atrium at the onset of isovolumic contraction, which corresponds to the closing of the mitral valve (S1). This explains why the murmur in mitral regurgitation starts at the same time as S1. This difference in pressure extends throughout systole and can even continue after the aortic valve has closed, explaining how it can sometimes drown the sound of S2. Hence named Holosystolic Murmur.
- If the murmur is heard in late systolic phase, it may be due to mitral valve prolapse or papillary muscle dysfunction. In these cases, S1 will probably be normal since initial closure of mitral valve cusps is unimpeded.
- Mid systolic click is suggestive of mitral valve prolapse.
Effect of Maneuvers: Murmur of mitral regurgitation may be difficult to distinguish from that of other valves' diseases. Certain maneuvers may be helpful in this regard.
- Respiration: There is little variation on intensity of mitral regurgitation murmur with respiration. However in some, there is increase in intensity of murmur during expiration.
- Valsalva Maneuver: The intensity of mitral regurgitation murmur decreases with valsalva maneuver as the venous return to heart is reduced. However in mitral regurgitation due to mitral valve prolapse, systolic murmur becomes longer and often louder.
- Hand grip Maneuver: Mitral regurgitation murmur becomes louder with hand grip as afterload increases.
- Positional changes:
- Standing- Intensity of mitral regurgitation murmur decreases while increases in mitral valve prolapse due to decreased venous return (preload).
- Leg raising- Intensity of mitral regurgitation murmur increase while mitral valve prolapse murmur decreases due to increase preload.
- Squatting- Intensity of murmur increases due to increased venous return while murmur of mitral valve prolapse, softens.
- Vasodilators (Amyl nitrate): Mitral regurgitation murmur softens due to decrease in afterload and hence increased stroke volume. Murmur of mitral valve prolapse is biphasic - initially soft, then loud.
Example of a Holosystolic Murmur
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