@ Sarim or others MVP murmur - drwinusmle

[ArchivalUser]

Can someone pls explain that what is the effect of increase in after load especially (squatting, passive leg raise) on the murmur of Mitral valve prolapse.

My understanding is that whatever increases after load would increase the intensity of this murmur. However in UW they say that it decreases with squating and passive leg raise. That made me think that if something is increasing after load as well as preload (e.g. squatting) would decrease the MVP murmur b/c of the effect of increase preload in atria that ---> increase pressure and less tension of the valve back ward during ventricular systole, and that makes sense. However, FA says that squating and hand grip both ---> increase MVP murmur, so that is confusing. May be I am missing some thing here.

[ArchivalUser]

I hope it helps ....

SQUATTING Squatting from a standing position is associated with a simultaneous increase in venous return and systemic vascular resistance and a rise in arterial pressure. This causes changes in the following murmurs:

• Increased intensity of the murmur of mitral regurgitation.

• Increase in the magnitude of the left-to-right shunt in ventricular septal defect associated with an increased intensity of the systolic murmur.

• In patients with tetralogy of Fallot, a decreased left-to-right shunt and increased pulmonary flow are associated with an increased intensity of the pulmonary ejection systolic murmur.

• Intensity of the diastolic murmur of aortic regurgitation increases due to augmented regurgitation; intensity of the Austin-Flint murmur also may increase.

• In hypertrophic cardiomyopathy, intensity of the ejection systolic murmur promptly declines because of an increased left ventricular volume and arterial pressure, which increase the effective orifice size of the outflow tract; the carotid pulse upstroke remains sharp, and the volume may increase.

• Intensity of the murmur of valvular aortic stenosis shows variable changes, depending upon the type of hemodynamic response; a significant increase in systemic vascular resistance is associated with a decreased intensity of the murmur, an increased left ventricular volume with increased intensity of the murmur.

*************************************************************************
• In patients with mitral valve prolapse there is a delay in the onset of the click and late systolic murmur.
*************************************************************************

VALSALVA MANEUVER : The hemodynamic changes resulting from a Valsalva maneuver vary with the different phases.

• During phase 1, with the onset of the maneuver, there is a transient increase in left ventricular output.

• During the straining phase, phase 2, there is a decrease in venous return, right and left ventricular volumes, stroke volumes, mean arterial pressure, and pulse pressure; this is associated with a reflex increase in heart rate.

• During phase 3 (release of Valsalva), which only lasts for a few cardiac cycles, there is a further reduction in left ventricular volume.

• Phase 4 is characterized by an increase in stroke volume and arterial pressure and reflex slowing of heart rate (the overshoot).

Analysis of changes in the intensity and character of the murmur during phase 2 of the Valsalva maneuver is most useful and practical for the differential diagnosis.

• The intensity of flow murmurs, murmurs of aortic and pulmonary stenosis, tricuspid and mitral regurgitation, aortic and pulmonary regurgitation, and mitral and tricuspid stenosis decreases. The volume of the carotid pulse also decreases.

• The murmur of hypertrophic cardiomyopathy increases in intensity as the left ventricular outflow size decreases with a decreased venous return. The carotid pulse volume also declines.
***************************************************************************
• In mitral valve prolapse there is an early onset of the click and murmur due to the decrease in left ventricular volume. The opposite effects are observed during phase 4.
***************************************************************************

HAND GRIP : Sustained hand grip for 20 to 30 seconds leads to an increase in systemic vascular resistance, arterial pressure, cardiac output, and left ventricular volume and filling pressure. Hemodynamic changes during hand grip are variable and not always similar in all patients. As an example, the increase in arterial pressure may be relatively greater than the increase in heart rate or cardiac output. Thus, changes in intensity of murmurs are not always predictable.

Hand grip is most useful in differentiating between the ejection systolic murmur of aortic stenosis and the regurgitant murmur of mitral insufficiency. Intensity of the murmur of aortic stenosis tends to decrease along with a decreased transvalvular pressure gradient, while the severity and murmur of mitral regurgitation increase. Other murmurs change as follows:

• Increased severity and murmur of aortic regurgitation

• Increased left-to-right shunt in ventricular septal defect with an increased intensity of the murmur

• The diastolic murmur of mitral stenosis becomes accentuated because of an increased heart rate and cardiac output

• In hypertrophic cardiomyopathy, intensity of the ejection systolic murmur softens due to an increased left ventricular volume
****************************************************************************
• The click and the murmur of mitral valve prolapse are delayed because of the increased left ventricular volume
****************************************************************************

[ArchivalUser]

Maryam,,you are greatttt, it sloves lot of my confusions. Thanks a million!!!!!!!

[ArchivalUser]

u r welcome

[ArchivalUser]

very nice maryam thanks.

MVP murmur:

Click appear Later- SHORTER Less Intense Murmur. (Inc Preload and/or Inc Afterload)

.Squatting...................(Inc Preload and Incr Afterload)
.Sustained Hand Grip...(Inc Afterload.....not much effect on venous return)
.Passive Leg raise .......(Inc Preload)


Click appear Earlier - LONGER More Intense Murmur.(Decr Preload and/or Decr Afterload)

.Standing .......(Decr Preload)
.Valsalva ........(Decr Preload)
.Amyl Nitrite... (Decr afterload)
.Anxiety (Inc Heart rate--->less time for LV filling--->smaller cavity)



Mechanism:

Think of "LV chamber" (it is a Systolic murmur)....In this case when we say Inc/decr preload, we are talking about LV volume load.

when LV volume load Increased---->it stretches and incr the cavity size---->"The Stretch will pull tight the Chordae Tendinae"...resisting the prolaps of the mitral valve into LA cavity.......hence the Click get delayed and murmur get Shorter and less intense.

the opposite is true when LV volume Decreases.


How is it that "Afterload" affect the murmur ?

when u increase the afterload, it will resist LV emptying during systole....hence more blood volume gets to stay in LV for longer period keeping the LV stretched which pulls tight C.Tendinae----->delayed prolaps.

when u decrease afterload e.g with Amyl Nitrire.....will allow faster emptying of LV----->and u know the rest.

[ArchivalUser]

Thanks Sarim, it clarifies further; now, I can kill the murmurs