Can any one explain what does Goljan mean by:
Increased preload causes the click and murmur in mitral valve prolapse to move closer to the S2 heart sound.
I did not understand how you bring it closer to S2. can some one explain this
MVP is a systolic murmur - increased preload causes increased blood flow into the right heart and hence the left side as well, since MVP is associated with a midsystolic click, which means that you hear the murmur after S1 in between S2, if you increase the volume you accentuate the murmur because you are slamming more blood against the prolapsed valve as it goes from the LA to the LV.
if i am wrong someone please clarify.
more blood in LV so longer time for systole (Starling law) and hence longer time for the murmur to be closer to S2. Does that make sense?
it's because of the flopping nature of the valve and chordae in MVP ..
see, when preload increases, that means ventricular end diastolic volume increases which makes the mitral valve leaflets fit together more .. n that accentuate the murmur .. and since it's a systolic murmur, meaning between S1 and S2, the murmur will be delayed (murmur is heard when leaflets separate from each other and that happens as the ventricle is pumping out blood and its volume is decreasing) and comes closer to the S2.
FYI: when mitral regurtiation becomes severe the murmur increases with squatting because it increases afterload (although it also increase preload).
Good luck!
i'm not sure about the "intensity" of the murmur in MVP.
But the pathophysiology of the murmur to be "SHORTER" (closer to S2) and "LONGER" (closer to S1) is due to "THE VARIATION IN PULLING STRETCH OF CHORDAE TENDINAE"
*Increased Preload--->stretches and increase the LV cavity size---->that "Pulls tight the Chordae Tendinae"----->thereby "Delaying the Prolaps"----->"Delayed Systolic Click" and "Shorter Murrmur" (Closer to S2)
*with Decreased Preload, it's the the opposite.