monam84
Forum Senior
Topics: 35
Posts: 135
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Hi All, I'm new to the forum, I was going through Goljan RR and I could not understand the following: In mitral valve prolapse, when you decrease the preload the murmur is heard closer to S1 whereas if the preload increases the murmur is heard closer to S2. How does this work? 
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| new_n_lost
Politically InCorrect
Topics: 650
Posts: 6,058
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In mitral valve prolapse, one or both leaflets of the valve are too large, or the chordae tendinea (the strings attached to the underside of the leaflets, connected to the ventricular wall) are too long (redundant), resulting in uneven closure of the valve during each heartbeat. Because of uneven closure of the leaflets, the valve bulges back, or "prolapses," into the left atrium like a parachute. When this happens, a very small amount of blood may leak through, moving backward from the ventricle to the atrium.
Mitral valve prolapse (MVP), the most common anomaly of the mitral valve apparatus, occurs when one or both mitral valve leaflets excessively billows (swells) into the left atrium toward the end of systole.
Apical, single or multiple, mid-to-late systolic clicks, which result from the tightening of the chordae tendineae or the redundant valve, can be heard.
The classic auscultatory finding is a mid-to-late systolic click, which is present due to the leaflets prolapsing into the left atrium resulting in tensing of the mitral valve apparatus. The midsystolic click can vary in intensity and timing, primarily depending on left ventricular volume. Low left ventricular end-diastolic volume shortens the mitral annular papillary muscle distance, allowing the leaflets to prolapse earlier in systole.
Timing and degree of the prolapse are determined by the position of the mitral leaflets at end diastole, which, in turn, is dependent on the distance from the mitral valve annulus to the attachment of the chordae to papillary muscles.
So the More the Volume the late is going to be the click
Edited by new_n_lost on 04/18/07 - 06:04 PM
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| monam84
Forum Senior
Topics: 35
Posts: 135
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Thanks, that makes a lot more sense. I was driving myself crazy trying to understand it. I liked the parachute analogy- really helped me visualize it.
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