i have never understood why the various murmurs make the sounds they do - thus i can never get the questions right because memorizing simply does not work for me. anyone know of a good site that explains that stuff well?
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Step I heart murmurs
Started by kellysmith
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I don't know about a website, but there is an interactive CD called "Beyond Heart Sounds" that is very instructive. Your school's library probably has it.
kellysmith said:
i know very little about heart murmurs, so i'm not claiming to be an expert...but for my standardized patient exam i looked at a wigger's diagram while reading the description about the various murmurs and tried to predict what they'd sound like and at what point during the cardiac cycle they occurred. for example, mitral stenosis would be lub---dub-click---swwwwwwwwwwwwh---
you know the valve is stenotic so you should hear the murmur during diastole following the click of the mitral valve opening.
we only had to know aortic stenosi, regurg, and mitral stenosis and regurg...so i don't know about the numerous other ones.
then i'd google the specific murmur (ie., "mitral stenosis heart sounds") and listen to audio file of it to confirm or correct myself while following along on the wigger's diagram.
hope this helps.
anyone else going to chime in?
Mitral stenosis is actually an opening 'snap' in diastole (obviously), with a decrescendo rush of blood into the LV.
Aortic stenosis is crescendo-decrescendo, because of the buidup in pressure that has to occur to move blood through the narrowed valve. The valve still semi-opens when the pressure between LV and aorta equalizes, but not enough to move blood and therefore the pressure has to increase after the valve has opened.
Mitral regurgitation is obviously systolic and the best thing to remember with the regurg murmurs (tricuspid and aortic also) is that there is no discernible delay between the start of systole (tricuspid/mitral) or diastole (aortic/pulmonary) and the actual murmur. The valves never achieve patency and close all the way, so there is no opening sound or delay in the 'swooshing' murmur of blood rushing back through the valve. This is what they mean by a pansystolic/pandiastolic murmur.
Mitral valve prolapse is a 'click' then murmur during systole, as the valve leaflet gets pulled back by the blood flow from LV.
I would remember things like this for USMLE:
a) effect of Valsalva/carotid massage on a murmur.
b) effect of increasing/decreasing preload on a murmur
c) radiation sites of various murmurs (i.r. apex, axilla, etc.)
d) clinical findings associated with murmurs (most notably aortic regurg. and Marfans with MVP)
Hope this helps.
Aortic stenosis is crescendo-decrescendo, because of the buidup in pressure that has to occur to move blood through the narrowed valve. The valve still semi-opens when the pressure between LV and aorta equalizes, but not enough to move blood and therefore the pressure has to increase after the valve has opened.
Mitral regurgitation is obviously systolic and the best thing to remember with the regurg murmurs (tricuspid and aortic also) is that there is no discernible delay between the start of systole (tricuspid/mitral) or diastole (aortic/pulmonary) and the actual murmur. The valves never achieve patency and close all the way, so there is no opening sound or delay in the 'swooshing' murmur of blood rushing back through the valve. This is what they mean by a pansystolic/pandiastolic murmur.
Mitral valve prolapse is a 'click' then murmur during systole, as the valve leaflet gets pulled back by the blood flow from LV.
I would remember things like this for USMLE:
a) effect of Valsalva/carotid massage on a murmur.
b) effect of increasing/decreasing preload on a murmur
c) radiation sites of various murmurs (i.r. apex, axilla, etc.)
d) clinical findings associated with murmurs (most notably aortic regurg. and Marfans with MVP)
Hope this helps.
