welcome redditors!to snoo-finity ... and beyond!

NBME 23 Answers

nbme23/Block 4/Question#14

A 61-year-old woman comes to the physician for a ...

Closure of the mitral valve

Login to comment/vote.

 +9  upvote downvote
submitted by lfsuarez(68),

First heart sound (S1) is generated by two heart valves: the mitral valve and tricuspid valve. Nearly simultaneous closing of these valves normally generates a single S1 sound. Splitting of the S1 sound is heard when mitral and tricuspid valves close at slightly different times, with usually the mitral closing before tricuspid

yotsubato  Then why the fuck is it describing a mitral valve sound in the tricuspid area +4  
dr.xx  it's describing a splitting S1 — consisting of mitral and tricuspid valve closure — that is best heard at the tricuspid (left lower sternal border) and mitral (cardiac apex) listening posts. +2  
titanesxvi  tricky question, I though what sound it is in the left sternal border, so I chose tricuspid valve, but what they where asking was, what is the first component of the S1 sound +  
titanesxvi  tricky question, I though what sound it is in the left sternal border, so I chose tricuspid valve, but what they where asking was, what is the first component of the S1 sound +  






 +1  upvote downvote
submitted by yogi(9),

Q: Split S1 heard over Left sternal border - tricuspid area. First component of S1? A: anything (MC in RBBB) that causes delayed closure of tricuspid valve compared to mitral valve- will cause split S1 with delayed T1 and early M1 heard at Tricuspid area.





 +0  upvote downvote
submitted by rolubui(0),

The way I remember it, S1: Mitral & tricuspid bc blood goes from atria to ventricles then from ventricles to outside the heart --> S2. Now, when you have a Split S1 the way I think about is that when you inhale you have extra blood coming into the right side of the heart so the tricuspid valves closes later and causes a split S1 upon respiration. Hope that helps.