Mehl. S2, S3, S4, P2 Flashcards
S3 and S4, what cycle?
Both are diastolic sounds.
S3 is due to?
High volume/preload in the left ventricle, causing a reverberation against the wall.
S3 can sometimes be physiologic in what conditions? 2
In pregnancy and high-endurance athletes. Patient will have eccentric hypertrophy (sarcomeres laid in linear sequence).
S3 if pathologic, what changes/condition?
If pathologic, it is due to dilated cardiomyopathy with reduced ejection fraction (<55%) or high-output cardiac failure (EF >70%).
There is one question on IM CMS form 7 where they give an S3 in diastolic dysfunction. I’m convinced this is an erratum, but I need to mention it because it exists on the NBME form.(???)
Tai kad S3 ir S4 yra diastolic, wtf
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S4 is due to?
high pressure/afterload on the left (but sometimes right) ventricle, causing a stiffened ventricle with diastolic dysfunction and concentric hypertrophy (sarcomeres laid in parallel).
S4 is always pathologic.!!!!!!!!!!!!!!! (S3 not)
It is usually caused by systemic hypertension causing afterload on the LV, or aortic stenosis.
S4 can sometimes be right-sided on USMLE. There is a 2CK Q where they give severe mitral stenosis and say there’s an S4, but it’s for the RV not LV. Some weird/annoying points: The combo of S3 and S4, seen together in the same vignette, can be seen in????
high-output cardiac failure.
S3+S4 can be seen in high-output cardiac failure. For example, they will say a patient as an AV fistula/conduit, or has Paget disease, and they will say there’s S3 and S4 and ask for diagnosis =?
high-output cardiac failure.
The take- home point is that high-output failure can present with either an isolated S3 or the combo of S3 and S4 together, but never S4 alone on USMLE.
!!high-output failure can present with ???
either an isolated S3 or the combo of S3 and S4 together, but never S4 alone on USMLE
One of the highest yield cardiac sounds on USMLE, almost always overlooked by students.??
Loud P2
Loud P2 - means what?
pulmonary hypertension or cor pulmonale on USMLE.
The pulmonic valve slams shut due to high pressure distal to it.
or example, they’ll give a smoker who simply has a loud P2 -> this just means patient has???
pulmonary hypertension.
Also recall that I said above that highest yield cause of tricuspid regurg on USMLE is pulmonary hypertension / cor pulmonale.
So both what I want you to remember is both TR and loud P2 for this.
Loud P2. Sometimes the UMSLE will just say “loud pulmonic component of S2,” or “loud S2,” rather than saying “loud P2.
I’ve never seen “loud A2” on USMLE, but in theory this means systemic hypertension.
A soft P2 refers to pulmonic stenosis, but is LY.
Means right ventricular hypertrophy on USMLE.??
Wide splitting of S2
Wide splitting of S2 mens what?
Means right ventricular hypertrophy on USMLE.
A2 and P2 are far apart.
You don’t have to worry about the mechanism. But in short, the more pressure you have in a ventricle, the more delayed the semilunar valve will close. So if we have RVH, P2 occurs later, widening the split.
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Wide splitting of S2, right-axis deviation on ECG, and right bundle branch block (RBBB) all = ?
right ventricular hypertrophy on USMLE.
Means left ventricular hypertrophy on USMLE.?
Paradoxical splitting of S2
Paradoxical splitting of S2 means what?
Means left ventricular hypertrophy on USMLE.
A2 occurs after P2 (normally we have A2 before P2). name?
Paradoxical splitting of S2
Left ventricular pressure is high and A2 delayed to the point that it actually occurs on the opposite side of P2.
Paradoxical splitting of S2, left-axis deviation on ECG, and left bundle branch block (LBBB) all =?
left ventricular hypertrophy on USMLE.
