Systolic murmurs: AS/PS, MR/TR & Mitral Valve prolapse
Systolic murmurs mnemonics: MR. ASS (Mitral Regurgitation Aortic Stenosis Systolic).
Systolic murmurs mnemonics by Qt: MR(TR). AS(PS)S (Remember M&T are 'equivalent' valve and thus will have similar functions/pathology => Remember AP & MT (mnemonics of APT M). Similarly, remember M&T are 'equivalent' valves and thus will have similar functions/pathology => remember from AP&MT (Mnemonics of APT M)
Systolic murmurs:
Normally, during systole (S1 to S2 period), M valve (S1) is supposed to close completely and A valve (S2) is supposed to open completely. Systolic murmur occurs when M valve fails to close completely leading to an 'eruption 'of blood flowing thru the otherwise closed valve (regurgitation). Systolic murmur also occurs when the A valve fails to open completely leading to leaking of blood flow thru the stenosis valve. Similarly, that's what happens in the T & P valves. ~By Qt.
Aortic stenosis is a systolic murmur (ejection systolic mumur).
Systolic murmurs mnemonics: MR. ASS (Mitral Regurgitation Aortic Stenosis Systolic).
Systolic murmurs mnemonics by Qt: MR(TR). AS(PS)S (Remember M&T are 'equivalent' valve and thus will have similar functions/pathology => Remember AP & MT (mnemonics of APT M). Similarly, remember M&T are 'equivalent' valves and thus will have similar functions/pathology => remember from AP&MT (Mnemonics of APT M)
Systolic murmurs:
Normally, during systole (S1 to S2 period), M valve (S1) is supposed to close completely and A valve (S2) is supposed to open completely. Systolic murmur occurs when M valve fails to close completely leading to an 'eruption 'of blood flowing thru the otherwise closed valve (regurgitation). Systolic murmur also occurs when the A valve fails to open completely leading to leaking of blood flow thru the stenosis valve. Similarly, that's what happens in the T & P valves. ~By Qt.
AORTIC STENOSIS
Aortic stenosis is a systolic murmur (ejection systolic mumur).
During this time (right after S1), the M valve & the A valve are closed as the pressure is building up in the Lt ventricle. Therefore, there are some msecs until which the the stenotic aortic valve starts to open up. However, since the A valve is stenotic, it won't open all the way creating the murmurs as the blood flows thru the stenotic valve. At first, when the A valve is pushed open, an ejection click (a few miliseconds after the S1) is audible. At this time, blood flow keeps going stronger (crescendo). Then, at a point, the blood flow will be slower gradually (descendo). Thus, the term 'crescendo-descendo' or 'diamond'.
This murmur can also radiate to the neck/carotid as remember that this is an aortic murmur due to aortic stenosis which has blood flows to the carotid
PULMONIC STENOSIS
Pulmonic stenosis is similar to aortic stenosis in terms of mechanism: it's a systolic ejection murmur. The only difference is that it doesn't radiate to the neck (because the blood flow goes to the lungs, evidently).
MITRAL VALVE REGURGITATION
Normally, during S1, the M valve will close tightly preventing the backflow (regurgitation) of blood from the Lt ventricle to the Lt atrium. However, due to some pathology, the M valve will not close tightly, thus, termed 'mitral valve regurgitation'. This murmur occurs right when S1 is heard because recall S1 signifies the closure of M valve. M valve is unable to close completely, therefore, the murmur is heard right at S1.
This regurgitation persists throughout the systole because the blood regurgitates with high pressure from the Lt ventricle to the Lt atrium throughout systole. During diastole (S2 thru S1), the M valve open for blood to flow to the Lt ventricle and you won't hear the regurgitaiton during diastole. Therefore, it's a systolic murmur.
Note that Mitral regurgitation can be heard in the axilla due to anatomic location.
TRICUSPID REGURGITATION
Tricuspid regurgitation is similar to Mitral regurgitation in terms of mechanism except that you won't hear it in the armpit due to anatomic location.
MITRAL VALVE PROLAPSE
Mitral valve prolapse occurs when the tendon chordae that anchors the valve to the ventricles become flail and unable to completely close off during systole. Instead, the valve will billow up (prolapse) and cause a mid-systolic click which is non-ejection. It only causes the ejection click in the mid systole because it will take some time to build up enuf pressure to cause a sound heard to ur ears as the pressure builds up in the Left ventricle.
Sometimes, it can accompany with a mitral valve prolapse when the valve is not only prolapsed but also is unable to open completely.
Midsystolic click is diagsnotic of Mitral valve prolapse.
References:
Some videos & screenshots are from Khan Academy: https://youtu.be/6YY3OOPmUDA
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