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University of Calgary Medicine Class of 2014 Hellbenders

Cause of S1 sound

Closing of AV valves, tricuspid and mitral

S1 sound heard best at:

apex (i.e. the 'bottom' of the heart)

Cause of S2 sound

Closing of aortic and pulmonary (semilunar) valves

S2 sound heard best at:

Base ( near aorta and pulmonary valves)

Normal, or physiologic splitting occurs in this heart sound


On inspiration, there is reduced pressure in the chest cavity
...the LV fills slower/less, so closes aortic valve earlier - A2
...the RV fills faster/more. so closes pulmonary valve later - P2

in split S2, which comes first, A2 or P2?


Factors contributing to louder heart sounds
(all valves)

Higher activity (exercise)
Bigger, tougher valve (e.g. mild-mod rheumatic fever)
Higher pressure in aortic / pulmonary arteries

Factors contributing to quieter heart sounds

AV regurgitation
Long PR interval

Pathologic / Fixed causes of S2 splitting

RBBB (A2 before P2)
LBBB (P2 before A2, paradoxical splitting
Severe aortic stenosis (P2 before A2)

Sequence of normal heart sounds S1-S4

4 - 1 - 2 - 3

Cause of S3 heart sound

LV coming to a quick stop when being rapidly filled
An indication of a volume loaded heart or ventricular dysfunction (L or R)
"Sloshing in" "montreal"

Cause of S4 heart sound

Artria contracting into a non-compliant ventricle
e.g. in systemic hypertension
This is NEVER normal
"A stiff wall" "toronto"

Cause of constant systolic murmur

mitral regurgitation

Cause of crescendo-decrescendo systolic murmur
"diamond shape murmur"

aortic stenosis
(also get S2 split)

Mitral regurg radiates to the


Aortic stenosis radiates to the

clavicle/carotids(not bruit)

Mitral valve prolapse

click, crescendo, happens later in systole than regurg

Opening Snap occurs in

Mitral stenosis
Mid diastolic murmur

'Ejection Click' occurs in

Aortic Stenosis
Systolic 'Ejection click'
Delayed and forceful opening

Systolic click occurs in

MVP: louder with hand grip (increased afterload)
HCM: softer with hand grip

Effect of valsalva on AS and HCM systolic murmurs

AS: quieter (reduced preload)
HCM: louder (decreased volume / preload)

Squatting does what to preload/afterload

Increases afterload (constricted femoral arteries)
Decreases preload (pools blood in high capacitace femoral veins)

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