How can we help?
You can also find more resources in our
Select a category
Something is confusing
Something is broken
I have a suggestion
What is your email?
What is 1 + 3?
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
Higher activity (exercise)
Bigger, tougher valve (e.g. mild-mod rheumatic fever)
Higher pressure in aortic / pulmonary arteries
Factors contributing to quieter heart sounds
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
Cause of crescendo-decrescendo systolic murmur
"diamond shape murmur"
(also get S2 split)
Mitral regurg radiates to the
Aortic stenosis radiates to the
Mitral valve prolapse
click, crescendo, happens later in systole than regurg
Opening Snap occurs in
Mid diastolic murmur
'Ejection Click' occurs in
Systolic 'Ejection click'
Delayed and forceful opening
Systolic click occurs in
MVP, HCM, AS
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)