S4
which is due to diastolic dysfunction of heart is produced due to forceful
atrial contraction. S4 can occur in both obstructive and non obstructive HCM.
S3 can also occur due to associated MR.
In patient with ESM with brisk raise of
pulse which goes against valvular AS, one has to consider HOCM. Valvular AS
produces slow raising pulse
Pulse of HOCM is bisferance type i.e.
initial spike is brisk during this initial part (around 80 to 90% of systolic
ejection occurs). This is followed by dip in pulse due occurrence of obstruction
and again on more slow raising peak.
Bisferance pulse is classically
described with severe AR, which is associated with EDM but not HOCM with
bisference pulse.
Apical impulse of HCM is very important
sign. S4 is palpable, this is followed by early systolic contraction, followed
by one more impulse due to occurrence of obstruction, so patient may have triple
ripple.
Presence of Loud S4 is a rule in HCM
About 30-50% of HOCM are associated with
mitral regurgitation. HCM with MR produces a systolic murmur, which is much
longer with both ejection and regurgitant quality. Site of maximal intensity is
lower than the site of ejection murmur.
Differential
diagnosis
·
Valvular
aortic stenosis
o Cardinal
differential feature between HCM and AS is carotid impulse which is slow
raising in valvular AS and brisk in HCM
o Carotid
thrill is present in AS and rare in HCM
o ESM
of HCM is lower down in precardium where as of valvular AS is on right side
o Post
PVC augmentation is more pronounced in HCM than AS
·
Mitral
regurgitation
o Presence
of holosystolic murmur at apex suggest possibility of MR than HCM
o S4
which cardinal sign of HCM is unusual in chronic MR, but in acute MR S4 can
occur
o LVH
is much more common in HCM.
o Both
HCM and MR have quick raise of carotid impulse.
o Reversed
splitting is heard in HCM, but in MR wide splitting is heard.
o Post
PVC, MR murmur does not change but HCM and AS murmur increases.
·
Mitral
valve prolapse
o Dynamic auscultation
behaviour of MVP and HCM are in similar way
o S4
and is not heard in MVP
o Post
PVC murmur of MVP does not increase
