All except one is true regarding murmur heard in hypertrophic obstructive  cardiomyopathy
Murmur in HOCM decreases with handgrip
DYNAMIC CARDIAC ASCULTATION
Effect of Murmurs.
Systolic murmur decreases on squatting
Systolic  murmur increases on valsalva manoeuvre
Systolic murmur increases with hand grip
Systolic murmur decreases on taking beta blocker