This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiomyopathies, Subject name: Medicine
In all cases intensity of murmur increases on sit-up and hand grip except? 
Select and explain. 
A. MS, B. HOCM, C. AS, D. TR
B: HOCM
Answer: B: HOCM 
Explanation: On standing: The venous return is going be reduced & there is decrease blood coming to the hea, therefore intensity of murmurs get reduced. Eg : Valsalva, Amyl nitrate (Except HOCM: louder murmur; MVP: longer murmur) Note: All murmurs increase on doing sit ups, hand grip as there is increase of peripheral resistance HOCM: soften MVP: shoer HOCM: AD defect in chromosome 14, b- myosin gene disorder