This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Medicine
Standing increases murmur intensity in 
Select and explain. 
A. Aoic stenosis, B. Aoic regurgitation, C. Hyperophic obstructive cardiomyopathy, D. Mitral stenosis
C: Hyperophic obstructive cardiomyopathy
Answer: C: Hyperophic obstructive cardiomyopathy 
Explanation: The classic ECG finding in hyperophic obstructive cardiomyopathy is large dagger-like "septal Q waves" in the lateral -- and sometimes inferior -- leads due to the abnormally hyperophied interventricular septum.. Wolff-Parkinson-White, or WPW, syndrome can be associated with HOCM The murmur that is pathognomonic for HCM is a crescendo-decrescendo holosystolic murmur best heard at the left sternal boarder. The murmur classically increases with standing and valsalva, while it decreases with squatting, hand-grip, and passive leg lift . Ref Davidson edition23rd pg 463