Which of the following murmur increases on standing?
On standing: The venous return is going be reduced & there is decrease blood coming to the hea, therefore intensity of murmurs get reduced. E.g.: Valsalva, Amyl nitrate (Except HOCM: louder murmur; MVP: longer murmur) Note: All murmurs increase on doing sit ups, hand grip or exercise as there is increase of peripheral resistance HOCM: soften MVP: shoer Therefore, HOCM and MVP behave opposite of normal LVOT dynamic/ Sub valvular Aoic stenosis: Volume of blood in left Ventricle is directly propoional to left ventricular output tract obstruction (LVOT) i.e. if more amount of blood coming in then aoic gap separated so less intensity of murmur. But in case of standing, volume of blood in LV is less, so the LVOTO will also be lesser and thus the intensity of murmur increases.
HOCM
MR
MS
VSD
NEET 2019