All of the follwing statements regarding valsalva manoeuvre is true, EXCEPT:
Valsalva maneuvre is performed by forcefully attempt to exchale against a closed glotis after taking a normal breath. When it is performed intrathoracic pressure increases, increaing both end diastolic and end systolic ventricular pressure. There is decreased ventricular filling and cardiac output. This causes sound diminishing in intensity in most of the cardiac murmurs. The only two murmurs that will increase in intensity with valsalva maneuver is Murmur of hyperophic cardiomyopathy Murmur of mitral valve prolapse Ref: Primary Cardiology, edited by Eugene Braunwald, 2nd Edition, Page 156.
It decreases left ventricular volume
Systolic murmur of mitral stenosis becomes softer
Ejection systolic murmur of aoic stenosis becomes softer
Systolic murmur of hyperophic cardiomyopathy becomes softer