Monday, May 14, 2012


For all left heart stenotic murmurs, reducing preload (e.g diuretics) prolongs devt of pulmonary congestion

For all left heart regurgitant murmurs, drug treatment is aimed at reducing afterload (vasodilators)

For mitral valve prolapse, drug treatment (if symptomatic), is aimed at increasing preload (propanolol)

For hypertrophic cardiomyopathy, increasing preload reduces the murmur( squatting increases VR, beta blockers and calcium channel blockers allow more ventricular filling)

note: Valsava manoeuvre increases afterload, reduces preload. It therefore increases intensity of murmur in aortic stenosis but reduces the intensity in HCM.


  1. Per USMLE world, valsalva will first decrease preload, then upon release increases preload. Valsalva does not affect afterload. A decrease in preload will decrease the intraventricular volume allowing for a greater degree of obstruction from HOCM or and prolapsing from MVP. Therefore, the valsalva maneuver will INCREASE the intensity of both HOCM and MVP

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