What are the three things you need to do extra maneuvers for (e.g. valsalva and standing to squatting) in order to change loading conditions (preload, afterload, contractility)? explain
HOCM (Hypertrophic Obstructive cardiomyopathy): valsalva increases intrathoracic pressure and decreases venous return, transiently reducing LV size (makes murmur worse)
Aortic stenosis: valsalva transiently decreases flow through aorta and the murmur decreases
Mitral valve prolapse (MVP): valsalva decreases blood to LV (altering the geometry), causing the click and murmur to occur earlier.