During physical examination of a patient with Aortic regurgitation it is said that the murmur is best heard at end expiration, leaning forward. What is the mechanism? I mean, what does leaning forward have to do with AR?
At end expiration, more blood volume return to left heart. Increased blood volume in LV means more regurgitant in AR -> louder noise.
Pericarditis friction rub can also be best heard when leaning forward.