Austin Flint murmur [Austin Flint, American physiologist, 1812–1886] , a low-pitched sound characteristic of severe aortic regurgitation without mitral valve disease. It is typically heard during ventricular middiastole at the mitral valve area. It is caused by premature closure of the mitral valve by the jet of aortic regurgitation. Amyl nitrate may help differentiate this murmur from that of mitral valve stenosis.
