Austin Flint murmur: A murmur due to aortic regurgitation, originating at the mitral valve when blood enters simultaneously from both the aorta and the left atrium.

The murmur is named for Austin Flint who described it in 1862: "In some cases in which free aortic regurgitation exists, the left ventricle becoming filled before the auricles contract, the mitral curtains are floated out, and the valve closed when the mitral current takes place, and, under these circumstances, this murmur may be produced by the current just named, although no mitral lesion exists."

Dr. Flint (1812-1886) was a pioneer in the use of the stethoscope. His "Principles and Practice of Medicine" (1866) was a leading textbook of medicine.