Production of abnormal systolic sounds by vibration of torn leaflet of porcine xenograft.

A 72-year-old woman was initially seen with increasing dyspnea and a new murmur occurring six years after mitral valve replacement with a glutaraldehyde-stabilized porcine xenograft. Prominent systolic sounds, superimposed on a softer holosystolic murmur, were audible, with a frequency of 22 to 40 Hz documented by phonocardiography. The mitral valve echo showed a prominent systolic flutter with frequency characteristics identical to those of the discrete systolic sounds, indicating that fluttering of the mitral valve was responsible for the generation of the unusual auscultatory findings. A torn porcine cusp was found at operation.