Mitral valve prolapse: jet stream causing mural endocarditis.

A 53 year old man died of cerebral hemorrhage while being treated for Streptococcus mutans endocarditis. At autopsy the only endocarditic lesion was on the left atrial mural endocardium. The noninfected mitral valve demonstrated prolapse and mucinous degeneration. The latter had led to rupture of several chordae tendineae, with the resultant jet stream predisposing to endocarditis at its point of atrial impact. The case provides confirmation of current concepts of the pathogenesis of endocarditis and has important therapeutic implications.