Failure of a Björk-Shiley mitral valve prosthesis to open: clinical recognition.

Failure of a Björk-Shiley mitral valve prosthesis to open was recognized early in the postoperative period and required immediate replacement. The clinical finding was sudden, intermittent, severe hypotension associated with absent poppet sounds and simultaneous elevation in left atrial pressure. This unique and unusual hemodynamic picture was duplicated in four animal experiments. Routine monitoring of left atrial pressure is a useful postoperative adjunct that can provide early documentation of obstruction to left atrial outflow. Early recognition of the problem and immediate operative correction are mandatory.