Left ventricular function and mitral valve opening in massive pulmonary embolism.

M-mode echocardiograms are demonstrated from a patient with subacute massive pulmonary embolism before and after thrombolytic treatment and clinical recovery. Severely impaired left ventricular contraction returned to normal. A reversible reduction in mitral valve opening velocity was also seen and was thought to be in part the result of diminished left atrial filling. This hypothesis was tested experimentally; mitral valve opening velocity was measured in normal subjects and found to be significantly reduced when pulmonary blood flow was impeded during the Valsalva manoeuvre.