Direct evaluation of mitral valve function during surgery following conservative procedures.

A method is described whereby mitral valve function can be tested during cardiopulmonary bypass under physiological conditions. This method avoids the risk of systemic air embolism during testing and can be used even in the presence of aortic regurgitation. Monitoring left ventricular pressure simultaneously with aortic root pressure prevents any overdistention of the left ventricle. This method has been in use at Guy's Hospital since 1970 and has been satisfactory and safe.