Problems in the interpretation of left atrial left ventricular mean diastolic gradients

Two patients are described in whom the mitral diastolic gradients noted during left heart catheterization were not satisfactorily explained by the anatomic findings observed at cardiac surgery. In one subject aortic and tricuspid stenosis was found at surgery without significant stenosis of the mitral valve. In the second patient a large mitral diastolic gradient persisted after the mitral valve was opened to a size of 4.5 sq. cm. In both instances marked hypertrophy of the anterior papillary muscle in the left ventricular cavity is considered one of the causes of these anomalous mitral diastolic gradients.