An improved method for detecting and quantifying cardiac muscle disarray in hypertrophic cardiomyopathy.

The presence of muscle disarray in hypertrophic cardiomyopathy (HC), although well established, has only been semiquantitatively assessed. A quantitative method that uses polarized light microscopy is described. Hematoxylin and eosin-stained sections of ventricular septa from six HC patients and six normal hearts were examined. Cell orientations were measured in five regions from each section using a polarizing microscope with a rotating stage. Histograms of cell orientation angles were plotted and the mean and angular deviation of each sample were calculated. In normal hearts, cells were predominantly aligned parallel to each other. Orientation distributions were sharply peaked, with angular deviations ranging from 4 to 13 degrees. For HC, the sharp peak was lacking and angular deviations varied from 7 to 37 degrees; some distributions were bimodal. Areas in HC septa that appeared normal by gross inspection had abnormal orientation distributions. Polarized light microscopy provides an improved method of detecting and quantifying cellular disorganization in HC.