Simple method for quantifying disorientation of myofiber in endomyocardial biopsy specimens using an image analyzer

The disarray of cardiac myofibers was morphometrically evaluated in biopsy specimens, obtained from patients with hypertrophic cardiomyopathy (HCM), hypertensive heart disease (HHD), chronic phase myocarditis and controls. Microphotographs of myocardium were taken at a final magnification of x 250. For each segment of myofibers, the longitudinal direction was traced on a transparent sheet, and the angle of the traced direction to the baseline was measured by an image analyzer. The standard deviation of the angles was used as an indicator of myofiber disarray. The histograms showed a narrow variation in the control group, but a wide variation in the patients with HCM, HHD and chronic phase myocarditis. The mean value of standard deviations of myofiber angles in HCM was significantly larger than that in the other groups. In HCM, the standard deviation of the myofiber angle proved to correlate positively with IVST/LVPWT (the thickness ratio of interventricular septum to the left ventricular posterior wall) (r = 0.70, p < 0.05), and also with LVEDP (left ventricular end-diastolic pressure) (r = 0.66, p < 0.05). In conclusion, the image analyzer serves as a simple and useful tool in quantifying the disorientation of myofibers and estimating the correlation between the histological and clinical findings.