The reliability of the tracing-method of fine cardiac fibrosis at a magnification of x10--preliminary study for quantitative analysis of fibrosis in large tissue sections of hearts with cardiomyopathy.

to define the reliability of the tracing method of fine fibrosis at low magnification (x10), the percentage area of fine fibrosis was compared between the traced pictures at magnifications of x10 and x250, using an image analyzer (Olympus VIP-21). A total of 25 tissue areas, each approximately 4 x 7 mm, from the inner and middle thirds of the left ventricular free wall and ventricular septum were selected from ten hearts with hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) and were stained with Masson trichrome. The percentage areas of fine fibrosis traced at a magnification of x10 correlated well with those traced at a magnification of x250 (Y = 1.08X - 1.1, r = 0.95, P less than 0.01). It is concluded that the overall percentage area of fibrosis is the same at magnifications of x10 and x250, despite the fact that at x10 one is unable to detect individual fibers which can be detected at x250. The tracing method of fine cardiac fibrosis at a magnification of x10 is reliable. Therefore, fine fibrosis in large tissue sections of hearts with cardiomyopathy, such as entire transverse sections of the left ventricular wall, can be quantitatively analyzed by this method.