Fig. 5.

Samples from the intraoperative myocardial biopsies stained with Picrosirius red. a Shows fibrous septae, which show perivascular collagen to support mural arteries. There is no scarring, but only a slight increase in collagen fibres surrounding each cardiomyocyte (light red). b Shows interstitial fibrosis only, each cardiomyocyte is supported by a thin collagen layer (light red), there is only focal perivascular(pericapillary–capillary encircled) increase in collagen fibers (dark red area annotated). c Shows an annotated red area, qualifying as scar, as the dimension of the area exceeds double the diameter of the adjacent hypertrophic cardiomyocyte indicated with ⟷