Fig. 7.

Histological images of the LV cross-sections of the native porcine hearts showed the ultrastructure of the endocardial layer (A–D). Endocardial elastin fibers covered a thickness range of 100 μm–250 μm and showed location-dependency and depth-dependency. The endocardial elastin fibers were finer and formed much denser networks, with a higher degree of waviness when compared to the epicardial elastin network. Note that Purkinje fibers (pale pink staining) were identified beneath the endocardial layer and above the myocardium (red staining). We noticed that the Purkinje cells were also associated with fine collagen and elastin fibers (Arrows). Movat's pentachrome staining: Collagen in yellow, elastin fibers in black, cardiac muscles in red, and the Purkinje fibers in pale pink. Scale bar = 100 μm.