(A) SEM images of cardiomyocyte surface topology at 0, 3, and 8 h post-isolation, with protrusions of the sarcolemmal membrane (arrows labeled M) increasingly prominent. (B–D) Area (B), diameter (C), and circularity (D) of membrane protrusions increased with time (3 cells per time point; mitochondria n = 40 (0 h), n = 27 (3 h), and n = 39 (8 h)). Significance is indicated for the overall effect of time. Scale bars represent 2 μm.