Electron micrographs of fresh and frozen myocardium. (A–F) Representative electron microscope images of fresh (A–C) and frozen (D–F) porcine myocardium in the longitudinal section at low and high magnification. (G–I) Sarcomere length (SL; G), A-band length (H), and Z-line width (I) are shown for fresh (Fre) and frozen (Fro) tissue. ns: P ≥ 0.05. Solid and open symbols are from different biological repeats. The error bars in the graphs are SEM.