Scanning and transmission electron microscopy of dissociated normal and cardiomyopathic hamster heart cells (author's transl)

Normal and cardiomyopathic (CM) hamster hearts were dissociated into single cells and examined by scanning and transmission electron microscopy. The size of CM and normal myocytes are comparable. In addition, both have morphologically similar intercalated discs and T-tubule openings. However, in contrast to normal, the CM myocytes contain unusually large aggregations of mitochondria. Also, cell surface pits and peripheral vesicles are more numerous in CM cells. The most striking abnormality of CM myocytes is their aberrant shapes. Many of the CM cells have branching irregular shapes or a helical morphology； the myofibrils within these cells are disarrayed or helically arranged as well(8). Most normal cells exhibit straight cylindrical configurations with straight myofibrils. The abnormal morphology in itself would seem to provide an explanation for the decreased efficiency of heart contractions in cardiomyopathic hamsters and presumably is related to the observed heart failure in this genetically-based cardiomyopathy.