Electron microscopy of myocardial tissue. A nine year review

Aim-To review and reassess the role of this department's experience with ro utine electron microscopy of myocardial tissues. Methods-A nine year series of myocardial samples that underwent electron mi croscopy analysis were audited. Fifty nine samples were derived from 46 mal e and 13 female subjects with an age range of 15-90 years (mean, 50.6). For ty two samples were endomyocardial specimens, with 13 being derived from ex planted hearts, and four from necropsies. Two cases were from transplanted hearts. These were all reviewed in a blinded fashion, by all three authors separately, in terms of the myocardium at the ultrastructural level. Subseq uently, the interpretations/diagnoses were cross compared with the light mi croscopy and clinical data results. Results-Four cases of amyloid were identified; in addition, one case of gra nulomatous inflammation and one case of basophilic degeneration were seen, although all these had been evident on light microscopy. One case of possib le mitochondrial myopathy was found. A total of 18 cases revealed changes o f a presumed non-specific type including glycogen, lipid, and mitochondrial accumulations. Varying types of degeneration involving myofibres were seen together with variations in interstitial fibrosis and occasional cytoplasm ic inclusions. Conclusion-Overall, although interesting, the electron microscopy of myocar dial tissue added little to the understanding of the patient's disease, wit h only one case showing changes not found at light microscopy or with other investigations. Further study might shed light on the "non-specific" ultra structural findings encountered.