The occurrence of alpha-glycogen in humans

Value of endomyocardial biopsy

The role of endomyocardial biopsy may be restricted to the diagnosis of myocarditis. On the other hand, a broad utilization of the biopsy technique may be championed by those who believe that the light and electron microscopic characteristics of the tissue are important and that the biochemical features of the tissue may hold important clues to the diagnosis and therapy of dilated cardiomyopathy. The popularity of endomyocardial biopsy arises from the ease and safety of the procedure. Light microscopy of the tissue is useful not only to diagnose myocarditis but also to discover infiltrative cardiomyopathies and to characterize the dilated cardiomyopathies by the amount of fibrosis and cellular hypertrophy. Electron microscopy supplies more detailed information on the myofibrils, nuclei, tubular structures, mitochondria, glycogen, and lipofuscin. At present, these data are clinically applicable only to the anthracycline cardiomyopathies. On an investigational basis, subcellular characteristics may help us better understand the etiology and pathogenesis of dilated cardiomyopathy. The greatest promise lies in the biochemical assessment of tissue, which may uncover single or multiple biochemical abnormalities in heart failure. Although the clinical usefulness of endomyocardial biopsy is quite restricted at present, its future looks quite promising.

Long-term study of the ultrastructural changes of myocardium in patients undergoing cardiac surgery, with more than 10 years follow-up

The myocardium from 44 patients undergoing open cardiac surgery was studied to determine if alterations demonstrable with the electron microscope could be related to prognosis. Planimetric methods were used to evaluate myofibrils, Golgi, mitochondria, myelin figures, other organelles, and intracellular space in order to achieve as objective a measurement as possible. Morphologic changes were graded and correlated with clinical findings and results after long-term follow-up. Factors evaluated in terms of survival included patient age, degree and extent of valvular disease, the presence of coronary artery disease, and degenerative changes of the myocardium as demonstrated ultrastructurally. Patients dying, of cardiac causes, within the first 5 years, had a higher ultrastructural grade than those surviving for more than 10 years. Statistical analysis, using stepwise regression methods, demonstrated a highly significant correlation (P less than 0.001) between cardiac ultrastructural integrity and prognosis. The addition of age to the prediction model was also significant (P less than 0.04), using the two variable models, EM grade and age were, similarly, highly significant (P less than 0.001).

Transvascular endomyocardial biopsy in infants and small children. Myocardial findings in 10 cases of cardiomyopathy

Transvascular endomyocardial biopsy specimens from nine children with congestive cardiomyopathy and one with hypertrophic cardiomyopathy were studied by light microscopy using sections 1 mu thick cut from Epon embedded tissue and by electron microscopy. There was a disparity between the severity of the physiologic impairment and the morphologic abnormalities. Interstitial fibrosis was present only in the one case in which significant viral antibody titers were obtained. The sizes of the cardiac muscle cells varied abnormally in all specimens. Cardiac muscle cells in two patients contained abnormal mitochondria, and a leptomeric fibril was found in one patient. Virologic cultures of the tissues were negative and no viral particles were identified by electron microscopy. An attempt was made to correlate the clinical and pathologic findings.

Myocardial ultrastructure in patients with chronic aortic valve disease

Light and electron microscopic observations were made on left ventricular myocardium removed at operation from 16 patients with chronic aortic valve disease. In all 16 patients most cardiac muscle cells were hypertrophid, and surrounded by small amounts of fibrous tissue. In two of the six patients with pure aortic regurgitation and in four of the five patients with combined aortic stenosis and regurgitation, cardiac muscle cells with evidence of degeneration were present in addition to hypertrophied, nondegenerated cells. Degenerated cardiac muscle cells were not observed in the six patients with predominant aortic stenosis. Cardiac muscle cells with mild degeneration showed focal myofibrillar lysis, with preferential loss of thick myofilaments, and focal proliferation of tubules of sarcoplasmic reticulum. More severely degenerated muscle cells showed a marked decrease in the numbers of myofibrils and T tubules and proliferation of sarcoplasmic reticulum or mitochondria, or both. Severly degenerated cells usually were present in areas of marked fibrosis, often were atrophic, had thickened basement membranes and had lost their intercellular connections. These findings suggest that degenerated cardiac muscle cells have poor contractile function and may be responsible for impaired cardiac performance in some patients with chronic aortic valve disease.

Differences in distribution of myocardial abnormalities in patients with obstructive and nonobstructive asymmetric septal hypertrophy (ASH). Light and electron microscopic findings

Previous studies have shown that abnormal cellular morphology is present in the ventricular septum of patients with asymmetric septal hypertrophy (ASH). The present study was undertaken to determine whether these morphologic abnormalities are limited to the ventricular septum of patients with ASH or are more diffusely distributed throughout the heart, and whether different patterns of distribution of the cellular abnormalities exist in patients with and patients without left ventricular outflow obstruction. Myocardium was obtained at operation or necropsy from 22 patients, including 14 with obstructive and eight with non-obstructive ASH, and studied by both light and electron microscopy. Many hypertrophied, bizarrely shaped, and abnormally arranged cardiac muscle cells, presumably a morphologic manifestation of the genetically transmitted myocardial defect in ASH, were present in the ventricular septum of all patients. In patients with obstructive ASH, these abnormalities were either absent or rarely found in muscle from the left and right ventricular free walls. This observation suggests that functional limitation in these patients is due largely to left ventricular outflow obstruction. In contrast, numerous disorganized cells were extensively distributed in the left and right ventricular feee walls from seven of eight symptomatic patients with non-obstructive ASH, suggesting that these abnormalities probably contribute importantly to functional impairment in such patients.