Left ventricular endomyocardial biopsy findings in patients with essential hypertension and hypertrophic cardiomyopathy with special reference to the incidence of bizarre myocardial hypertrophy with disorganization and biopsy score

[Hypertrophic cardiomyopathy. Cardiomyocyte ultrastructure, the specific or stereotypic signs]

Hypertrophic cardiomyopathy (HCM) is a congenital disease caused by mutations in a number of sarcomere proteins. According to the type of mutation, clinical observations record similar clinical manifestations, myocardial pathological changes, and the timing of manifestation of the disease in HCM patients.

OBJECTIVE

To study cardiomyocyte (CMC) ultrastructural changes in the interventricular septum (IVS) of patients with HCM and evaluate their specificity for this pathology.

MATERIAL AND METHODS

IVS myocardial samples taken from 44 HCM patients aged 18-59 years at IVS myoectomy underwent an electron microscopic study. The diameter of CMCs and their nuclei was measured in semithin sections.

RESULTS

A morphometric examination of the IVS myocardium in HCM patients revealed moderate hypertrophy of CMCs and their nuclei, the diameters of which averaged 23.7±4.4 and 5.2±0.9 μm, respectively. The IVS CMCs were characterized by the ultrastructural signs of hypertrophy: the larger size and number of structures ensuring contractile and synthetic functions; the myocytes contained higher amounts of myofibrils, intermyofibrillar mitochondria, granular endoplasmic reticulum cisterns, and free ribosomes. On the contrary, some CMCs had fewer myofibrils in the perinuclear region, which is an adaptive change under hemodynamic overload conditions. In addition, a number of myocytes displayed signs of dystrophic changes: the appearance of lipofuscin granules, myelin figures, phagosomes, lipid droplets, and vacuoles, which can fill all free sarcoplasmic zones.

CONCLUSION

Ultrastructural changes characteristic of hypertrophy were found in IVS CMCs in HCM patients. In addition, there was partial myofibrillar loss and dystrophic changes in a number of myocytes, which are stereotypic compensatory-adaptive changes under hemodynamic overload conditions. All the above-mentioned changes in the CMC ultrastructure are characteristic of myocardial hypertrophy, but not specific for hypertrophic cardiomyopathy.

The co-segregation of the MYL2 R58Q mutation in Chinese hypertrophic cardiomyopathy family and its pathological effect on cardiomyopathy disarray

Hypertrophic cardiomyopathy (HCM), a major cause of sudden death in youth, is largely affected by genetic factors. The R58Q mutation in the MYL2 gene was identified in some HCM patients and was considered as a deleterious HCM mutation. However, the passing of R58Q between generations along with HCM symptoms was observed only in small families with only two or three members; thus, whether R58Q is as deleterious as previously claimed remains questionable. Here, we reported a large four-generation Chinese family, and found that R58Q existed in all six members with HCM and two healthy juveniles who had not yet developed HCM yet, and presumably in three deceased members who suffered from sudden death. In addition, we also found that compared with other mutations, R58Q had a more severe effect on the cellular level. Therefore, we confirmed that R58Q could be passed from generation to generation along with HCM symptoms and that it was indeed a deleterious mutation for HCM. However, further study is needed to identify additional factors that may determine the various symptoms shown in different family members within the same family.

More than 50 Years after Konno's Development of the Endomyocardial Biopsy

The endomyocardial biopsy (EMB) method was first developed by Japan's Dr. Souji Konno in 1962. Since then, this technique has been used worldwide in clinical cardiology for the recognition and diagnosis of cardiomyopathies, arrhythmias, and other heart conditions. Many studies relating to the EMB have been published at the global level, including a large review by Cooper, et al.,¹⁾ wherein a limited selection of Japanese papers were cited despite considerable pioneering work on the EMB having been done in Japan. Following this, the Cardiac Biopsy Conference (CABIC) organization, which was founded in Japan in 1979, conducted a nationwide survey of the English language literature on the EMB. Among the collection of 500 studies compiled, approximately 40 abstracts have been selected by the co-editors in CABIC for further discussion. This report aims to supplement Cooper's work and bring to light other prominent contributions of Japanese researchers on the EMB.

Two-dimensional strain profiles in patients with physiological and pathological hypertrophy and preserved left ventricular systolic function: a comparative analyses

OBJECTIVE

This study was designed to examine the utility of two-dimensional strain (2DS) or speckle tracking imaging to typify functional adaptations of the left ventricle in variant forms of left ventricular hypertrophy (LVH).

DESIGN

Cross-sectional study.

SETTING

Urban tertiary care academic medical centres.

PARTICIPANTS

A total of 129 subjects, 56 with hypertrophic cardiomyopathy (HCM), 34 with hypertensive left ventricular hypertrophy (H-LVH), 27 professional athletes with LVH (AT-LVH) and 12 healthy controls in sinus rhythm with preserved left ventricular systolic function.

METHODS

Conventional echocardiographic and tissue Doppler examinations were performed in all study subjects. Bi-dimensional acquisitions were analysed to map longitudinal systolic strain (automated function imaging, AFI, GE Healthcare, Waukesha, Wisconsin, USA) from apical views.

RESULTS

Subjects with HCM had significantly lower regional and average global peak longitudinal systolic strain (GLS-avg) compared with controls and other forms of LVH. Strain dispersion index, a measure of regional contractile heterogeneity, was higher in HCM compared with the rest of the groups. On receiver operator characteristics analysis, GLS-avg had excellent discriminatory ability to distinguish HCM from H-LVH area under curve (AUC) (0.893, p<0.001) or AT-LVH AUC (0.920, p<0.001). Tissue Doppler and LV morphological parameters were better suited to differentiate the athlete heart from HCM.

CONCLUSIONS

2DS (AFI) allows rapid characterisation of regional and global systolic function and may have the potential to differentiate HCM from variant forms of LVH.

Cardiac muscle cell disorganization in apical hypertrophic cardiomyopathy: a cardiac biopsy study

Apical hypertrophic cardiomyopathy has been divided into two entities: apical asymmetric septal hypertrophy (apical ASH) and apical symmetric hypertrophy (AH). The latter differs clinically from hypertrophic cardiomyopathy (HCM) with ASH, and it is unclear whether AH represents a distinct subtype of HCM. In the present study, the presence or absence and the extent of cardiac muscle cell disorganization, a histologic characteristic of HCM, were compared in patients with AH (n = 10) and ASH (n = 29) in whom cardiac biopsy specimens were obtained from the left ventricular apex and interventricular septum. Disorganization was graded as (1+) in only 1 patient in the AH group and (-) in the remaining 9. In contrast, in the ASH group disorganization was graded as (1+) in 15 patients, (2+) in 7, (3+) in 3, and (-) in only 4 (P < 0.0001). Thus, it was observed that in AH disorganization is virtually absent or at most limited to a very narrow area. It is concluded from a histological stand point as well that the type of apical hypertrophic cardiomyopathy showing apical symmetric hypertrophy differs from usual HCM.

Relationship between thallium-201 myocardial SPECT and findings of endomyocardial biopsy specimens in dilated cardiomyopathy

The purpose of this study was to clarify which myocardial histological findings associated with dilated cardiomyopathy (DCM) are reflected in quantitative 201Tl myocardial SPECT. We obtained studied SPECT images from 21 patients with DCM 10 minutes and 2 hours after they received an injection of 111 MBq 201Tl at rest. We calculated the percent coefficient of variation of myocardial 201Tl counts [%CV(TI)], the washout rate (WR), standard deviation of WR [SD(WR)], extent score (ES) and severity score (SS). We used image analysis to measure % fibrosis, % myocytes, the ratio of fibrous tissue to myocyte tissue (F/My), myocyte size and standard deviation of myocyte size [SD(My)] in left ventricular endomyocardial biopsy specimens. The %CV(Tl) was correlated with % fibrosis and F/My. The ES and SS also correlated with F/My. The correlation between SD(WR) and SD(My) was significant. The present findings suggest that %CV(Tl), ES and SS of rest 201Tl SPECT reflect myocardial fibrosis and that the standard deviation of washout reflects the distribution of myocyte size.

A case of pediatric cardiomyopathy with severely restrictive physiology

A rare case of a 6-year-old male with idiopathic familial cardiomyopathy manifesting severely restrictive physiology is reported. The patient showed congestive heart failure with dilatation of both atria with a normal ventricular cavity. A square-root configuration was revealed in the ventricular pressure tracings. His elder brother had died of hypertrophic cardiomyopathy at the age of 3 years. Endomyocardial biopsy disclosed marked disorganization of muscle bundles with hypertrophy of the myocytes and interstitial fibrosis. The patient died suddenly during hospitalization. Autopsy revealed diffuse hypertrophy of both the ventricular walls and the ventricular septum with extensive myocardial disorganization and interstitial fibrosis. These advanced myopathic changes in the myocardium may have been related to the restrictive physiology in this case.

A case of hypereosinophilic syndrome with asymmetric septal hypertrophy

A case of idiopathic hypereosinophilic syndrome (HES) with asymmetric septal hypertrophy (ASH) is described: this is a very rare association. The patient was a 56-year-old male with hypereosinophilia lasting for 10 years. The white blood cell count was 11200/mm3, with 22% eosinophils, and eosinophilic hyperplasia (7.2%) was noted in the bone marrow. A peripheral blood smear showed vacuolated eosinophils with a reduced content of granules. An ultrastructure study of the eosinophils revealed reduced numbers of crystalloid granules which appeared to be dissolving with reversal of normal staining. An echocardiogram and a biventriculoglam indicated ASH with the interventricular septal wall thickness of 2.4 cm and the left ventricular posterior wall thickness of 1.5 cm. Right ventricular endomyocardial biopsy revealed no eosinophilic infiltration, but endocardial thickening, subendocardial fibrosis, hypertrophy, myocytolysis, and fragmentation of muscle bundles were observed.

Feasibility of identifying amyloid and hypertrophic cardiomyopathy with the use of computerized quantitative texture analysis of clinical echocardiographic data

Ultrasound tissue characterization, the evaluation of certain physical properties of a tissue based on its acoustic properties, is an evolving application in echocardiography. The ability to identify acutely and chronically injured tissue has been demonstrated in a number of animal studies, but data in humans are limited. The present study tested the hypothesis that quantitative echocardiographic texture analysis, a method of evaluating the spatial pattern of echoes in echocardiographic images, would differentiate amyloid and hypertrophic cardiomyopathy from normal myocardium. Routine clinical echocardiographic data were obtained on 34 subjects at the Mayo Clinic (10 normal subjects, 10 patients with amyloid heart disease, 8 patients with hypertrophic cardiomyopathy and 6 patients with left ventricular hypertrophy due to hypertension). Standard videotape recordings of these echocardiograms were analyzed at the University of Iowa. Echocardiographic data were digitized with use of a calibrated, 256 gray level digitization system. Quantitative texture analysis was performed on data from the ventricular septum and posterior left ventricular wall in end-diastolic and end-systolic, short-axis and long-axis echocardiographic images. The gray level run length texture variables were able to discriminate hypertrophic cardiomyopathy and amyloid heart disease from normal myocardium and from each other (p less than 0.0083 for comparisons of the quantitative texture features of amyloid versus hypertrophic cardiomyopathy versus normal by multivariate analysis of variance). The texture of the myocardium in hypertensive left ventricular hypertrophy not associated with amyloid or hypertrophic cardiomyopathy was in general not significantly different from that of normal myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitation of myocardial fibrosis and its relation to function in essential hypertension and hypertrophic cardiomyopathy

Myocardial interstitial fibrosis is an important microscopic feature of hypertrophic cardiomyopathy. To determine whether interstitial fibrosis of the myocardium in hypertrophic cardiomyopathy and essential hypertension differ in quality or quantity, and to determine whether fibrosis affects cardiac function directly, we measured the percentage of fibrosis in patients of both categories and compared the severity of fibrosis with several cardiac functions. Left and right ventricular endomyocardial biopsies were performed in 25 patients with essential hypertension and in 19 patients with hypertrophic cardiomyopathy. Interstitial fibrosis was classified into four different microscopic types, and the percentage of total and of each type was calculated using the point-counting method. Although the percentage of total fibrosis was similar between the two groups, the type of fibrosis was different. There was no correlation between the percentage of total fibrosis and the mean size of myocytes in either group. Although there was a significant correlation between the percentage of total fibrosis and the thickness of the interventricular septum in hypertrophic cardiomyopathy, such correlation was lacking in hypertension. There was no correlation between the percentage of total fibrosis and the ejection fraction, cardiac index, or left ventricular end-diastolic pressure in either group. We concluded that the amount of myocardial interstitial fibrosis in hypertrophic cardiomyopathy is no greater than that in essential hypertension, but the type of fibrosis is different. Furthermore, in subjects in whom the ejection fraction is normal or only slightly decreased, fibrosis does not influence global cardiac functions.