Cardiac function at diagnosis is important prognostic factor in patients with cardiac sarcoidosis -from Japanese nationwide questionnaire survey-

Background

Sarcoidosis is a systemic non-caseating granulomatous disease of unknown etiology. Cardiac involvement (cardiac sarcoidosis, CS) has been reported to be an important prognostic factor in this disease because of heart failure and/or ventricular arrhythmia, and corticosteroid therapy is usually prescribed to prevent cardiac events. However, little is known about the relationship of cardiac function and concomitant corticosteroid therapy on later cardiac events in CS.

Objective

We evaluated the relationship between prognosis and left ventricular ejection fraction (LVEF) at the time of diagnosis in CS patients from the Japanese nationwide questionnaire survey.

Methods

Total of 757 Japanese patients from 57 hospitals who diagnosed CS were examined. Patients who unsatisfied the criteria of the Japanese new guidelines, or who underwent cardiac transplantations were excluded, and 420 patients (287 females, mean age 60±13 years old, median follow-up periods 1864 days [interquartile range: 845–3159 days]) were analyzed. The relationship of adverse events (all-cause death, cardiovascular death, and appropriate ICD [Implantable Cardioverter Defibrillator] discharge) and LVEF (with corticosteroid 84%) (low LVEF: LVEF≤35% n=98 [with corticosteroid in 78%], moderate LVEF: LVEF 35–50% n=104 [with corticosteroid in 93%], normal LVEF: 50≤LVEF n=218 [with corticosteroid in 83%]) were evaluated respectively.

Results

89 CS patients developed all-cause death (n=50), cardiovascular death (n=30) or appropriate ICD discharge (n=48). The frequency of corticosteroid therapy was not different in the each LVEF group, but Kaplan-Meier analysis revealed that all-cause death, cardiovascular death, and all cardiovascular adverse events were more observed in lower LVEF group (log-rank p<0.0001). Furthermore, multivariate Cox hazard analysis revealed that LVEF was a most important independent prognostic factor in CS.

Conclusion

This Japanese nationwide questionnaire survey data showed that initial LVEF was an independent and strong prognostic predictor in CS, therefore primary prevention would be needed even after starting corticosteroid in patients with decreased cardiac function.

Funding Acknowledgement

Type of funding source: None

Long time clinical course of cardiac sarcoidosis with corticosteroid therapy -from Japanese nationwide questionnaire survey-

Background

Sarcoidosis is a systemic inflammatory syndrome of unknown etiology and cardiac involvement has been reported to be an important prognostic factor in this disease. An autopsy study has reported that the frequency of this cardiac involvement (cardiac sarcoidosis: CS) varies in the different countries and races and very frequent in Japanese patients. We therefore performed the nationwide questionnaire survey and try to clarify the clinical characteristics and corticosteroid effect in CS, especially focused on arrhythmic events in this disease.

Methods

Total of 757 Japanese patients from 57 hospitals who diagnosed CS were examined. Patients who unsatisfied the criteria of the Japanese new guidelines, or who underwent cardiac transplantations were excluded, and 420 patients (287 females, median follow-up periods 1864 days [interquartile range: 845–3159 days]) were analyzed. The clinical outcome and corticosteroid effect were evaluated.

Results

Clinical characteristics at diagnosis was as follows: female dominant (68%), mean age of 60±13 years old, mean left ventricular ejection fraction was 49±16%. Arrhythmic events were very frequently observed as an initial cardiac manifestation in 263 patients (62%) of CS, of which atrioventricular block (AVB) in 174 (41%), ventricular tachycardia (VT) in 73 (17%) and AVB with VT in 17 (4%) (Figure 1A). Pacemaker was implanted in 166 patients (40%) and defibrillators was 137 patients (33%). Corticosteroid was prescribed in 144 (83%) of 174 patients with AVB and in 62 (85%) of 73 patients with VT. Initial dose was mean 47.9 mg and maintenance dose of mean 7.3 mg. Corticosteroid improved VT as good as AVB (27% vs. 29%). However, corticosteroid sometimes worsened VT events compared with AVB (10% vs. 2%) (Figure 1B). During the course of follow-up, 32 patients were needed to increase corticosteroid in 23 of AVB and 10 of VT cases. However, there were no difference in mortality between the groups, whether or not to increase corticosteroid. All survival rate was 92% (5-year mortality), 83% (10-year mortality) and free from all cause death and defibrillator charge was 81% (5 year), 71% (10 year).

Conclusion

Fatal arrhythmia is commonly observed in CS as a primary symptom. Corticosteroid sometimes worsen ventricular arrhythmia and appropriate defibrillator discharge was common. Thus, careful attention for activating ventricular arrhythmia would be needed during the follow-up period even after corticosteroid therapy.

Funding Acknowledgement

Type of funding source: None

Long-term follow up ventricular tachycardia patients with preserved cardiac function -from Japanese cardiac sarcoidosis nationwide questionnaire survey-

Background

Prior ventricular tachycardia (VT) and low left ventricular ejection fraction (LVEF) are the most important prognostic factors in cardiac sarcoidosis (CS). Recently diagnosis of CS was renewed according to Japanese new guidelines. Patients with preserved cardiac function often have VT events, thus new guidelines recommends to assess the implantable cardioverter defibrillator (ICD) implantation for CS patients with preserved LVEF (35%≤LVEF<50%). However, the long-term prognosis of CS patients with preserved LVEF is unclear.

Objective

In CS patients with preserved LVEF, we evaluated the prognosis between VT manifestation and non-VT manifestation groups at CS diagnosis from Japanese nationwide questionnaire survey.

Methods

Total of 757 Japanese patients from 57 hospitals who diagnosed CS were examined. Patients who unsatisfied the criteria of the Japanese new guidelines, who had LVEF≤35%, LVEF>50%, or who underwent cardiac transplantations were excluded. 104 patients with LVEF 35–50% (67 females, mean age 60±15 years old, median follow-up periods 2134 days [interquartile range: 758–2935 days]) were analyzed. The prognosis between VT manifestation and non-VT manifestation groups at CS diagnosis were evaluated.

Results

30 patients had VT manifestation at CS diagnosis and 24 patients (80%) received ICDs. 74 patients had no VT manifestation at CS diagnosis and 19 patients (44%) received ICDs during follow up period. All-cause mortality was not different between two groups (Figure). Appropriate ICD therapy of non-VT manifestation group was significantly lower compared with that of VT manifestation group (log-rank p=0.001), however considerable number (n=7, 15%) of non-VT manifestation group had appropriate ICD therapy event during follow-up period. Cox hazard analysis revealed that concomitant non-sustained VT (NSVT) with atrioventricular block (AVB) was a predictor of appropriate ICD therapy in non-VT manifestation group.

Conclusion

This nationwide survey showed that considerable number of CS patients with preserved LVEF had VT events, independent of VT manifestation. Concomitant NSVT with AVB was a predictor of VT events, and ICD implantation should be assessed.

Funding Acknowledgement

Type of funding source: None

Ultrastructural and immunohistochemical studies on myocardial biopsies from a patient with eosinophilic endomyocarditis

Right ventricular endomyocardial biopsy specimens from a 13-year-old boy with hypereosinophilia were studied by light and electron microscopy using the EG2 monoclonal antibody, which recognizes a common epitope of eosinophil cationic protein and eosinophil protein-X. Although the endocardial layer was of normal thickness, many eosinophils, mononuclear cells, and free eosinophil granules were observed in the endocardium and in the vicinity of degenerated myocardial cells. Under electron microscopy, many of the specific granules in and out of eosinophils had lost their crystalloid internae and displayed reversed density, and there were many degranulated eosinophils with reduced number of granules. Immunohistochemically, large amounts of eosinophil cationic protein and protein-X were observed within cardiocytes when many of them were degenerated. Deposits of the proteins were also found in some small vessels. On electron microscopy, accumulations of gold particles, which bind to eosinophil cationic protein and protein-X, were seen in association with specific granules and on the myofilaments in both degenerated and normal-appearing cardiocytes. The presence of eosinophil cationic proteins within cardiocytes may play an important role in the pathogenesis of eosinophilic endomyocardial disease.

Angiotensin II receptor blockade prevents microangiopathy and preserves diastolic function in the diabetic rat heart

BACKGROUND

Cardiac microangiopathy may be involved in the development of heart failure in diabetes mellitus.

OBJECTIVE

To evaluate the effect of angiotensin II receptor blockade on cardiac function and fine structures in diabetes.

METHODS

Male Otsuka Long-Evans Tokushima Fatty (OLETF) rats (n = 30), a model of spontaneously developing diabetes mellitus, and their diabetes resistant counterparts (n = 20) were used. At 30 weeks of age, when the OLETF rats show hyperglycaemic obesity with hyperinsulinaemia, the animals were divided into two groups and given candesartan, an angiotensin II receptor blocker, 0.2 mg/kg/day, or vehicle for six weeks. Capillary density was evaluated in the left ventricular myocardium by electron microscopy, matrix metalloproteinase (MMP) activity by zymography, and cytokines by reverse transcriptase polymerase chain reaction.

RESULTS

Compared with the control rats, the OLETF rats at 36 weeks showed decreased peak negative dP/dt (mean (SD): 2350 (250) v 3492 (286) mm Hg/s) and increased cardiomyocyte diameter (24.3 (0.6) v 18.9 (0.6) microm) (both p < 0.05). Thickening of the capillary basement membranes and decreased capillary density were observed. Angiotensin receptor blockade improved almost all the haemodynamic variables, and the histological findings became similar to those of the controls. Angiotensin receptor blockade also activated MMP-2 and prevented an increase of inflammatory cytokines, especially interleukin (IL)-1beta and IL-6, in the diabetic heart.

CONCLUSIONS

Angiotensin II receptor blockade preserved left ventricular diastolic function. It was also potent at improving cardiomyocyte diameter and the thickening of the capillary basement membrane, increasing MMP-2 activity, and decreasing inflammatory cytokines. With all these changes, candesartan could contribute to cardioprotection in diabetes mellitus.

Autophagic degeneration as a possible mechanism of myocardial cell death in dilated cardiomyopathy

In failing hearts, cardiomyocytes degenerate and interstitial fibrosis, which indicates cardiomyocyte loss, becomes more prominent in the myocardium. However, the precise mechanism of cardiomyocyte degeneration that leads to cell death is still unclear, although it is presumed that lysosomal function and autophagy play an important role because lysosomal activity increases under stress such as hypoxia. Myocardium that had been resected during partial left ventriculectomy performed in patients with dilated cardiomyopathy (DCM) was examined. Under light microscopy, some cardiomyocytes had a marked scarcity of myofibrils and had prominent cytoplasmic vacuolization. Atrophic and degenerated cardiomyocytes were often observed adjacent to replacement fibrotic tissue. Immunohistochemistry showed positivity for lysosome-associated membrane protein and a lysosomal catheptic enzyme in vacuoles of various sizes in the cardiomyocytes and these lysosomal markers were markedly increased in atrophic and degenerated cardiomyocytes. Electron microscopy revealed that degenerated cardiomyocytes had many vacuoles containing intracellular organelles, such as mitochondria, and were considered to be autophagic vacuoles. In DCM hearts, autophagy appeared to be associated not only with degradation of damaged intracellular organelles but also with progressive destruction of cardiomyocytes. It is possible that autophagic degeneration is one of the mechanisms of myocardial cell death.

Myocardial inflammatory cell infiltrates in cases of dilated cardiomyopathy as a determinant of outcome following partial left ventriculectomy

Partial left ventriculectomy (PLV) can be used to treat refractory congestive heart failure caused by dilated cardiomyopathy (DCM). In order to understand the relationship between the underlying myocardial injury and early clinical outcomes after PLV, histopathologic, immunohistochemical and virologic studies of the resected myocardium were performed. The posterolateral left ventricular walls from 27 patients with idiopathic DCM were examined. Cardiomyocyte diameter, degree of myocardial fibrosis, degree of cardiomyocyte degeneration, and degree of inflammatory cell infiltration were compared with mortality rates. Polymerase chain reaction was performed to detect enterovirus genome in the myocardium. Some patients had inflammatory cell infiltrates with focal accumulations of lymphocytes and macrophages, including both cytotoxic/suppressor T-cells and helper/inducer T-cells. The number of inflammatory cells (activated lymphocytes plus macrophages/mm2) was significantly greater in patients who died of cardiac insufficiency after surgery (27.8 +/- 5.7; n = 7) than in the survivors (11.1 +/- 2.5; n = 15). There was no significant difference in the degree of myocardial fibrosis, cardiomyocyte diameter or degree of cardiomyocyte degeneration between the 2 groups. Enterovirus genome was detected in the myocardium of 9 (38%) of 24 patients examined and 5 of these enterovirus-positive hearts had severe inflammatory cell infiltrates (37.9 +/- 2.5/mm2). Early survival in patients undergoing PLV for DCM is significantly affected by the degree of myocardial inflammation, so patients with more severe or ongoing inflammation may have poor clinical outcomes. Chronic myocarditis may play an important role in the etiology and pathophysiology of idiopathic DCM.

A case of cardiomyopathy showing progression from the hypertrophic to the dilated form: association of Mt8348A-->G mutation in the mitochondrial tRNA(Lys) gene with severe ultrastructural alterations of mitochondria in cardiomyocytes

This report describes a case of cardiomyopathy with a novel point mutation of mitochondrial DNA coding lysine tRNA in association with severe ultrastructural alterations of the mitochondria in the cardiomyocytes. Abnormalities of energy production and/or abnormal protein synthesis because of the mutation of mitochondrial DNA may have played an important role in the pathogenesis of this case, which showed severe cardiomyocyte degeneration and deterioration from hypertrophic cardiomyopathy to severe dilated cardiomyopathy.

Enterovirus RNA replication in cases of dilated cardiomyopathy: light microscopic in situ hybridization and virological analyses of myocardial specimens obtained at partial left ventriculectomy

OBJECTIVE

Recently, attention has been focused on enteroviral infection of the heart in the genesis of dilated cardiomyopathy (DCM). To determine the location of enteroviral RNA in the myocardium, we performed light microscopic in situ hybridization (ISH) and virological analyses of myocardial specimens obtained at partial left ventriculectomy (PLV).

METHODS

Posterolateral walls of the left ventricle from 26 DCM patients were examined. Myocardial specimens were tested for the presence of enteroviral genomes by polymerase chain reaction (PCR). We selected two age-matched groups (10 patients each) in which enteroviruses were either present (EV-plus group) or not (EV-minus group). For both groups, we examined in situ localization of enteroviral RNA in the myocardium by ISH.

RESULTS

In PCR studies, both sense and antisense enteroviral RNA were detected in the myocardium of seven patients in the EV-plus group. The presence of this RNA indicates active viral replication in the myocardium. Five of seven patients who exhibited both sense and antisense enteroviral RNA died early after surgery. On ISH, three patients had evidence of active replication of enteroviral genomes. Viral genomes were present in myocardial lesions, especially in endocardial sites. Viral signals were found in degenerating myocardial cells, interstitial inflammatory cells, and endothelial cells of small vessels. These positive signals were not detected in the myocardium of the EV-negative group.

CONCLUSIONS

We detected both sense and antisense enteroviral RNA in various myocardial lesions. This suggests that active enteroviral replication plays a role in the development of myocardial lesions in DCM patients. Active viral replication appears to be a prognostic factor for DCM after PLV. Further study of active viral replication in myocardial lesions will provide information useful for evaluating different therapeutic strategies for DCM.

Myocardial integrated ultrasonic backscatter in patients with dilated cardiomyopathy: prediction of response to beta-blocker therapy

BACKGROUND

Myocardial integrated backscatter (IB) imaging has been reported to be useful for ultrasonic tissue characterization and delineation of myocardial viability or fibrosis. beta-Blocker therapy has beneficial effects for patients with dilated cardiomyopathy (DCM), but there are no clear findings that indicate which patients with DCM will respond to this therapy. This study was performed to evaluate whether myocardial IB analysis can predict the response to beta-blocker therapy.

METHODS AND RESULTS

We prospectively performed echocardiographic examination with IB analysis in 29 patients with DCM (20 men, 9 women) before starting bisoprolol therapy and in 15 normal subjects. Standard echocardiographic examination and IB analysis in the left ventricular wall in the 2-dimensional short-axis view were performed and the magnitude of cyclic variation (CV) of IB and calibrated myocardial IB intensity (subtracted pericardial) were obtained from the interventricular septum and the left ventricular posterior wall. Sixteen patients responded to bisoprolol therapy and 13 did not respond after 12 months of full-dose therapy. Calibrated myocardial IB intensity was lower in responders relative to nonresponders in both the interventricular septum (responders, -20.1 +/- 3.6 dB vs nonresponders, -9.8 +/- 5.1 dB, P <.0001; controls, -20.1 +/- 4.4 dB) and posterior wall (responders, -20.6 +/- 3.6 dB vs nonresponders, -14.6 +/- 4.2 dB, P =.0002; controls, -22.7 +/- 3.3 dB). Also, the lower the myocardial intensity in the interventricular septum or posterior wall, the better left ventricular systolic function improved after beta-blocker therapy. However, CV was lower in both DCM groups than in the controls, and CV in the interventricular septum was lower in nonresponders than in responders (responders, 4.0 +/- 4.1 dB vs nonresponders, -0.8 +/- 6. 1 dB, P <.02; controls, 8.3 +/- 2.4 dB). In addition, CV in the posterior wall showed no difference between the 2 DCM groups (responders, 5.6 +/- 1.3 dB vs nonresponders, 5.1 +/- 3.5 dB, P = not significant; controls, 9.6 +/- 2.5 dB). Also, the percent fibrosis on right ventricular endomyocardial biopsy specimens showed no distinctions between these 2 groups (responders, 25.1% +/- 16.1% vs nonresponders, 24.9% +/- 15.0%, P = not significant).

CONCLUSIONS

These findings suggest that left ventricular myocardial IB data, especially IB intensity, provide useful information for predicting the response to beta-blocker therapy in patients with DCM. However, right ventricular endomyocardial biopsy findings do not appear to contribute to discriminating between the 2 groups.

Up-regulation of natriuretic peptides in the ventricle of Csx/Nkx2-5 transgenic mice

A cardiac homeobox-containing gene Csx/Nkx2-5, which is essential for cardiac development, is abundantly expressed in the adult heart as well as in the heart primordia. Targeted disruption of this gene results in embryonic lethality due to abnormal heart morphogenesis. To elucidate the role of Csx/Nkx2-5 in the adult heart, we generated transgenic mice which overexpress human Csx/Nkx2-5. The transgene was expressed abundantly in the heart and the skeletal muscle. mRNA levels of several cardiac genes including natriuretic peptides, CARP, MLC2v, and endogenous Csx/Nkx2-5 were increased in the ventricle of the transgenic mice. Electron microscopic analysis revealed that the ventricular myocardium of the transgenic mice had many secretory granules, which disappeared after administration of vasopressin. These results suggest that Csx/Nkx2-5 regulates many cardiac genes and induces formation of secretory granules in the adult ventricle.

Backscattered electron imaging: A new method for the study of cardiomyocyte architecture using scanning electron microscopy

Scanning electron microscopy (SEM) with secondary electron emissions is useful for the study of cardiomyocyte architecture, however, the information is limited from the cell surface. Whereas backscattered electron (BSE) emission can give a high-resolution image of the specimen's intracellular structure after heavy metal staining. In this study, we applied BSE imaging analysis to the study of the arrangement of cardiomyocytes in the myocardium. The tissue specimens from a normal fresh monkey heart, normal human heart obtained at autopsy, and surgically resected tissue from a patient with old myocardial infarction in the left ventricular aneurysmectomy were used. The tissue specimens were fixed in neutral formalin, treated with NaOH and then stained with Gomori's silver methenamine reagent followed by tannic acid and osmium tetroxide. After dehydration and drying, the specimens were coated with carbon and examined by SEM with a BSE detector. In the tissue preparations, the A bands of sarcomeres were selectively stained with silver so that the arrangements of subsarcolemmal myofibrils and the intercalated discs were clearly seen in the BSE images. In the left ventricular aneurysmal walls of old myocardial infarction, atrophied cardiomyocytes with disarray of subsarcolemmal myofibrils were observed. The results strongly suggest that BSE images are further applicable to the study of the architecture of cardiac myocytes and their branches, and the arrangement of intracellular myofibrils in various diseased myocardium.

Increased digitalis-like immunoreactive substances in patients with hypertrophic cardiomyopathy

AIMS

Although increased digitalis-like immunoreactive substances have been found in cases of hypertension and heart failure, no information is available about digitalis-like immunoreactive substances in patients with hypertrophic cardiomyopathy. We investigated digitalis-like immunoreactive substances in the plasma and biopsied specimens of patients with hypertrophic cardiomyopathy.

METHODS AND RESULTS

In 40 patients with hypertrophic cardiomyopathy (27 with the non-obstructive type and 13 with the obstructive type), the plasma concentration of digitalis-like immunoreactive substances was studied by fluorescence polarization immunoassay. Right ventricular endomyocardial biopsy specimens were analysed immunohistochemically, using a monoclonal antibody against digoxin. An increase in digitalis-like immunoreactive substances of more than 0.2 ng. ml(-1)in plasma was found in six of 27 patients with non-obstructive hypertrophic cardiomyopathy (22.2%) and five of 13 with obstructive hypertrophic cardiomyopathy (38.4%). Under light microscopy, positive staining against the antibody was observed heterogeneously on some cardiocytes. In non-obstructive hypertrophic cardiomyopathy, digitalis-like immunoreactive substances in the plasma correlated with the left atrial dimension and inversely with the cardiac index. In obstructive hypertrophic cardiomyopathy, plasma and myocardial digitalis-like immunoreactive substances were positively correlated; they also correlated with left ventricular end-diastolic pressures. Under electron microscopy, digitalis-like immunoreactive substances were detected at the sarcolemma in the free wall, T-tubules, intercalated discs and Z-bands of cardiocytes.

CONCLUSIONS

Increased digitalis-like immunoreactive substances in plasma and cardiocytes, which may have been caused by pressure and/or volume overload, were found in patients with hypertrophic cardiomyopathy. Digitalis-like immunoreactive substances may act on the sarcolemma of cardiocytes and be transported into the cytoplasm.

Remodeling of cardiomyocytes and their branches in juvenile, adult, and senescent spontaneously hypertensive rats and Wistar Kyoto rats: comparative morphometric analyses by scanning electron microscopy

Scanning electron microscopy was used to compare the shape, size, and connection of left ventricular (LV) myocytes between spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY) at 3, 8, 15, 35, and 63 weeks of age. For either strain at each age, five rats were studied, in which LV myocytes consisted of a cylindrical trunk with series (SB) and/ or lateral branch(es) (LB) and step formations; cell junctions had 12 common basic patterns. The length (L), width (W), and L/W ratio of the myocytes, and various indices for SB, LB, and three selected types of cell junctions were measured in 100 cells from each heart and averaged for comparison studies. In the growing period (3-8 weeks of age), the LV myocytes were similar in shape and width in the two age-matched strains and grew similarly with the same L/W ratio. In adolescent (15-week-old) WKY, LV cells grew with the same L/W ratio as in the younger rats, whereas in adolescent SHR, the cells showed a much greater increase in width than in length (disproportionate hypertrophy), the LB proliferated significantly, and the numbers of step-to-step and side-to-side junctions were diminished. In adult (15-35-week-old) WKY, LV cells continued to grow without much change in SB, LB, and the cell junctions, whereas in adult SHR, LV hypertrophy progressed with enhanced cardiomyocyte hypertrophy, increased number of SB, LB, and step-to-end junctions, and reduction in the number of step-to-step and side-to-side junctions per cell. In aged (63-week-old) WKY and SHR, the indices of LV myocytes, SB, LB, and cell junctions did not differ from those in adult WKY and SHR, except for LB thinning in the WKY and significant LB loss in the SHR. Age-related reductions in side-to-side- and step-to-step junctions, and LB loss with myocardial fibrosis in adult and aged SHR may indicate increased loss of gap junctions which couple the cells for transverse conduction, and contribute to anisotropic discontinuous propagation and potential reentrant LV arrhythmias.

Heart-specific activation of LTK results in cardiac hypertrophy, cardiomyocyte degeneration and gene reprogramming in transgenic mice

Leukocyte tyrosine kinase (LTK) is a receptor-type protein tyrosine kinase belonging to the insulin receptor superfamily. To elucidate its biological role, we generated transgenic mice expressing LTK under the control of cytomegarovirus enhancer and beta-actin promoter. The transgenic mice exhibited growth retardation and most of the transgenic mice died within several months after birth. Interestingly, although LTK was expressed in several major organs, the activation (tyrosine-phosphorylation, kinase activity, and multimerization) of LTK was observed selectively in the heart, where LTK was localized on intracellular membrane, presumably on endoplasmic reticulum. Echocardiography showed that the transgenic heart underwent severe concentric hypertrophy, which resulted in reduced cardiac output, low blood pressure, and increased heart rate. Histological examination of the heart exhibited focal degeneration of cardiomyocytes. These histological changes were considered to be due to apoptosis, based on the finding that the sarcolemmas of the degenerative cardiomyocytes were well preserved. In addition, expression of fetal genes, such as atrial natriuretic peptide and skeletal alpha-actin, was markedly induced in the transgenic heart. These results indicate that a certain tissue-specific mechanism of activating LTK exists in the heart and that the activated LTK resulted in cardiac hypertrophy, cardiomyocyte degeneration and gene reprogramming. These findings will provide novel insights into the activating mechanism and biological role of LTK in vivo.

Myocardial inflammatory cell infiltrates in cases of dilated cardiomyopathy: light microscopic, immunohistochemical, and virological analyses of myocardium specimens obtained by partial left ventriculectomy

OBJECTIVE

Partial left ventriculectomy was introduced for the treatment of refractory dilated cardiomyopathy (DCM). To determine the presence and degree of inflammatory cell infiltrates in DCM and the correlation between the underlying myocardial injury and early clinical outcomes after the operation, we performed histopathological, immunohistochemical, and virological studies of the resected myocardium.

METHODS

Posterolateral walls of the left ventricle from 13 idiopathic DCM patients (9 males and 4 females; mean age = 53+/-14 years) were examined. Qualitative and quantitative analyses of the interstitial fibrosis and of the infiltrating inflammatory cells were conducted. For the immunohistochemistry, leukocyte surface markers and antibodies to adhesion molecules and cytokines were used. The histopathological findings were compared with the clinical results, including outcome within 1 year, and pre- and postoperative hemodynamic data. Genomic analysis of the myocardium with polymerase chain reaction was performed for enterovirus, mumps, influenza A, cytomegalovirus, and hepatitis C virus.

RESULTS

(1) The three patients who died of cardiac insufficiency after surgery had a higher count of infiltrating inflammatory cells than the eight survivors (32.1+/-10.4 vs 16.3+/-11.9 cells/mm2, p = 0.07). The severity of interstitial fibrosis (percent fibrosis) did not differ significantly between these two groups (28.3+/-15.0 vs 24.0+/-11.7%). (2) In patients who died of myocardial dysfunction, focal accumulations of lymphocytes were common, in which cytotoxic/suppressor T cells and helper/inducer T cells were observed. (3) Enterovirus genome was detected in the myocardium of two patients, both of them died after surgery.

CONCLUSIONS

Inflammatory cell infiltrates or active myocarditis appear in some cases to play an important role in the etiology and pathophysiology of clinically diagnosed DCM. There is a possibility that those patients with a more severe or ongoing inflammatory process might have poor outcomes after partial left ventriculectomy.

A case of malignant lymphoma with diastolic heart failure

In patients with malignant lymphoma, the first signs and symptoms are frequently noncardiac and clinical manifestations of cardiac involvement are often nonspecific. This case report presents a patient with malignant lymphoma whose first manifestation was characteristic of heart failure, mainly due to diastolic dysfunction, and whose postmortem examination revealed massive myocardial invasion.

Collagen subtypes and matrix metalloproteinase in idiopathic restrictive cardiomyopathy

BACKGROUND

Idiopathic restrictive cardiomyopathy is a rare disease characterized by diastolic dysfunction, and the pathogenesis of the stiff heart remains unclear. The purpose of this study was to analyze the subpopulation of collagen fibers and determine the expression of matrix metalloproteinase in restrictive cardiomyopathy.

METHODS AND RESULTS

In endomyocardial biopsy specimens obtained from seven patients with restrictive cardiomyopathy, collagen fiber types I, III, and IV, and matrix metalloproteinase- and two were observed by light and electron microscopy, using monoclonal antibodies. Type I collagen was less prominent in the interstitium, whereas the immunoreactivity for type III collagen was marked. The immunoreactivity against matrix metalloproteinase-1 was observed along with types I and III collagen fibers and in the cytoplasm of some fibrocytes/fibroblasts. The matrix metalloproteinase-1 tended to increase when the reactivity against types I and III collagen was prominent. Both type IV collagen and matrix metalloproteinase-2 were observed along arterial walls and the basement membrane of cardiocytes.

CONCLUSIONS

Increased type III collagen may play an important role as the cause of left ventricular stiffness in restrictive cardiomyopathy. The matrix metalloproteinase appeared to be involved in a cascade of collagen synthesis and the remodeling of the heart in patients with restrictive cardiomyopathy.

Evolution to dilated cardiomyopathy from acute eosinophilic pancarditis in Churg-Strauss syndrome

We describe the clinical manifestations of a patient with Churg-Strauss syndrome who presented with severe acute cardiac involvement and whose disease evolved to dilated cardiomyopathy (DCM), with special reference to the histopathological findings. Endomyocardial biopsies, conducted sequentially, three times within 10 months, revealed severe eosinophilic endomyocarditis in the acute phase, interstitial fibrosis in the subacute phase, and endocardial thickening with mural thrombi, at 10 months. Although acute inflammation associated with elevation of eosinophil granule proteins subsided with steroid therapy, left ventricular dilatation with reduced contractility progressed. A subgroup of DCM is not considered to be idiopathic but, rather, an aftereffect of hypereosinophilic heart disease.

Vasospastic angina in patients with systemic triglyceride storage disease with Jordans' anomaly and cardiomyopathy

Vasospastic angina was demonstrated clinically and angiographically in a 54-year-old patient with systemic triglyceride storage disease and cardiomyopathy. He and his younger sister had been diagnosed in 1985 as having systemic triglyceride storage with Jordans' anomaly. In 1993, he began complaining of rest and effort chest pain in the morning, which was accompanied by ST depression by ECG. Sublingual nitroglycerine was effective for treating this pain. Intracoronary injection of acetylcholine induced severe coronary vasoconstriction in the left anterior descending artery. Left ventricular contraction was diffusely impaired. Deposits of numerous triglyceride droplets and a decrease in the density of myofibrils in cardiocytes were found in the specimens obtained by endomyocardial biopsy. The impaired left ventricular contraction may have been due to the changes in myocardial cells. His sister complained of a similar chest pain that was completely controlled by calcium channel antagonis. Thus, our cases demonstrated vasospastic angina associated with cardiomyopathy secondary to systemic triglyceride storage disease with Jordans' anomaly, though the causal relationship between these conditions remains unclear.

Effect of sulfo-N-succinimidyl palmitate on the rat heart: myocardial long-chain fatty acid uptake and cardiac hypertrophy

Abnormal long-chain fatty acid metabolism has been suggested as having a role in the genesis of certain cardiac diseases, and depressed myocardial long-chain fatty acid uptake has been clinically demonstrated in some patients with hypertrophic cardiomyopathy. However, the site where long-chain fatty acid metabolism is affected in cardiomyopathy remains unclear. Although cardiac hypertrophy is reported to be induced in rats by a fat-free diet, little is known of the consequences of depressed myocardial long-chain fatty acid uptake. Sulfo-N-succinimidyl derivatives of long-chain fatty acids have been shown to irreversibly inhibit long-chain fatty acid transport. To investigate the possible linkage of abnormal long-chain fatty acid uptake with cardiac hypertrophy, myocardial long-chain fatty acid uptake was blocked in rats using a sulfo-N-succinimidyl derivative of palmitate (SSP). SSP was intraperitoneally administered to rats for 12 weeks, and its effects on physiological parameters, and cardiac morphology were studied, SSP treatment (20 mg/kg) caused a 12% increase in heart weight (663.7 +/- 33.6 mg in controls v 741.2 +/- 26.5 mg after SSP treatment) and an 11% increase in the heart weight to body weight ratio (2.46 +/- 0.10 in controls v 2.72 +/- 0.17 after SSP) without any significant change of body weight. No significant differences were observed in blood pressure, heart rate, and serum hormones (insulin and triiodothyronine) between the control and SSP-treated groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Anatomy of the sinus node, AV node, and His bundle of the heart of the sperm whale (Physeter macrocephalus), with a note on the absence of an os cordis

BACKGROUND

Atrioventricular (AV) conduction time in large whales is only slightly greater than in smaller mammals even though their hearts are enormously larger. Little is known of the detailed histology or cytology of the conduction system of large whales. Such knowledge could be useful in defining the nature of cardiac rhythm and conduction of the whale as well as smaller mammals including humans.

METHODS

We studied hearts from seven sperm whales. After fixation in formaldehyde and later dissection, specimens were prepared for histological examination.

RESULTS

Cell size, histological organization, and innervation of the sperm whale's sinus node, AV node, and His bundle are similar to most mammalian hearts, except the sinus node is substantially larger. There is no central fibrous body between the atrial and ventricular septa, and the whale has no os cordis. Only the upper quarter of the interventricular septum is fully formed; below that there is only a thin layer of fatty connective tissue between the two ventricles.

CONCLUSIONS

Given our morphological findings, we believe that the whale's comparatively short AV conduction time may be best explained by the sinus node and AV node functioning as coupled relaxation oscillators. Absence of an os cordis or central fibrous body or strong attachment between the two ventricles may pose both electrophysiological and hemodynamic hazards when the whale is no longer in its normally buoyant aquatic environment.

Apoptosis and pleomorphic micromitochondriosis in the sinus nodes surgically excised from five patients with the long QT syndrome

Sinus nodes of five symptomatic patients with the long QT syndrome were surgically excised and followed by permanent electronic pacing as part of a new surgical treatment. We examined those sinus nodes by light and electron microscopy with tissue that was promptly fixed at the time of surgery. All five sinus nodes were similarly abnormal. By light microscopy we found distinctive focal fibrosis, some degenerating myocytes and neural elements, and numerous narrowed small vessels. Except in the nerves there was no evidence of inflammation. In electron micrographs the mitochondria within nodal myocytes were abnormally abundant, remarkably pleomorphic, and smaller than those in normal human sinus nodal cells. The ultrastructural features of the degenerated nodal cells were typical of apoptosis, characterized by the absence of inflammation, well-preserved mitochondria, the presence of apoptotic bodies, phagocytosis of these cells by neighboring myocytes, and especially in smooth muscle cells of arterioles, nuclear chromatin margination and nucleolar disintegration. Apoptotic degeneration of nodal myocytes was stochastic, with adjacent cells appearing unaffected. Focal ischemia caused by narrowed vessels may be a contributory factor, and the nerves may harbor some viral infection, but for the nodal myocytes the abnormality appears to be primarily apoptosis, sometimes called programmed cell death. Both the typically episodic clinical features and the terminal event in fatal cases of the long QT syndrome may be due to apoptosis.

Electron microscopic demonstration of intercellular junctions between subendocardial smooth muscle and myocardium in the sheep heart

The eustachian ridge of 11 sheep hearts was examined by light and electron microscopy to elucidate the morphologic relationship between cardiac smooth muscle cells and myocardial cells. Smooth muscle cells were commonly observed in the subendocardial connective tissue and they were usually arranged in strands. When mixed with myocardial cells at the margin of these strands, smooth muscle cells exhibited numerous direct connections with the myocardial cells. These intercellular junctions were composed primarily of simple appositions (undifferentiated regions), but occasional desmosomes and fasciae adherents (intermediate junctions) were seen. We found no nexus (gap junctions) at these sites. The existence of direct intercellular junctions between smooth muscle and myocardium suggests several possible electrical and mechanical interactions.

Cardiac conduction system in the chicken: gross anatomy plus light and electron microscopy

Twenty-three chicken hearts were used to study the cardiac conduction system by light and electron microscopy. In addition to a sinus node, atrioventricular node (AVN), His bundle, left and right bundle branches (LBB, RBB), the chicken also has an AV Purkinje ring and a special middle bundle branch (MBB). The sinus node lies near the base of the lower portion of the right sinoatrial valve. The AV node is just above the tricuspid valve and anterior to the coronary sinus. The His bundle descends from the anterior and inferior margin of the AV node into the interventricular septum, then dividing into right, left and middle branches some distance below the septal crest. The middle bundle branch turns posteriorly toward the root of the aorta. The AV Purkinje ring originates from the proximal AV node and then encircles the right AV orifice, joining the MBB to form a figure-of-eight loop. The chicken conduction system contains four types of myocytes: 1) The P cell is small and rounded, with a relatively large nucleus and sparse myofibrils. 2) The transitional cell is slender and full of myofibrils. 3) The Purkinje-like cell resembles the typical Purkinje cell, but is smaller and darker. 4) The Purkinje cell is found in the His bundle, its branches, and the periarterial and subendocardial Purkinje network.

Histological organization of the right and left atrioventricular valves of the chicken heart and their relationship to the atrioventricular Purkinje ring and the middle bundle branch

In the avian heart the right and left atrioventricular (AV) valves not only exhibit their own special anatomical characteristics, but they also are in close proximity to the conduction system. The right AV valve is a single, spiral plane of myocardium, in remarkable contrast to the fibrous structure characteristic of the mammalian tricuspid valve. A ring of Purkinje tissue encircles the avian right AV orifice and connects to the muscular valve. The chicken has no crista supraventricularis, its right AV valve serving that function as well as opening and closing the right AV orifice. The left AV valve consists of three leaflets instead of the two typical of mammalian hearts. Its anterior and posterior leaflets are small; its large aortic (medial) leaflet merges with the bases of both the left and noncoronary cusps of the aortic valve by fibrous tissue, resembling that of the mammalian heart. However, unlike in mammals, there is a slim cylinder of continuous myocardium coursing parallel to this fibrous junction. This unusual arc of myocardium in the chicken serves to complete an entire subaortic ring of myocardium and is thus potentially capable of constricting the outflow tract of the chicken's left ventricle. The middle bundle branch connects with both the muscle arch and the AV Purkinje ring. Thus the myocardium in or near both AV valves (and the left ventricular outflow tract) in the chicken heart is so arranged that it may receive direct early activation from the conduction system.

Comparative ultrastructure of the tip of ventricular papillary muscle

Electron microscopic studies of the tips of left ventricular papillary muscles from seven human, two monkey, three sheep, and two chicken hearts were done to elucidate the fine structure of myotendinous junctions. The human specimens were from normal hearts obtained 3 to 9 hours postmortem from persons aged 7 months to 30 years (mean, 13.3 years). We found no significant ultrastructural differences between the human hearts and those of monkey, sheep, and chicken. Myocardial fibers were elongated and thinner (tapered) in the tips of papillary muscles. In addition to usual working myocardial cells, the distal end of narrowing muscle fibers also contained small pale cardiocytes containing fewer myofibrils and smaller mitochondria. These cells were similar to P cells or transitional cells in the conduction system. Nerve axons and Schwann cells were commonly seen in the interstitium, usually in association with capillaries. Fibroblasts and axon varicosities were occasionally seen extremely close to the cardiocytes. These specialized myocardial cells associated with rich neural tissue in the papillary muscle tip possibly function as foci of local automaticity. This histologic organization may also represent neurosensory function responding to and monitoring local pressure changes, efferent adrenergic or cholinergic neural activity, or both.

Ultrastructural alterations of the conduction system in mice exhibiting sinus arrest or heart block during Coxsackievirus B3 acute myocarditis

By light and electron microscopy we studied the sinus nodes and atrioventricular (AV) conducting tissue of six C3H/He mice having coxsackievirus B3 acute myocarditis. Sinus arrest was documented in all six mice, and second- or third-degree AV block was documented in three of the six mice. Although myocarditic changes in the conduction system, especially in the sinus node, were less than those in atrial and ventricular working myocardium, there were distinct abnormalities within both the sinus node and AV conducting tissue in all six hearts. Important ultrastructural alterations were inflammatory cell infiltrates and significant injury of specialized cells and of neural tissue. Specialized cells showed various features of degeneration and necrosis. Neural tissue damage included degeneration of axons and Schwann cells and disorganization of the neuromuscular junctions. Inflammatory cells, particularly macrophages, were often in intimate contact with injured specialized cells and neural tissue. Interstitial edema and bleeding and lymphatic vessel dilatation were also observed. These pathologic changes are considered to play an important role in the development of the documented disturbances of rhythm and conduction.

Hydrogen-Induced Cracking of Steels Under Wet Hydrogen Sulfide Environment

The hydrogen induced cracking (HIC) of as-rolled steels has been investigated. The specimens were immersed into the synthetic sea water saturated with H2S. Since the cracks initiated at the elongated MnS particles, the HIC susceptibility decreased with decreasing sulfur content. It was, however, often observed that the HIC occurred even in the steels containing extremely low sulfur. These cracks propagated along an anomalous structure, which consisted of low temperature transformation products. Such an anomalous structure arose from the segregation of manganese and phosphorus during the solidification of steels. As to the controlled-rolled steels, the effects of texture, residual strain, and the shape of inclusions on the HIC were examined. It was revealed that the rolling at lower temperature did affect the HIC susceptibility with elongating the sulfide inclusions, while little effect of controlled rolling was recognized in the extremely low sulfur steels. It was also demonstrated that the addition of small amount of copper markedly reduced the amount of hydrogen absorbed. This could be due to the interface reaction between steel and wet H2S environment. As the application of the foregoing results, the steel highly resistant to the HIC under the present experimental environment has been developed.