Human myocardial histologic characteristics in congestive heart failure

Correlations of Serum Lipid Parameters and Atherogenic Indices With Left Ventricular Diastolic Dysfunction Among Apparently Healthy Patients With Type 2 Diabetes Mellitus: A Multicenter In-Hospital Cross-Sectional Study

Background: In adolescents with Type 1 diabetes, lipid ratios are predictors of left ventricular diastolic dysfunction (LVDD). However, whether this also applies to adults with Type 2 Diabetes Mellitus (T2DM) is unclear. This study is aimed at assessing the correlations of serum lipid parameters and atherogenic indices with LVDD in patients with T2DM. Methods: This cross-sectional study included 203 patients with T2DM aged 59.9 ± 13.6 years (111 males, sex ratio: 1 : 2 in favor of males) from eight randomly selected urban hospitals. Demographic information was collected, an anthropometric assessment was performed, and blood pressure was measured. Fasting blood samples were obtained to assess total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TGs), glucose, and glycated hemoglobin. The atherogenic index of plasma (AIP), Castelli Risk Index I (CRI-I), Castelli Risk Index II (CRI-II), atherogenic coefficient, and non-HDL-C were determined using specific formulas. Diastolic function was assessed using echocardiography as per the 2016 updated guidelines of the American Society of Echocardiography (ASE) and the European Association of Cardiovascular Imaging (EACVI). Results: Approximately 47.8% of the participants had LVDD. Compared with participants with normal diastolic function, those with LVDD were more likely to be older than 55 years (p < 0.001), tended to have obesity (p = 0.045), had a higher risk of developing dyslipidemia (p = 0.041), and higher AIP and CRI-II (p < 0.05) levels while having similar low HDL-C and hypertriglyceridemia frequencies. In the multivariate model adjusting for age, high AIP (adjusted odds ratio [aOR], 3.37; 95% confidence interval [CI], 1.22-5.34) and high CRI-II (aOR: 3.80; 95% CI: 2.25-6.35) were independent determinants of LVDD. Conclusions: These results highlight the importance of considering atherogenic indices, primarily AIP and CRI-II in the management of T2DM patients. High AIP and high CRI-II could serve as surrogate markers of LVDD, an early cardiovascular manifestation in patients with T2DM.

Multi-level transcriptome sequencing identifies COL1A1 as a candidate marker in human heart failure progression

BACKGROUND

Heart failure (HF) has been recognized as a global pandemic with a high rate of hospitalization, morbidity, and mortality. Although numerous advances have been made, its representative molecular signatures remain largely unknown, especially the role of genes in HF progression. The aim of the present prospective follow-up study was to reveal potential biomarkers associated with the progression of heart failure.

METHODS

We generated multi-level transcriptomic data from a cohort of left ventricular heart tissue collected from 21 HF patients and 9 healthy donors. By using Masson staining to calculate the fibrosis percentage for each sample, we applied lasso regression model to identify the genes associated with fibrosis as well as progression. The genes were further validated by immunohistochemistry (IHC) staining in the same cohort and qRT-PCR using another independent cohort (20 HF and 9 healthy donors). Enzyme-linked immunosorbent assay (ELISA) was used to measure the plasma level in a validation cohort (139 HF patients) for predicting HF progression.

RESULTS

Based on the multi-level transcriptomic data, we examined differentially expressed genes [mRNAs, microRNAs, and long non-coding RNAs (lncRNAs)] in the study cohort. The follow-up functional annotation and regulatory network analyses revealed their potential roles in regulating extracellular matrix. We further identified several genes that were associated with fibrosis. By using the survival time before transplantation, COL1A1 was identified as a potential biomarker for HF progression and its upregulation was confirmed by both IHC and qRT-PCR. Furthermore, COL1A1 content ≥ 256.5 ng/ml in plasma was found to be associated with poor survival within 1 year of heart transplantation from heart failure [hazard ratio (HR) 7.4, 95% confidence interval (CI) 3.5 to 15.8, Log-rank p value < 1.0 × 10^- 4].

CONCLUSIONS

Our results suggested that COL1A1 might be a plasma biomarker of HF and associated with HF progression, especially to predict the 1-year survival from HF onset to transplantation.

Histopathologic features of alcoholic cardiomyopathy compared with idiopathic dilated cardiomyopathy

BACKGROUND

The histologic difference between alcoholic cardiomyopathy (ACM) and idiopathic dilated cardiomyopathy (IDCM) is unclear. The present study aimed to identify the quantitative pathologic features of ACM compared with IDCM.

METHODS

Specimens from 6 regions (anterior left ventricle [LV], lateral LV, inferior LV, interventricular septum [IVS], anterior right ventricle [RV], and inferior RV) were sampled from each explanted heart. Specimens from 4 healthy donor hearts were obtained as normal control. Tissues were sectioned and Masson trichrome stained. Histomorphometry was performed to evaluate the amount of myocyte, fibrosis, fatty tissue, and interstitium by Image-Pro Plus 6.0 (Media Cybernetics).

RESULTS

A total of 408 specimens were obtained from 34 ACMs and 34 IDCMs; 8 specimens were obtained from 4 healthy donor hearts. Compared to healthy donor hearts, we observed an increase in fibrosis which replaces myocytes in myocardium of end-stage cardiomyopathy. The overall myocyte ratio in myocardium was 69.5 ± 8.7% in ACM vs 71.9 ± 7.4% in IDCM (P < .05). The percentage of interstitium was 10.8 ± 4.8% in ACM vs 9.2 ± 6.2% in IDCM (P < .05). A significant difference of fibrosis, fatty tissue was not discovered. Moreover, the myocyte area was 65.37 ± 11.8% in ACM LV vs 70.03 ± 9.0% in IDCM LV (P < .001).

CONCLUSION

We described histologic characteristics in ACM and IDCM. There might be a quantitative difference of myocyte, interstitium in myocardium between ACM and IDCM, especially in LV. No difference was found in the percentage of fibrosis between the 2 groups.

Taxonomy of segmental myocardial systolic dysfunction

The terms used to describe different states of myocardial health and disease are poorly defined. Imprecision and inconsistency in nomenclature can lead to difficulty in interpreting and applying trial outcomes to clinical practice. In particular, the terms ‘viable’ and ‘hibernating’ are commonly applied interchangeably and incorrectly to myocardium that exhibits chronic contractile dysfunction in patients with ischaemic heart disease. The range of inherent differences amongst imaging modalities used to define myocardial health and disease add further challenges to consistent definitions. The results of several large trials have led to renewed discussion about the classification of dysfunctional myocardial segments. This article aims to describe the diverse myocardial pathologies that may affect the myocardium in ischaemic heart disease and cardiomyopathy, and how they may be assessed with non-invasive imaging techniques in order to provide a taxonomy of myocardial dysfunction.

Characterization of the Changes in Cardiac Structure and Function in Mice Treated With Anthracyclines Using Serial Cardiac Magnetic Resonance Imaging

BACKGROUND

Anthracyclines are cardiotoxic; however, there are limited data characterizing the serial changes in cardiac structure and function after anthracyclines. The aim of this study was to use cardiac magnetic resonance to characterize anthracycline-induced cardiotoxicity in mice.

METHODS AND RESULTS

This was a longitudinal cardiac magnetic resonance and histological study of 45 wild-type male mice randomized to doxorubicin (n=30, 5 mg/kg of doxorubicin/week for 5 weeks) or placebo (n=15). A cardiac magnetic resonance was performed at baseline and at 5, 10, and 20 weeks after randomization. Measures of primary interest included left ventricular ejection fraction, myocardial edema (multiecho short-axis spin-echo acquisition), and myocardial fibrosis (Look-Locker gradient echo). In doxorubicin-treated mice versus placebo, there was an increase in myocardial edema at 5 weeks (T2 values of 32±4 versus 21±3 ms; P<0.05), followed by a reduction in left ventricular ejection fraction (54±6 versus 63±5%; P<0.05) and an increase in myocardial fibrosis (extracellular volume of 0.34±0.03 versus 0.27±0.03; P<0.05) at 10 weeks. There was a strong association between the early (5 weeks) increase in edema and the subacute (10 weeks) increase in fibrosis (r=0.90; P<0.001). Both the increase in edema and fibrosis predicted the late doxorubicin-induced mortality in mice (P<0.001).

CONCLUSIONS

Our data suggest that, in mice, anthracycline-induced cardiotoxicity is associated with an early increase in cardiac edema and a subsequent increase in myocardial fibrosis. The early increase in edema and subacute increase in fibrosis are strongly linked and are both predictive of late mortality.

Studying Dynamic Myofiber Aggregate Reorientation in Dilated Cardiomyopathy Using In Vivo Magnetic Resonance Diffusion Tensor Imaging

Supplemental Digital Content is available in the text.

Background—

The objective of this study is to assess the dynamic alterations of myocardial microstructure and strain between diastole and systole in patients with dilated cardiomyopathy relative to healthy controls using the magnetic resonance diffusion tensor imaging, myocardial tagging, and biomechanical modeling.

Methods and Results—

Dual heart-phase diffusion tensor imaging was successfully performed in 9 patients and 9 controls. Tagging data were acquired for the diffusion tensor strain correction and cardiac motion analysis. Mean diffusivity, fractional anisotropy, and myocyte aggregate orientations were compared between both cohorts. Cardiac function was assessed by left ventricular ejection fraction, torsion, and strain. Computational modeling was used to study the impact of cardiac shape on fiber reorientation and how fiber orientations affect strain. In patients with dilated cardiomyopathy, a more longitudinal orientation of diastolic myofiber aggregates was measured compared with controls. Although a significant steepening of helix angles (HAs) during contraction was found in the controls, consistent change in HAs during contraction was absent in patients. Left ventricular ejection fraction, cardiac torsion, and strain were significantly lower in the patients compared with controls. Computational modeling revealed that the dilated heart results in reduced HA changes compared with a normal heart. Reduced torsion was found to be exacerbated by steeper HAs.

Conclusions—

Diffusion tensor imaging revealed reduced reorientation of myofiber aggregates during cardiac contraction in patients with dilated cardiomyopathy relative to controls. Left ventricular remodeling seems to be an important factor in the changes to myocyte orientation. Steeper HAs are coupled with a worsening in strain and torsion. Overall, the findings provide new insights into the structural alterations in patients with dilated cardiomyopathy.

Aldosterone Antagonism in an Inflammatory State: Evidence for Myocardial Protection

Introduction. Chagas' disease is one of the most important causes of dilated cardiomyopathy in South and Central America. It is an inflammatory cardiomyopathy. We wanted to investigate whether it could have the same response to aldosterone antagonism as demonstrated before in other dilated cardiomyopathies.

Objective. To evaluate the role of spironolactone in myocardial remodelling in a Chagas' cardiomyopathy model.

Material and Methods. We studied 60 Sirius Hamsters divided into: control (C) infected (Inf) and Inf plus spironolactone (Infsp, 40 mg/kg/day) groups, for 11 months. Echocardiography with colour doppler was performed. Left ventricular end diastolic diameter (LVEDD), fractional shortening (FS) and corrected isovolumic relaxation time (IRT) were evaluated, as well as interstitial collagen volume fraction (ICVF) and myocardial inflammation.

Result. The results demonstrated that survival was improved by use of spironolactone in the chronic phase (p<0.04). Body weight (BW) was C:190 g, Inf:167 g*, Infsp:198 g (*p<0.05, compared to C and Infsp), LVEDD/BW was C:0.31, Inf: 0.35*, Infsp: 0.29 (*p<0.05, compared to C and Infsp), FS was C:38, Inf: 35.5, Infsp: 38 (with no statistical difference) and IRT was C: 23 msec, Inf: 26 msec*, Infsp: 22 msec (p<0.05, compared to C and Infsp). ICVF (%) was attenuated at LV (C: 0.34±0.1, Inf: 1.75±0.7*†, Infsp: 0.95±0.2*; *p<0.05, †p<0.05).

Conclusion. Spironolactone attenuated the myocardial remodelling in Chagas' cardiomyopathy, reduced mortality during the chronic phase and reduced inflammatory infiltration.

Anthracycline-Induced Cardiomyopathy in Adults

Anthracyclines are one of the most commonly used antineoplastic agent classes, and a core part of the treatment in breast cancers, hematological malignancies, and sarcomas. Their benefit is decreased by their well-recognized cardiotoxicity. The purpose of this review is to outline the presentation, mechanisms, diagnosis, and treatment of anthracyclines-induced cardiotoxicity. Symptomatic heart failure occurs in 2% to 5% of patients treated with anthrayclines and may be higher in older patients or patients with cardiovascular risk factors. The mechanisms involved in anthracycline-induced cardiotoxicity involve myocyte loss by apoptosis in the presence of a limited regenerative capacity. Once symptomatic, anthracycline-induced cardiotoxicity is associated with markedly decreased survival. Left ventricular ejection fraction (LVEF), mostly determined using echocardiography, is used to monitor patients treated with anthracyclines. As more than 1/3 of patients treated with anthracyclines do not recover their baseline LVEF once it is decreased, more sensitive echocardiographic indices of LV function such as myocardial deformation or biomarkers have been studied in patients monitoring. Cardioprotective treatments such as angiotensin-converting enzyme inhibitors, beta-blockers, iron chelators, statins, and metformin are also the topic of research efforts.

Cardiotoxicity due to chemotherapy: role of cardiac imaging

The identification of patients at risk of cardiac toxicity (cardiotoxicity) from cancer therapy is challenging. There is an increasing focus on early detection of cardiotoxicity such that interventions can be instituted to prevent advanced heart failure. Clinical risk prediction tools are limited and clinical symptoms are not specific. Direct assessment of myocardial function before and during cancer treatment using cardiac imaging appears to be an objective method to identify patients at risk. Although, multiple imaging modalities and measures of cardiac function are available, the best modality or the optimal measure of function is unknown. Measurement of left ventricular ejection fraction is most commonly used; however, growing literature suggests that it is inadequate for the detection of early cardiac injury. Other measures include left ventricular diastolic function, myocardial deformation, and myocardial tissue characterization. This review will provide an overview of the clinically available measures for the assessment of cardiotoxicity.

Single bolus versus split dose gadolinium administration in extra-cellular volume calculation at 3 Tesla

BACKGROUND

Diffuse myocardial fibrosis may be quantified with cardiovascular magnetic resonance (CMR) by calculating extra-cellular volume (ECV) from native and post-contrast T1 values. Accurate ECV calculation is dependent upon the contrast agent having reached equilibrium within tissue compartments. Previous studies have used infusion or single bolus injections of contrast to calculate ECV. In clinical practice however, split dose contrast injection is commonly used as part of stress/rest perfusion studies. In this study we sought to assess the effects of split dose versus single bolus contrast administration on ECV calculation.

METHODS

Ten healthy volunteers and five patients ( 4 ischaemic heart disease, 1 hypertrophic cardiomyopathy) were studied on a 3.0 Tesla (Philips Achieva TX) MR system and underwent two (patients) or three (volunteers) separate CMR studies over a mean of 12 and 30 days respectively. Volunteers underwent one single bolus contrast study (Gadovist 0.15mmol/kg). In two further studies, contrast was given in two boluses (0.075mmol/kg per bolus) as part of a clinical adenosine stress/rest perfusion protocol, boluses were separated by 12 minutes. Patients underwent one bolus and one stress perfusion study only. T1 maps were acquired pre contrast and 15 minutes following the single bolus or second contrast injection.

RESULTS

ECV agreed between bolus and split dose contrast administration (coefficient of variability 5.04%, bias 0.009, 95% CI -3.754 to 3.772, r2 = 0.973, p = 0.001)). Inter-study agreement with split dose administration was good (coefficient of variability, 5.67%, bias -0.018, 95% CI -4.045 to 4.009, r2 = 0.766, p > 0.001).

CONCLUSION

ECV quantification using split dose contrast administration is reproducible and agrees well with previously validated methods in healthy volunteers, as well as abnormal and remote myocardium in patients. This suggests that clinical perfusion CMR studies may incorporate assessment of tissue composition by ECV based on T1 mapping.

Characterization of diffuse fibrosis in the failing human heart via diffusion tensor imaging and quantitative histological validation

Non-invasive imaging techniques are highly desirable as an alternative to conventional biopsy for the characterization of the remodeling of tissues associated with disease progression, including end-stage heart failure. Cardiac diffusion tensor imaging (DTI) has become an established method for the characterization of myocardial microstructure. However, the relationships between diffuse myocardial fibrosis, which is a key biomarker for staging and treatment planning of the failing heart, and measured DTI parameters have yet to be investigated systematically. In this study, DTI was performed on left ventricular specimens collected from patients with chronic end-stage heart failure as a result of idiopathic dilated cardiomyopathy (n = 14) and from normal donors (n = 5). Scalar DTI parameters, including fractional anisotropy (FA) and mean (MD), primary (D1 ), secondary (D2 ) and tertiary (D3 ) diffusivities, were correlated with collagen content measured by digital microscopy. Compared with hearts from normal subjects, the FA in failing hearts decreased by 22%, whereas the MD, D2 and D3 increased by 12%, 14% and 24%, respectively (P < 0.01). No significant change was detected for D1 between the two groups. Furthermore, significant correlation was observed between the DTI scalar indices and quantitative histological measurements of collagen (i.e. fibrosis). Pearson's correlation coefficients (r) between collagen content and FA, MD, D2 and D3 were -0.51, 0.59, 0.56 and 0.62 (P < 0.05), respectively. The correlation between D1 and collagen content was not significant (r = 0.46, P = 0.05). Computational modeling analysis indicated that the behaviors of the DTI parameters as a function of the degree of fibrosis were well explained by compartmental exchange between myocardial and collagenous tissues. Combined, these findings suggest that scalar DTI parameters can be used as metrics for the non-invasive assessment of diffuse fibrosis in failing hearts.

Myocardial extracellular volume by cardiac magnetic resonance imaging in patients treated with anthracycline-based chemotherapy

We aimed to determine whether the myocardial extracellular volume (ECV), measured using T1 measurements obtained during cardiac magnetic resonance imaging were increased in patients treated with anthracyclines. We performed cardiac magnetic resonance imaging and echocardiography and measured the ECV in 42 patients treated with anthracyclines. The data from the cardiac magnetic resonance study were compared to those from healthy volunteers. The anthracycline-treated cohort consisted of 21 men and 21 women with a mean age of 55 ± 17 years, who presented a median of 84 months after chemotherapy with a cumulative anthracycline exposure of 282 ± 65 mg/m(2) and a mean left ventricular ejection fraction of 52 ± 12%. The ECV was elevated in the anthracycline-treated patients compared to the age- and gender-matched controls (0.36 ± 0.03 vs 0.28 ± 0.02, p <0.001). A positive association was found between the ECV and left atrial volume (ECV vs indexed left atrial volume, r = 0.65, p <0.001), and negative association was found between the ECV and diastolic function (E' lateral, r = -0.64, p <0.001). In conclusion, the myocardial ECV is elevated in patients with previous anthracycline treatment and is associated with the diastolic function and increased atrial volumes.

Left ventricular mass in patients with a cardiomyopathy after treatment with anthracyclines

We aimed to describe the cardiac magnetic resonance (CMR) findings and determine the prognostic variables in patients with a cardiomyopathy after treatment with anthracyclines. CMR imaging was performed in 91 patients (58% men, mean age 43 ± 18 years, and mean anthracycline dose of 276 ± 82 mg/m(2)) with a reduced ejection fraction after anthracycline-based chemotherapy. Major adverse cardiovascular events were defined as cardiovascular death, appropriate implantable cardioverter-defibrillator therapy, and admission for decompensated heart failure. Patients presented a median of 88 months (interquartile range 37 to 138) after chemotherapy and were followed for 27 months (interquartile range 22 to 38). Late gadolinium enhancement was an uncommon finding (5 patients, 6%) despite a reduced ejection fraction (36 ± 8%). An inverse association was found between the anthracycline dose and the indexed left ventricular (LV) mass by CMR (r = -0.67, p <0.001). A total of 52 adverse cardiac events occurred (event rate of 22%/year). When the patients were grouped according to the presence or absence of a major adverse cardiovascular event, the indexed LV mass and glomerular filtration rate were lower and the anthracycline dose was greater among the patients who experienced an adverse event. In a multivariate model, the indexed LV mass demonstrated the strongest association with major adverse cardiovascular events (hazard ratio 0.89, chi-square 26, p <0.001). In conclusion, myocardial scar by late gadolinium enhancement-CMR is infrequent in patients with anthracycline-cardiomyopathy despite a reduced ejection fraction, the event rate in patients with established anthracycline-cardiotoxicity is high, and indexed LV mass by CMR imaging is a predictor of adverse cardiovascular events.

Diastolic dysfunction of aging is independent of myocardial structure but associated with plasma advanced glycation end-product levels

Background

Heart failure is associated with abnormalities of myocardial structure, and plasma levels of the advanced glycation end-product (AGE) N^ε-(carboxymethyl)lysine (CML) correlate with the severity and prognosis of heart failure. Aging is associated with diastolic dysfunction and increased risk of heart failure, and we investigated the hypothesis that diastolic dysfunction of aging humans is associated with altered myocardial structure and plasma AGE levels.

Methods

We performed histological analysis of non-ischemic left ventricular myocardial biopsies and measured plasma levels of the AGEs CML and low molecular weight fluorophores (LMWFs) in 26 men undergoing coronary artery bypass graft surgery who had transthoracic echocardiography before surgery. None had previous cardiac surgery, myocardial infarction, atrial fibrillation, or heart failure.

Results

The patients were aged 43–78 years and increasing age was associated with echocardiographic indices of diastolic dysfunction, with higher mitral Doppler flow velocity A wave (r = 0.50, P = 0.02), lower mitral E/A wave ratio (r = 0.64, P = 0.001), longer mitral valve deceleration time (r = 0.42, P = 0.03) and lower early diastolic peak velocity of the mitral septal annulus, e’ (r = 0.55, P = 0.008). However, neither mitral E/A ratio nor mitral septal e’ was correlated with myocardial total, interstitial or perivascular fibrosis (picrosirius red), immunostaining for collagens I and III, CML, and receptor for AGEs (RAGE), cardiomyocyte width, capillary length density, diffusion radius or arteriolar dimensions. Plasma AGE levels were not associated with age. However, plasma CML levels were associated with E/A ratio (r = 0.44, P = 0.04) and e’ (r = 0.51, P = 0.02) and LMWF levels were associated with E/A ratio (r = 0.49, P = 0.02). Moreover, the mitral E/A ratio remained correlated with plasma LMWF levels in all patients (P = 0.04) and the mitral septal e’ remained correlated with plasma CML levels in non-diabetic patients (P = 0.007) when age was a covariate.

Conclusions

Diastolic dysfunction of aging was independent of myocardial structure but was associated with plasma AGE levels.

Central arterial aging and the epidemic of systolic hypertension and atherosclerosis

The structure and function of central arteries change throughout the lifetime of humans and animals. Since atherosclerosis and hypertension are prevalent in epidemic proportion among older persons, it is reasonable to hypothesize that specific mechanisms that underlie the arterial substrate that has been altered by an "aging process" are intimately linked to arterial diseases. Indeed, recent studies reveal a profile of arterial cell and matrix properties that emerges with advancing age within the grossly normal appearing aortic wall of both animals and humans. This profile is proinflammatory, and is manifested by intimal infiltration of fetal cells, increased production of angiotensin II (Ang II)-signaling pathway molecules, eg, matrix metalloproteases (MMPs), and monocyte chemoattractant protein (MCP-1), transforming growth factor B1 (TGF-beta1), enhanced activation of MMPs, TGF-beta, and NADPH oxidase, and reduced nitric oxide (NO) bioavailability. This profile is similar to that induced at younger ages in experimental animal models of hypertension or atherosclerosis. In humans, this proinflammatory state, which occurs in the absence of lipid deposition, appears to be attributable to aging, per se. Other well known human risk factors, eg, altered lipid metabolism, smoking, and lack of exercise, interact with this arterial substrate that is altered by aging and render the aging human artery fertile soil for facilitation of the initiation and progression of arterial diseases. Therapies to reduce or retard this age-associated proinflammatory state within the grossly appearing arterial wall central arteries, in addition to slowing arterial aging, per se, may have a substantial impact on the quintessential age-associated arterial diseases of our society.

Left ventricular myocardial remodeling and contractile state in chronic aortic regurgitation

BACKGROUND

In chronic aortic regurgitation, eccentric hypertrophy, with combined concentric hypertrophy of the left ventricle, is an important adaptive response to volume overload, which in itself is a compensatory mechanism for permitting the ventricle to normalize its afterload and to maintain normal ejection performance (physiologic hypertrophy). However, progressive dilatation of the left ventricle leads to depressed left ventricular (LV) contractility and myocardial structural changes, including cellular hypertrophy and interstitial fibrosis (pathological hypertrophy).

HYPOTHESIS

The study was undertaken to determine the relationship between left ventricular myocardial structure and contractile function in 14 patients with chronic aortic regurgitation by cardiac catheterization and endomyocardial biopsies.

METHODS

Myocardial cell diameter and percent interstitial fibrosis were obtained from biopsy samples. Contractile function was evaluated from the ratio of end-systolic wall stress to end-systolic volume index (ESS/ESVI) and the ejection fraction-end-systolic stress (EF-ESS) relationship, which was obtained from 30 normal control subjects.

RESULTS

Myocardial cell diameter correlated significantly with the ESVI (r = 0.72, p < 0.005), ejection fraction (r = -0.58, p < 0.05), and ESS/ESVI (r = -0.58, p < 0.05). The percent interstitial fibrosis also correlated inversely with ESS/ESVI (r = -0.71, p < 0.005). Compared with very few patients with an ESVI < 70 ml/m2, the majority of patients with ESVI > or = 70 ml/m2 had a cell diameter of > or = 30 microns and a percent interstitial fibrosis of > or = 10%. The nine patients who had depressed contractile function, as assessed from the EF-ESS relationship, had a higher percent interstitial fibrosis (p < 0.05) than five patients showing a normal EF-ESS relationship, despite the fact that there was no significant difference in myocardial cell diameter between them. Thus, advanced cellular hypertrophy and excessive interstitial fibrosis were significantly and independently associated with myocardial contractile dysfunction and appeared to be responsible for ventricular remodeling.

CONCLUSION

Our findings suggest that in many patients with aortic regurgitation, eccentric hypertrophy changes its nature from physiologic to nonphysiologic during the earlier stages in the course of the disease rather than during the stage described previously.

Does Myocardial Fibrosis Hinder Contractile Function and Perfusion in Idiopathic Dilated Cardiomyopathy? PET and MR Imaging Study

PURPOSE

To prospectively evaluate, by using positron emission tomography (PET) and magnetic resonance (MR) imaging, the interrelationships between regional myocardial fibrosis, perfusion, and contractile function in patients with idiopathic dilated cardiomyopathy (DCM).

MATERIALS AND METHODS

The study protocol was approved by the hospital ethics committee, and all subjects gave written informed consent. Sixteen patients with idiopathic DCM (mean age, 54 years +/- 11 [standard deviation]; nine men) and six healthy control subjects (mean age, 28 years +/- 2; five men) were examined with PET and MR tissue tagging. Oxygen 15-labeled water and carbon monoxide were used as tracers at PET to assess myocardial blood flow (MBF) and the perfusable tissue index (PTI), which is inversely related to fibrosis. MBF was determined at rest and during pharmacologically induced hyperemia. Maximum circumferential shortening (E(cc)) was determined with MR tissue tagging. Student t tests were performed for comparison of data sets, and linear regression was used to investigate the association between parameters.

RESULTS

Mean global hyperemic MBF (2.23 mL/min/mL +/- 0.73), E(cc) (-10.5% +/- 2.9), and PTI (0.95 +/- 0.10) were lower in the patients with DCM than in the control subjects (4.33 mL/min/mL +/- 0.85, -17.4% +/- 0.6, and 1.09 +/- 0.12, respectively; P < .05 for all). In the patients with DCM, regional PTI was related to E(cc) (r = -0.21, P = .009) but not to resting or hyperemic MBF. Furthermore, regional E(cc) was correlated to both resting (r = -0.28, P = .004) and hyperemic MBF (r = -0.29, P < .001). In addition, the ratio of left ventricular end-diastolic volume to mass, as a reflection of wall stress, was related to global hyperemic MBF (r = -0.52, P = .047) and to global E(cc) (r = 0.69, P = .003).

CONCLUSION

In idiopathic DCM, the extent of myocardial fibrosis is related to the impairment in contractile function, whereas fibrosis and perfusion do not seem to be interrelated. The degree of impairment of hyperemic myocardial perfusion is related to contractility and end-diastolic wall stress.

Ultrastructural damage in vascular endothelium in rats treated with paclitaxel and doxorubicin

Endothelium is the first physiological barrier between blood and tissues and can be injured by physical or chemical stress, particularly by the drugs used in the cancer therapy. Paclitaxel and doxorubicin are frequently used anticancer drugs and their cardiac side effects are well observed in clinical setting. Their side effects on the endothelium are still not clear enough. There are few investigations assessing the damages elicited by the combination use of chemotherapy agents in animal experimental models. The purpose of this study was to examine and compare the side effects of doxorubicin and paclitaxel on endothelium in vivo. The drugs were administered weekly to rats via intraperitoneal injections singly or in combinations. Lastly, aorta endothelium was examined. The most familiar parts of the aorta endothelium are the nucleus, free ribosomes, Weibel-Palada granules, plasmalemmal vesicles, and clear basement membrane. Examination of the endothelium and the related structures revealed some clear degenerative findings. Notably, administration of a paclitaxel and doxorubicin combinations caused the most dramatic change in ultrastructure, which may disrupt many functions of the endothelium.

Prognostic significance of morphometric endomyocardial biopsy analysis in patients with idiopathic dilated cardiomyopathy

BACKGROUND

To date, considerable controversy exists on the prognostic significance of morphometric endomyocardial biopsy findings in patients with idiopathic dilated cardiomyopathy (IDC).

METHODS

Quantitative analyses of interstitial structured tissue, myofibril volume fraction, and myocytic fiber diameters of left ventricular endomyocardial biopsy specimens were performed in 124 patients with IDC.

RESULTS

During 51 +/- 22 months follow-up after left ventricular endomyocardial biopsy, major arrhythmic events, defined as sustained ventricular tachycardia (VT), ventricular fibrillation (VF), or sudden cardiac death, were observed in 24 patients (19%). Death from any cause or heart transplant was observed in 39 patients (31%). The amount of interstitial structured tissue, myofibril volume fraction, and myocytic fiber diameters determined from left ventricular endomyocardial biopsy specimens did not differ significantly between patients with and patients without major arrhythmic events or between patients with and patients without transplant-free survival during follow-up.

CONCLUSIONS

Quantitative analysis of the amount of interstitial structured tissue, myofibril volume fraction, and myocytic fiber diameters in left ventricular endomyocardial biopsy specimens does not appear to be useful for predicting arrhythmic events and transplant-free survival in IDC.

Changes in myocardial cytoskeletal intermediate filaments and myocyte contractile dysfunction in dilated cardiomyopathy: an in vivo study in humans

AIM

To investigate in vivo the intermediate cytoskeletal filaments desmin and vimentin in myocardial tissues from patients with dilated cardiomyopathy, and to determine whether alterations in these proteins are associated with impaired contractility.

METHODS

Endomyocardial biopsies were performed in 12 patients with dilated cardiomyopathy and in 12 controls (six women with breast cancer before anthracycline chemotherapy and six male donors for heart transplantation). Biopsy specimens were analysed by light microscopy and immunochemistry (desmin, vimentin). Myocyte contractile protein function was evaluated by the actin-myosin in vitro motility assay. Left ventricular ejection fraction was assessed by echocardiography and radionuclide ventriculography.

RESULTS

Patients with dilated cardiomyopathy had a greater cardiomyocyte diameter than controls (p < 0.01). The increase in cell size was associated with a reduction in contractile function, as assessed by actin-myosin motility (r = -0.643; p < 0.01). Quantitative immunochemistry showed increased desmin and vimentin contents (p < 0.01), and the desmin distribution was disturbed in cardiomyopathy. There was a linear relation between desmin distribution and actin-myosin sliding in vitro (r = 0.853; p < 0.01) and an inverse correlation between desmin content and ejection fraction (r = -0.773; p < 0.02). Negative correlations were also found between myocardial vimentin content and the actin-myosin sliding rate (r = -0.74; p < 0.02) and left ventricular ejection fraction (r = -0.68; p < 0.01).

CONCLUSIONS

Compared with normal individuals, the myocardial tissue of patients with dilated cardiomyopathy shows alterations of cytoskeletal intermediate filament distribution and content associated with reduced myocyte contraction.

Cyclosporin-induced dyslipoproteinemia is associated with selective activation of SREBP-2

The use of cyclosporin A has contributed greatly to the success of organ transplantation. However, cyclosporin-associated side effects of hypertension, nephrotoxicity, and dyslipoproteinemia have tempered these benefits. Cyclosporin-induced dyslipoproteinemia may be an important risk factor for the accelerated atherosclerosis observed posttransplantation. Using a mouse model, we treated Swiss-Webster mice for 6 days with a daily dose of 20 microg/g body wt of cyclosporin and observed significant elevations of plasma cholesterol, triglyceride, and apolipoprotein B (apoB) levels relative to vehicle-alone treated control animals. Measurement of the rate of secretion of very low-density lipoprotein (VLDL) by the liver in vivo showed that cyclosporin treatment led to a significant increase in the rate of hepatic VLDL triglyceride secretion. Total apoB secretion was unaffected. Northern analysis showed that cyclosporin A treatment increased the abundance of hepatic mRNA levels for a number of key genes involved in cholesterol biosynthesis relative to vehicle-alone treated animals. Two key transcriptional factors, sterol regulatory element-binding protein (SREBP)-1 and SREBP-2, also showed differential expression; SREBP-2 expression was increased at the mRNA level, and there was an increase in the active nuclear form, whereas the mRNA and the nuclear form of SREBP-1 were reduced. These results show that the molecular mechanisms by which cyclosporin causes dyslipoproteinemia may, in part, be mediated by selective activation of SREBP-2, leading to enhanced expression of lipid metabolism genes and hepatic secretion of VLDL triglyceride.

Abnormal action potential conduction in isolated human hypertrophied left ventricular myocardium

INTRODUCTION

Cardiac hypertrophy is associated with an increased incidence of arrhythmias that result from altered action potential configuration or propagation velocity. These variables were measured in isolated preparations of human left ventricular myocardium and correlated with the degree of hypertrophy.

METHODS AND RESULTS

Cardiac mass was estimated by echocardiography and cell diameter was measured from fixed isolated specimens; the two variables correlated significantly. Action potential duration was measured under field stimulation but was independent of the degree of hypertrophy; however, the duration was longer in septal preparations (405 +/- 12 msec, 37 degrees C, 1-Hz stimulation) than in papillary muscles (342 +/- 11 msec). Conduction velocity decreased progressively as cell diameter increased both in septal and papillary muscle preparations. Cable analysis showed that the variation of conduction velocity could be accounted for adequately by an increase of the intracellular resistivity of the preparations.

CONCLUSION

The data suggest that conduction defects occur in a progressive manner in human hypertrophy, which would provide an important substrate for dysrhythmias in human left ventricular hypertrophy and could result from a decrease of electrical coupling between adjacent myocardial cells.

Left atrial myopathy in idiopathic dilated cardiomyopathy

To investigate whether left atrial systolic dysfunction in dilated cardiomyopathy is the result of left atrial dilatation, atrial involvement in the myopathic process, or both, 20 patients with aortic stenosis, 14 patients with idiopathic dilated cardiomyopathy, and 10 normal control subjects were studied. Left atrial volumes (cubic centimeters) were echocardiographically measured at mitral valve opening (maximal), mitral valve closure (minimal), and onset of atrial systole (P wave of the electrocardiogram) with the biplane area-length method. Atrial systolic function was assessed by calculating the active emptying fraction, equal to (volume at onset of atrial systole minus minimal volume)/volume at onset of atrial systole. Heart rate was similar in patients with aortic stenosis and dilated cardiomyopathy (83 +/- 11 vs 86 +/- 15 beats/min, respectively). Maximal volume was similar in patients with aortic stenosis (74.8 +/- 26.4 cm3) and dilated cardiomyopathy (79.7 +/- 25.3 cm3) but greater (p < 0.0001) than in control subjects (46.4 +/- 11.9 cm3). Active emptying fraction was inversely related to volume at onset of atrial systole and to tension at end of atrial systole (aortic stenosis r = -0.61 and r = -0.81, respectively; dilated cardiomyopathy r = -0.79 and r = -0.66, respectively). At any given level of volume at onset of atrial systole and tension at end of atrial systole, however, active emptying fraction was lower in patients with dilated cardiomyopathy compared with those with aortic stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

New approach to the estimation of the extent of myocardial fibrosis in patients with dilated cardiomyopathy: use of signal-averaged electrocardiography

To determine whether the extent of myocardial fibrosis in dilated cardiomyopathy could be estimated noninvasively, signal-averaged electrocardiograms were recorded in 32 patients with dilated cardiomyopathy, followed by left ventricular endomyocardial biopsy. The root mean square voltage for the last 40 msec (V40), the duration of the filtered QRS complex (fQRSd) and the duration of low amplitude signals < 40 microV (LAS) were obtained by signal-averaged electrocardiography. The extent of fibrosis in all biopsy samples was measured by the point-counting method. The extent of myocardial fibrosis closely correlated with fQRSd (r = 0.623, p < 0.001), LAS (r = 0.570, p < 0.001), and V40 (r = -0.355, p < 0.05). When fibrosis was classified into intercellular and interfascicular types, the extent of intercellular fibrosis more closely correlated with fQRSd (r = 0.695, p < 0.0001), LAS (r = 0.640, p < 0.0001), and V40 (r = -0.533, p < 0.005). These results suggest that signal-averaged electrocardiograms might be useful for estimation of the extent of myocardial fibrosis, especially intercellular fibrosis in patients with dilated cardiomyopathy.

Myocardial electrical propagation in patients with idiopathic dilated cardiomyopathy

Myocardial propagation may contribute to fatal arrhythmias in patients with idiopathic dilated cardiomyopathy (IDC). We examined this property in 15 patients with IDC undergoing cardiac transplantation and in 14 control subjects. An 8 x 8 array with electrodes 2 mm apart was used to determine the electrical activation sequence over a small region of the left ventricular surface. Tissue from the area beneath the electrode array was examined in the patients with IDC. The patients with IDC could be divided into three groups. Group I (n = 7) had activation patterns and estimates of longitudinal (theta L = 0.84 +/- 0.09 m/s) and transverse (theta T = 0.23 +/- 0.05 m/s) conduction velocities that were no different from controls (theta L = 0.80 +/- 0.08 m/s, theta T = 0.23 +/- 0.03 m/s). Group II (n = 4) had fractionated electrograms and disturbed transverse conduction with normal longitudinal activation, features characteristic of nonuniform anisotropic properties. Two of the control patients also had this pattern. Group III (n = 4) had fractionated potentials and severely disturbed transverse and longitudinal propagation. The amount of myocardial fibrosis correlated with the severity of abnormal propagation. We conclude that (a) severe contractile dysfunction is not necessarily accompanied by changes in propagation, and (b) nonuniform anisotropic propagation is present in a large proportion of patients with IDC and could underlie ventricular arrhythmias in this disorder.

Which subgroup of patients with dilated cardiomyopathy would benefit from long-term beta-blocker therapy? A histologic viewpoint

OBJECTIVES

The purpose of this study was to elucidate whether the effectiveness of long-term beta-blocker therapy could be predicted before this therapy is started.

BACKGROUND

Long-term beta-blocker therapy has recently been reported to provide a favorable effect in treatment of congestive heart failure due to dilated cardiomyopathy.

METHODS

Several measurements including histologic variables before administration of metoprolol were retrospectively compared among 18 good responders (showing improvement of at least one New York Heart Association functional class or an increase in ejection fraction > or = 0.10 12 months after drug administration) and 12 poor responders without such improvement.

RESULTS

Although there were no significant differences between the two groups in age, gender, functional class, heart rate, blood pressure, pulmonary capillary wedge pressure, cardiac index, left ventricular end-diastolic dimension and ejection fraction, percent fibrosis estimated by the point-counting method in endomyocardial biopsy specimens was significantly lower in good than in poor responders (7.6 +/- 5.7 vs. 14.2 +/- 9.7%, p < 0.05). Moreover, when the types of fibrosis were classified as interfascicular and intercellular by the dominance of counted points, there were 13 cases of interfascicular fibrosis and 5 cases of intercellular fibrosis in good responders and 1 case of interfascicular fibrosis and 11 cases of intercellular fibrosis in poor responders (p < 0.001, sensitivity 72%, specificity 91%, predictive accuracy 80%). These results suggest that improvement with long-term beta-blocker therapy may be more likely to occur in patients with less myocardial fibrosis, with interfascicular fibrosis the dominant type.

CONCLUSIONS

The extent and type of fibrosis may be important factors in the prediction of the effectiveness of long-term beta-blocker therapy for dilated cardiomyopathy.

Myocarditis: unresolved issues in diagnosis and treatment

Myocarditis is an enigmatic disease. Lymphocytic myocarditis is most commonly viral in origin. Considerable evidence suggests that myocardial damage is due to an immune-mediated mechanism rather than to direct effects of the virus itself. The presentation is variable, ranging from a clinically inapparent or relatively benign illness to acute progressive heart failure and death. Although examination of the endomyocardial biopsy specimen is the "gold standard" for the diagnosis of myocarditis there are problems with this technique, relating particularly to sampling error and histologic interpretation. Considerable evidence, both animal and human, suggests that a link between viral myocarditis and dilated cardiomyopathy does exist. There is a rational basis for the use of immunosuppressive therapy in myocarditis. Although many favorable responses have been reported with the use of these agents, the results of more definitive studies are awaited to determine the role of immunosuppressive therapy in myocarditis more clearly. Recommendations for the practical management of patients with myocarditis are made. Whenever possible, patients with this diagnosis should be entered into the ongoing NIH trial.

Functional and structural abnormalities in patients with dilated cardiomyopathy

Passive diastolic properties of the left ventricle were determined in 10 control subjects and 12 patients with dilated cardiomyopathy. Simultaneous left ventricular angiography and high fidelity pressure measurements were performed in all patients. Left ventricular chamber stiffness was calculated from left ventricular pressure-volume and myocardial stiffness from left ventricular stress-strain relations with use of a viscoelastic model. Patients with dilated cardiomyopathy were classified into two groups according to the diastolic constant of myocardial stiffness (beta). Group 1 consisted of seven patients with a normal constant of myocardial stiffness less than or equal to 9.6 (normal range 2.2 to 9.6) and group 2 of 5 patients with a beta greater than 9.6. Structural abnormalities (percent interstitial fibrosis, fibrous content) in patients with dilated cardiomyopathy were assessed by morphometry from right ventricular endomyocardial biopsies. Heart rate was similar in the three groups. Left ventricular end-diastolic pressure was significantly greater in patients with cardiomyopathy (18 mm Hg in group 1 and 22 mm Hg in group 2) than in the control patients (10 mm Hg). Left ventricular ejection fraction was significantly lower in groups 1 (37%) and 2 (36%) than in the control patients (66%). Left ventricular muscle mass index was significantly increased in both groups with cardiomyopathy. The constant of chamber stiffness (beta*) was slightly although not significantly greater in groups 1 and 2 (0.58 and 0.58, respectively) than in the control group (0.35). The constant of myocardial stiffness beta was normal in group 1 (7.0; control group 6.9, p = NS) but was significantly increased in group 2 (23.5). Interstitial fibrosis was 19% in group 1 and 43% (p less than 0.001) in group 2 (normal less than or equal to 10%). There was an exponential relation between both diastolic constant of myocardial stiffness (beta) and interstitial fibrosis (IF) (r = 0.95; p less than 0.001) and beta and fibrous content divided by end-diastolic volume index (r = 0.93; p less than 0.001). It is concluded that myocardial stiffness can be normal in patients with dilated cardiomyopathy despite severely depressed systolic function. Structural alterations of the myocardium with increased amounts of fibrous tissues are probably responsible for the observed changes in passive elastic properties of the myocardium in patients with dilated cardiomyopathy. The constant of myocardial stiffness (beta) helps to identify patients with severe structural alterations (group 2), representing possibly a more advanced stage of the disease.

Determinants of end-stage idiopathic dilated cardiomyopathy: a multivariate analysis of 104 patients

Our purpose in this study was to investigate the correlation of clinical, electrocardiographic, hemodynamic, and histopathologic features at diagnosis with the long-term prognosis in 104 patients with idiopathic dilated cardiomyopathy to determine which factors are the independent determinants of the end-stage disease. During a mean follow-up of 3.8 +/- 3.5 years, 35 patients (33%) died, 14 (13%) suddenly and 21 (20%) from congestive heart failure. Univariate analysis of survival curves disclosed that clinical and electrocardiographic variables at diagnosis were similar in survivors and non-survivors. On the contrary, patients who subsequently died had higher mean right atrial pressure (p = 0.0001), right ventricular end-diastolic pressure (p = 0.0061), mean pulmonary artery pressure (p = 0.0001), and left ventricular systolic (p = 0.0049) and end-diastolic (p = 0.0021) pressure than survivors. They also exhibited larger left ventricular end-diastolic (p = 0.0046) and end-systolic (p = 0.0027) volumes, lower ejection fraction (p = 0.0001), and a greater proportion had severe mitral regurgitation (p = 0.0095). Univariate analysis of histologic findings collected in a subgroup of patients referred since 1984 revealed a mild degree of myocellular hypertrophy to be associated with a poor prognosis (p = 0.0217). Multivariate analysis selected only mean right atrial pressure (p = 0.0022), ejection fraction (p = 0.0089), and end-systolic volume (p = 0.0265) as independent determinants of cardiac death. Our results suggest that cardiac catheterization is mandatory for risk stratification of patients with idiopathic dilated cardiomyopathy, since it allows the assessment of hemodynamic, angiographic, and histopathologic features helpful in identifying patients with a poor prognosis.

Diagnostic and prognostic utility of right-sided catheterization and endomyocardial biopsy in idiopathic dilated cardiomyopathy

To determine the value of cardiac catheterization and endomyocardial biopsy in patients with heart failure and dilated cardiomyopathy, the records of 61 patients (36 men, 25 women, ages 13 to 65 years) with this disorder were reviewed. Myocardial lymphocytic infiltration was present in 8 (13%). Three had myocyte degeneration and necrosis ("definite" myocarditis), whereas the other 5 had no degeneration or necrosis ("equivocal" myocarditis). Compared with the 53 without lymphocytic infiltration, these 8 patients more often had symptoms of a preceding viral illness (88 vs 30%, p = 0.002) and had a shorter duration of cardiac symptoms (18 +/- 18 vs 109 +/- 132 days [mean +/- standard deviation], p less than 0.001). Histologic features of the biopsy did not relate to survival, but right- and left-sided intracardiac pressures were higher (p less than 0.05) in nonsurvivors. Thus, (1) endomyocardial biopsy is most likely to show lymphocytic infiltration in patients with symptoms of a preceding viral illness and a short duration of cardiac symptoms, and (2) right- and left-sided hemodynamic variables at the time of biopsy may offer insight into prognosis.

Influence of age on left ventricular contractility

Controversy exists about whether left ventricular (LV) function is affected by aging. Therefore, peak systolic pressure to end-systolic diameter, peak systolic pressure to end-systolic volume, systolic wall stress to fractional shortening and systolic wall stress to end-systolic diameter relations were calculated in the left ventricle of 10 healthy subjects greater than 65 years old (age 70 +/- 4 years) (group B). They were compared with a control group composed by 10 healthy subjects (group A, age 22 +/- 1 years). LV measurements were obtained with M-mode echocardiography and an automatic cuff was used to determine blood pressure. Changes in the load conditions were obtained by 15 mg sublingual isosorbide dinitrate. There were no differences in resting end-systolic diameter, end-systolic volume, end-diastolic diameter, end-diastolic volume, fractional shortening, ejection fraction or systolic wall stress. Older subjects had higher values of resting peak systolic pressure (p less than 0.05) and lower heart rates (p less than 0.05). Young subjects had a steeper peak systolic pressure to end-systolic diameter slope (92 +/- 11 vs 51 +/- 11 mm Hg/cm; p less than 0.001) and peak systolic pressure to end-systolic volume slope (3.4 +/- 0.7 vs 1.9 +/- 0.6 mm Hg/ml; p less than 0.001). There was a slight difference in systolic wall stress to fractional shortening slopes between both groups (group A -0.215 vs group B -0.49%/10(3) dynes/cm2, p = 0.02) but not between systolic wall stress to end-systolic diameter slopes (group A 0.013 vs group B 0.019 cm/10(3) dynes/cm2, difference not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Pathophysiology of hypertension in older patients

More than half of the United States population over 65 years of age has essential hypertension. In 1984, there were 10 million elderly hypertensive persons and this number will reach 25 million in the near future. These patients are at high risk for congestive heart failure, stroke, heart attack, and dissecting aneurysm. Successful reduction of blood pressure can lower these risks considerably, but rational treatment depends on understanding the complex pathophysiology of hypertension in older patients. In fact, treatment that does not take into account the combined effects of aging and hypertension on the cardiovascular system and the kidneys may do more harm than the hypertension itself. Among the prominent age-related cardiovascular changes are stiffening of the arterial tree, with or without a contribution from atherosclerosis. This reduces arterial compliance and increases afterload, resulting in the left-ventricular hypertrophy seen in old age and leading to a progressive rise in systolic pressure. There is considerable shrinkage of the kidneys, due primarily to loss of glomerular and tubular tissue in the cortex, along with sclerosis of the glomeruli and formation of tubular diverticula. Arteriolar changes lead to reduced renal blood flow, the shunting of blood around the glomeruli, and thus a reduction in glomerular filtration rate. Renal water and electrolyte excretion are changed, making homeostasis more difficult to maintain, and the renin-angiotensin system is altered, helping to blunt the kidneys' response to pressure changes. Essential hypertension superimposed on all the foregoing effects exacerbates them. Peripheral resistance is usually markedly elevated in older hypertensive persons, which increases afterload directly.(ABSTRACT TRUNCATED AT 250 WORDS)

Fontan hemodynamics

Right atrial-pulmonary artery connection places the pulmonary circulation in series with the systemic circulation rather than the single ventricular "parallel" circulatory arrangement that usually is present prior to repair. The accompanying central cardiac shunt and volume overload physiology are eliminated. Favorable changes in ventricular dimension, ventricular wall stress, cardiovascular efficiency, relative systemic perfusion, and arterial oxygen saturation should result. The ongoing myocardial injury associated with the single-ventricle volume overload is presumably arrested and repair is initiated to a variable degree. Some candidates for right atrial-pulmonary artery connection may not benefit from repair because of irreversible ventricular injury. More accurate indices of systolic and diastolic ventricular function should be applied to this difficult group of borderline patients to further define potential for myocardial recovery and, therefore, candidacy for Fontan repair.

Idiopathic dilated cardiomyopathy. Role of programmed electrical stimulation and Holter monitoring in predicting those at risk of sudden death

The prognostic role of programmed electrical stimulation and Holter monitoring was evaluated in 21 patients with idiopathic dilated cardiomyopathy who had no prior history of ventricular tachyarrhythmias. During a mean follow-up period of 23 months, sudden death or ventricular fibrillation occurred in four (20 percent). One patient died of complications of sepsis, and one underwent cardiac transplantation. Programmed electrical stimulation (PES) resulted in five or more beats of induced ventricular tachycardia in seven patients (33 percent), but was a poor predictor of sudden death (sensitivity = 20 percent). Thirteen patients (62 percent) had complex ventricular ectopy (Lown class 4A or 4B) by ambulatory monitoring. This was a sensitive (80 percent) but not specific (31 percent) marker for sudden death. The predictive value of a negative Holter monitor study was high (80 percent) for identifying those at low risk of sudden death. The results of this prospective study suggest that programmed ventricular stimulation and routine ambulatory monitoring are poor predictors of sudden death in this population.

Dilated cardiomyopathy and myocarditis: natural history, etiology, clinical manifestations, and management

This monograph begins and ends with a statement of uncertainty regarding many aspects of dilated cardiomyopathy. Natural history studies identify patients with widely differing outcomes. A host of prognostic factors have emerged, yet it would appear that the major determinants of survival are as yet unrecognized. The diagnosis remains primarily one of exclusion, and management is largely nonspecific and supportive. The frequency of sudden cardiac death is well documented, but the ability to accurately identify patients at risk and the efficacy of antiarrhythmic therapy is unestablished. The emerging success of cardiac transplantation is a source of encouragement. The causes of dilated cardiomyopathy remain a source of intense investigation. Accumulating evidence (much of it circumstantial) does, however, implicate a viral etiology and perhaps altered function of the immunoregulatory system. However, the disparity between the severity of functional disturbance with the relative lack of histologic markers of cellular necrosis implies a disturbance at a cellular level. The etiology or etiologies remain elusive. Future investigation directed at fundamental aspects of cardiac cellular biology may provide the answers.

Cardiac and skeletal muscle abnormalities in cardiomyopathy: comparison of patients with ventricular tachycardia or congestive heart failure

Results of cardiac muscle and skeletal muscle biopsies were compared in 22 patients with cardiomyopathy; 11 patients presented with symptoms secondary to ventricular tachycardia (Group 1) and 11 had symptoms of severe congestive heart failure (Group 2). No patient had structural or ischemic cardiac disease. In Group 1 patients, hemodynamic abnormalities were subtle, but invasive study demonstrated dilated cardiomyopathy in two patients and restrictive cardiomyopathy in nine. In Group 2, eight patients had dilated cardiomyopathy and three had restrictive cardiomyopathy. Cardiac biopsy results were abnormal in all 22 patients and the abnormalities were similar for the two groups. Cardiac histologic study revealed a spectrum of abnormalities including fibrosis, dilated sarcoplasmic reticulum, increased numbers of intercalated discs and mitochondrial abnormalities. Histologic abnormalities of skeletal muscle were similar in each group, consisting of endomysial fibrosis and increased lipid deposits. Slightly more than half of the Group 1 and Group 2 patients also had a low concentration of skeletal muscle long chain acylcarnitine. These data demonstrate that abnormalities of both cardiac and skeletal muscle are common in patients with cardiomyopathy; abnormalities are similar whether initial symptoms are due to ventricular tachycardia or congestive heart failure. It is suggested that these patients with cardiomyopathy may have a generalized myopathy.

Dilated cardiomyopathy: diagnostic accuracy of endomyocardial biopsy

A histopathological index of contractility failure, which was reported to be accurate for the diagnosis of idiopathic dilated or congestive cardiomyopathy in Japan, was used to assess endomyocardial biopsy specimens from 41 Dutch patients with suspected dilated cardiomyopathy. The calculated index had a sensitivity of 62.5% and a specificity of 68% for idiopathic dilated or congestive cardiomyopathy. These disappointing results indicate that the histopathological index of contractility failure does not reliably distinguish between idiopathic dilated cardiomyopathy and other diseases that cause congestive heart failure.