A randomized trial of low-dose beta-blockade therapy for idiopathic dilated cardiomyopathy

Comparative Efficacy of Different Drugs for the Treatment of Dilated Cardiomyopathy: A Systematic Review and Network Meta-analysis

BACKGROUND AND OBJECTIVE

At present, the therapies of dilated cardiomyopathy concentrated on the symptoms of heart failure and related complications. The study is to evaluate the clinical efficacy of a combination of various conventional and adjuvant drugs in treating dilated cardiomyopathy via network meta-analysis.

METHODS

The study was reported according to the PRISMA 2020 statement. From inception through 27 June 2022, the PubMed, Embase, Cochrane library, and Web of Science databases were searched for randomized controlled trials on medicines for treating dilated cardiomyopathy. The quality of the included studies was evaluated according to the Cochrane risk of bias assessment. R4.1.3 and Revman5.3 software were used for analysis.

RESULTS

There were 52 randomized controlled trials in this study, with a total of 25 medications and a sample size of 3048 cases. The network meta-analysis found that carvedilol, verapamil, and trimetazidine were the top three medicines for improving left ventricular ejection fraction (LVEF). Ivabradine, bucindolol, and verapamil were the top 3 drugs for improving left ventricular end-diastolic dimension (LVEDD). Ivabradine, L-thyroxine, and atorvastatin were the top 3 drugs for improving left ventricular end-systolic dimension (LVESD). Trimetazidine, pentoxifylline, and bucindolol were the top 3 drugs for improving the New York Heart Association classification (NYHA) cardiac function score. Ivabradine, carvedilol, and bucindolol were the top 3 drugs for reducing heart rate (HR).

CONCLUSION

A combination of different medications and conventional therapy may increase the clinical effectiveness of treating dilated cardiomyopathy. Beta-blockers, especially carvedilol, can improve ventricular remodeling, cardiac function, and clinical efficacy in patients with dilated cardiomyopathy (DCM). Hence, they can be used if patients tolerate them. If LVEF and HR do not meet the standard, ivabradine can also be used in combination with other treatments. However, since the quality and number of studies in our research were limited, large sample size, multi-center, and high-quality randomized controlled trials are required to corroborate our findings.

Revisiting the clinical evidence of heart rate target in patients with heart failure treated with beta-blockers

Objective

On evaluating the guidelines from previous studies, we found no randomized controlled trials on the use of beta-blockers for heart failure (HF) that employed as evidence for heart rate targets of 60 or 70 beats/min. In this study, we aimed to assess the target heart rate in patients with HF treated with beta-blockers.

Methods

We used the keywords, “heart failure” and “beta-blocker” to search PubMed, Ovid, EMBASE, and Cochrane from 1966 to June 2021. Two authors independently reviewed the results of the search strategy and selected all the studies that reported the effect of beta-blockers on all-cause mortality in patients with HFrEF. We conducted analyses using Review Manager, version 5.0 and Stata version 12.0. Risk of bias was assessed regarding randomization, allocation sequence concealment, blinding, incomplete outcome data, and other biases. Sensitivity analysis was carried out to compare the results of fixed effect model with the results of random effect.

Results

No clinical trial supported the optimal heart rate of 60 beats/min. Risk ratio (RR) and 95% confidence interval (CI) were 0.77 (0.71, 0.83) and 0.86 (0.76, 0.97) in the subgroup with a baseline heart rate >80 beats/min and subgroup with baseline of ≤80 beats/min, respectively. RR and 95% CI were 0.92 (0.82, 1.02) and 0.77 (0.65, 0.92) in 2 subgroups with heart rate controlled ≥70 beats/min and 60–70 beats/min, respectively. Accumulated to MOCHA 1 trial (heart rate controlled 70 beats/min), there was no significant difference in mortality between the experimental group and the control group (RR=0.91, 95% CI 0.82–1.02). Accumulated to SENIORS trial (heart rate controlled 68.8 beats/min), there was a difference in mortality between the experimental and the control groups (RR=0.90, 95% CI 0.82–0.99).

Conclusion

The main effect of beta-blockers in the treatment of HF is achieved by lowering heart rate. The use of beta-blockers did not benefit in people with HFrEF whose heart rate was 77 beats/min before they started the treatment regimen. In patients with HFrEF, the purpose of beta-blockers is to control the heart rate to 65–70 beats min.

Beta-blockers in hypertension: overview and meta-analysis of randomized outcome trials

BACKGROUND

Meta-analyses from randomized outcome-based trials have challenged the role of beta-blockers for the treatment of hypertension. However, because they often include trials on diseases other than hypertension, the role of these drugs in the choice of the blood pressure (BP)-lowering treatment strategies remains unclear.

METHODS

Electronic databases were searched for randomized trials that compared beta-blockers vs. placebo/no-treatment/less-intense treatment (BP-lowering trials) or beta-blockers vs. other antihypertensive agents in patients with or without hypertension (comparison trials). Among BP-lowering trials and according to baseline comorbidity, we separately considered trials in hypertension, trials without chronic heart failure or acute myocardial infarction, and trials with either chronic heart failure or acute myocardial infarction. Seven fatal and nonfatal outcomes were calculated (random-effects model) for BP-lowering or comparison trials.

RESULTS

A total of 84 BP-lowering or comparison trials (165 850 patients) were eligible. In 67 BP-lowering trials (68 478 patients; mean follow-up 2.5 years; baseline SBP/DBP, 136/82 mmHg), beta blockers were associated with a lower incidence of major cardiovascular events [risk ratio 0.85 and 95% confidence interval (95% CI) 0.78-0.92] and all-cause death (risk ratio 0.81 and 95% CI 0.75-0.86). Restriction of the analysis to five trials recruiting exclusively hypertensive patients (18 724 patients; mean follow-up 5.1 years; baseline SBP/DBP 163/94 mmHg), a -10.5/-7.0 mmHg BP decrease was accompanied by reduction of major cardiovascular events by 22% (95% CI, 6-34). In 24 comparison trials (103 764 patients, 3.92 years of mean follow-up), beta-blockers compared with other agents were less protective for stroke and all-cause death in all trials and in trials conducted exclusively in hypertensive patients (averaged risk ratio increase 20 and 6%, respectively, for both cases).

CONCLUSION

Compared with other antihypertensive agents, beta-blockers appear to be substantially less protective against stroke and overall mortality. However, they exhibit a substantial risk-reducing ability for all events when prescribed to lower BP in patients with modest or more clear BP elevations, and therefore can be used as additional agents in hypertensive patients.

H2AK119ub1 guides maternal inheritance and zygotic deposition of H3K27me3 in mouse embryos

Parental epigenomes are established during gametogenesis. While they are largely reset after fertilization, broad domains of Polycomb repressive complex 2 (PRC2)-mediated formation of lysine 27-trimethylated histone H3 (H3K27me3) are inherited from oocytes in mice. How maternal H3K27me3 is established and inherited by embryos remains elusive. Here, we show that PRC1-mediated formation of lysine 119-monoubiquititinated histone H2A (H2AK119ub1) confers maternally heritable H3K27me3. Temporal profiling of H2AK119ub1 dynamics revealed that atypically broad H2AK119ub1 domains are established, along with H3K27me3, during oocyte growth. From the two-cell stage, H2AK119ub1 is progressively deposited at typical Polycomb targets and precedes H3K27me3. Reduction of H2AK119ub1 by depletion of Polycomb group ring finger 1 (PCGF1) and PCGF6-essential components of variant PRC1 (vPRC1)-leads to H3K27me3 loss at a subset of genes in oocytes. The gene-selective H3K27me3 deficiency is irreversibly inherited by embryos, causing loss of maternal H3K27me3-dependent imprinting, embryonic sublethality and placental enlargement at term. Collectively, our study unveils preceding dynamics of H2AK119ub1 over H3K27me3 at the maternal-to-zygotic transition, and identifies PCGF1/6-vPRC1 as an essential player in maternal epigenetic inheritance.

Cortical cellular diversity and development in schizophrenia

While a definitive understanding of schizophrenia etiology is far from current reality, an increasing body of evidence implicates perturbations in early development that alter the trajectory of brain maturation in this disorder, leading to abnormal function in early childhood and adulthood. This atypical development likely arises from an interaction of many brain cell types that follow distinct developmental paths. Because both cellular identity and development are governed by the transcriptome and epigenome, two levels of gene regulation that have the potential to reflect both genetic and environmental influences, mapping "omic" changes over development in diverse cells is a fruitful avenue for schizophrenia research. In this review, we provide a survey of human brain cellular composition and development, levels of genomic regulation that determine cellular identity and developmental trajectories, and what is known about how genomic regulation is dysregulated in specific cell types in schizophrenia. We also outline technical challenges and solutions to conducting cell type-specific functional genomic studies in human postmortem brain.

A Modern History RAAS Inhibition and Beta Blockade for Heart Failure to Underscore the Non-equivalency of ACEIs and ARBs

Beta blockers and renin-angiotensin-aldosterone-inhibitors (RAAS-i) including angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) have been a mainstay of guideline-based medical therapy for heart failure with reduced ejection fraction (HFrEF) for decades. However, initial evidence supporting each of the aforenoted class of drug for heart failure indications was largely found independently of the other two classes with the exception of the addition of BBs to ACEIs. In the initial ACEI trials for HFrEF, few participants were on BBs as BBs were seen as contraindicated in HFrEF at the time. The seminal BB in HFrEF trials had high prevalence of ACEIs use as ACEIs for HF were standard of care by then, but ARBs as a class were still in their infancy. We closely examine the evidence for combinations of BB and ACEIs versus ARBs in HFrEF. In doing so, we demonstrate the lack of evidence for consideration of ARBs to be interchangeable with ACEIs when used in combination with BB and provide evidence that calls in to question the validity of assuming benefits from each drug class are independently cumulative, widening the gap between ACEIs and ARBs when used with BBs. Modern guidelines should emphasize this lack of evidence for the combination use of ARB and BB in HFrEF, except for candesartan. Even as practice moves towards the widespread uptake of angiotensin receptor-neprilysin inhibitors (which contain the ARB valsartan) in heart failure, the distinction has important implications for the ongoing role of combination therapy with BB, which thus far has been assumed, but not proven.

Spatiotemporal DNA methylome dynamics of the developing mouse fetus

Cytosine DNA methylation is essential for mammalian development but understanding of its spatiotemporal distribution in the developing embryo remains limited^1,2. Here, as part of the mouse Encyclopedia of DNA Elements (ENCODE) project, we profiled 168 methylomes from 12 mouse tissues or organs at 9 developmental stages from embryogenesis to adulthood. We identified 1,808,810 genomic regions that showed variations in CG methylation by comparing the methylomes of different tissues or organs from different developmental stages. These DNA elements predominantly lose CG methylation during fetal development, whereas the trend is reversed after birth. During late stages of fetal development, non-CG methylation accumulated within the bodies of key developmental transcription factor genes, coinciding with their transcriptional repression. Integration of genome-wide DNA methylation, histone modification and chromatin accessibility data enabled us to predict 461,141 putative developmental tissue-specific enhancers, the human orthologues of which were enriched for disease-associated genetic variants. These spatiotemporal epigenome maps provide a resource for studies of gene regulation during tissue or organ progression, and a starting point for investigating regulatory elements that are involved in human developmental disorders.

Analysis of 168 methylomes from 12 mouse tissues at 9 developmental stages sheds light on the epigenetic and regulatory landscape during mammalian fetal development.

Evolutionary conserved role of neural cell adhesion molecule-1 in memory

The neural cell adhesion molecule 1 (NCAM-1) has been implicated in several brain-related biological processes, including neuronal migration, axonal branching, fasciculation, and synaptogenesis, with a pivotal role in synaptic plasticity. Here, we investigated the evolutionary conserved role of NCAM-1 in learning and memory. First, we investigated sustained changes in ncam-1 expression following aversive olfactory conditioning in C. elegans using molecular genetic methods. Furthermore, we examined the link between epigenetic signatures of the NCAM1 gene and memory in two human samples of healthy individuals (N = 568 and N = 319) and in two samples of traumatized individuals (N = 350 and N = 463). We found that olfactory conditioning in C. elegans induced ncam-1 expression and that loss of ncam-1 function selectively impaired associative long-term memory, without causing acquisition, sensory, or short-term memory deficits. Reintroduction of the C. elegans or human NCAM1 fully rescued memory impairment, suggesting a conserved role of NCAM1 for memory. In parallel, DNA methylation of the NCAM1 promoter in two independent healthy Swiss cohorts was associated with memory performance. In two independent Sub-Saharan populations of conflict zone survivors who had faced severe trauma, DNA methylation at an alternative promoter of the NCAM1 gene was associated with traumatic memories. Our results support a role of NCAM1 in associative memory in nematodes and humans, and might, ultimately, be helpful in elucidating diagnostic markers or suggest novel therapy targets for memory-related disorders, like PTSD.

A genome-scale map of DNA methylation turnover identifies site-specific dependencies of DNMT and TET activity

DNA methylation is considered a stable epigenetic mark, yet methylation patterns can vary during differentiation and in diseases such as cancer. Local levels of DNA methylation result from opposing enzymatic activities, the rates of which remain largely unknown. Here we developed a theoretical and experimental framework enabling us to infer methylation and demethylation rates at 860,404 CpGs in mouse embryonic stem cells. We find that enzymatic rates can vary as much as two orders of magnitude between CpGs with identical steady-state DNA methylation. Unexpectedly, de novo and maintenance methylation activity is reduced at transcription factor binding sites, while methylation turnover is elevated in transcribed gene bodies. Furthermore, we show that TET activity contributes substantially more than passive demethylation to establishing low methylation levels at distal enhancers. Taken together, our work unveils a genome-scale map of methylation kinetics, revealing highly variable and context-specific activity for the DNA methylation machinery.

Structural basis for impairment of DNA methylation by the DNMT3A R882H mutation

DNA methyltransferase DNMT3A is essential for establishment of mammalian DNA methylation during development. The R882H DNMT3A is a hotspot mutation in acute myeloid leukemia (AML) causing aberrant DNA methylation. However, how this mutation affects the structure and function of DNMT3A remains unclear. Here we report structural characterization of wild-type and R882H-mutated DNMT3A in complex with DNA substrates with different sequence contexts. A loop from the target recognition domain (TRD loop) recognizes the CpG dinucleotides in a +1 flanking site-dependent manner. The R882H mutation reduces the DNA binding at the homodimeric interface, as well as the molecular link between the homodimeric interface and TRD loop, leading to enhanced dynamics of TRD loop. Consistently, in vitro methylation analyses indicate that the R882H mutation compromises the enzymatic activity, CpG specificity and flanking sequence preference of DNMT3A. Together, this study uncovers multiple defects of DNMT3A caused by the R882H mutation in AML.

The DNA methyltransferase DNMT3A plays an important role in establishing the DNA methylation patterns during development and deregulation of DNMT3A is associated with hematological cancers, with the R882H mutation the most frequently occurring DNMT3A missense mutation in acute myeloid leukemia. Here, the authors present the crystal structures of wild-type and R882H DNMT3A in complex with different DNA substrates and explain why the R882H mutation compromises the enzymatic activity of DNMT3A.

Candidate silencer elements for the human and mouse genomes

The study of gene regulation is dominated by a focus on the control of gene activation or increase in the level of expression. Just as critical is the process of gene repression or silencing. Chromatin signatures have identified enhancers, however, genome-wide identification of silencers by computational or experimental approaches are lacking. Here, we first define uncharacterized cis-regulatory elements likely containing silencers and find that 41.5% of ~7500 tested elements show silencer activity using massively parallel reporter assay (MPRA). We trained a support vector machine classifier based on MPRA data to predict candidate silencers in over 100 human and mouse cell or tissue types. The predicted candidate silencers exhibit characteristics expected of silencers. Leveraging promoter-capture HiC data, we find that over 50% of silencers are interacting with gene promoters having very low to no expression. Our results suggest a general strategy for genome-wide identification and characterization of silencer elements.

Identification of silencer elements by computational or experimental approaches in a genome-wide manner is still challenging. Here authors define uncharacterized cis-regulatory elements (CREs) in human and mouse genomes likely containing silencer elements, and test them in cells using massively parallel reporter assays to identify silencer elements that showed silencer activity.

β-Adrenergic Blocker, Carvedilol, Abolishes Ameliorating Actions of Adipose-Derived Stem Cell Sheets on Cardiac Dysfunction and Remodeling After Myocardial Infarction

BACKGROUND

Treatment of myocardial infarction (MI) includes inhibition of the sympathetic nervous system (SNS). Cell-based therapy using adipose-derived stem cells (ASCs) has emerged as a novel therapeutic approach to treat heart failure in MI. The purpose of this study was to determine whether a combination of ASC transplantation and SNS inhibition synergistically improves cardiac functions after MI.Methods and Results:ASCs were isolated from fat tissues of Lewis rats. In in vitro studies using cultured ASC cells, mRNA levels of angiogenic factors under normoxia or hypoxia, and the effects of norepinephrine and a β-blocker, carvedilol, on the mRNA levels were determined. Hypoxia increased vascular endothelial growth factor (VEGF) mRNA in ASCs. Norepinephrine further increased VEGF mRNA; this effect was unaffected by carvedilol. VEGF promoted VEGF receptor phosphorylation and tube formation of human umbilical vein endothelial cells, which were inhibited by carvedilol. In in vivo studies using a rat MI model, transplanted ASC sheets improved contractile functions of MI hearts; they also facilitated neovascularization and suppressed fibrosis after MI. These beneficial effects of ASC sheets were abolished by carvedilol. The effects of ASC sheets and carvedilol on MI heart functions were confirmed by Langendorff perfusion experiments using isolated hearts.

CONCLUSIONS

ASC sheets prevented cardiac dysfunctions and remodeling after MI in a rat model via VEGF secretion. Inhibition of VEGF effects by carvedilol abolished their beneficial effects.

Heart failure as a substrate and trigger for ventricular tachycardia

Heart failure (HF) is a major cause of morbidity and mortality with more than 5.1 million individuals affected in the USA. Ventricular tachyarrhythmias (VAs) including ventricular tachycardia and ventricular fibrillation are common in patients with heart failure. The pathophysiology of these mechanisms as well as the contribution of heart failure to the genesis of these arrhythmias is complex and multifaceted. Myocardial hypertrophy and stretch with increased preload and afterload lead to shortening of the action potential at early repolarization and lengthening of the action potential at final repolarization which can result in re-entrant ventricular tachycardia. Myocardial fibrosis and scar can create the substrate for re-entrant ventricular tachycardia. Altered calcium handling in the failing heart can lead to the development of proarrhythmic early and delayed after depolarizations. Various medications used in the treatment of HF such as loop diuretics and angiotensin converting enzyme inhibitors have not demonstrated a reduction in sudden cardiac death (SCD); however, beta-blockers (BB) are effective in reducing mortality and SCD. Amongst patients who have HF with reduced ejection fraction, the angiotensin receptor-neprilysin inhibitor (sacubitril/valsartan) has been shown to reduce cardiovascular mortality, specifically by reducing SCD, as well as death due to worsening HF. Implantable cardioverter-defibrillator (ICD) implantation in HF patients reduces the risk of SCD; however, subsequent mortality is increased in those who receive ICD shocks. Prophylactic ICD implantation reduces death from arrhythmia but does not reduce overall mortality during the acute post-myocardial infarction (MI) period (less than 40 days), for those with reduced ejection fraction and impaired autonomic dysfunction. Furthermore, although death from arrhythmias is reduced, this is offset by an increase in the mortality from non-arrhythmic causes. This article provides a review of the aforementioned mechanisms of arrhythmogenesis in heart failure; the role and impact of HF therapy such as cardiac resynchronization therapy (CRT), including the role, if any, of CRT-P and CRT-D in preventing VAs; the utility of both non-invasive parameters as well as multiple implant-based parameters for telemonitoring in HF; and the effect of left ventricular assist device implantation on VAs.

DNA methylation loss in late-replicating domains is linked to mitotic cell division

DNA methylation loss occurs frequently in cancer genomes, primarily within lamina-associated, late-replicating regions termed Partially Methylated Domains (PMDs). We profiled 39 diverse primary tumors and 8 matched adjacent tissues using Whole-Genome Bisulfite Sequencing (WGBS), and analyzed them alongside 343 additional human and 206 mouse WGBS datasets. We identified a local CpG sequence context associated with preferential hypomethylation in PMDs. Analysis of CpGs in this context (“Solo-WCGWs”) revealed previously undetected PMD hypomethylation in almost all healthy tissue types. PMD hypomethylation increased with age, beginning during fetal development, and appeared to track the accumulation of cell divisions. In cancer, PMD hypomethylation depth correlated with somatic mutation density and cell-cycle gene expression, consistent with its reflection of mitotic history, and suggesting its application as a mitotic clock. We propose that late replication leads to lifelong progressive methylation loss, which acts as a biomarker for cellular aging and which may contribute to oncogenesis.

A Review of the External Validity of Clinical Trials with Beta-Blockers in Heart Failure

BACKGROUND

Beta-blockers (BBs) are the mainstay prognostic medication for all stages of chronic heart failure (CHF). There are many classes of BBs, each of which has varying levels of evidence to support its efficacy in CHF. However, most CHF patients have one or more comorbid conditions such as diabetes, renal impairment, and/or atrial fibrillation. Patient enrollment to randomized controlled trials (RCTs) often excludes those with certain comorbidities, particularly if the symptoms are severe. Consequently, the extent to which evidence drawn from RCTs is generalizable to CHF patients has not been well described. Clinical guidelines also underrepresent this point by providing generic advice for all patients. The aim of this review is to examine the evidence to support the use of BBs in CHF patients with common comorbid conditions.

METHODS

We searched MEDLINE, PubMed, and the reference lists of reviews for RCTs, post hoc analyses, systematic reviews, and meta-analyses that report on use of BBs in CHF along with patient demographics and comorbidities.

RESULTS

In total, 38 studies from 28 RCTs were identified, which provided data on six BBs against placebo or head to head with another BB agent in ischemic and nonischemic cardiomyopathies. Several studies explored BBs in older patients. Female patients and non-Caucasian race were underrepresented in trials. End points were cardiovascular hospitalization and mortality. Comorbid diabetes, renal impairment, or atrial fibrillation was detailed; however, no reference to disease spectrum or management goals as a focus could be seen in any of the studies. In this sense, enrollment may have limited more severe grades of these comorbidities.

CONCLUSIONS

RCTs provide authoritative information for a spectrum of CHF presentations that support guidelines. RCTs may provide inadequate information for more heterogeneous CHF patient cohorts. Greater Phase IV research may be needed to fill this gap and inform guidelines for a more global patient population.

A meta-analysis of the effects of β-adrenergic blockers in chronic heart failure

Adrenergic β-blockers are drugs that bind to, but do not activate β-adrenergic receptors. Instead they block the actions of β-adrenergic agonists and are used for the treatment of various diseases such as cardiac arrhythmias, angina pectoris, myocardial infarction, hypertension, headache, migraines, stress, anxiety, prostate cancer, and heart failure. Several meta-analysis studies have shown that β-blockers improve the heart function and reduce the risks of cardiovascular events, rate of mortality, and sudden death through chronic heart failure (CHF) of patients. The present study identified results from recent meta-analyses of β-adrenergic blockers and their usefulness in CHF. Databases including Medline/Embase/Cochrane Central Register of Controlled Trials (CENTRAL), and PubMed were searched for the periods May, 1985 to March, 2011 and June, 2013 to August, 2015, and a number of studies identified. Results of those studies showed that use of β-blockers was associated with decreased sudden cardiac death in patients with heart failure. However, contradictory results have also been reported. The present meta-analysis aimed to determine the efficacy of β-blockers on mortality and morbidity in patients with heart failure. The results showed that mortality was significantly reduced by β-blocker treatment prior to the surgery of heart failure patients. The results from the meta-analysis studies showed that β-blocker treatment in heart failure patients correlated with a significant decrease in long-term mortality, even in patients that meet one or more exclusion criteria of the MERIT-HF study. In summary, the findings of the current meta-analysis revealed beneficial effects different β-blockers have on patients with heart failure or related heart disease.

Clinical Characteristics and Treatment of Cardiomyopathies in Children

Cardiomyopathies are diseases of the heart muscle, a term introduced in 1957 to identify a group of myocardial diseases not attributable to coronary artery disease. The definition has since been modified to refer to structural and or functional abnormalities of the myocardium where other known causes of myocardial dysfunction, such as systemic hypertension, valvular disease and ischemic heart disease, have been excluded. In this review, we discuss the pathophysiology, clinical assessment and therapeutic strategies for hypertrophic, dilated and hypertrophic cardiomyopathies, with a particular focus on aspects unique to children.

β-Blockers for the prevention of sudden cardiac death in heart failure patients: a meta-analysis of randomized controlled trials

Background

In many studies, beta-blockers have been shown to decrease sudden cardiac death (SCD) in heart failure patients; other studies reported mixed results. Recently, several large randomized control trials of beta blockers have been carried out. It became necessary to conduct a systematic review to provide an up-to-date synthesis of available data.

Methods

We conducted a meta-analysis of all randomized controlled trials examining the use of beta-blockers vs. placebo/control for the prevention of SCD in heart failure patients. We identified 30 trials, which randomized 24,779 patients to beta-blocker or placebo/control. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Eligible studies had to be randomized controlled trials and provide information on the incidence of sudden cardiac death in heart failure patients. Additional inclusion criteria included: treatment for >30 days and follow-up ≥ 3 months. Studies of patients <18 years, randomization to beta-blocker vs. an angiotensin converting enzyme (without placebo) and/or beta-blocker in both arms were excluded from the analysis. Pre-specified outcomes of interest included SCD, cardiovascular death (CVD), and all-cause mortality and were analyzed according to intention-to-treat.

Results

We found that beta-blockers are effective in the prevention of SCD [OR 0.69; 95% CI, 0.62–0.77, P < 0.00001], cardiovascular death (CVD) [OR 0.71; 95% CI, 0.64–0.79, P < 0.00001], and all-cause mortality [OR 0.67; 95% CI, 0.59–0.76, P < 0.00001]. Based on the study analysis, 43 patients must be treated with a beta-blocker to prevent one SCD, 26 patients to prevent one CVD and 21 patients to prevent all-cause mortality in one year.

Conclusion

Beta-blockers reduce the risk of sudden cardiac death (SCD) by 31%, cardiovascular death (CVD) by 29% and all-cause mortality by 33%. These results confirm the mortality benefits of these drugs and they should be recommended to all patients similar to those included in the trials.

β-Blockers in heart failure: benefits of β-blockers according to varying male proportions of study patients

BACKGROUND

In patients with heart failure (HF), b-blockers reduce mortality. It's not known whether the beneficial effects of the b-blockers were associated with the differing male proportions of study patients. It also remains to be clarified regarding the true beneficial effects of the 3 b-blockers recommended by the guideline on mortality in the real world.

HYPOTHESIS

The benefits of b-blockers in HF patients were sex-related different.

METHODS

Randomized, placebo controlled clinical trials were included if they evaluated the beneficial effects of the three b-blockers on mortality and on hospital admissions on an intention-to-treat basis, and lasted at least 3 months.

RESULTS

Twenty-eighty trials with 14,829 patients were included. The b-blockers significantly reduced all cause mortality by 29.6%, cardiac death by 29.8%, sudden death by 49.4%, respectively. The magnitude of benefits of b-blockers in HF patients was increased with the increased male proportion. A similar magnitude of reduction in all cause mortality was observed among the three b blockers. A trend toward to reduced cardiac death was observed among the three b blockers, but only in bisoprolol was this statistically different (RR, 0.72; 95%CI, [0.59-0.87]). Metoprolol was significantly superior to carvedilol (P = 0.008) or bisoprolol (P = 0.034) in reduced sudden death.

CONCLUSIONS

In patients with HF, the 3 commonly used b-blockers significantly reduced mortality. Greater benefits of b-blockers were observed in the higher male proportion studies. The metoprolol was significantly superior to carvedilol or bisoprolol in reduced sudden death. Additional trials are required to determine whether the benefits of b-blockers will be observed in female HF patients.

Beneficial effects of beta-blockers on left ventricular function and cellular energy reserve in patients with heart failure

Beta-blockers have been shown to improve left ventricular (LV) function in patients with heart failure. The aim of this study is to non-invasively assess, by means of in vivo 31P-magnetic resonance spectroscopy (31P-MRS), the effects of beta-blockers on LV cardiac phosphocreatine and adenosine triphosphate (PCr/ATP) ratio in patients with heart failure. Ten heart failure patients on full medical therapy were beta-blocked by either carvedilol or bisoprolol. Before and after 3 months of treatment, exercise testing, 2D echocardiography, MRS, New York Heart Association (NYHA) class, ejection fraction (EF), maximal rate-pressure product and exercise metabolic equivalent system (METS) were evaluated. Relative concentrations of PCr and ATP were determined by cardiac 31P-MRS. After beta-blockade, NYHA class decreased (from 2.2 ± 0.54 to 1.9 ± 0.52, P = 0.05), whereas EF (from 33 ± 7 to 44 ± 6%, P = 0.0009) and METS (from 6.74 ± 2.12 to 8.03 ± 2.39, P = 0.01) increased. Accordingly, the mean cardiac PCr/ATP ratio increased by 33% (from 1.48 ± 0.22 to 1.81 ± 0.48, P = 0.03). Beta-blockade-induced symptomatic and functional improvement in patients with heart failure is associated to increased PCr/ATP ratio, indicating preservation of myocardial high-energy phosphate levels.

Safety and tolerability of once-daily controlled-release carvedilol 10-80 mg in Japanese patients with chronic heart failure

BACKGROUND

The aim of the present study was to assess the safety and tolerability of the controlled-release (CR) formulation of the β-blocker carvedilol in Japanese patients with chronic heart failure (HF).

METHODS AND RESULTS

In this multicenter, randomized, open-label, phase I/II dose-escalation study, 41 patients receiving standard therapy for chronic HF were randomized in a ratio of 1:1 to carvedilol CR or immediate-release (IR) carvedilol. The primary objective was to evaluate the tolerability and safety of escalating doses of carvedilol CR (10-40 mg/day), with a reference arm of 5-20 mg/day of carvedilol IR. In addition, the tolerability and safety of titration to a carvedilol CR dose up to 80 mg/day were examined, as were plasma concentrations of carvedilol and changes in vital signs. The proportions of patients who completed 40-mg/day carvedilol CR and 20-mg/day carvedilol IR were 42% (8/19) and 50% (11/22), respectively. In the CR group, 7/19 (37%) attained a dose of 80 mg. During the primary evaluation period, 7/19 (37%) and 4/22 (18%) patients experienced drug-related adverse events in the CR and IR groups, respectively, the characteristics of which were similar between groups.

CONCLUSIONS

No new safety issues emerged in Japanese chronic HF patients treated with carvedilol CR in contrast to those known in carvedilol IR.

Treatment of chronic heart failure with β-adrenergic receptor antagonists: a convergence of receptor pharmacology and clinical cardiology

Despite the absence of a systematic development plan, β-blockers have reached the top tier of medical therapies for chronic heart failure. The successful outcome was due to the many dedicated investigators who produced, over a 30-year period, increasing evidence that β-blocking agents should or actually did improve the natural history of dilated cardiomyopathies and heart failure. It took 20 years for supportive evidence to become undeniable, at which time in 1993 the formidable drug development resources of large pharmaceutical companies were deployed into Phase 3 trials. Success then came relatively quickly, and within 8 years multiple agents were on the market in the United States and Europe. Importantly, there is ample room to improve antiadrenergic therapy, through novel approaches exploiting the nuances of receptor biology and/or intracellular signaling, as well as through pharmacogenetic targeting.

Myocardial perfusion reserve and contractile pattern after beta-blocker therapy in patients with idiopathic dilated cardiomyopathy

BACKGROUND

In Idiopathic Dilated Cardiomyopathy (IDC) an imbalance between myocardial oxygen consumption and supply has been postulated. The ensuing subclinical myocardial ischemia may contribute to progressive deterioration of LV function. beta-blocker is the therapy of choice in these patients. However, not all patients respond to the same extent. The aim of this study was to elucidate whether differences between responders and non-responders can be identified with respect to regional myocardial perfusion reserve (MPR) and contractile performance.

METHODS

Patients with newly diagnosed IDC underwent Positron Emission Tomography (PET) scanning using both (13)N-ammonia as a perfusion tracer (baseline and dipyridamole stress), and (18)F-fluoro-deoxyglucose as a metabolism tracer, and a dobutamine stress MRI. MRI and PET were repeated 6 months after maximal beta-blocker therapy. MPR (assessed by PET) as well as wall motion score (WMS, assessed by MRI) were evaluated in a 17 segment-model. Functional response to beta-blocker therapy was assigned as a stable or improved LVEF or diminished LVEF.

RESULTS

Sixteen patients were included (age 47.9 +/- 11.5 years; 12 males, LVEF 28.6 +/- 8.4%). Seven patients showed improved LVEF (9.7 +/- 3.1%), and nine patients did not show improved LVEF (-3.4 +/- 3.9%). MPR improved significantly in responders (1.56 +/- .23 to 1.93 +/- .49, P = .049), and MPR decreased in non-responders; however, not significantly (1.98 +/- .70 to 1.61 +/- .28, P = .064), but was significantly different between both groups (P = .017) after beta-blocker therapy. A significant correlation was found between change in perfusion reserve and change in LVEF: a decrease in perfusion reserve was associated with a decrease in LVEF and vice versa. Summed rest score of wall motion in responders improved from 26 to 21 (P = .022) whereas in non-responders no change was observed from 26 to 25) (P = ns). Summed stress score of wall motion in responders improved from 23 to 21 (P = .027) whereas in non-responders no change was observed from 27 to 26) (P = ns).

CONCLUSION

In IDC patients, global as well as regional improvement after initiation of beta-blocker treatment is accompanied by an improvement in regional perfusion parameters. On the other hand in IDC patients with further left ventricular function deterioration after initiation of beta-blocker therapy this is accompanied by a decrease in perfusion reserve.

Dilated cardiomyopathy with hypertension: prevalence and response to high-dose β1-adrenoceptor antagonist therapy

1. The aim of the present study was to investigate the prevalence of hypertension in patients with dilated cardiomyopathy (DCM) and to determine the tolerance and efficacy of a high dose of the β1-adrenoceptor antagonist metoprolol in the long-term treatment of DCM patients. 2. The prevalence of hypertension in DCM patients (n = 362) and age-matched controls (n = 401) was evaluated and compared. To investigate the effects of metoprolol, DCM patients were divided into hypertensive (DCM-H) or normotensive (DCM-N) subgroups. Metoprolol was administered at a starting dosage of 6.25 mg/day and increased gradually to 250 mg/day or the maximum tolerable dose. Blood pressure (BP), heart rate (HR), left ventricular (LV) end-diastolic dimension (LVEDD), left atrial end-diastolic dimension (LAEDD), LV ejection fraction (LVEF), LV posterior wall thickness (LVPWT) and ventricular septal thickness (VST) were determined at baseline and 6 and 12 months after metoprolol treatment. 3. The prevalence of hypertension was significantly higher in DCM patients than in age-matched controls (32.8 vs 20.1%, respectively; P < 0.01). Resting HR and a family history of hypertension were highest in the DCM-H group. There were no significant differences in age, gender and occupation between the DCM-H, DCM-N and age-matched control groups. 4. The tolerable dose for metoprolol was significantly higher in the DCM-H group than the DCM-N group (189.6 ± 14.8 vs 133.9 ± 12.0 mg/day, respectively; P < 0.05). Metoprolol significantly reduced BP and HR in the DCM-H group and improved LVEDD, LAEDD and LVEF in all DCM patients, with a greater effect seen in the DCM-H group. 5. In conclusion, DCM patients have a higher prevalence of hypertension than the general population. Patients in the DCM-H subgroup were characterized by a higher resting HR and a family history of hypertension and were more tolerant of and more responsive to metoprolol treatment. These data suggest that this subgroup of DCM patients could have higher sympathetic nerve activity and is suitable for treatment with a higher dose of metoprolol.

Idiopathic dilated cardiomyopathy in children: a single medical center's experience

BACKGROUND

The prognosis of patients with idiopathic dilated cardiomyopathy (DCM) is poor. Most patients die while waiting for cardiac transplantation because of the small number of donors in Taiwan. The purpose of this study was to review our experience with pediatric patients diagnosed with idiopathic DCM and attempt to discover prognostic factors.

METHODS

Eighteen patients with idiopathic DCM presenting between 1990 and 2004 were identified. They were classified into 2 groups according to outcome: group 1 comprised 13 patients who died; group 2 comprised 5 who survived. Clinical findings and laboratory investigations were compared between the 2 groups.

RESULTS

The age at initial diagnosis for the 18 patients (11 males, 7 females) ranged from fetus to 13 years (median, 3 months). The follow-up period ranged from 12 days to 44 months (median, 7 months) in group 1, and from 1 to 48 months (median, 39 months) in group 2. Of the 18 patients, 13 (72%) died: 11 died from severe heart failure while waiting for cardiac transplantation. The cumulative survival rate was 50% at 1 year and 28% at 4 years. The presence of arrhythmia and low left ventricular ejection fraction were predictive of a poor outcome.

CONCLUSION

The diagnosis of idiopathic DCM in children is associated with a generally poor prognosis. The lack of available donors results in significant mortality for pediatric patients awaiting transplantation. Advocating organ donation to increase the size of the organ donor pool is needed to significantly reduce the mortality rate in such patients.

COMPARISON OF LOW and HIGH DOSES OF CARVEDILOL ON RESTORATION OF CARDIAC FUNCTION and CALCIUM-HANDLING PROTEINS IN RAT FAILING HEART

1. The beta-adrenoceptor antagonist carvedilol reverses cardiac dysfunction in the failing heart. A recent study showed that beta-adrenoceptor antagonists indirectly normalize Ca(2+)-regulatory proteins. The relationship between these two phenomena and the suitable dosage of carvedilol remains unclear. 2. We investigated the change in left ventricular (LV) remodelling and function in a rat model of heart failure due to myocardial infarction (MI) with or without carvedilol (30 or 2 mg/kg per day) treatment for 6 weeks. The expression of mRNA and proteins of sarcoplasmic reticulum Ca(2+)-ATPase (SERCA) and phospholamban (PLB) in cardiomyocytes was also measured. 3. There was significant LV remodelling and cardiac contractile dysfunction in MI rats. The expression of SERCA mRNA and protein were downregulated (P < 0.01), but the expression of PLB mRNA and protein were upregulated (P < 0.01) in MI rats compared with sham-operated rats. After treatment with carvedilol, LV remodelling and cardiac contractile dysfunction were clearly improved. Low-dose carvedilol was better at improving some parameters of LV remodelling and function than the high dose. Carvedilol partially restored the low expression of SERCA (P < 0.05), but had no effect on PLB expression (P > 0.05). Moreover, low-dose carvedilol induced a more significant improvement in SERCA expression than did the high dose (P < 0.05). 4. The results of the present study suggest that carvedilol is effective in improving LV remodelling and cardiac contractile dysfunction after MI. This may be related to the normalization of SERCA expression.

[Clinical trials of beta-blockers in heart failure: history, overview and future prospects]

Although beta-blockers have been classically contraindicated in heart failure patients, their administration at progressively increasing doses provides long-term benefit in such patients with altered left ventricular function, and prevents the direct and indirect deleterious cardiac effects of catecholamines. By improving left ventricular function and preventing severe arrhythmias, beta-blockade improves survival, reduces the occurrence of sudden death and hospital admissions for worsening heart failure. The degree of benefit is dose dependent, although few prospective data confirm this fact. Among tested compounds, bisoprolol, metoprolol and carvedilol have produced similar improvements in survival with a 34% reduction in mortality in large-scale clinical trials. Bucindolol, however, did not significantly improve survival in the BEST trial. Different hypotheses may explain such results. In terms of therapeutic strategy, beta-blocker treatment must be initiated in stabilised patients already receiving diuretics and an angiotensin-converting enzyme inhibitor. Ongoing studies are evaluating the potential benefit of starting treatment first with beta-blockers in order to better prevent sudden death, particularly as this most often occurs in the early stages of the disease.

[Prediction of intolerance to beta blocker therapy in chronic heart failure patients using BNP]

Beta-blocker therapy is actually recommended as first line therapy for systolic heart failure. However, beta-blocker have a low prescription rate comparatively to ACEI. Beta-blocker potential side effects as bradycardia, hypotension and especially acute decompensation could explain this under prescription. Clinical data could easily identify high-risk patients for hypotension or bradycardia but not high-risk patients for induced decompensation linked to beta-blocker therapy. BNP could identify these patients with a high sensitivity. Patients with BNP above 1000 pg/ml had a 40% risk of acute decompensation after introduction or increase of beta-blocker therapy. As a conclusion, clinicians must be very cautious for introducing or increasing Carvedilol therapy in patients with high BNP levels.

Failure of benefit and early hazard of bucindolol for Class IV heart failure

OBJECTIVES

The risks and benefits of beta-blockade with bucindolol were assessed in heart failure (HF) patients with Class IV symptoms within the Beta-blocker Evaluation of Survival Trial (BEST).

BACKGROUND

beta-blockade is accepted therapy for mild to moderate HF, but its safety and efficacy in advanced HF have not been established.

METHODS

BEST recruited 2708 HF patients; of these, 226 with Class IV symptoms (n=114 randomized to bucindolol, n=112 to placebo) formed the basis of this study. All-cause death, HF hospitalization, and drug discontinuations occurring early during therapy (< or =6 months) and overall during follow-up were assessed. Compared with Class III, Class IV patients were older and had higher plasma norepinephrine levels, prevalence of coronary disease, S3 gallops, and lower ejection fractions, but characteristics of the 2 Class IV treatment groups were similar.

RESULTS

During a mean of 1.6 years, 49% Class IV patients died, and 54% were hospitalized for HF. Bucindolol increased the combined endpoint of death or HF hospitalization within the first 6 months (hazard ratio [HR]=1.7, 95% confidence interval [CI]=1.1-2.7) and did not result in benefit overall (HR=1.2, 95% CI=0.9-1.6). HF hospitalization alone within 6 months was increased by bucindolol (HR=1.7), and an early adverse trend for death was seen (HR=1.6) with no benefit overall (HR=1.1). Bucindolol was discontinued more frequently than placebo for worsening HF (11% versus 4%) and hypotension (3% versus 0%).

CONCLUSIONS

Class IV HF patients in BEST were at high risk. Bucindolol did not reduce death or HF hospitalization and was associated with early hazard.

Beta-blockers for chronic heart failure: surviving longer but feeling better?

Beta-blockers, as determined by four landmark placebo-controlled studies, impart a significant survival advantage to the chronic heart failure population. What ancillary benefits might be expected from beta-blockade, in terms of symptom relief and improvement in exercise capacity, is less clear. This situation in part reflects the heterogeneity of tools used to quantify quality of life and exercise performance as well as factors concerning the statistical handling of symptom and exercise data. In this review we explore the methodology and results of over 20 trials of carvedilol, metoprolol and bisoprolol where quality of life and measures of exercise capacity were end-points. A consistent message relating to a benefit from beta-blockade on these outcomes was elusive but the finding that patients on beta-blockers did at least as well as patients prescribed placebo was a unanimous verdict. There remains a dearth of data to help identify those patients that are at high risk of adverse events from beta-blocker therapy.

Echocardiography-derived variables predict outcome in patients with nonischemic dilated cardiomyopathy with or without a restrictive filling pattern

BACKGROUND

Despite recent therapeutic advances, patients with heart failure caused by dilated cardiomyopathy (DCM) still have high morbidity and mortality rates. In this study, we sought to assess the prognostic value of echocardiographic variables in patients with DCM and to assess the impact of a restrictive left ventricle filling pattern.

DESIGN

We conducted a retrospective cohort study of 337 patients with DCM, using the Royal Brompton Hospital Echocardiography database for the years 1994 to 1998.

METHODS AND RESULTS

There were 337 patients with a mean age of 53 +/- 15 years. One hundred ninety-five patients (58%) had a restrictive left ventricle filling pattern (RFP). There was a total of 74 deaths (22%) during the follow-up period (43 +/- 25 months). RFP more than tripled the risk of death (adjusted hazard ratio 3.2, 95% CI 1.8-5.7, P =.003). RFP is correlated with isovolumic relaxation time, incoordinate wall-motion, amplitude of right ventricular long axis excursion on M-mode echocardiography, and mitral regurgitation.

CONCLUSION

RFP is a powerful independent predictor of mortality in patients with nonischemic DCM. The risk associated with RFP is greatest among patients who had short isovolumic relaxation time, mitral regurgitation, incoordinate wall-motion, and depressed amplitude of right ventricular long axis excursion. Thus, echocardiography-derived variables may stratify patients with heart failure with DCM who are at high risk, for whom aggressive medical treatment or heart transplantation should be considered early.

Use of ejection fraction (or lack thereof), morbidity/mortality and heart failure drug trials: a review

Ejection fraction (EF) is an ejection phase parameter used to assess the performance of the heart in normal individuals and pathologic states such as myocardial infarction, dilated cardiomyopathy, and congestive heart failure (CHF). It can be measured by radionuclide ventriculography, angiocardiography, echocardiography and magnetic resonance imaging. EF is dependent on the loading conditions of the heart as well as contractility of the myocardium which makes it a less useful measure of cardiac performance. Nevertheless, it has been widely utilized and discussed for years. EF has been used as an entry criteria for many trials in CHF and has been used to characterize the hemodynamic effects of various classes of drugs which are used in treating CHF. How predictive an increase in EF on therapy is of morbidity and mortality is a matter of debate. This review outlines the utilization (or lack thereof), of EF in various CHF drug trials, its relationship to symptomatic improvement and morbidity/mortality.

Dose-related effects of metoprolol on heart rate and pharmacokinetics in heart failure

BACKGROUND

The pharmacokinetics and pharmacodynamics of immediate-release (IR) metoprolol, 50 mg 3 times daily, were compared with those of different doses of controlled-release/extended-release metoprolol (CR/XL) given once daily.

METHODS AND RESULTS

Fifteen patients with chronic heart failure were randomized to a 3-way crossover study to receive metoprolol IR 50 mg 3 times daily, CR/XL 100 mg once daily, and CR/XL 200 mg once daily for 7 days. On the seventh day of each treatment, serial plasma samples were drawn and standardized exercise tests and a 24-hour Holter recording were performed. Metoprolol IR 50 mg produced peak plasma levels comparable to those observed for CR/XL 200 mg (285 v 263 nmol/L). The difference in mean 24-hour heart rate between CR/XL 100 mg and IR 50 mg was 1.0 bpm (95% confidence interval [CI]), -2.9 to 4.9; NS) compared with -3.8 bpm (95% CI, -7.6 to -0.04; P = .048) between CR/XL 200 mg and IR 50 mg. Submaximal exercise heart rate was lower for patients receiving CR/XL 200 mg than those receiving IR 50 mg. No difference in tolerance or exercise performance was observed between treatment regimens.

CONCLUSIONS

Peak plasma levels produced by metoprolol 200 mg CR/XL were similar to those of 50 mg IR. Metoprolol CR/XL 200 mg was associated with a more pronounced suppression of heart rate than metoprolol IR 50 mg. It is suggested that patients can safely be switched from multiple dosing of metoprolol IR 50 mg to a once-daily dose of metoprolol CR/XL.

Systematic review of the impact of beta blockers on mortality and hospital admissions in heart failure

Heart failure is a common condition that carries a high burden of mortality and morbidity. Several randomised trials have evaluated the effects of beta blockers in heart failure. This paper gives a systematic overview of published randomised trials of beta blockers in heart failure using standard methods. In all, 22 randomised controlled trials were identified with a total of 10480 patients, and an average of 11 months of treatment. The average age was 61 years and 4% were female. Most studies excluded patients with severe heart failure. Death rates in patients randomised to receive beta blockers compared to controls were 458/5657 (8.0%) and 635/4951 (12.8%) respectively, odds ratio 0.63, 95% CI 0.55-0.72, P<0.00001. Similar reductions were observed for hospital admissions for worsening heart failure (11.3 vs. 17.1%, respectively, odds ratio 0.63) and for the composite outcome of death or heart-failure hospital admission (19.4 vs. 26.9%, respectively, odds ratio 0.66). These results show that beta blockers reduce the risk of mortality or the need for heart-failure hospital admission by approximately one third. Absolute reductions of 5-6% in event rates were observed over approximately 1 year of treatment period. These important benefits should be implemented as a priority, since treatment with beta blockers is inexpensive and heart failure carries a high risk of death and disability. Further information on the effect of beta blockers in elderly patients and women would be helpful.

Effect of metoprolol CR/XL on exercise tolerance in chronic heart failure - a substudy to the MERIT-HF trial

BACKGROUND

Beta-blockade usually causes a slight reduction in exercise capacity among healthy subjects, while more variable results have been observed in chronic heart failure (CHF), probably related to patients studied, methods and agent used. The effect of metoprolol controlled release/extended release (CR/XL) on peak oxygen uptake (peak VO(2)) in this patient population has not previously been investigated.

AIMS

We examined the effect of long-term treatment with the selective beta(1)-receptor blocker metoprolol CR/XL once daily on exercise capacity in patients with CHF.

METHODS

Ninety-four patients (70 males and 24 females; mean age 63.6+/-10.6 years) with chronic symptomatic heart failure in New York Heart Association (NYHA) functional class II-IV, and with ejection fraction <or=40%, stabilized on optimum standard therapy were randomized to metoprolol CR/XL or placebo in a double-blind trial. Exercise capacity was evaluated by peak VO(2) at baseline, after 3 months and at the end of study (mean follow-up 11.4+/-0.4 months).

RESULTS

Compared with placebo metoprolol CR/XL produced a significant decrease in heart rate by 11 beats/min at rest and 18 beats/min at peak exercise. There was a tendency for a temporal decline in peak VO(2) after 3 months of therapy in both groups, but altogether peak VO(2) remained unchanged from baseline with no difference between the groups at 1 year.

CONCLUSIONS

In patients with moderate to severe CHF, 11.4 months of beta(1)-blockade with metoprolol CR/XL had no effect on exercise capacity when compared with placebo or baseline.

Beta-blocking in heart failure patients. Balancing the evidence

Evidence for the effectiveness of beta-blockers in the management of patients with heart failure is now compelling with a database of over 13000 patients enrolled in randomised prospective placebo-controlled clinical trials. However this therapy remains vastly underused in clinical practice. The different points challenging the widespread use beta blockade agents in the routine treatment in heart failure are presented and discussed. After a review of the potential mechanism hypothesised behind the benefits of beta-blockers in heart failure, the controversial effects on the haemodynamics, exercise tolerance, hospitalisation and mortality are underlined.

Using isoproterenol stress echocardiography to predict the response to carvedilol in patients with dilated cardiomyopathy

Trials have demonstrated that carvedilol can produce hemodynamic, symptomatic, and prognostic improvements in dilated cardiomyopathy (DCM), but some DCM patients have deteriorated after carvedilol, developing congestive heart failure. The present study investigated the use of isoproterenol (ISP) stress echocardiography to select those patients with DCM who would respond to carvedilol. ISP was infused intravenously in 22 patients with DCM and they were classified into 2 groups based on the left ventricular systolic response: good response to ISP [change in fractional shortening (FS) with ISP > 0.05, n=13] and poor response to ISP (change < or = 0.05, n=9). In the good response group, FS significantly increased from 0.12+/-0.04 to 0.17+/-0.08 (mean+/-SD, p<0.05) with carvedilol, and 7 patients improved symptomatically (New York Heart Association class). However, in the poor response group, no significant difference was observed between FS at baseline and that at the end of follow-up. Moreover, only 1 patient in the poor response group improved symptomatically. ISP stress echocardiography can assist in selecting patients with DCM who will respond positively to carvedilol.

[Evidence based medical treatment of heart failure]

INTRODUCTION AND OBJECTIVES

Recommendations for the treatment of heart failure were carried out by a systematic review of the available evidence of the different pharmacologic treatments.

MATERIAL AND METHODS

The review focused on the treatment of chronic and systolic heart failure. All the studies published in english about the pharmacologic treatment of heart failure where identified. The evidence of every pharmacologic treatment was classified according to: a) efficacy variables (reduction of mortality and hospitalizations, improvement of functional class, ejection fraction and exercise tolerance), and b) the level of quality of the evidence according to an evaluation scale. The evidence was also reviewed for the comparisons and the combinations of the pharmacologic treatments, as well as for the toxicity and costs of treatments.

RESULTS

The recommendations were defined according to the NYHA functional class and were classified in the A, B and C categories according to the level of quality of the available evidence. The evidence on mortality was considered the most important. First line drugs, the alternatives and other possible treatments were take into account.

CONCLUSIONS

There is enough evidence based on information about some variables such as reduction of mortality or hospitalizations to carry out treatment recommendations in all stages of heart failure. This point out the interest ant the priority of used them in the evaluation and improvement of the results of heart failure.

Beta-blocker therapy in heart failure

beta-blocker therapy in heart failure offers the possibility of arresting or reversing the progressive deterioration in this clinical syndrome. While the mechanism is unclear, improvement in cardiac function has been apparent in virtually every study. Clinical results have shown less consistent improvement. Decrease in hospitalization has been noted, but large-scale clinical trials are underway to assess the effect of beta-blockers on mortality.

Beta-blocker treatment in heart failure

Heart failure treatment has markedly changed during the last few decades, with demonstration of benefit of afterload reduction by vasodilator therapy and introduction of the concept of the deleterious consequences of the neuro-hormonal compensatory stimulation. Blockade of beta-adrenergic receptors, initially contra-indicated in heart failure, provide a marked reduction of mortality and morbidity in combination with diuretics and angiotensin-converting enzyme inhibitors, as demonstrated in many clinical trials. We performed a review of all clinical trials that compare beta-blockers vs. placebo in chronic heart failure. Beta-blockers with different pharmacological profiles have been tested, mainly metoprolol, bisoprolol, bucindolol and carvedilol. With progressive dose increment, tolerance of such treatment was generally good, left ventricular function improved, hospitalisations for heart failure were less frequent and mortality was reduced. The meta-analysis of the 16 randomised trials, with at least one death in each treatment group, provides a 24% relative risk reduction for such hospitalisations (95% CI=19%-29%) and 22% reduction for mortality (95% CI=16%-28%). Heterogeneity of beta-blocker effect for mortality was found and related to the non-significant benefit obtained in the BEST trial with bucindolol. When such a trial is excluded, the effect model analysis shows that relative risk reduction (beta-blocker induced benefit) is constant whatever the severity of the disease. The mechanism of beta-blocker induced benefit remains unclear, but is at least partly related to left ventricular function improvement and prevention of severe ventricular arrhythmias. In conclusion, beta-blocker treatment has become an established therapy for heart failure, in combination with diuretics and ACE inhibitors. Complementary informations will be needed to clarify the mechanism of benefit and to define the best therapeutic strategy according to the individual characteristics of patients with heart failure.

Carvedilol enhances atrial and brain natriuretic peptide mRNA expression and release in rat heart

To clarify the role of the natriuretic peptide (NP) system in the myocardial protective effects of carvedilol, a beta-blocking agent, we investigated the effects of carvedilol on the NP system in the rat heart. After oral administration of carvedilol (low-dose group: 2 mg/kg/day, group C2; high-dose group: 20 mg/kg/day, group C20) for 1 week, plasma rat atrial NP (r-ANP), atrial mRNA levels of ANP, left ventricular mRNA of brain NP (BNP), NP receptor-A and NP receptor-C (NPR-C) (as a clearance receptor) were measured. Values were compared with those in vehicle-treatment rats (group V). The concentration of r-ANP was significantly higher in group C2 (135 +/- 9 pg/ml) and group C20 (161 +/- 11 pg/ml) than group V (75 +/- 6 pg/ml; both p < 0.01). ANP and BNP mRNA levels were significantly increased and NPR-C was significantly down regulated in group C2 (151 +/- 7, 120 +/- 8 and 78 +/- 7%, respectively, vs. group V) and group C20 (164 +/- 8. 133 +/- 7 and 72 +/- 8%, respectively, vs. group V) compared with group V (all p < 0.01). These results suggest that not only a high dose, but a low dose of carvedilol has the effect of increasing plasma ANP and BNP levels. This effect was closely related to the upregulation of ANP and BNP mRNA expression, and the down regulation of NPR-C mRNA expression in the heart. These mechanisms seem to account for a sizable portion of the protective effect of carvedilol for heart diseases.