Beta-blockade in heart failure: a comparison of carvedilol with metoprolol

Sequencing Quadruple Therapy for Heart Failure with Reduced Ejection Fraction: Does It Really Matter?

The conventional sequence of guideline-directed medical therapy (GDMT) initiation in heart failure with reduced ejection fraction (HFrEF) assumes that the effectiveness and tolerability of GDMT agents mirror their order of discovery, which is not true. In this review, the authors discuss flexible GDMT sequencing that should be permitted in special populations, such as patients with bradycardia, chronic kidney disease, or atrial fibrillation. Moreover, the initiation of certain GDMT medications may enable tolerance of other GDMT medications. Most importantly, the achievement of partial doses of all four pillars of GDMT is better than achievement of target dosing of only a couple.

Short-term deceleration capacity: a novel non-invasive indicator of parasympathetic activity in patients undergoing pulmonary vein isolation

BACKGROUND

Subtypes of atrial fibrillation (AF) can differ, and exact mechanisms in which patients benefit from the pulmonary vein isolation (PVI) remain not fully understood. During PVI, vagal innervation of the heart may also be affected. Thus, non-invasive methods of intraprocedural assessment of such PVI impact are sought.

METHODS

From 1-minute ECG recordings performed before and after PVI, we investigated short-term deceleration capacity (ST-DC) and short-term heart rate variability (ST-HRV) to determine their potential as indicators of parasympathetic activity before and after ablation.

RESULTS

In 24 consecutive patients with paroxysmal AF included in the study, there were a significant differences in ST-DC and ST-HRV parameters measured before and after PVI. After 3 months, patients with baseline ST-DC ≥ 7.5 ms were less likely to experience AF recurrence when compared to patients with baseline ST-DC < 7.5 ms (0% vs 31%, p = 0.0496). There were no differences in AF recurrence after 12 months of follow-up (36% vs 38%, p = 0.52).

CONCLUSION

PVI leads to significant changes in ST-DC and ST-HRV, and these parameters can serve as indicators of vagal denervation after AF ablation. Patients with more prominent baseline ST-DC are less likely to experience AF recurrence during the post-PVI 3-month blanking period.

Efficacy of Beta-Blockers and Angiotensin-Converting Enzyme Inhibitors in Non-Ischemic Dilated Cardiomyopathy: A Systematic Review and Meta-Analysis

Background

Non-ischemic dilated cardiomyopathy (NIDCM) is a form of heart failure with a poor prognosis and unclear optimal management. The aim of the study was to systematically review the literature and assess the efficacy and safety of beta-blockers and angiotensin-converting enzyme (ACE) inhibitors in the management of chronic heart failure secondary to NIDCM and explore their putative mechanisms of action.

Methods

Studies from 1990 to 2023 were reviewed using PubMed and EMBASE, focusing on their effects on left ventricular ejection fraction (LVEF) in NIDCM patients, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

Results

Beta-blockers showed a significant beneficial effect on LVEF improvement in NIDCM, with an overall effect size of Cohen's d = 1.30, 95% confidence interval (CI) (0.76, 1.84), high heterogeneity (Tau2 = 0.90; Chi2 = 162.05, df = 13, P < 0.00001; I2 = 92%), and a significant overall effect (Z = 4.72, P < 0.00001). ACE inhibitors also showed a beneficial role, but with less heterogeneity (Tau2 = 0.02; Chi2 = 1.09, df = 1, P = 0.30; I2 = 8%) and a nonsignificant overall effect (Z = 1.36, P = 0.17), 95% CI (-0.24, 1.31).

Conclusions

The study highlights the efficacy of carvedilol in improving LVEF in NIDCM patients over ACE inhibitors, recommends beta-blockers as first-line therapy, and advocates further research on ACE inhibitors.

Sequencing Quadruple Therapy for Heart Failure with Reduced Ejection Fraction: Does It Really Matter?

The conventional sequence of guideline-directed medical therapy (GDMT) initiation in heart failure with reduced ejection fraction (HFrEF) assumes that the effectiveness and tolerability of GDMT agents mirror their order of discovery, which is not true. In this review, the authors discuss flexible GDMT sequencing that should be permitted in special populations, such as patients with bradycardia, chronic kidney disease, or atrial fibrillation. Moreover, the initiation of certain GDMT medications may enable tolerance of other GDMT medications. Most importantly, the achievement of partial doses of all four pillars of GDMT is better than achievement of target dosing of only a couple.

The Arrhythmogenicity of Sotalol and its Role in Heart Failure: A Literature Review

ABSTRACT

According to the American Heart Association, approximately 6 million adults have been afflicted with heart failure in the United States in 2020 and are more likely to have sudden cardiac death accounting for approximately 50% of the cause of mortality. Sotalol is a nonselective β-adrenergic receptor antagonist with class III antiarrhythmic properties that has been mostly used for atrial fibrillation treatment and suppressing recurrent ventricular tachyarrhythmias. The use of sotalol in patients with left ventricular dysfunction is not recommended by the American College of Cardiology or American Heart Association because studies are inconclusive with conflicting results regarding safety. This article aims to review the mechanism of action of sotalol, the β-blocking effects on heart failure, and provide an overview of clinical trials on sotalol use and its effects in patients with heart failure. Small- and large-scale clinical trials have been controversial and inconclusive about the use of sotalol in heart failure. Sotalol has been shown to reduce defibrillation energy requirements and reduce shocks from implantable cardioverter-defibrillators. Torsades de Pointes is the most life-threatening arrhythmia that has been documented with sotalol use and occurs more commonly in women and heart failure patients. Thus far, mortality benefits have not been demonstrated with sotalol use and larger multicenter studies are required going forward.

Efficacy of Add-on Therapy with Carvedilol and the Direct Renin Inhibitor Aliskiren for Improving Cardiac Sympathetic Nerve Activity, Cardiac Function, Symptoms, Exercise Capacity and Brain Natriuretic Peptide in Patients with Dilated Cardiomyopathy

Purpose/Method: Aliskiren is a direct renin inhibitor that has been reported to be effective for CHF, but the usefulness of combined therapy with carvedilol and aliskiren has not been reported. Forty-four patients with dilated cardiomyopathy (DCM) were randomized into a group receiving add-on therapy with carvedilol plus aliskiren and another group receiving carvedilol alone for 6 months. Nuclear imagings with ¹²³I-Metaiodobenzylguanidine (MIBG) and ^99mTc-Sestamibi were performed. Exercise capacity using a specific activity scale (SAS) and the New York Heart Association (NYHA) class were evaluated. Cardiac sympathetic nerve activity was evaluated by ¹²³I-MIBG imaging, with the delayed heart-to-mediastinum activity ratio (H/M), delayed total defect score (TDS), and washout rate (WR). Results: Combined add-on therapy with carvedilol and aliskiren improved several parameters much more than carvedilol alone (p<0.05) with respect to TDS, ejection fraction (EF), NYHA, SAS on 6 months and the changes in TDS, EF, end-diastolic volume and brain natriuretic peptide (BNP). Conclusion: Add-on therapy with carvedilol and aliskiren is more effective than carvedilol alone for improving cardiac sympathetic nerve activity, cardiac function, symptoms, exercise capacity, and brain natriuretic peptide in patients with DCM.

Pharmacotherapy for heart failure with reduced ejection fraction and health-related quality of life: a systematic review and meta-analysis

AIMS

The aim of this study was to synthesize the evidence on the effect of heart failure with reduced ejection fraction (HFrEF) pharmacotherapy on health-related quality of life (HRQoL).

METHODS AND RESULTS

We searched MEDLINE, Embase, CENTRAL, CINAHL, ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform in June 2020. Randomized placebo-controlled trials evaluating contemporary HFrEF pharmacotherapy and reporting HRQoL as an outcome were included. Two reviewers independently assessed studies for eligibility, extracted data, and assessed risk of bias and GRADE certainty of evidence. The primary outcome was HRQoL at last available follow-up analysed using a random-effects model. We included 37 studies from 5770 identified articles. Risk of bias was low in 10 trials and high/unclear in 27 trials. High certainty evidence from meta-analyses demonstrated improved HRQoL over placebo with sodium-glucose co-transporter 2 (SGLT2) inhibitors [standardized mean difference (SMD) 0.16, 95% confidence interval (CI) 0.08-0.23] and intravenous iron (SMD 0.52, 95% CI 0.04-1.00). Furthermore, high certainty evidence from ≥1 landmark trial further supported improved HRQoL with angiotensin receptor blockers (ARBs) (SMD 0.09, 95% CI 0.02-0.17), ivabradine (SMD 0.14, 95% CI 0.04-0.23), hydralazine-nitrate (SMD 0.24, 95% CI 0.04-0.44) vs. placebo, and for angiotensin receptor-neprilysin inhibitor (ARNI) compared with an angiotensin-converting enzyme (ACE) inhibitor (SMD 0.09, 95% CI 0.02-0.17). Findings were inconclusive for ACE inhibitors, beta-blockers, digoxin, and oral iron based on low-to-moderate certainty evidence.

CONCLUSION

ARBs, ARNIs, SGLT2 inhibitors, ivabradine, hydralazine-nitrate, and intravenous iron improved HRQoL in patients with HFrEF. These findings can be incorporated into discussions with patients to enable shared decision-making.

Male Patients With Dilated Cardiomyopathy Exhibiting a Higher Heart Rate Acceleration Capacity or a Lower Deceleration Capacity Are at Higher Risk of Cardiac Death

The effects of dilated cardiomyopathy (DCM) on cardiac autonomic regulation and electrophysiology, and the consequences of such changes, remain unclear. We evaluated the associations between heart rate acceleration capacity (AC) and deceleration capacity (DC), heart structural and functional changes, and cardiac death in 202 healthy controls and 100 DCM patients. The DC was lower and the AC was higher in DCM patients (both males and females). Multivariable, linear, logistic regression analyses revealed that in males, age was positively associated with AC in healthy controls (N = 85); the left atrial diameter (LAD) was positively and the left ventricular ejection fraction (LVEF) was negatively associated with AC in DCM patients (N = 65); age was negatively associated with DC in healthy controls (N = 85); and the LAD was negatively and the LVEF was positively associated with DC in DCM patients (N = 65). In females, only age was associated with either AC or DC in healthy controls (N = 117). Kaplan–Meier analysis revealed that male DCM patients with greater LADs (≥46.5 mm) (long-rank chi-squared value = 11.1, P = 0.001), an elevated AC (≥-4.75 ms) (log-rank chi-squared value = 6.8, P = 0.009), and a lower DC (≤4.72 ms) (log-rank chi-squared value = 9.1, P = 0.003) were at higher risk of cardiac death within 60 months of follow-up. In conclusion, in males, DCM significantly affected both the AC and DC; a higher AC or a lower DC increased the risk of cardiac death.

Autonomic imbalance in cardiac surgery: A potential determinant of the failure in remote ischemic preconditioning

Remote ischemic preconditioning (RIPC) is a cardioprotective strategy against myocardial damage by ischemia-reperfusion. Many in-vivo and ex-vivo animal researches have demonstrated that RIPC decreases significantly the ischemia-reperfusion myocardial damage, by up to 58% in isolated rat heart. Cardiac artery bypass graft surgery (CABG) is a clinical model of myocardial ischemia-reperfusion and a clinical potential application to RIPC. However, although RIPC has shown successful results in experimental studies, clinical trials on CABG have failed to demonstrate a benefit of RIPC in humans. Strikingly, the main proposed factors associated with this translational failure also impair the balance of the autonomic nervous system (ANS), which has shown to play a key role in RIPC cardioprotection in animal models. Comorbidities, chronic pharmacological treatment and anesthesic drugs - common conditions in CABG patients - cause an ANS imbalance through parasympathetic activity decrement. On the other hand, ANS and specially the parasympathetic branch are essentials to get cardioprotection by RIPC in animal models. Consequently, we propose that ANS imbalance in CABG patients would explain the failure of RIPC clinical trials. Whether our hypothesis is true, many patients could be benefited by RIPC: a cheap, simple and virtually broad-available cardioprotective maneuver. In this paper we discuss the evidence that support this hypothesis and its clinical implications.

Effect of carvedilol vs metoprolol succinate on mortality in heart failure with reduced ejection fraction

BACKGROUND

Beta blocker therapy is indicated in all patients with heart failure with reduced ejection fraction (HFrEF) as per current guidelines. The relative benefit of carvedilol to metoprolol succinate remains unknown. This study aimed to compare survival benefit of carvedilol to metoprolol succinate.

METHODS

The VA's databases were queried to identify 114,745 patients diagnosed with HFrEF from 2007 to 2015 who were prescribed carvedilol and metoprolol succinate. The study estimated the survival probability and hazard ratio by comparing the carvedilol and metoprolol patients using propensity score matching with replacement techniques on observed covariates. Sub-group analyses were performed separately for men, women, elderly, duration of therapy of more than 3 months, and diabetic patients.

RESULTS

A total of 43,941 metoprolol patients were matched with as many carvedilol patients. The adjusted hazard ratio of mortality for metoprolol succinate compared to carvedilol was 1.069 (95% CI: 1.046-1.092, P value: < .001). At six years, the survival probability was higher in the carvedilol group compared to the metoprolol succinate group (55.6% vs 49.2%, P value < .001). The sub-group analyses show that the results hold true separately for male, over or under 65 years old, therapy duration more than three months and non-diabetic patients.

CONCLUSION

Patients with HFrEF taking carvedilol had improved survival as compared to metoprolol succinate. The data supports the need for furthering testing to determine optimal choice of beta blockers in patients with heart failure with reduced ejection fraction.

Low heart deceleration capacity imply higher atrial fibrillation-free rate after ablation

How deceleration capacity (DC) and acceleration capacity (AC) of heart rate associated with atrial fibrillation (AF) and ablation is still not clear. The dynamic changes of AC, DC and conventional heart rate variability (HRV) parameters were characterized in 154 subjects before circumferential pulmonary veins isolation (CPVI) and three days, 3 months and 6 months after CPVI. The DCs of the recurrent group decreased significantly at each time point after CPVI; the DCs of the recurrence-free group before CPVI and three days, 3 months and 6 months after CPVI were 7.06 ± 1.77, 3.79 ± 1.18, 4.22 ± 1.96 and 3.97 ± 0.98 ms respectively, which also decreased significantly at each time point and were significantly lower than these of recurrent group. Conversely, the AC of recurrent and recurrence-free groups increased significantly at each time point after CPVI; the ACs of recurrence-fee group were significantly higher than these of recurrent group at each time point. No stable difference trend of HRV parameters was found between two groups. Further Kaplan–Meier analysis showed that DC < 4.8 ms or AC ≥ −5.1 ms displayed significant higher recurrence-free rates. In conclusion, high AC and low DC imply higher AF-free rate after ablation.

2017 Comprehensive Update of the Canadian Cardiovascular Society Guidelines for the Management of Heart Failure

Since the inception of the Canadian Cardiovascular Society heart failure (HF) guidelines in 2006, much has changed in the care for patients with HF. Over the past decade, the HF Guidelines Committee has published regular updates. However, because of the major changes that have occurred, the Guidelines Committee believes that a comprehensive reassessment of the HF management recommendations is presently needed, with a view to producing a full and complete set of updated guidelines. The primary and secondary Canadian Cardiovascular Society HF panel members as well as external experts have reviewed clinically relevant literature to provide guidance for the practicing clinician. The 2017 HF guidelines provide updated guidance on the diagnosis and management (self-care, pharmacologic, nonpharmacologic, device, and referral) that should aid in day-to-day decisions for caring for patients with HF. Among specific issues covered are risk scores, the differences in management for HF with preserved vs reduced ejection fraction, exercise and rehabilitation, implantable devices, revascularization, right ventricular dysfunction, anemia, and iron deficiency, cardiorenal syndrome, sleep apnea, cardiomyopathies, HF in pregnancy, cardio-oncology, and myocarditis. We devoted attention to strategies and treatments to prevent HF, to the organization of HF care, comorbidity management, as well as practical issues around the timing of referral and follow-up care. Recognition and treatment of advanced HF is another important aspect of this update, including how to select advanced therapies as well as end of life considerations. Finally, we acknowledge the remaining gaps in evidence that need to be filled by future research.

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.

Quality of life assessment in heart failure interventions: a 10-year (1996–2005) review

The increasing prevalence and poor prognosis associated with heart failure have prompted research to focus on improving quality of life (QoL) for heart failure patients. Research from 1996–2005 was systematically reviewed to identify randomized controlled trials that assessed QoL in heart failure. In 120 studies, 44 were medication trials; 19 surgical/procedural interventions; and 57 patient care/service delivery interventions. Studies were summarized in terms of aim, population, QoL measures used and QoL findings. Studies used 47 different measures of QoL-generic, health-related, condition-specific, domain-specific and utility measures. Most used a single QoL measure. In 87%, a condition specific QoL measure was used, with the Minnesota Living with Heart Failure Questionnaire being the favoured assessment tool. The range of QoL measures in use poses challenges for development of cumulative knowledge. Although comparability across studies is important, this must be informed by the responsiveness of the instrument selected. As carried out in other cardiac groups, comparative evaluations of instrument responsiveness are needed in heart failure. Eur J Cardiovasc Prev Rehabil 14:589-607 © 2007 The European Society of Cardiology

Pharmacodynamics ofβ-Blockers in Heart Failure: Lessons from the Carvedilol Or Metoprolol European Trial

Heart failure is a growing public health problem in the United States, and the approach to the treatment of heart failure has undergone a radical transformation in the past decade. The use of β-blocker therapy in heart failure patients is now widely recommended, based on evidence from large-scale clinical trials demonstrating that bisoprolol, carvedilol, and extended-release metoprolol succinate significantly reduce morbidity and mortality in patients with heart failure. Although these agents appear to provide similar benefits, the question remains whether pharmacologic differences among them could translate to differences in clinical outcomes. The Carvedilol Or Metoprolol European Trial (COMET) compared nonselective blockade of the β1-/β2-/α1-adrenergic receptors with carvedilol versus selective β1-blockade with immediate-release metoprolol tartrate in patients with chronic heart failure. The trial found that carvedilol significantly reduced all-cause mortality compared with immediate-release metoprolol tartrate, although there were no differences in hospitalizations. Herein we review the pharmacokinetics and pharmacodynamics of metoprolol and carvedilol. In doing so, several issues regarding the design of COMET are identified that could alter the interpretation of the results of this trial. These include the choice of dose and dosage regimen of immediate-release metoprolol tartrate, a dosage form that has never been shown to reduce mortality in patients with heart failure. Additional studies are needed to fully understand whether there are any advantages of selective versus nonselective adrenergic blockade and whether there are any clinically meaningful differences in effectiveness between β-blockers with proven benefit in the management of chronic heart failure. The results of COMET demonstrate that all β-blockers and dosage forms are not interchangeable when prescribed for heart failure. Clinicians should choose only those agents (and dosage forms) that have been proven to reduce mortality in this patient population.

Deceleration and acceleration capacities of heart rate associated with heart failure with high discriminating performance

Accurate measurements of autonomic nerve regulation in heart failure (HF) were unresolved. The discriminating performance of deceleration and acceleration capacities of heart rate in HF was evaluated in 130 HF patients and 212 controls. Acceleration capacity and deceleration capacity were independent risk factors for HF in males, evaluated by multiple logistic regression analysis, with odds ratios (ORs) of 5.94 and 0.13, respectively. Acceleration capacity was also an independent risk factor for HF in females, with an OR of 8.58. Deceleration capacity was the best cardiac electrophysiological index to classify HF in males, with an area under the receiver operating characteristic curve (AUC) of 0.88. Deceleration capacity was the best classification factor of HF in females with an AUC of 0.97, significantly higher than even left ventricular ejection fraction (LVEF). Acceleration capacity also showed high performance in classifying HF in males (0.84) and females (0.92). The cut-off values of deceleration capacity for HF classification in males and females were 4.55 ms and 4.85 ms, respectively. The cut-off values of acceleration capacity for HF classification in males and females were −6.15 ms and −5.75 ms, respectively. Our study illustrates the role of acceleration and deceleration capacity measurements in the neuro-pathophysiology of HF.

Drug therapy for heart failure in older patients-what do they want?

Chronic heart failure (CHF) is predominantly seen in older patients, and therefore real life medicine often requires the extrapolation of findings from trials conducted in much younger populations. Prescribing patterns and potential benefits in the elderly are heavily influenced by polypharmacy and co-morbid pathologies. Increasing longevity may become less relevant in the frail elderly, whereas improving quality of life (QoL) often becomes priority; the onus being on improving wellbeing, maintaining independence for longer, and delaying institutionalisation. Specific studies evaluating elderly patients with CHF are lacking and little is known regarding the tolerability and side-effect profile of evidence based drug therapies in this population. There has been recent interest on the impact of heart rate in patients with symptomatic CHF. Ivabradine, with selective heart rate lowering capabilities, is of benefit in patients with CHF and left ventricular systolic dysfunction in sinus rhythm, resulting in reduction of heart failure hospitalisation and cardiovascular death. This manuscript will focus on CHF and the older patient and will discuss the impact of heart rate, drug therapies and tolerability. It will also highlight the unmet need for specific studies that focus on patient-centred study end points rather than mortality targets that characterise most therapeutic trials. An on-going study evaluating the impact of ivabradine on QoL that presents a unique opportunity to evaluate the tolerability and impact of an established therapy on a wide range of real life, older patients with CHF will be discussed.

Depressive symptoms and the relationship of inflammation to physical signs and symptoms in heart failure patients

BACKGROUND

Depressive symptoms in patients with heart failure can affect the relationship between physical signs and symptoms and inflammation.

OBJECTIVE

To examine the relationship between soluble tumor necrosis factor receptor I and physical signs and symptoms and the effects of depressive symptoms on this relationship in patients with heart failure.

METHODS

Data on physical signs and symptoms (Symptom Status Questionnaire-Heart Failure), depressive symptoms (Beck Depression Inventory-II), and levels of the receptor (blood samples) were collected from 145 patients with heart failure. Data on the receptor were square root transformed to achieve normality. Patients were divided into 2 groups according to their scores for depressive symptoms (nondepressed <14 and depressed ≥14). Hierarchical multiple regression was used to analyze the data.

RESULTS

In the total sample, with controls for covariates, higher levels of the receptor were significantly related to more severe physical signs and symptoms (F = 7.915; P < .001). In subgroup analyses, with controls for covariates, levels of the receptor were significantly related to physical signs and symptoms only in the patients without depression (F = 3.174; P = .005).

CONCLUSION

Both depressive symptoms and inflammation should be considered along with physical signs and symptoms in patients with heart failure. Further studies are needed to determine the effects of improvement in inflammation on improvement in physical signs and symptoms, with consideration given to the effects of depressive symptoms.

Carvedilol: use in chronic heart failure

Carvedilol is a beta-adrenergic antagonist with vasodilatory properties (alpha1-antagonism), which has been extensively evaluated in the treatment of patients with heart failure. In patients with chronic heart failure carvedilol improves left-ventricular (LV) ejection fraction over 6 to 12 months of treatment, and attenuates LV remodelling. Large-scale randomised, placebo controlled trials involving more than 4000 patients with chronic heart failure have demonstrated that carvedilol improves survival and reduces hospitalizations. Comparative studies with metoprolol in patients with heart failure have suggested that carvedilol may be associated with greater survival benefit although differences in the preparation of metoprolol have left uncertainty in this area. Carvedilol has a high safety profile and the clinical benefits appear maintained across a wide range of patients with comorbidities such as diabetes and renal failure. Carvedilol has also been shown to attenuate LV remodeling and improve clinical outcomes in patients with LV dysfunction and/or heart failure following acute myocardial infarction. As a result of these data, carvedilol is recommended for treatment of patients with heart failure in heart-failure guidelines. This evidence-based treatment should be widely implemented to ensure that patients with heart failure receive appropriate medical therapy.

Effect of race on left ventricular ejection fraction decline after initial improvement with beta blockers in patients with non-ischemic cardiomyopathy: a retrospective analysis

Background

Although beta blockers (BBs) are established therapy in heart failure, some patients whose left ventricular ejection fraction (LVEF) initially increases on BB therapy experience a subsequent LVEF decline. This study aimed to evaluate the proportion of patients with non-ischemic cardiomyopathy (NICM) whose LVEF declines while on BB therapy and determine important predictors of LVEF decline.

Methods

A retrospective analysis of 238 patients receiving a BB (carvedilol, metoprolol succinate, or tartrate), with an ejection fraction of ≤40 % and NICM, whose LVEF initially rose ≥5 % after 1 year of BB therapy, was conducted. Post-response LVEF decline ≥5 % to a final LVEF of ≤35 % was evaluated within 4 years of BB initiation.

Results

In our study, we had 52 Caucasians (22 %), 78 Hispanics (33 %), and 108 African Americans (45 %). Overall, 32 patients (13.44 %) had post-response LVEF decline. The nadir LVEF of patients with post-response LVEF decline was 25 % (interquartile range 20–27). Compared with others, Hispanics had lower nadir LVEF (22 %, p < 0.001). Important predictors of LVEF decline were Hispanic race (odds ratio (OR) 6.094, p < 0.001), New York Heart Association (NYHA) class (OR 2.287, p < 0.05), baseline LVEF (OR 1.075, p < 0.05), and age (OR 0.933, p < 0.001).

Conclusion

A significant proportion (13.44 %) of NICM patients with LVEF increase over 1 year of BB therapy experienced subsequent LVEF decline. Race, NYHA class, baseline LVEF, and age are important predictors of this decline.

Effects of β-adrenergic blockade on left ventricular remodeling among Hispanics and African Americans with chronic heart failure

BACKGROUND

Although β-blockers (BBs) have been shown to improve cardiac function, there is individual and ethnic variation in BB clinical response. We examined the effects of BBs on left ventricular remodeling among African Americans (AAs), Hispanics, and Caucasians with systolic heart failure.

HYPOTHESIS

There is ethnic variability in the effects of BBs on cardiac remodeling.

METHODS

There were 185 AAs, 159 Hispanics, and 74 Caucasians selected with ejection fraction ≤ 40% from any etiology. Change in left ventricular ejection fraction (LVEF), left ventricular end-diastolic dimensions (LVEDD), and degree of mitral regurgitation (MR) in response to 1 year of BBs was evaluated retrospectively.

RESULTS

Overall, there was a significant improvement in LVEF, LVEDD, and degree of MR in AAs and Caucasians after 1 year of BBs (P < 0.001 vs baseline). Compared with other races, Hispanics (%) had no significant improvement in LVEDD and degree of MR, and had fewer patients with reverse remodeling: LVEF (42.77%), LVEDD (5.03%), and MR (16.35%). In multivariable analysis, Hispanic and AA race were important predictors of LVEF and LVEDD (P < 0.01) but not MR response.

CONCLUSIONS

Although most patients demonstrated improvement of LVEF, there seems to be ethnic variability in the effects of BBs on cardiac remodeling. Degree of MR and LVEDD failed to show improvement among Hispanics.

Comorbid Heart Failure and Renal Impairment: Epidemiology and Management

Heart failure mortality is significantly increased in patients with baseline renal impairment and those with underlying heart failure who subsequently develop renal dysfunction. This accelerated progression occurs independent of the cause or grade of renal dysfunction and baseline risk factors. Recent large prospective databases have highlighted the depth of the current problem, while longitudinal population studies support an increasing disease burden. We have extensively reviewed the epidemiological and therapeutic data among these patients. The evidence points to a progression of heart failure early in renal impairment, even in the albuminuric stage. The data also support poor prescription of prognostic therapies. As renal function is the most important prognostic factor in heart failure, it is important to establish the current understanding of the disease burden and the therapeutic implications.

What is the methodological and reporting quality of health related quality of life in chronic heart failure clinical trials?

BACKGROUND

Although the number of clinical trials assessing health related quality of life (HRQoL) in chronic heart failure (CHF) has increased exponentially over the last decade, little is known about the quality of reporting. The purpose of this review was to assess the methodological and reporting rigor of HRQoL in RCTs of pharmacological therapy in CHF.

METHODS

The electronic data bases, Medline and EMBASE were searched from 1990 to 2009 using the key search terms 'heart failure' combined with 'quality of life', 'pharmacological therapy' and 'randomized controlled trials'. A total of 136 articles were identified and evaluated according to the "Minimum Standard Checklist (MSC) for Evaluating HRQoL Outcomes".

RESULTS

According to the MSC criteria, 26 (19.1%) studies were considered 'very limited', 91 (66.9%) were 'limited' and only 19 (14.0%) studies were considered to be of a 'probably robust' in terms of methodological and reporting rigor. In fact, the quality of HRQoL reporting has not improved over time.

CONCLUSION

HRQoL is a critical consideration in CHF management, yet reporting is highly variable. There is a need to develop a standardized method for measuring and reporting HRQoL measures in clinical trials to aid in the interpretation and application of findings.

Contemporary medical management of systolic heart failure

Pharmacological therapy of systolic left ventricular dysfunction has evolved over the past 3 decades. Current therapy is focused primarily on the regulation of the renin-angiotensin-aldosterone axis and sympathetic nervous system. Additional targets of pharmacotherapy include vasoconstriction, impaired nitric oxide metabolism, inflammation and improving myocardial function. As therapies in chronic systolic heart failure have evolved beyond diuretics and digoxin, so too has mortality improved. Future directions in the management of heart failure include cell-based and genetic therapy, and further refinement of current therapy through genetics.

Albumin levels predict survival in patients with heart failure and preserved ejection fraction

AIMS

Low serum albumin is common in patients with systolic heart failure and is associated with increased mortality. However, the relationship between albumin and outcome in patients with heart failure and preserved ejection fraction (HFPEF) is not known. The aim of this study was to investigate the effect of serum albumin level on survival in patients with HFPEF.

METHODS AND RESULTS

We studied 576 consecutive HFPEF patients (left ventricular ejection fraction ≥50%) admitted to our hospital from 2006 to 2009. Standard demographics, transthoracic echocardiography, and routine blood testing including albumin levels were obtained shortly after admission. Outcome was assessed at 1 year after admission. Hypoalbuminaemia (≤34 g/L) was detected in 160 (28%) at admission; and all patients were then divided into hypoalbuminaemia and non-hypoalbuminaemia groups. In the hypoalbuminaemia group, the prevalence of chronic renal failure history, serum creatinine, and urea nitrogen levels were higher when compared with those without hypoalbuminaemia (all P < 0.05). Kaplan-Meier analysis showed that patients with hypoalbuminaemia had a significantly lower survival rate (53% vs. 84%, log-rank χ(2) = 53.3, P < 0.001) and a higher rate of cardiovascular death (21.8% vs. 8.9%, log-rank χ(2) = 19.7, P < 0.001) when compared with those without hypoalbuminaemia. Cox regression further revealed that hypoalbuminaemia, a history of cerebrovascular disease, and older age were the most powerful independent predictors of all-cause mortality in HFPEF patients at 1 year.

CONCLUSIONS

Hypoalbuminaemia is common in HFPEF patients and is associated with increased risk of death. Renal dysfunction may be the main pathophysiological mechanism underlying hypoalbuminaemia in HFPEF patients.

The prognostic value of non-linear analysis of heart rate variability in patients with congestive heart failure--a pilot study of multiscale entropy

AIMS

The influences of nonstationarity and nonlinearity on heart rate time series can be mathematically qualified or quantified by multiscale entropy (MSE). The aim of this study is to investigate the prognostic value of parameters derived from MSE in the patients with systolic heart failure.

METHODS AND RESULTS

Patients with systolic heart failure were enrolled in this study. One month after clinical condition being stable, 24-hour Holter electrocardiogram was recording. MSE as well as other standard parameters of heart rate variability (HRV) and detrended fluctuation analysis (DFA) were assessed. A total of 40 heart failure patients with a mea age of 56±16 years were enrolled and followed-up for 684±441 days. There were 25 patients receiving β-blockers treatment. During follow-up period, 6 patients died or received urgent heart transplantation. The short-term exponent of DFA and the slope of MSE between scale 1 to 5 were significantly different between patients with or without β-blockers (p = 0.014 and p = 0.028). Only the area under the MSE curve for scale 6 to 20 (Area(6-20)) showed the strongest predictive power between survival (n = 34) and mortality (n = 6) groups among all the parameters. The value of Area(6-20)21.2 served as a significant predictor of mortality or heart transplant (p = 0.0014).

CONCLUSION

The area under the MSE curve for scale 6 to 20 is not relevant to β-blockers and could further warrant independent risk stratification for the prognosis of CHF patients.

The role of beta-blockers in the treatment of chronic heart failure

The introduction of beta-blockers in the treatment of cardiovascular diseases was a milestone and one of the most important contributions to clinical medicine in the 20th century. For many years, beta-blockers were considered contraindicated in patients with chronic heart failure owing to the negative inotropic action of these substances. With increasing evidence of neurohormonal activation in heart failure patients, there was a focus on the potential role of beta-blockers in the treatment of chronic heart failure. Several large randomized placebo- controlled clinical trials have shown favorable effects of beta-blockers on mortality and morbidity in heart failure patients with impaired systolic function. Beneficial effects in patients with preserved left ventricular systolic function are less clear. A reduction in heart rate is one of several mechanisms by which beta-blockers exert beneficial effects in chronic heart failure. In this article we present results from major clinical trials examining beta-blocker treatment in chronic heart failure patients and discuss heart rate as a therapeutic target in these patients.

The 2010 Canadian Cardiovascular Society guidelines for the diagnosis and management of heart failure update: Heart failure in ethnic minority populations, heart failure and pregnancy, disease management, and quality improvement/assurance programs

Since 2006, the Canadian Cardiovascular Society heart failure (HF) guidelines have published annual focused updates for cardiovascular care providers. The 2010 Canadian Cardiovascular Society HF guidelines update focuses on an increasing issue in the western world - HF in ethnic minorities - and in an uncommon but important setting - the pregnant patient. Additionally, due to increasing attention recently given to the assessment of how care is delivered and measured, two critically important topics - disease management programs in HF and quality assurance - have been included. Both of these topics were written from a clinical perspective. It is hoped that the present update will become a useful tool for health care providers and planners in the ongoing evolution of care for HF patients in Canada.

Role of β-blocker therapy in pediatric heart failure

Heart failure is becoming an increasingly common and significant problem in the field of pediatric cardiology. The numerous types of cardiomyopathies, and more recently, long-term survival of patients with congenital heart disease, have added to a growing patient population. Over the last several decades, our knowledge base regarding mechanisms of disease and therapeutic intervention in adult patients with heart failure has drastically changed. The most recent and important breakthrough in the pharmacologic treatment of heart failure has been the particular role of β-blocker therapy. This medication has led to significant improvements in survival and symptoms in adults, with less convincing findings in limited studies in pediatrics. The ability to study the benefits of this therapy in patients has been challenging owing to the heterogeneity of the patient population and lack of large sample sizes. However, as we investigate the mechanisms behind the disease process, the differences that exist between disease conditions and ages, and the significant alterations that may exist at the molecular and genetic level, our understanding of β-blocker therapy in pediatric heart failure will improve, and ultimately may lead to patient-specific therapy.

Pediatric heart failure therapy with beta-adrenoceptor antagonists

Management of chronic heart failure in pediatrics has been altered by the adult literature showing improvements in mortality and hospitalization rates with the use of beta-adrenoceptor antagonists (beta-blockers) for routine therapy of all classes of ischemic and non-ischemic heart failure. Many pediatric heart failure specialists have incorporated these agents into their routine management of pediatric heart failure related to dilated cardiomyopathy or ventricular dysfunction in association with congenital heart disease. Retrospective and small prospective case series have shown encouraging improvements in cardiac function and symptoms, but interpretation has been complicated by the high rate of spontaneous recovery in pediatric patients. A recently completed pediatric double-blind, randomized, placebo-controlled clinical trial showed no difference between placebo and two doses of carvedilol over a 6-month period of follow-up, with significant improvement of all three groups over the course of evaluation. Experience with adults has suggested that only certain beta-blockers, including carvedilol, bisoprolol, nebivolol, and metoprolol succinate, should be used in the treatment of heart failure and that patients with high-grade heart failure may derive the most benefit. Other studies surmise that early or prophylactic use of these medications may alter the risk of disease progression in some high-risk subsets, such as patients receiving anthracyclines or those with muscular dystrophy. This article reviews these topics using experience as well as data from all the recent pediatric studies on the use of beta-blockers to treat congestive heart failure, especially when related to systolic ventricular dysfunction.

Analysis of randomized controlled trials on the effect of magnitude of heart rate reduction on clinical outcomes in patients with systolic chronic heart failure receiving beta-blockers

Beta blockers improve cardiac function and prolong survival in patients with systolic chronic heart failure (CHF). However, the exact mechanisms underlying these benefits are uncertain. Specifically, it is unclear whether a close relation exists between heart rate (HR) reduction and clinical outcomes with these agents. This hypothesis was therefore tested within randomized controlled trials of beta blockers in systolic CHF. Left ventricular ejection fraction (LVEF) and HR values at baseline and study end were obtained from available beta-blocker randomized clinical trials. The relation between change in HR and all-cause mortality as well as the LVEF was determined using regression analysis. Thirty-five trials, which included 22,926 patients with a mean follow-up duration of 9.6 months, were analyzed for all-cause mortality, the LVEF, and HR. There was a close relation between all-cause annualized mortality rate and HR (adjusted R2 = 0.51, p = 0.004). A strong correlation between change in HR and change in LVEF (adjusted R2 = 0.48, p = 0.000) was also observed. When only trials with >100 patients were included, an even tighter correlation was seen (adjusted R2 = 0.60, p = 0.0004). In conclusion, these analyses indicate that a major contributor to the clinical benefits of beta-blocker therapy in systolic CHF may be the HR-lowering effect of these agents. Therefore, the magnitude of HR reduction may be more important than the achievement of target dose in beta-blocker treatment of systolic CHF.

Comparative Dose Titration Responses to the Introduction of Bisoprolol or Carvedilol in Stable Chronic Systolic Heart Failure

INTRODUCTION

Several beta blocking drugs (BB) reduce mortality in systolic heart failure (LVSD). We have compared the initial response to introduction of carvedilol and bisoprolol during the standard dose titration protocols for each drug.

METHODS

Approximately 31 unselected patients with stable LVSD were randomised to either carvedilol or bisoprolol measuring blood pressure, heart rate responses and both time and frequency domain heart rate variability (HRV).

RESULTS

One subject died; five withdrew due to intolerable BB related side effects. Carvedilol (n = 13) and bisoprolol (n = 12) attained similar maximal heart rate reduction and induced comparable falls in systolic and diastolic blood pressure. Higher carvedilol doses were associated with lower blood pressure compared to baseline. Individual time domain HRV indices remained unchanged over the initial titration period. Significant increases in triangular Index (TI) were seen with both BB. Carvedilol demonstrated greater (but non-significant) rises in TI compared to Bisoprolol.

CONCLUSIONS

In this study we found similar degrees and rate of onset of HR, HRV and BP response to both carvedilol and bisoprolol in treated LVSD patients. Carvedilol appears to show superior HRV rises compared to bisoprolol during initial titration. Any significant increases in HRV attributable to carvedilol compared to bisoprolol may emerge over a longer treatment interval in LVSD.

Beta-Blocker Treatment of Chronic Heart Failure: Comparison of Carvedilol and Metoprolol

Beta blockers have been shown to prolong survival in chronic heart failure. It is currently a matter of debate whether any beta blocker is superior to the other in terms of improving symptoms, left ventricular function, or prognosis. A number of comparative studies have been performed with metoprolol, a beta1-selective second-generation beta blocker, and carvedilol, a nonselective and vasodilatative third-generation beta blocker. This review will focus on the different pharmacological profiles of carvedilol and metoprolol as well as on the clinical consequences derived from these differences. The results indicate that in some studies carvedilol is superior to metoprolol in improving left ventricular ejection fraction. However, because there is no conclusive evidence that carvedilol is superior to metoprolol in terms of prognosis, it is not justified to substitute metoprolol with carvedilol. Comparative data on mortality reduction are not available before termination of the Carvedilol or Metoprolol European Trial. Nevertheless, the different effects of both beta blockers on the beta-adrenergic system have an impact on tolerability and beta-adrenergic responsiveness and thus exercise tolerance in heart-failure patients.

Early Initiation of β Blockade in Heart Failure: Issues and Evidence

Despite clinical trials demonstrating that inhibitors of the renin-angiotensin and sympathetic nervous systems can reduce the mortality and morbidity risk associated with heart failure, these drugs have remained underutilized in general clinical practice. In particular, many patients with heart failure due to left ventricular systolic dysfunction fail to receive beta blockers, although this class of drugs, as well as other antihypertensive agents such as angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, are recommended as part of routine heart failure therapy by national expert consensus guidelines. In-hospital initiation of beta-blocker therapy may improve long-term utilization by physicians and compliance by patients through obviating many of the misperceived dangers associated with beta blockade. The following review of the clinical trial data from the Randomized Evaluation of Strategies for Left Ventricular Dysfunction (RESOLVD) trial, the Metoprolol Controlled-Release Randomized Intervention Trial in Heart Failure (MERIT-HF), the Cardiac Insufficiency Bisoprolol Study II (CIBIS-II), the Carvedilol Prospective Randomized Cumulative Survival (COPERNICUS) trial, and the Initiation Management Predischarge Process for Assessment of Carvedilol Therapy for Heart Failure (IMPACT-HF) trial on the efficacy, safety, and tolerability of beta blockers indicates that early initiation can be safely achieved and can improve patient outcomes.

Chronic treatment with carvedilol improves Ca(2+)-dependent ATP consumption in triton X-skinned fiber preparations of human myocardium

Evidence is given that beta-blocker treatment differentially influences gene expression and up-regulation of beta(1)-adrenoceptors in human myocardium. Here, we investigate whether long-term treatment with carvedilol or metoprolol may functionally alter myofibrillar function in end-stage human heart failure. Investigations were performed in Triton X (1%, 4 degrees C, 20 h)-skinned fiber preparations of explanted hearts from patients undergoing heart transplantation due to idiopathic dilative cardiomyopathy. Five patients were not on beta-adrenoceptor blocker treatment (DCM_NBB), and 5 patients received either carvedilol (DCM_CAR) or metoprolol (DCM_MET). Nonfailing (NF) donor hearts (n = 5), which could not be transplanted due to technical reasons, were investigated for comparison. Ca(2+)-dependent tension (DT) development and actomyosin-ATPase activity (MYO) were measured and tension-dependent ATP consumption was calculated by the ratio of DT and MYO ("tension cost"). In addition, we measured the phosphorylation of troponin I (TNI) by back phosphorylation. Maximal DT and TNI phosphorylation were reduced, with myofibrillar Ca(2+) sensitivity of DT and MYO as well as tension cost being increased in DCM_NBB compared with NF. Metoprolol treatment restored TNI phosphorylation, decreased Ca(2+) sensitivity of tension development and of myosin-ATPase activity, but did not alter the tension-dependent ATP consumption. Carvedilol treatment improved maximal DT and significantly decreased tension-dependent ATP consumption without altering myofibrillar Ca(2+) sensitivity. TNI dephosphorylation was increased in patients treated with carvedilol. In conclusion, chronic beta-adrenoceptor blockade functionally alters myofibrillar function. The more economic cross-bridge cycling in patients under carvedilol treatment may provide an explanation for the efficacy of carvedilol in the treatment of chronic heart failure patients.

Carvedilol Protects Better Against Vascular Events Than Metoprolol in Heart Failure

OBJECTIVES

We explored whether vascular protection by carvedilol could contribute to its superior effects in the treatment of heart failure (HF) compared with metoprolol tartrate in the COMET (Carvedilol Or Metoprolol European Trial) study.

BACKGROUND

Full adrenergic blockade by carvedilol and additional (e.g., antioxidative) properties may lead to vascular protection relative to beta-1 blockade alone, and contribute to its efficacy in HF treatment.

METHODS

Three thousand twenty-nine patients with HF due to ischemic (51%) or idiopathic cardiomyopathy (44%) were randomized double-blind to carvedilol (n = 1,511) or metoprolol (n = 1,518) and followed for 58 months. Vascular end points were cardiovascular death, stroke, stroke death, myocardial infarction (MI), and unstable angina.

RESULTS

The effect of carvedilol on cardiovascular death improved consistently in subgroups with prespecified baseline variables. Myocardial infarctions were reported in 69 carvedilol and 94 metoprolol patients (hazard ratio [HR] 0.71, 95% confidence interval [CI] 0.52 to 0.97, p = 0.03). Cardiovascular death or nonfatal MI combined were reduced by 19% in carvedilol (HR 0.81, 95% CI 0.72 to 0.92, p = 0.0009 vs. metoprolol). Unstable angina was reported as an adverse event in 56 carvedilol and in 77 metoprolol patients (HR 0.71, 95% CI 0.501 to 0.998, p = 0.049). A stroke occurred in 65 carvedilol and 80 metoprolol patients (HR 0.79, 95% CI 0.57 to 1.10). Stroke or MI combined occurred in 130 carvedilol and 168 metoprolol patients (HR 0.75, 95% CI 0.60 to 0.95, p = 0.015), and fatal MI or fatal stroke occurred in 34 carvedilol and in 72 metoprolol patients (HR 0.46, 95% CI 0.31 to 0.69, p = 0.0002). Death after a nonfatal MI or stroke occurred in 61 of 124 carvedilol and in 106 of 160 metoprolol patients (HR 0.66, 95% CI 0.48 to 0.90, p = 0.0086).

CONCLUSIONS

Carvedilol improves vascular outcomes better than metoprolol. These results suggest a ubiquitous protective effect of carvedilol against major vascular events.

Beneficial effects of carvedilol as a concomitant therapy to angiotensin-converting enzyme inhibitor in patients with ischemic left ventricular systolic dysfunction

Studies are scant on the effects of short-term carvedilol treatment as an adjuvant to angiotensin-converting enzyme (ACE) inhibitor in patients with left ventricular (LV) systolic dysfunction. The objective of this study was to find the effects of short-term treatment of carvedilol on patients with ischemic LV systolic dysfunction (defined as LV ejection fraction (LVEF) ≤30% on 2D echocardiography) undergoing coronary artery bypass surgery (CABG). There were 74 patients that received ACE inhibitor without any β-blocker (control) and 67 patients that received carvedilol in addition to ACE inhibitor following CABG (carvedilol group). After 1 month of drug administration following CABG, the control group was found to have significantly greater percent improvement in LVEF (29.1% ± 5.39%) as compared with the carvedilol group (15.3% ± 4.89%). However, after 3 and 6 months, LVEF levels were found to be significantly greater in the carvedilol group as compared with the control group. Further, at 6 months of drug administration, LV end systolic diameter was significantly less in the carvedilol group (39.11 ± 1.10 mm) as compared with the control group (43.49 ± 1.39 mm). Thus, carvedilol produces beneficial effect on short-term administration in terms of LV contractility when given along with ACE inhibtior as compared with ACE inhibitor therapy alone.

Effects of carvedilol on heart rate dynamics in patients with congestive heart failure

BACKGROUND

Patients with congestive heart failure (CHF) have alterations in the traditional and nonlinear indices of heart rate (HR) dynamics, which have been associated with an increased risk of mortality. This study was designed to test the effects of carvedilol, a nonselective beta-blocker with alpha-1 blocking properties, on HR dynamics in patients with CHF.

METHODS

We studied 15 patients with CHF secondary to ischemic or idiopathic cardiomyopathy who met the following inclusion criteria: NYHA functional class II-III, optimal conventional medical therapy, normal sinus rhythm, left ventricular ejection fraction (LVEF) of < 40%, and resting systolic blood pressure greater than 100 mmHg. The 6-minute corridor walk test, estimation of LVEF, and 24-hour Holter recording were performed at baseline and after 12 weeks of therapy with carvedilol. Traditional time and frequency domain measures and short-term fractal scaling exponent of HR dynamics were analyzed.

RESULTS

After 12 weeks of therapy with carvedilol, the mean LVEF improved significantly (from 0.27 +/- 0.08 to 0.38 +/- 0.08, P < 0.001). The average HR decreased significantly (from 86 +/- 11 to 70 +/- 8 beats/min, P < 0.001). The mean distance traveled in the 6-minute walk test increased significantly (from 177 +/- 44 to 273 +/- 55 m, P < 0.01). The frequency-domain indices (HF and LF), the time domain indices (rMSSD and PNN5 ), and the short-term fractal scaling exponent increased significantly. The scaling exponent increased particularly among the patients with the lowest initial values (< 1.0), and the change in the fractal scaling exponent correlated with the change in ejection fraction (r = 0.63, P < 0.01).

CONCLUSION

Carvedilol improves time and frequency domain indices of HR variability and corrects the altered scaling properties of HR dynamics in patients with CHF. It also improves LVEF and functional capacity. These specific changes in HR behavior caused by carvedilol treatment may reflect the normalization of impaired cardiovascular neural regulation of patients with CHF.