Aggressive beta-blocker titration in stabilized acute heart failure patients with low left ventricular ejection fraction

Objectives

A beta-blocker should be initiated in patients with stable acute heart failure (AHF). Beta-blocker titration should be conducted after a two-week interval. The benefits of aggressive beta-blocker titration are still unclear. This study aimed to investigate the aggressive beta-blocker titration outcomes in stabilized AHF patients with low left ventricular ejection fraction (LVEF).

Methods

In this retrospective cohort study, we analysed clinical data from the heart failure (HF) registry. AHF Patients with LVEF <40% were divided into aggressive and guideline-directed beta-blocker titration groups. The composite of worsening HF, ventricular arrhythmia, and mortality during hospitalization were defined as the primary outcomes. We considered secondary outcomes as the components of primary outcomes and also the outcomes during a 90-day follow-up after hospital discharge, including HF readmission and mortality.

Results

The primary outcomes between both groups were not significantly different (12.3% vs 24.4%; relative risk [RR] 0.51; 95% confidence interval [CI] 0.25–1.01; p = 0.055). However, the aggressive beta-blocker titration reduced ventricular arrhythmia events (5.7% vs 17.8%; RR 0.32; 95% CI 0.12–0.84; p = 0.016). The 90-day HF readmission rate (2.6% vs 7.5%; RR 0.35; 95% CI 0.07–1.66; p = 0.179) and mortality rate (4.3% vs 5%; RR 0.87; 95% CI 0.18–4.31; p = 1.000) between both groups were not found to be significantly different.

Conclusion

Compared to the guideline-directed beta-blocker titration, the aggressive beta-blocker titration was safe in low LVEF AHF patients who have been previously stabilized. Additionally, aggressive beta-blocker titration effectively reduced ventricular arrhythmia events.

Treatment optimization of beta-blockers in chronic heart failure therapy

Although evidence based guidelines recommend optimal use of beta blockers in all patients with chronic heart failure unless contraindicated, they are often underutilized and/or prescribed below the recommended dosage in the majority of patients with heart failure. To our knowledge, however, the optimal use of beta-blockers in chronic heart failure is not investigated in Ethiopia. Therefore, the aim of our study was to investigate the utilization and optimization of beta blockers in the management of patients with chronic heart failure in Ethiopia. A prospective observational study was conducted among ambulatory patients with chronic heart failure in Ethiopia. We included adult patients with a diagnosis of heart failure with a baseline left ventricular ejection fraction < 40% who had been on follow-up for at least 6 months. Patients were recruited into the study during their appointment for medication refilling using simple random sampling technique. All patients were followed for at least 6 months to determine the optimal use of beta blockers. The optimal use of beta blockers was determined according to evidence based guidelines. After explaining the purpose of the study, we obtained written informed consent from all participants. Data were collected through patient interview and review of patients' medical records. Binary logistic regression analysis was performed to identify factors associated with utilization of beta blockers. A total of 288 patients were included in the study. Out of the total, 67% of the patients were receiving beta blockers. Among the patients who received beta blockers, 34.2% were taking guideline recommended beta blockers while 65.8% were taking atenolol, which is not guideline recommended beta blocker. Among the patients who received guideline recommended beta blockers, only 3% were taking optimal dose. Prior hospitalization [Adjusted Odds ratio (AOR) 0.38, 95% confidence interval (CI) 0.19-0.76], dose of furosemide > 40 mg (AOR 0.39, 95% CI 0.20-0.76), ischemic heart disease (AOR 3.27, 95% CI 1.66-6.45), atrial fibrillation (AOR 4.41, 95% CI 1.38-14.13) were significantly associated with the utilization of beta-blockers. Despite proven benefit, beta blockers were not optimally used in most of the participants in this study. The presence of ischemic heart disease and atrial fibrillation were positively associated with the utilization of beta blockers while hospitalization and higher diuretic dose were negatively associated with the utilization of beta blockers. Clinicians should attempt to use evidence based beta blockers at guideline recommended target doses that have been shown to have morbidity and mortality benefit in chronic heart failure. Moreover, more effort needs to be done to minimize the potentially modifiable risk factors for underutilization of beta blocker in chronic heart failure therapy.

Improving exercise capacity and quality of life using non-invasive heart failure treatments: evidence from clinical trials

Endpoints of large-scale trials in chronic heart failure have mostly been defined to evaluate treatments with regard to hospitalizations and mortality. However, patients with heart failure are also affected by very severe reductions in exercise capacity and quality of life. We aimed to evaluate the effects of heart failure treatments on these endpoints using available evidence from randomized trials. Interventions with evidence for improvements in exercise capacity include physical exercise, intravenous iron supplementation in patients with iron deficiency, and - with less certainty - testosterone in highly selected patients. Erythropoiesis-stimulating agents have been reported to improve exercise capacity in anaemic patients with heart failure. Sinus rhythm may have some advantage when compared with atrial fibrillation, particularly in patients undergoing pulmonary vein isolation. Studies assessing treatments for heart failure co-morbidities such as sleep-disordered breathing, diabetes mellitus, chronic kidney disease and depression have reported improvements of exercise capacity and quality of life; however, the available data are limited and not always consistent. The available evidence for positive effects of pharmacologic interventions using angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, and mineralocorticoid receptor antagonists on exercise capacity and quality of life is limited. Studies with ivabradine and with sacubitril/valsartan suggest beneficial effects at improving quality of life; however, the evidence base is limited in particular for exercise capacity. The data for heart failure with preserved ejection fraction are even less positive, only sacubitril/valsartan and spironolactone have shown some effectiveness at improving quality of life. In conclusion, the evidence for state-of-the-art heart failure treatments with regard to exercise capacity and quality of life is limited and appears not robust enough to permit recommendations for heart failure. The treatment of co-morbidities may be important for these patient-related outcomes. Additional studies on functional capacity and quality of life in heart failure are required.

Restriction of Pharmacoepidemiologic Cohorts to Initiators of Medications in Unrelated Preventive Drug Classes to Reduce Confounding by Frailty in Older Adults

Nonexperimental studies of the effectiveness of seasonal influenza vaccine in older adults have found 40%-60% reductions in all-cause mortality associated with vaccination, potentially due to confounding by frailty. We restricted our cohort to initiators of medications in preventive drug classes (statins, antiglaucoma drugs, and β blockers) as an approach to reducing confounding by frailty by excluding frail older adults who would not initiate use of these drugs. Using a random 20% sample of US Medicare beneficiaries, we framed our study as a series of nonrandomized "trials" comparing vaccinated beneficiaries with unvaccinated beneficiaries who had an outpatient health-care visit during the 5 influenza seasons occurring in 2010-2015. We pooled data across trials and used standardized-mortality-ratio-weighted Cox proportional hazards models to estimate the association between influenza vaccination and all-cause mortality before influenza season, expecting a null association. Weighted hazard ratios among preventive drug initiators were generally closer to the null than those in the nonrestricted cohort. Restriction of the study population to statin initiators with an uncensored approach resulted in a weighted hazard ratio of 1.00 (95% confidence interval: 0.84, 1.19), and several other hazard ratios were above 0.95. Restricting the cohort to initiators of medications in preventive drug classes can reduce confounding by frailty in this setting, but further work is required to determine the most appropriate criteria to use.

Arrhythmogenic Mechanisms in Heart Failure: Linking β-Adrenergic Stimulation, Stretch, and Calcium

Heart failure (HF) is associated with elevated sympathetic tone and mechanical load. Both systems activate signaling transduction pathways that increase cardiac output, but eventually become part of the disease process itself leading to further worsening of cardiac function. These alterations can adversely contribute to electrical instability, at least in part due to the modulation of Ca²⁺ handling at the level of the single cardiac myocyte. The major aim of this review is to provide a definitive overview of the links and cross talk between β-adrenergic stimulation, mechanical load, and arrhythmogenesis in the setting of HF. We will initially review the role of Ca²⁺ in the induction of both early and delayed afterdepolarizations, the role that β-adrenergic stimulation plays in the initiation of these and how the propensity for these may be altered in HF. We will then go onto reviewing the current data with regards to the link between mechanical load and afterdepolarizations, the associated mechano-sensitivity of the ryanodine receptor and other stretch activated channels that may be associated with HF-associated arrhythmias. Furthermore, we will discuss how alterations in local Ca²⁺ microdomains during the remodeling process associated the HF may contribute to the increased disposition for β-adrenergic or stretch induced arrhythmogenic triggers. Finally, the potential mechanisms linking β-adrenergic stimulation and mechanical stretch will be clarified, with the aim of finding common modalities of arrhythmogenesis that could be targeted by novel therapeutic agents in the setting of HF.

Are targeted therapies for diabetic cardiomyopathy on the horizon?

Diabetes increases the risk of heart failure approximately 2.5-fold, independent of coronary artery disease and other comorbidities. This process, termed diabetic cardiomyopathy, is characterized by initial impairment of left ventricular (LV) relaxation followed by LV contractile dysfunction. Post-mortem examination reveals that human diastolic dysfunction is closely associated with LV damage, including cardiomyocyte hypertrophy, apoptosis and fibrosis, with impaired coronary microvascular perfusion. The pathophysiological mechanisms underpinning the characteristic features of diabetic cardiomyopathy remain poorly understood, although multiple factors including altered lipid metabolism, mitochondrial dysfunction, oxidative stress, endoplasmic reticulum (ER) stress, inflammation, as well as epigenetic changes, are implicated. Despite a recent rise in research interrogating these mechanisms and an increased understanding of the clinical importance of diabetic cardiomyopathy, there remains a lack of specific treatment strategies. How the chronic metabolic disturbances observed in diabetes lead to structural and functional changes remains a pertinent question, and it is hoped that recent advances, particularly in the area of epigenetics, among others, may provide some answers. This review hence explores the temporal onset of the pathological features of diabetic cardiomyopathy, and their relative contribution to the resultant disease phenotype, as well as both current and potential therapeutic options. The emergence of glucose-optimizing agents, namely glucagon-like peptide-1 (GLP-1) agonists and sodium/glucose co-transporter (SGLT)2 inhibitors that confer benefits on cardiovascular outcomes, together with novel experimental approaches, highlight a new and exciting era in diabetes research, which is likely to result in major clinical impact.

Effect of 35 years beta-adrenergic blockade therapy on autonomic cardiovascular modulation. A case study

The influence of long duration beta-blockade on autonomic and cardiovascular function remains not completely understood. The aim of this study was to evaluate the effect of long duration beta-adrenergic blockade treatment for hypertension control, on autonomic cardiovascular control in a 78-year-old male patient in relation to population findings. Heart rate variability was determined in the frequency domain (Total power, low frequency power and high frequency power), during baseline (supine and standing) and during 24 hour Holter recording. Results were compared with heart rate and heart rate variability data obtained from a normal healthy male population as a function of age. Circadian rhythm remained present. Heart rate during daytime was lower compared to the population group. None of the heart rate variability parameters were different from the normal population age group. Our results show that after 35 years of beta-blockade treatment, autonomic modulation of cardiac function remains within normal limits for that age group. Blood pressure remained at the higher limits (120-150/60-80 mmHg), but under control.

Heart rate, lifespan, and mortality risk

An increasing body of scientific research and observational evidence indicates that resting heart rate (HR) is inversely related to the lifespan among homeothermic mammals and within individual species. In numerous human studies with patients stratified by resting HR, increased HR is universally associated with greater risk of death. The correlation between HR and maximum lifespan seems to be due to both basal metabolic rate and cardiovascular-related mortality risk. Both intrinsic and extrinsic factors are already postulated to determine how the biological clock works, through regulating and modulating the processes such as protein oxidation, free radical production, inflammation and telomere shortening. Given the remarkable correlation between HR and lifespan, resting HR should be seriously considered as another possible cap on maximum lifespan. Future research is needed to determine whether deliberate cardiac slowing, through methods like lifestyle modification, pharmacological intervention, or medical devices, can decelerate biological clock of aging, reduce cardiovascular mortality and increase maximum lifespan in humans in general.