Effect of Selective Heart Rate Slowing in Heart Failure With Preserved Ejection Fraction

Ivabradine Approved and Other Uses in Clinical Practice: A Systematic Review

ABSTRACT

Heart rate (HR) stands as a prognostic indicator of cardiovascular disease and a modifiable risk factor in heart failure (HF). Medication intolerance can curtail the application of conventional HR-lowering β-blockers to the optimum target dose. Ivabradine (IVA), a specific negative-chronotropic agent, selectively inhibits I f current in pacemaker cells of the sinoatrial node without depressing myocardial contractility or comprising hemodynamics. This review summarized ivabradine's clinical labeled and off-label uses and mechanism of action focusing on the clinical outcomes. PubMed was searched up to January 2024 using the main keywords of IVA, coronary artery disease (CAD), HF, postural tachycardia syndrome (POTS), and tachyarrhythmia. To comprehensively review IVA's clinical indications, mechanisms, and therapeutic effects, all studies investigating treatment with IVA in humans were included, comprising different types of studies such as randomized controlled trials and longitudinal prospective observational studies. After screening, 141 studies were included in our review. A large number of reviewed articles were allocated to heart failure with reduced ejection fraction and CAD, suggesting IVA as an alternative to β-blockers in case of contraindications or intolerance. The beneficial effects of IVA as premedication for coronary computed tomography angiography, HR lowering in POTS, and inappropriate sinus tachycardia constituted most studies among off-label uses. The promising results have been reported on the efficacy of IVA in controlling HR, especially in patients with inappropriate sinus tachycardia or POTS. Owing to the unique mechanism of action, IVA has the potential to be used more frequently in future clinical practice.

Physiological effects of ivabradine in heart failure and beyond

Ivabradine is a pharmacologic agent that inhibits the funny current responsible for determining heart rate in the sinoatrial node. Ivabradine's clinical potential has been investigated in the context of heart failure since it is associated with reduced myocardial oxygen demand, enhanced diastolic filling, stroke volume, and coronary perfusion time; however, it is yet to demonstrate definitive mortality benefit. Alternative effects of ivabradine include modulation of the renin-angiotensin-aldosterone system, sympathetic activation, and endothelial function. Here, we review key clinical trials informing the clinical use of ivabradine and explore opportunities for leveraging its potential pleiotropic effects in other diseases, including treatment of hyperadrenergic states and mitigating complications of COVID-19 infection.

Insights into the post-translational modifications in heart failure

Heart failure (HF), as the terminal manifestation of multiple cardiovascular diseases, causes a huge socioeconomic burden worldwide. Despite the advances in drugs and medical-assisted devices, the prognosis of HF remains poor. HF is well-accepted as a myriad of subcellular dys-synchrony related to detrimental structural and functional remodelling of cardiac components, including cardiomyocytes, fibroblasts, endothelial cells and macrophages. Through the covalent chemical process, post-translational modifications (PTMs) can coordinate protein functions, such as re-localizing cellular proteins, marking proteins for degradation, inducing interactions with other proteins and tuning enzyme activities, to participate in the progress of HF. Phosphorylation, acetylation, and ubiquitination predominate in the currently reported PTMs. In addition, advanced HF is commonly accompanied by metabolic remodelling including enhanced glycolysis. Thus, glycosylation induced by disturbed energy supply is also important. In this review, firstly, we addressed the main types of HF. Then, considering that PTMs are associated with subcellular locations, we summarized the leading regulation mechanisms in organelles of distinctive cell types of different types of HF, respectively. Subsequently, we outlined the aforementioned four PTMs of key proteins and signaling sites in HF. Finally, we discussed the perspectives of PTMs for potential therapeutic targets in HF.

Beta-blocker use and outcomes in patients with heart failure and mildly reduced and preserved ejection fraction

AIMS

In the absence of randomized trial evidence, we performed a large observational analysis of the association between beta-blocker (BB) use and clinical outcomes in patients with heart failure (HF) and mildly reduced (HFmrEF) and preserved ejection fraction (HFpEF).

METHODS AND RESULTS

We pooled individual patient data from four large HFmrEF/HFpEF trials (I-Preserve, TOPCAT, PARAGON-HF, and DELIVER). The primary outcome was the composite of cardiovascular death or HF hospitalization. Among the 16 951 patients included, the mean left ventricular ejection fraction (LVEF) was 56.8%, and 13 400 (79.1%) had HFpEF (LVEF ≥50%). Overall, 12 812 patients (75.6%) received a BB. The median bisoprolol-equivalent dose of BB was 5.0 (Q1-Q3: 2.5-5.0) mg with BB continuation rates of 93.1% at 2 years (in survivors). The unadjusted hazard ratio (HR) for the primary outcome did not differ between BB users and non-users (HR 0.98, 95% confidence interval [CI] 0.91-1.05), but the adjusted HR was lower in BB users than non-users (0.81, 95% CI 0.74-0.88), and this association was maintained across LVEF (pinteraction = 0.88). In subgroup analyses, the adjusted risk of the primary outcome was similar in BB users and non-users with or without a history of myocardial infarction, hypertension, or a baseline heart rate <70 bpm. By contrast, a better outcome with BB use was seen in patients with atrial fibrillation compared to those without atrial fibrillation (pintreraction = 0.02).

CONCLUSIONS

In this observational analysis of non-randomized BB treatment, there was no suggestion that BB use was associated with worse HF outcomes in HFmrEF/HFpEF, even after extensive adjustment for other prognostic variables.

Differences in the Effects of Beta-Blockers Depending on Heart Rate at Discharge in Patients With Heart Failure With Preserved Ejection Fraction and Atrial Fibrillation

Background and Objectives

Beta-blockers (BBs) improve prognosis in heart failure (HF), which is mediated by lowering heart rate (HR). However, HR has no prognostic implication in atrial fibrillation (AF) and also BBs have not been shown to improve prognosis in heart failure with preserved ejection fraction (HFpEF) with AF. This study assessed the prognostic implication of BB in HFpEF with AF according to discharge HR.

Methods

From the Korean Acute Heart Failure Registry, 687 patients with HFpEF and AF were selected. Study subjects were divided into 4 groups based on 75 beats per minute (bpm) of HR at discharge and whether or not they were treated with BB at discharge.

Results

Of the 687 patients with HFpEF and AF, 128 (36.1%) were in low HR group and 121 (36.4%) were in high HR group among those treated with BB at discharge. In high HR group, HR at discharge was significantly faster in BB non-users (85.5±9.1 bpm vs. 89.2±12.5 bpm, p=0.005). In the Cox model, BB did not improve 60-day rehospitalization (hazard ratio, 0.93; 95% confidence interval [95% CI], 0.35-2.47) or mortality (hazard ratio, 0.77; 95% CI, 0.22-2.74) in low HR group. However, in high HR group, BB treatment at discharge was associated with 82% reduced 60-day HF rehospitalization (hazard ratio, 0.18; 95% CI, 0.04-0.81), but not with mortality (hazard ratio, 0.77; 95% CI, 0.20-2.98).

Conclusions

In HFpEF with AF, in patients with HR over 75 bpm at discharge, BB treatment at discharge was associated with a reduced 60-day rehospitalization rate.

The efficacy and safety of ivabradine hydrochloride in hemodialysis patients with chronic heart failure

INTRODUCTION

There is little evidence for ivabradine hydrochloride in patients undergoing hemodialysis.

METHODS

In this open-label prospective interventional trial of hemodialysis patients with chronic heart failure, during 12 weeks of treatment, changes in Heart rate (HR), frequency of dialysis-related hypotension were examined, and we investigated health-related quality of life (HR-QOL) and adverse effects.

RESULTS

18 patients from 6 facilities were enrolled in the study. HR significantly decreased over time, from 87 ± 12.61/min at baseline to 75.85 ± 8.91/min (p = 0.0003), and systolic blood pressure also increased significantly (p < 0.0001). The frequency of dialysis-related hypotension was markedly reduced (p = 0.0001). The HR-QOL survey showed significant improvements in Social Functioning among others (p = 0.0178). No specific adverse events occurred.

CONCLUSION

Ivabradine hydrochloride improved dialysis-related hypotension. Furthermore, the HR-QOL improvement effect were suggested. These results demonstrated the safety and effectiveness of ivabradine hydrochloride.

Drug Therapy for Acute and Chronic Heart Failure with Preserved Ejection Fraction with Hypertension: A State-of-the-Art Review

In this comprehensive state-of-the-art review, we provide an evidence-based analysis of current drug therapies for patients with heart failure with preserved ejection fraction (HFpEF) in the acute and chronic phases with concurrent hypertension. Additionally, we explore the latest developments and emerging evidence on the efficacy, safety, and clinical outcomes of common and novel drug treatments in the management of HFpEF with concurrent hypertension. During the acute phase of HFpEF, intravenous diuretics, mineralocorticoid receptor antagonists (MRAs), and vasodilators are pivotal, while in the chronic phase, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers have proven effective in enhancing clinical outcomes. However, the use of calcium channel blockers in HFpEF with hypertension should be approached with caution, owing to their potential negative inotropic effects. We also explored emerging drug therapies for HFpEF, such as sodium-glucose co-transporter 2 (SGLT2) inhibitors, angiotensin receptor-neprilysin inhibitor (ARNI), soluble guanylate cyclase (sGC) stimulators, novel MRAs, and ivabradine. Notably, SGLT2 inhibitors have shown promise in reducing heart failure hospitalizations and cardiovascular mortality in patients with HFpEF, regardless of their diabetic status. Additionally, ARNI and sGC stimulators have demonstrated potential in improving symptoms, functional capacity, and quality of life. Nonetheless, additional research is necessary to pinpoint optimal treatment strategies for HFpEF with concurrent hypertension. Furthermore, long-term studies are essential to assess the durability and sustained benefits of emerging drug therapies. Identification of novel targets and mechanisms underlying HFpEF pathophysiology will pave the way for innovative drug development approaches in the management of HFpEF with concurrent hypertension.

Contemporary Use and Implications of Beta-Blockers in Patients With HFmrEF or HFpEF: The DELIVER Trial

BACKGROUND

Although beta-blockers are not recommended for the treatment of heart failure with preserved ejection fraction (HFpEF) according to the latest European Society of Cardiology and American Heart Association/American College of Cardiology/Heart Failure Society of America guidelines, these therapies remain commonly used for comorbidity management. There has been concern that beta-blockers may adversely influence clinical outcomes by limiting chronotropic response in HFpEF.

OBJECTIVES

This study sought to examine the contemporary use and implications of beta-blockers in patients with heart failure with mildly reduced ejection fraction (HFmrEF) or HFpEF.

METHODS

In the DELIVER (Dapagliflozin Evaluation to Improve the Lives of Patients With Preserved Ejection Fraction Heart Failure) trial, a total of 6,263 patients with symptomatic heart failure (HF) with a left ventricular ejection fraction (LVEF) >40% were randomized to dapagliflozin or placebo across 20 countries. In this prespecified analysis, efficacy and safety outcomes were examined according to beta-blocker use at randomization. The primary outcome was cardiovascular death or worsening HF.

RESULTS

Overall, beta-blockers were used in 5,177 patients (83%), with wide variation by geographic region. Beta-blocker use was associated with a lower risk of the primary outcome in covariate-adjusted models (HR: 0.70; 95% CI: 0.60-0.83). Dapagliflozin consistently reduced the risk of the primary outcome in patients taking beta-blockers (HR: 0.82; 95% CI: 0.72-0.94) and in patients not taking beta-blockers (HR: 0.79; 95% CI: 0.61-1.03; Pinteraction = 0.85), with similar findings for key secondary endpoints. Adverse events were balanced between patients randomized to dapagliflozin and placebo, regardless of background beta-blocker use.

CONCLUSIONS

In patients with HFmrEF or HFpEF who were enrolled in DELIVER, 4 out of 5 participants were treated with a beta-blocker. Beta-blocker use was not associated with a higher risk of worsening HF or cardiovascular death. Dapagliflozin consistently and safely reduced clinical events, irrespective of background beta-blocker use. (Dapagliflozin Evaluation to Improve the Lives of Patients With Preserved Ejection Fraction Heart Failure [DELIVER]; NCT03619213).

Impact of heart rate changes during hospitalization on outcome in heart failure with preserved ejection fraction

AIMS

The benefits of lowering heart rate (HR) in heart failure (HF) with preserved ejection fraction (HFpEF) patients are still a matter of debate. This study aimed to investigate the relationship between changes in HR during hospitalization and cardiovascular (CV) events and all-cause death in hospitalized HFpEF patients.

METHODS AND RESULTS

Hospitalized HF patients between January 2017 and December 2021 were consecutively enrolled in a national, multicentred, and prospective registry database, the China Cardiovascular Association Database-HF Center Registry. HF patients with a left ventricular ejection fraction of ≥50% were defined as HFpEF patients. The study analysed admission/discharge HR, change in HR during hospitalization (∆HR), and ∆HR ratio (∆HR/admission HR). The patients were categorized into three groups: no HR dropping group (ΔHR ratio > 0.0%), moderate HR dropping group (-15% < ΔHR ratio ≤ 0.0%), and excessive HR dropping group (ΔHR ratio ≤ -15%). All patients were followed up for 12 months. The primary endpoint was CV events (CV death or HF rehospitalization). The secondary endpoint was all-cause death. A total of 19 510 HFpEF patients (9750 males, mean age 71.9 ± 12.2 years) were included, with 4575 in the no HR dropping group, 8434 in the moderate HR dropping group, and 6501 in the excessive HR dropping group. Excessive HR dropping during hospitalization was significantly associated with an increased risk of CV events (17.1%) compared with the no HR dropping group (14.5%, P < 0.001) or the moderate HR dropping group (14.0%, P < 0.001), although all-cause mortality was similar among the three groups. After adjusting for multiple confounding factors, excessive HR dropping remained an independent predictor of increased CV event risk [hazard ratio 1.197, 95% confidence interval (CI) 1.078-1.328]. Subgroup analysis revealed that the prognostic impact of excessive HR dropping on increased CV event risk remained in the subgroups of older age, New York Heart Association class IV, ischaemic HF, higher left ventricular ejection fraction, absence of chronic kidney disease, and use of beta-blockers or ivabradine. Independent determinants associated with excessive HR dropping during admission included use of beta-blockers [odds ratio (OR) 1.683, 95% CI 1.558-1.819], lower discharge diastolic blood pressure (OR 0.988, 95% CI 0.985-0.991), no pacemaker (OR 0.501, 95% CI 0.416-0.603), coexisting atrial fibrillation or atrial flutter (OR 1.327, 95% CI 1.218-1.445), and use of digoxin (OR 1.340, 95% CI 1.213-1.480).

CONCLUSIONS

In hospitalized HFpEF patients, excessive HR dropping during hospitalization is associated with an increased risk of CV death or HF rehospitalization. These findings highlight the importance of HR monitoring and avoiding excessively slowing down HR in hospitalized HFpEF patients to reduce the risk of CV events.

Implications of Atrial Fibrillation for Guideline-Directed Therapy in Patients With Heart Failure: JACC State-of-the-Art Review

Atrial fibrillation (AF) and heart failure (HF) are common cardiovascular conditions that frequently coexist. Among patients with HF, more than one-half also have AF. Both are associated with significant morbidity and mortality. Moreover, the prevalence of each is increasing globally, and this trend is expected to continue owing to an aging population and increased life expectancy. Diagnosis of AF in a patient with HF is associated with greater symptom burden, more frequent hospitalizations, and a worse prognosis. Guideline-directed medical therapy (GDMT) for HF can affect the incidence of AF. Once present, AF can influence the efficacy of some components of GDMT for HF. In this review, we discuss the effect of GDMT for HF across the spectrum of ejection fraction on prevention of AF as well as the benefit of GDMT in patients with vs without AF.

Calcium channel blocker use and outcomes in patients with heart failure and mildly reduced and preserved ejection fraction

AIMS

Patients with heart failure (HF) and mildly reduced ejection fraction (HFmrEF) and preserved ejection fraction (HFpEF) are often treated with calcium channel blockers (CCBs), although the safety of CCBs in these patients is uncertain. We aimed to investigate the association between CCB use and clinical outcomes in patients with HFmrEF/HFpEF; CCBs were examined overall, as well as by subtype (dihydropyridine and non-dihydropyridine).

METHODS AND RESULTS

We pooled individual patient data from four large HFpEF/HFmrEF trials. The association between CCB use and outcomes was assessed. Among the 16 954 patients included, the mean left ventricular ejection fraction (LVEF) was 56.8%, and 13 402 (79.0%) had HFpEF (LVEF ≥50%). Altogether, 5874 patients (34.6%) received a CCB (87.6% dihydropyridines). Overall, the risks of death and HF hospitalization were not higher in patients treated with a CCB, particularly dihydropyridines. The risk of pump failure death was significantly lower (hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.60-0.96), while the risk of stroke was higher (HR 1.26, 95% CI 1.06-1.50) in patients treated with a CCB compared to those not. These risks remained different in patients treated and not treated with a CCB after adjustment for other prognostic variables. Although the majority of patients were treated with dihydropyridine CCBs, the pattern of outcomes was broadly similar for both dihydropyridine and non-dihydropyridine CCBs.

CONCLUSION

Although this is an observational analysis of non-randomized treatment, there was no suggestion that CCBs were associated with worse HF outcomes. Indeed, CCB use was associated with a lower incidence of pump failure death.

Efficacy of Dapagliflozin According to Heart Rate: A Patient-Level Pooled Analysis of DAPA-HF and DELIVER

BACKGROUND

Although elevated resting heart rate (HR) is associated with a higher risk of cardiovascular events in patients with heart failure with reduced ejection fraction in sinus rhythm (SR), the relationship between HR and outcomes among patients with heart failure with mildly reduced ejection fraction/heart failure with preserved ejection fraction and in those with atrial fibrillation (AF) is uncertain. The aims of this study were to examine the association between baseline HR and outcomes across the range of left ventricular ejection fraction, in patients with and without AF, and evaluate the effect of dapagliflozin according to HR.

METHODS

A patient-level pooled analysis of the DAPA-HF (Dapagliflozin and Prevention of Adverse Outcomes in Heart Failure; heart failure with reduced ejection fraction) and DELIVER (Dapagliflozin Evaluation to Improve the Lives of Patients With Preserved Ejection Fraction Heart Failure trial; heart failure with mildly reduced ejection fraction/heart failure with preserved ejection fraction) trials. The primary outcome of each was the composite of worsening heart failure or cardiovascular death.

RESULTS

Among patients with SR (n=6401, 64%), the rate of the primary outcome was higher in those with higher HR: 16.8 versus 7.7 per 100 person-years for ≥80 bpm versus <60 bpm. The relationship between HR and risk was steeper in heart failure with reduced ejection fraction versus heart failure with mildly reduced ejection fraction/heart failure with preserved ejection fraction. HR was not associated with outcomes in patients in AF for either heart failure phenotype. The benefit of dapagliflozin on the primary outcome was consistent across the HR range in both SR (Pinteraction=0.28) and AF (Pinteraction=0.56), for example, for SR <60 bpm, hazard ratio for dapagliflozin versus placebo 0.72 (95% CI, 0.55-0.95); 60 to 69 bpm, 0.78 (0.63-0.97); 70 to 79 bpm, 0.73 (0.59-0.91); ≥80 bpm, 0.77 (0.61-0.97). The benefit was consistent across HR range in both heart failure with reduced ejection fraction and heart failure with mildly reduced ejection fraction/heart failure with preserved ejection fraction.

CONCLUSIONS

The risk of worsening heart failure or cardiovascular death increased with increasing baseline HR among patients in SR, but this association was not seen among patients in AF, irrespective of left ventricular ejection fraction. The benefit of dapagliflozin was consistent across HR range, irrespective of left ventricular ejection fraction or rhythm.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifiers: NCT03036124 and NCT03619213.

Ivabradine in patients with heart failure: a systematic literature review

Background: Heart failure is a chronic disease linked with significant morbidity and mortality, and uncontrolled resting heart rate is a risk factor for adverse outcomes. This systematic literature review aimed to assess the efficacy, safety, and patient-reported outcomes (PROs) of ivabradine in patients with heart failure (HF) with reduced ejection fraction (HFrEF) in randomized controlled trials (RCTs) and observational studies. Methods: We searched electronic databases from their inception to July 2021 to include studies that reported on efficacy, safety, or PROs of ivabradine in patients with HFrEF. Results: Of 1947 records screened, 51 RCTs and 6 observational studies were identified. Ivabradine on top of background therapy demonstrated a significant reduction in composite outcomes including hospitalization for HF or cardiovascular death. In addition, observational studies suggested that ivabradine was associated with a significant reduction in mortality. Across all studies, ivabradine use on top of background therapy was associated with greater reductions in heart rate, improved EF, and improved health-related quality of life (QoL) and comparable risk of total adverse events compared to those treated with background therapy alone. Conclusions: Ivabradine on top of background therapy is beneficial for heart rate, hospitalization risk for HF, mortality, EF, and patients' QoL. Moreover, these benefits were achieved with no significant increase in the overall risk of total adverse events.

How to Manage Heart Failure With Preserved Ejection Fraction: Practical Guidance for Clinicians

Although patients with heart failure with preserved ejection fraction (HFpEF) (left ventricular ejection fraction ≥50%) comprise nearly half of those with chronic heart failure, evidence-based treatment options for this population have historically been limited. Recently, however, emerging data from prospective, randomized trials enrolling patients with HFpEF have greatly altered the range of pharmacologic options to modify disease progression in selected patients with HFpEF. In the context of this evolving landscape, clinicians are increasingly in need of practical guidance regarding the best approach to management of this growing population. In this review, we build on the recently published heart failure guidelines by integrating contemporary data from recent randomized trials to provide a contemporary framework for diagnosis and evidence-based treatment of patients with HFpEF. Where gaps in knowledge persist, we provide "best available" data from post hoc analyses of clinical trials or data from observational studies to guide management until more definitive studies are available.

Rate-Adaptive Atrial Pacing for Heart Failure With Preserved Ejection Fraction: The RAPID-HF Randomized Clinical Trial

Importance

Reduced heart rate during exercise is common and associated with impaired aerobic capacity in heart failure with preserved ejection fraction (HFpEF), but it remains unknown if restoring exertional heart rate through atrial pacing would be beneficial.

Objective

To determine if implanting and programming a pacemaker for rate-adaptive atrial pacing would improve exercise performance in patients with HFpEF and chronotropic incompetence.

Design, Setting, and Participants

Single-center, double-blind, randomized, crossover trial testing the effects of rate-adaptive atrial pacing in patients with symptomatic HFpEF and chronotropic incompetence at a tertiary referral center (Mayo Clinic) in Rochester, Minnesota. Patients were recruited between 2014 and 2022 with 16-week follow-up (last date of follow-up, May 9, 2022). Cardiac output during exercise was measured by the acetylene rebreathe technique.

Interventions

A total of 32 patients were recruited; of these, 29 underwent pacemaker implantation and were randomized to atrial rate responsive pacing or no pacing first for 4 weeks, followed by a 4-week washout period and then crossover for an additional 4 weeks.

Main Outcomes and Measures

The primary end point was oxygen consumption (V̇o2) at anaerobic threshold (V̇o2,AT); secondary end points were peak V̇o2, ventilatory efficiency (V̇e/V̇co2 slope), patient-reported health status by the Kansas City Cardiomyopathy Questionnaire Overall Summary Score (KCCQ-OSS), and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels.

Results

Of the 29 patients randomized, the mean age was 66 years (SD, 9.7) and 13 (45%) were women. In the absence of pacing, peak V̇o2 and V̇o2 at anaerobic threshold (V̇o2,AT) were both correlated with peak exercise heart rate (r = 0.46-0.51, P < .02 for both). Pacing increased heart rate during low-level and peak exercise (16/min [95% CI, 10 to 23], P < .001; 14/min [95% CI, 7 to 21], P < .001), but there was no significant change in V̇o2,AT (pacing off, 10.4 [SD, 2.9] mL/kg/min; pacing on, 10.7 [SD, 2.6] mL/kg/min; absolute difference, 0.3 [95% CI, -0.5 to 1.0] mL/kg/min; P = .46), peak V̇o2, minute ventilation (V̇e)/carbon dioxide production (V̇co2) slope, KCCQ-OSS, or NT-proBNP level. Despite the increase in heart rate, atrial pacing had no significant effect on cardiac output with exercise, owing to a decrease in stroke volume (-24 mL [95% CI, -43 to -5 mL]; P = .02). Adverse events judged to be related to the pacemaker device were observed in 6 of 29 participants (21%).

Conclusions and Relevance

In patients with HFpEF and chronotropic incompetence, implantation of a pacemaker to enhance exercise heart rate did not result in an improvement in exercise capacity and was associated with increased adverse events.

Trial Registration

ClinicalTrials.gov Identifier: NCT02145351.

Effect of Personalized Accelerated Pacing on Quality of Life, Physical Activity, and Atrial Fibrillation in Patients With Preclinical and Overt Heart Failure With Preserved Ejection Fraction: The myPACE Randomized Clinical Trial

Importance

Patients with heart failure with preserved ejection fraction (HFpEF) with a pacemaker may benefit from a higher, more physiologic backup heart rate than the nominal 60 beats per minute (bpm) setting.

Objective

To assess the effects of a moderately accelerated personalized backup heart rate compared with 60 bpm (usual care) in patients with preexisting pacemaker systems that limit pacemaker-mediated dyssynchrony.

Design, Setting, and Participants

This blinded randomized clinical trial enrolled patients with stage B and C HFpEF from the University of Vermont Medical Center pacemaker clinic between June 2019 and November 2020. Analysis was modified intention to treat.

Interventions

Participants were randomly assigned to personalized accelerated pacing or usual care and were followed up for 1 year. The personalized accelerated pacing heart rate was calculated using a resting heart rate algorithm based on height and modified by ejection fraction.

Main Outcomes and Measures

The primary outcome was the serial change in Minnesota Living with Heart Failure Questionnaire (MLHFQ) score. Secondary end points were changes in N-terminal pro-brain natriuretic peptide (NT-proBNP) levels, pacemaker-detected physical activity, atrial fibrillation from baseline, and adverse clinical events.

Results

Overall, 107 participants were randomly assigned to the personalized accelerated pacing (n = 50) or usual care (n = 57) groups. The median (IQR) age was 75 (69-81) years, and 48 (48%) were female. Over 1-year follow-up, the median (IQR) pacemaker-detected heart rate was 75 (75-80) bpm in the personalized accelerated pacing arm and 65 (63-68) bpm in usual care. MLHFQ scores improved in the personalized accelerated pacing group (median [IQR] baseline MLHFQ score, 26 [8-45]; at 1 month, 15 [2-25]; at 1 year, 9 [4-21]; P < .001) and worsened with usual care (median [IQR] baseline MLHFQ score, 19 [6-42]; at 1 month, 23 [5-39]; at 1 year, 27 [7-52]; P = .03). In addition, personalized accelerated pacing led to improved changes in NT-proBNP levels (mean [SD] decrease of 109 [498] pg/dL vs increase of 128 [537] pg/dL with usual care; P = .02), activity levels (mean [SD], +47 [67] minutes per day vs -22 [35] minutes per day with usual care; P < .001), and device-detected atrial fibrillation (27% relative risk reduction compared with usual care; P = .04) over 1-year of follow-up. Adverse clinical events occurred in 4 patients in the personalized accelerated pacing group and 11 patients in usual care.

Conclusions and Relevance

In this study, among patients with HFpEF and pacemakers, treatment with a moderately accelerated, personalized pacing rate was safe and improved quality of life, NT-proBNP levels, physical activity, and atrial fibrillation compared with the usual 60 bpm setting.

Trial Registration

ClinicalTrials.gov Identifier: NCT04721314.

Could SGLT2 Inhibitors Improve Exercise Intolerance in Chronic Heart Failure?

Despite the constant improvement of therapeutical options, heart failure (HF) remains associated with high mortality and morbidity. While new developments in guideline-recommended therapies can prolong survival and postpone HF hospitalizations, impaired exercise capacity remains one of the most debilitating symptoms of HF. Exercise intolerance in HF is multifactorial in origin, as the underlying cardiovascular pathology and reactive changes in skeletal muscle composition and metabolism both contribute. Recently, sodium-related glucose transporter 2 (SGLT2) inhibitors were found to improve cardiovascular outcomes significantly. Whilst much effort has been devoted to untangling the mechanisms responsible for these cardiovascular benefits of SGLT2 inhibitors, little is known about the effect of SGLT2 inhibitors on exercise performance in HF. This review provides an overview of the pathophysiological mechanisms that are responsible for exercise intolerance in HF, elaborates on the potential SGLT2-inhibitor-mediated effects on these phenomena, and provides an up-to-date overview of existing studies on the effect of SGLT2 inhibitors on clinical outcome parameters that are relevant to the assessment of exercise capacity. Finally, current gaps in the evidence and potential future perspectives on the effects of SGLT2 inhibitors on exercise intolerance in chronic HF are discussed.

Ivabradine added to usual care in patients with heart failure: a systematic review with meta-analysis and trial sequential analysis

OBJECTIVES

To assess the beneficial and harmful effects of adding ivabradine to usual care in participants with heart failure.

DESIGN

A systematic review with meta-analysis and trial sequential analysis.

ELIGIBILITY CRITERIA

Randomised clinical trials comparing ivabradine and usual care with usual care (with or without) placebo in participants with heart failure.

INFORMATION SOURCES

Medline, Embase, CENTRAL, LILACS, CNKI, VIP and other databases and trial registries up until 31 May 2021.

DATA EXTRACTION

Primary outcomes were all-cause mortality, serious adverse events and quality of life. Secondary outcomes were cardiovascular mortality, myocardial infarction and non-serious adverse events. We performed meta-analysis of all outcomes. We used trial sequential analysis to control risks of random errors, the Cochrane risk of bias tool to assess the risks of systematic errors and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) to assess the certainty of the evidence.

RESULTS

We included 109 randomised clinical trials with 26 567 participants. Two trials were at low risk of bias, although both trials were sponsored by the company that developed ivabradine. All other trials were at high risk of bias. Meta-analyses and trial sequential analyses showed that we could reject that ivabradine versus control reduced all-cause mortality (risk ratio (RR)=0.94; 95% CI 0.88 to 1.01; p=0.09; high certainty of evidence). Meta-analysis and trial sequential analysis showed that ivabradine seemed to reduce the risk of serious adverse events (RR=0.90; 95% CI 0.87 to 0.94; p<0.00001; number needed to treat (NNT)=26.2; low certainty of evidence). This was primarily due to a decrease in the risk of 'cardiac failure' (RR=0.83; 95% CI 0.71 to 0.97; p=0.02; NNT=43.9), 'hospitalisations' (RR=0.89; 95% CI 0.85 to 0.94; p<0.0001; NNT=36.4) and 'ventricular tachycardia' (RR=0.59; 95% CI 0.43 to 0.82; p=0.001; NNT=212.8). However, the trials did not describe how these outcomes were defined and assessed during follow-up. Meta-analyses showed that ivabradine increased the risk of atrial fibrillation (RR=1.19; 95% CI 1.04 to 1.35; p=0.008; number needed to harm (NNH)=116.3) and bradycardia (RR=3.95; 95% CI 1.88 to 8.29; p=0.0003; NNH=303). Ivabradine seemed to increase quality of life on the Kansas City Cardiomyopathy Questionnaire (KCCQ) (mean difference (MD)=2.92; 95% CI 1.34 to 4.50; p=0.0003; low certainty of evidence), but the effect size was small and possibly without relevance to patients, and on the Minnesota Living With Heart Failure Questionnaire (MLWHFQ) (MD=-5.28; 95% CI -6.60 to -3.96; p<0.00001; very low certainty of evidence), but the effects were uncertain. Meta-analysis showed no evidence of a difference between ivabradine and control when assessing cardiovascular mortality and myocardial infarction. Ivabradine seemed to increase the risk of non-serious adverse events.

CONCLUSION AND RELEVANCE

High certainty evidence shows that ivabradine does not seem to affect the risks of all-cause mortality and cardiovascular mortality. The effects on quality of life were small and possibly without relevance to patients on the KCCQ and were very uncertain for the MLWHFQ. The effects on serious adverse events, myocardial infarction and hospitalisation are uncertain. Ivabradine seems to increase the risk of atrial fibrillation, bradycardia and non-serious adverse events.PROSPERO registration number: CRD42018112082.

Diastolic Filling Time, Chronotropic Response, and Exercise Capacity in Heart Failure and Preserved Ejection Fraction With Sinus Rhythm

Background

Exercise‐induced high heart rate may impair exercise tolerance by reducing diastolic filling time and ventricular filling in heart failure with preserved ejection fraction (HFpEF). Given the importance of chronotropic response, we hypothesized that reduction in diastolic filling time because of exercise‐induced increased heart rate would not impair cardiac output reserve and exercise capacity. We sought to determine the association between heart rate, diastolic filling time, hemodynamics, and exercise capacity in HFpEF.

Methods and Results

Patients with HFpEF (n=66) and controls without HF (n=107) underwent bicycle exercise echocardiography with simultaneous expired gas analysis to measure oxygen consumption. Diastolic filling time was assessed by the overlap time between mitral E‐ and A‐waves (longer overlap time indicates shorter diastolic filling duration). Overlap time increased (ie, diastolic filling time shortened) in HFpEF and controls as heart rate increased with exercise, and the relationship was similar between the groups. Greater heart rate response correlated with higher cardiac output (r=0.51, P<0.0001) and oxygen consumption (r=0.50, P<0.0001) during peak exercise. Shorter diastolic filling time, as assessed by longer overlap time, was correlated with higher cardiac output (r=0.47, P<0.0001) and peak oxygen consumption (r=0.38, P=0.007), not with E/e′ or right ventricular‐pulmonary artery uncoupling. Longer overlap time was associated with mitral A velocity (r=0.53, P<0.0001) and left atrial booster pump strain (r=0.42, P<0.0001).

Conclusions

Shortening of diastolic filling interval in tandem with increased heart rate during exercise does not limit cardiac output reserve or exercise capacity in HFpEF.

Mechanisms of Sinoatrial Node Dysfunction in Heart Failure With Preserved Ejection Fraction

BACKGROUND

The ability to increase heart rate during exercise and other stressors is a key homeostatic feature of the sinoatrial node (SAN). When the physiological heart rate response is blunted, chronotropic incompetence limits exercise capacity, a common problem in patients with heart failure with preserved ejection fraction (HFpEF). Despite its clinical relevance, the mechanisms of chronotropic incompetence remain unknown.

METHODS

Dahl salt-sensitive rats fed a high-salt diet and C57Bl6 mice fed a high-fat diet and an inhibitor of constitutive nitric oxide synthase (Nω-nitro-L-arginine methyl ester [L-NAME]; 2-hit) were used as models of HFpEF. Myocardial infarction was created to induce HF with reduced ejection fraction. Rats and mice fed with a normal diet or those that had a sham surgery served as respective controls. A comprehensive characterization of SAN function and chronotropic response was conducted by in vivo, ex vivo, and single-cell electrophysiologic studies. RNA sequencing of SAN was performed to identify transcriptomic changes. Computational modeling of biophysically-detailed human HFpEF SAN was created.

RESULTS

Rats with phenotypically-verified HFpEF exhibited limited chronotropic response associated with intrinsic SAN dysfunction, including impaired β-adrenergic responsiveness and an alternating leading pacemaker within the SAN. Prolonged SAN recovery time and reduced SAN sensitivity to isoproterenol were confirmed in the 2-hit mouse model. Adenosine challenge unmasked conduction blocks within the SAN, which were associated with structural remodeling. Chronotropic incompetence and SAN dysfunction were also found in rats with HF with reduced ejection fraction. Single-cell studies and transcriptomic profiling revealed HFpEF-related alterations in both the "membrane clock" (ion channels) and the "Ca2+ clock" (spontaneous Ca2+ release events). The physiologic impairments were reproduced in silico by empirically-constrained quantitative modeling of human SAN function.

CONCLUSIONS

Chronotropic incompetence and SAN dysfunction were seen in both models of HF. We identified that intrinsic abnormalities of SAN structure and function underlie the chronotropic response in HFpEF.

Effect of β-Blocker Withdrawal on Functional Capacity in Heart Failure and Preserved Ejection Fraction

BACKGROUND

Chronotropic incompetence has shown to be associated with a decrease in exercise capacity in heart failure with preserved ejection fraction (HFpEF), yet β-blockers are commonly used in HFpEF despite the lack of robust evidence.

OBJECTIVES

This study aimed to evaluate the effect of β-blocker withdrawal on peak oxygen consumption (peak Vo₂) in patients with HFpEF and chronotropic incompetence.

METHODS

This is a multicenter, randomized, investigator-blinded, crossover clinical trial consisting of 2 treatment periods of 2 weeks separated by a washout period of 2 weeks. Patients with stable HFpEF, New York Heart Association functional classes II and III, previous treatment with β-blockers, and chronotropic incompetence were first randomized to withdrawing from (arm A: n = 26) versus continuing (arm B: n = 26) β-blocker treatment and were then crossed over to receive the opposite intervention. Changes in peak Vo₂ and percentage of predicted peak Vo₂ (peak Vo₂%) measured at the end of the trial were the primary outcome measures. To account for the paired-data nature of this crossover trial, linear mixed regression analysis was used.

RESULTS

The mean age was 72.6 ± 13.1 years, and most of the patients were women (59.6%) in New York Heart Association functional class II (66.7%). The mean peakVo₂ and peak Vo₂% were 12.4 ± 2.9 mL/kg/min, and 72.4 ± 17.8%, respectively. No significant baseline differences were found across treatment arms. Peak Vo₂ and peak Vo₂% increased significantly after β-blocker withdrawal (14.3 vs 12.2 mL/kg/min [Δ +2.1 mL/kg/min]; P < 0.001 and 81.1 vs 69.4% [Δ +11.7%]; P < 0.001, respectively).

CONCLUSIONS

β-blocker withdrawal improved maximal functional capacity in patients with HFpEF and chronotropic incompetence. β-blocker use in HFpEF deserves profound re-evaluation. (β-blockers Withdrawal in Patients With HFpEF and Chronotropic Incompetence: Effect on Functional Capacity [PRESERVE-HR]; NCT03871803; 2017-005077-39).

Effect of ivabradine in heart failure: a meta-analysis of heart failure patients with reduced versus preserved ejection fraction

In clinical trials of heart failure reduced ejection fraction (HFrEF), ivabradine seemed to be an effective heart rate lowering agent associated with lower risk of cardiovascular death. In contrast, ivabradine failed to improve cardiovascular outcomes in heart failure preserved ejection fraction (HFpEF) despite the significant effect on heart rate. This meta-analysis is the first to compare the effects of ivabradine on heart rate and mortality parameters in HFpEF versus HFrEF. We screened three databases: PubMed, Embase, and Cochrane Library. The outcomes of these studies were mortality, reduction in heart rate, and left ventricular function improvement. We compared the efficacy of ivabradine treatment in HFpEF versus HFrEF. Heart rate analysis of pooled data showed decrease in both HFrEF (-17.646 beats/min) and HFpEF (-11.434 beats/min), and a tendency to have stronger bradycardic effect in HFrEF (p = 0.094) in randomized clinical trials. Left ventricular ejection fraction analysis revealed significant improvement in HFrEF (5.936, 95% CI: [4.199-7.672], p < 0.001) when compared with placebo (p < 0.001). We found that ivabradine significantly improves left ventricular performance in HFrEF, at the same time it exerts a tendency to have improved bradycardic effect in HFrEF. These disparate effects of ivabradine and the higher prevalence of non-cardiac comorbidities in HFpEF may explain the observed beneficial effects in HFrEF and the unchanged outcomes in HFpEF patients after ivabradine treatment.

How to Estimate the Optimal Heart Rate in Patients with Heart Failure with Preserved Ejection Fraction

Ideal heart rate (HR), particularly for those with heart failure with preserved ejection fraction (HFpEF), remains unknown. We hypothesized that cardiac output would be maximum when the overlap between E-wave and A-wave at the trans-mitral flow is "zero" in the Doppler echocardiography. We retrospectively investigated the association among the overlap length between two waves, actual HR, and other echocardiographic parameters to construct a formula for estimating theoretically ideal HR among those with HFpEF. In total, 48 HFpEF patients were included (70-year-olds, 18 males). Given the results of multivariate linear regression analyses, the overlap length was estimated as follows: -1,050 + 8.4 × (HR [bpm]) + 0.6 × (deceleration time [millisecond]) + 1.7 × (A-width [millisecond]), which had a strong agreement with the actually measured overlap length (r = 0.86, P < 0.001). Theoretically ideal HR was calculated by substituting zero into the estimated overlap length as follows: 125 - 0.07 × (deceleration time [millisecond]) - 0.20 × (A-width [millisecond]). In the validation cohort including another 143 HFpEF patients, the estimated overlap using the formula again had a strong agreement with the actually measured overlap (r = 0.72, P < 0.001). In this study, we proposed a novel formula for calculating theoretically ideal HR, consisting of deceleration time and A-width, in the HFpEF cohort. Clinical implication to optimize the HR targeting the theoretically ideal HR should be investigated in prospective studies.

Heart failure with preserved ejection fraction based on aging and comorbidities

Heart failure (HF) with preserved ejection fraction (HFpEF) is a leading cause of hospitalizations and mortality when diagnosed at the age of ≥ 65 years. HFpEF represents multifactorial and multisystemic syndrome and has different pathophysiology and phenotypes. Its diagnosis is difficult to be established based on left ventricular ejection fraction and may benefit from individually tailored approaches, underlying age-related changes and frequent comorbidities. Compared with the rapid development in the treatment of heart failure with reduced ejection fraction, HFpEF presents a great challenge and needs to be addressed considering the failure of HF drugs to improve its outcomes. Further extensive studies on the relationships between HFpEF, aging, and comorbidities in carefully phenotyped HFpEF subgroups may help understand the biology, diagnosis, and treatment of HFpEF. The current review summarized the diagnostic and therapeutic development of HFpEF based on the complex relationships between aging, comorbidities, and HFpEF.

Cellular and molecular pathobiology of heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) affects half of all patients with heart failure worldwide, is increasing in prevalence, confers substantial morbidity and mortality, and has very few effective treatments. HFpEF is arguably the greatest unmet medical need in cardiovascular disease. Although HFpEF was initially considered to be a haemodynamic disorder characterized by hypertension, cardiac hypertrophy and diastolic dysfunction, the pandemics of obesity and diabetes mellitus have modified the HFpEF syndrome, which is now recognized to be a multisystem disorder involving the heart, lungs, kidneys, skeletal muscle, adipose tissue, vascular system, and immune and inflammatory signalling. This multiorgan involvement makes HFpEF difficult to model in experimental animals because the condition is not simply cardiac hypertrophy and hypertension with abnormal myocardial relaxation. However, new animal models involving both haemodynamic and metabolic disease, and increasing efforts to examine human pathophysiology, are revealing new signalling pathways and potential therapeutic targets. In this Review, we discuss the cellular and molecular pathobiology of HFpEF, with the major focus being on mechanisms relevant to the heart, because most research has focused on this organ. We also highlight the involvement of other important organ systems, including the lungs, kidneys and skeletal muscle, efforts to characterize patients with the use of systemic biomarkers, and ongoing therapeutic efforts. Our objective is to provide a roadmap of the signalling pathways and mechanisms of HFpEF that are being characterized and which might lead to more patient-specific therapies and improved clinical outcomes.

Physical Functioning in Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is increasingly prevalent, yet interventions and therapies to improve outcomes remain limited. There has been increasing attention towards the impact of comorbidities and physical functioning (PF) on poor clinical outcomes within this population. In this review, we summarize and discuss the literature on PF in HFpEF, its association with clinical and patient-centered outcomes, and future advances in the care of HFpEF with respect to PF. Multiple PF metrics have been demonstrated to provide prognostic value within HFpEF, yet the data are less robust compared with other patient populations, highlighting the need for further investigation. The evaluation and detection of poor PF provides a potential strategy to improve care in HFpEF, and future studies are needed to understand if modulating PF improves clinical and/or patient-reported outcomes. LAY SUMMARY: • Patients with heart failure with preserved ejection fraction (HFpEF) commonly have impaired physical functioning (PF) demonstrated by limitations across a wide range of common PF metrics.• Impaired PF metrics demonstrate prognostic value for both clinical and patient-reported outcomes in HFpEF, making them plausible therapeutic targets to improve outcomes.• Clinical trials are ongoing to investigate novel methods of detecting, monitoring, and improving impaired PF to enhance HFpEF care.Heart failure with preserved ejection fraction (HFpEF) is increasingly prevalent, yet interventions and therapies to improve outcomes remain limited. As such, there has been increasing focus on the impact of physical performance (PF) on clinical and patient-centered outcomes. In this review, we discuss the state of PF in patients with HFpEF by examining the multitude of PF metrics available, their respective strengths and limitations, and their associations with outcomes in HFpEF. We highlight future advances in the care of HFpEF with respect to PF, particularly regarding the evaluation and detection of poor PF.

Determinants and consequences of heart rate and stroke volume response to exercise in patients with heart failure and preserved ejection fraction

AIMS

A hallmark of heart failure with preserved ejection fraction (HFpEF) is impaired exercise capacity of varying severity. The main determinant of exercise capacity is cardiac output (CO), however little information is available about the relation between the constituents of CO - heart rate and stroke volume - and exercise capacity in HFpEF. We sought to determine if a heterogeneity in heart rate and stroke volume response to exercise exists in patients with HFpEF and describe possible clinical phenotypes associated with differences in these responses.

METHODS AND RESULTS

Data from two prospective trials of HFpEF (n = 108) and a study of healthy participants (n = 42) with invasive haemodynamic measurements during exercise were utilized. Differences in central haemodynamic responses were analysed with regression models. Chronotropic incompetence was present in 39-56% of patients with HFpEF and 3-56% of healthy participants depending on the definition used, but some (n = 47, 44%) had an increase in heart rate similar to that of healthy controls. Patients with HFpEF had a smaller increase in their stroke volume index (SVI) (HFpEF: +4 ± 10 mL/m² , healthy participants: +24 ± 12 mL/m² , P < 0.0001), indeed, SVI fell in 28% of patients at peak exercise. Higher body mass index and lower SVI at rest were associated with smaller increases in heart rate during exercise, whereas higher resting heart rate, and angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker use were associated with a greater increase in SVI in patients with HFpEF.

CONCLUSION

The haemodynamic response to exercise was very heterogeneous among patients with HFpEF, with chronotropic incompetence observed in up to 56%, and 28% had impaired increase in SVI. This suggests that haemodynamic exercise testing may be useful to identify which HFpEF patients may benefit from interventions targeting stroke volume and chronotropic response.

Exercise Ventricular Rates, Cardiopulmonary Exercise Performance, and Mortality in Patients With Heart Failure With Atrial Fibrillation

BACKGROUND

In heart failure (HF) with sinus rhythm, resting and exercise heart rates correlate with exercise capacity and mortality. However, in HF with atrial fibrillation (AF), this correlation is unknown. Our aim is to investigate the association of resting and exercise ventricular rates (VRs) with exercise capacity and mortality in HF with AF.

METHODS

We identified 903 patients with HF and AF referred for cardiopulmonary stress testing. AF was defined as history of AF and AF during cardiopulmonary stress testing. We constructed multivariable models to evaluate the association of resting VR, peak exercise VR, VR reserve (peak VR-resting VR), and chronotropic index with (1) peak oxygen consumption (PVO₂) ≤18 mL/kg per minute, (2) continuous PVO₂, and (3) 10-year all-cause mortality.

RESULTS

Median (25th-75th percentile) age was 60 (52-67) years, left ventricular ejection fraction was 25 (15-50)%, and 76.1% were males. Patients with lower (quartile 1) compared with higher (quartile 4) peak VR, VR reserve, and chronotropic index were more likely to have PVO₂ ≤18 mL/kg per min (adjusted odds ratio [95% CI]: 14.92 [8.07-27.58], 24.60 [12.36-48.98], and 22.31 [11.24-44.27], respectively), and higher all-cause mortality (adjusted hazard ratio [95% CI]: 2.56 [1.62-4.04], 2.29 [1.47-3.59], and 2.30 [1.51-3.49], respectively). For every 10 beats per minute increase in VR reserve, PVO₂ increased by 1.05 mL/kg per minute (B-coefficient [95% CI]: 1.05 [0.94-1.15]) and mortality decreased by 12% (adjusted hazard ratio [95% CI]: 0.88 [0.83-0.94]). Resting VR was associated with PVO₂ (B-coefficient [95% CI]: -0.46 [-0.70 to -0.23]) but not mortality (adjusted hazard ratio [95% CI]: 0.97 [0.88-1.06]).

CONCLUSIONS

In patients with HF and AF, higher resting VR and lower peak exercise VR, VR reserve, and chronotropic index were all associated with worse peak exercise capacity, but only lower exercise VR parameters were associated with higher mortality. Dedicated studies are needed to gauge whether modulating exercise VR enhances exercise performance and outcomes.

Ivabradine in Cardiovascular Disease Management Revisited: a Review

Ivabradine is a unique agent that is distinct from beta-blockers and calcium channel blockers as it reduces heart rate without affecting myocardial contractility or vascular tone. Ivabradine is a use-dependent inhibitor targeting the sinoatrial node. It is approved for use in the United States as an adjunct therapy for heart rate reduction in patients with heart failure with reduced ejection fraction. In this scenario, ivabradine has demonstrated improved clinical outcomes due to reduction in heart failure readmissions. However, there has been conflicting evidence from prospective studies and randomized controlled trials for its use in stable ischemic heart disease regarding efficacy in symptom reduction and mortality benefit. Ivabradine may also play a role in the treatment of patients with inappropriate sinus tachycardia, who often cannot tolerate beta-blockers and/or calcium channel blockers. In this review, we highlight the evidence for the nuances of using ivabradine in heart failure, stable ischemic heart disease, and inappropriate sinus tachycardia to raise awareness for its vital role in the treatment of select populations.

Diagnostic utility of sub-maximum cardiopulmonary exercise testing in the ambulatory setting for heart failure with preserved ejection fraction

Pulmonary hypertension is commonly associated with heart failure with preserved ejection fraction. In heart failure with preserved ejection fraction, the elevated left-sided filling pressures result in isolated post-capillary pulmonary hypertension or combined pre- and post-capillary pulmonary hypertension. Although right heart catheterization is the gold standard for diagnosis, it is an invasive test with associated risks. The ability of sub-maximum cardiopulmonary exercise test as an adjunct diagnostic tool in pulmonary hypertension-associated heart failure with preserved ejection fraction is not known. Forty-six patients with heart failure with preserved ejection fraction and pulmonary hypertension (27 patients with combined pre- and post-capillary pulmonary hypertension and 19 patients with isolated post-capillary pulmonary hypertension) underwent sub-maximum cardiopulmonary exercise test followed by right heart catheterization. The study also included 18 age- and gender-matched control subjects. Several sub-maximum gas exchange parameters were examined to determine the ability of sub-maximum cardiopulmonary exercise test to distinguish between isolated post-capillary pulmonary hypertension and combined pre- and post-capillary pulmonary hypertension. Conventional echocardiogram measures did not distinguish between isolated post-capillary pulmonary hypertension and combined pre- and post-capillary pulmonary hypertension. Compared to isolated post-capillary pulmonary hypertension, combined pre- and post-capillary pulmonary hypertension had greater ventilatory equivalent for carbon dioxide (VE/VCO₂) slope, reduced delta end-tidal CO₂ change during exercise, reduced oxygen uptake efficiency slope, and reduced gas exchange determined pulmonary vascular capacitance. The latter was significantly associated with right heart catheterization determined pulmonary artery compliance (r = 0.5; p = 0.0004). On univariate analysis, sub-maximum VE/VCO₂, delta end-tidal carbon dioxide, and gas exchange determined pulmonary vascular capacitance emerged as independent predictors of the extrapolated maximum oxygen uptake (%predicted) (β-coefficient values of –7.32, 95% CI: –13.3 – (–1.32), p = 0.01; 8.01, 95% CI: 1.96–14.05, p = 0.01; 8.78, 95% CI: 2.26–15.29, p = 0.01, respectively). Sub-maximum gas exchange parameters obtained during cardiopulmonary exercise test in an ambulatory setting allows for discrimination between isolated post-capillary pulmonary hypertension and combined pre- and post-capillary pulmonary hypertension. Additionally, sub-maximum cardiopulmonary exercise test derived VE/VCO₂, delta end-tidal carbon dioxide, and gas exchange determined pulmonary vascular capacitance influences aerobic capacity in heart failure with preserved ejection fraction.

Ivabradine as adjuvant treatment for chronic heart failure

BACKGROUND

Chronic heart failure is one of the most common medical conditions, affecting more than 23 million people worldwide. Despite established guideline-based, multidrug pharmacotherapy, chronic heart failure is still the cause of frequent hospitalisation, and about 50% die within five years of diagnosis.

OBJECTIVES

To assess the effectiveness and safety of ivabradine in individuals with chronic heart failure.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and CPCI-S Web of Science in March 2020. We also searched ClinicalTrials.gov and the WHO ICTRP. We checked reference lists of included studies. We did not apply any time or language restrictions.

SELECTION CRITERIA

We included randomised controlled trials in which adult participants diagnosed with chronic heart failure were randomly assigned to receive either ivabradine or placebo/usual care/no treatment. We distinguished between type of heart failure (heart failure with a reduced ejection fraction or heart failure with a preserved ejection fraction) as well as between duration of ivabradine treatment (short term (< 6 months) or long term (≥ 6 months)).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, extracted data, and checked data for accuracy. We calculated risk ratios (RR) using a random-effects model. We completed a comprehensive 'Risk of bias' assessment for all studies. We contacted authors for missing data. Our primary endpoints were: mortality from cardiovascular causes; quality of life; time to first hospitalisation for heart failure during follow-up; and number of days spent in hospital due to heart failure during follow-up. Our secondary endpoints were: rate of serious adverse events; exercise capacity; and economic costs (narrative report). We assessed the certainty of the evidence applying the GRADE methodology.

MAIN RESULTS

We included 19 studies (76 reports) involving a total of 19,628 participants (mean age 60.76 years, 69% male). However, few studies contributed data to meta-analyses due to inconsistency in trial design (type of heart failure) and outcome reporting and measurement. In general, risk of bias varied from low to high across the included studies, with insufficient detail provided to inform judgement in several cases. We were able to perform two meta-analyses focusing on participants with heart failure with a reduced ejection fraction (HFrEF) and long-term ivabradine treatment. There was evidence of no difference between ivabradine and placebo/usual care/no treatment for mortality from cardiovascular causes (RR 0.99, 95% confidence interval (CI) 0.88 to 1.11; 3 studies; 17,676 participants; I2 = 33%; moderate-certainty evidence). Furthermore, we found evidence of no difference in rate of serious adverse events amongst HFrEF participants randomised to receive long-term ivabradine compared with those randomised to placebo, usual care, or no treatment (RR 0.96, 95% CI 0.92 to 1.00; 2 studies; 17,399 participants; I2 = 12%; moderate-certainty evidence). We were not able to perform meta-analysis for all other outcomes, and have low confidence in the findings based on the individual studies.

AUTHORS' CONCLUSIONS

We found evidence of no difference in cardiovascular mortality and serious adverse events between long-term treatment with ivabradine and placebo/usual care/no treatment in participants with heart failure with HFrEF. Nevertheless, due to indirectness (male predominance), the certainty of the available evidence is rated as moderate.

Therapeutic approaches in heart failure with preserved ejection fraction: past, present, and future

In contrast to the wealth of proven therapies for heart failure with reduced ejection fraction (HFrEF), therapeutic efforts in the past have failed to improve outcomes in heart failure with preserved ejection fraction (HFpEF). Moreover, to this day, diagnosis of HFpEF remains controversial. However, there is growing appreciation that HFpEF represents a heterogeneous syndrome with various phenotypes and comorbidities which are hardly to differentiate solely by LVEF and might benefit from individually tailored approaches. These hypotheses are supported by the recently presented PARAGON-HF trial. Although treatment with LCZ696 did not result in a significantly lower rate of total hospitalizations for heart failure and death from cardiovascular causes among HFpEF patients, subanalyses suggest beneficial effects in female patients and those with an LVEF between 45 and 57%. In the future, prospective randomized trials should focus on dedicated, well-defined subgroups based on various information such as clinical characteristics, biomarker levels, and imaging modalities. These could clarify the role of LCZ696 in selected individuals. Furthermore, sodium-glucose cotransporter-2 inhibitors have just proven efficient in HFrEF patients and are currently also studied in large prospective clinical trials enrolling HFpEF patients. In addition, several novel disease-modifying drugs that pursue different strategies such as targeting cardiac inflammation and fibrosis have delivered preliminary optimistic results and are subject of further research. Moreover, innovative device therapies may enhance management of HFpEF, but need prospective adequately powered clinical trials to confirm safety and efficacy regarding clinical outcomes. This review highlights the past, present, and future therapeutic approaches in HFpEF.

Addressing Orthostatic Hypotension in Heart Failure: Pathophysiology, Clinical Implications and Perspectives

Heart failure (HF)is a condition at high risk for orthostatic hypotension (OH)given the large proportion of patients at an advanced age and high burden of comorbidities contributing to OH, as well as a high prevalence of medications with neurovascular and volume modulating properties. Early identification of OH in HF seems to be crucial as OH can have an impact on patient symptoms, activity level and independence, be a marker of specific pathophysiological changes or be an indicator of need for personalized treatment. OH might contribute significantly to bad enough prognosis in HF, as, besides a risk of falls and cognitive decline, it was found to be associated with cardiovascular morbidity and mortality. In this review, we aimed to incentivize the routine use of orthostatic testing in HF, as well as stimulate future research in this field, which could lead to significant advances in the treatment and outcomes.

Impaired Exercise Tolerance in Heart Failure With Preserved Ejection Fraction: Quantification of Multiorgan System Reserve Capacity

Exercise intolerance is a principal feature of heart failure with preserved ejection fraction (HFpEF), whether or not there is evidence of congestion at rest. The degree of functional limitation observed in HFpEF is comparable to patients with advanced heart failure and reduced ejection fraction. Exercise intolerance in HFpEF is characterized by impairments in the physiological reserve capacity of multiple organ systems, but the relative cardiac and extracardiac deficits vary among individuals. Detailed measurements made during exercise are necessary to identify and rank-order the multiorgan system limitations in reserve capacity that culminate in exertional intolerance in a given person. We use a case-based approach to comprehensively review mechanisms of exercise intolerance and optimal approaches to evaluate exercise capacity in HFpEF. We also summarize recent and ongoing trials of novel devices, drugs, and behavioral interventions that aim to improve specific exercise measures such as peak oxygen uptake, 6-min walk distance, heart rate, and hemodynamic profiles in HFpEF. Evaluation during the clinically relevant physiological perturbation of exercise holds promise to improve the precision with which HFpEF is defined and therapeutically targeted.

Diastolic Ventricular Interaction in Heart Failure With Preserved Ejection Fraction

Background

Exercise‐induced pulmonary hypertension is common in heart failure with preserved ejection fraction (HFpEF). We hypothesized that this could result in pericardial constraint and diastolic ventricular interaction in some patients during exercise.

Methods and Results

Contrast stress echocardiography was performed in 30 HFpEF patients, 17 hypertensive controls, and 17 normotensive controls (healthy). Cardiac volumes, and normalized radius of curvature (NRC) of the interventricular septum at end‐diastole and end‐systole, were measured at rest and peak‐exercise, and compared between the groups. The septum was circular at rest in all 3 groups at end‐diastole. At peak‐exercise, end‐systolic NRC increased to 1.47±0.05 (P<0.001) in HFpEF patients, confirming development of pulmonary hypertension. End‐diastolic NRC also increased to 1.54±0.07 (P<0.001) in HFpEF patients, indicating septal flattening, and this correlated significantly with end‐systolic NRC (ρ=0.51, P=0.007). In hypertensive controls and healthy controls, peak‐exercise end‐systolic NRC increased, but this was significantly less than observed in HFpEF patients (HFpEF, P=0.02 versus hypertensive controls; P<0.001 versus healthy). There were also small, non‐significant increases in end‐diastolic NRC in both groups (hypertensive controls, +0.17±0.05, P=0.38; healthy, +0.06±0.03, P=0.93). In HFpEF patients, peak‐exercise end‐diastolic NRC also negatively correlated (r=−0.40, P<0.05) with the change in left ventricular end‐diastolic volume with exercise (ie, the Frank‐Starling mechanism), and a trend was noted towards a negative correlation with change in stroke volume (r=−0.36, P=0.08).

Conclusions

Exercise pulmonary hypertension causes substantial diastolic ventricular interaction on exercise in some patients with HFpEF, and this restriction to left ventricular filling by the right ventricle exacerbates the pre‐existing impaired Frank‐Starling response in these patients.

Effect of ivabradine on exercise capacity in individuals with heart failure with preserved ejection fraction

The prevalence of heart failure with preserved ejection fraction (HFpEF) is about 30-75% of the patients living with heart failure. A hallmark symptom of these patients is exercise intolerance. Ivabradine can, eventually, increase exercise capacity by heart rate control. However, clinical trials show conflicting results about the effects of ivabradine on exercise capacity, an important prognostic variable. The aim of this study was to investigate the effects of ivabradine on exercise capacity in individuals with HFpEF. This study was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement and supplemented by guidance from the Cochrane Collaboration Handbook for Systematic Reviews of Interventions. For the meta-analysis, a forest plot was used to graphically present the effect sizes and the 95% CIs. Four randomized controlled trials were included. Ivabradine did not change exercise capacity expressed by peak VO₂ and 6MWT (MD = 0.8; 95% CI - 2.5 to 4.3; P = 0.62) (Fig. 4a). In our secondary analysis, the ivabradine group showed a significant resting HR reduction when compared with placebo (MD = - 13.2; 95% CI - 16.6 to -9.8; P < 0.00001) and ivabradine showed increased values of E/e' ratio compared with placebo (MD = 0.8; 95% CI 0.0 to 1.6; P = 0.04). Current available evidence suggests that there is no effect of ivabradine on exercise capacity in patients with HFpEF. Also, questions about negative effects on E/e' values and adverse events associated with ivabradine treatment need to be considered in future studies.

Management of heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction is a highly heterogenous disease. There is emerging evidence that treatment should be tailored to the individual’s associated comorbidities

No current algorithms exist for the management of heart failure with preserved ejection fraction. Conventional therapies used in heart failure with reduced ejection fraction are yet to show a mortality benefit

Key treatment objectives include control of hypertension and fluid balance

Common comorbidities include coronary artery disease, atrial fibrillation, obesity, diabetes, renal impairment and pulmonary hypertension. These comorbidities should be considered in all patients and treatment optimised

Role of Ivabradine in Patients with Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) accounts for 50% of patients with heart failure. HFpEF carries almost similar morbidity and mortality outcomes to heart failure with reduced ejection fraction (HFrEF). Despite many trials, no management has been shown to improve mortality outcomes in HFpEF. An elevated heart rate in patients with HFpEF has been associated with worse outcomes. Previous trials on the use of beta-blockers in reducing the heart rate in patients with HFpEF have shown worse outcomes, possibly due to the negative inotropic effects. The funny current inhibitor, ivabradine, results in a reduced heart rate without affecting inotropy. Two randomized controlled trials and one cross-over study have evaluated the use of ivabradine in HFpEF patients. The outcomes of the trials have been heterogeneous; ivabradine showed improved exercise tolerance, no change in primary endpoints was seen l, and there was a worsening in the outcomes. Our review underscores the requirement of a large randomized clinical trial in the appropriate patient population.

Beta-blockers withdrawal in patients with heart failure with preserved ejection fraction and chronotropic incompetence: Effect on functional capacity rationale and study design of a prospective, randomized, controlled trial (The Preserve-HR trial)

Background

The pathophysiology of heart failure with preserved ejection fraction (HFpEF) is complex and multifactorial. Chronotropic incompetence (ChI) has emerged as a crucial pathophysiological mechanism. Beta‐blockers, drugs with negative chronotropic effects, are commonly used in HFpEF, although current evidence does not support its routine use in these patients.

Hypothesis

We postulate beta‐blockers may have deleterious effects in HFpEF and ChI. This work aims to evaluate the short‐term effect of beta‐blockers withdrawal on functional capacity assessed by the maximal oxygen uptake (peakVO2) in patients with HFpEF and ChI.

Methods

This is a prospective, crossover, randomized (1:1) and multicenter study. After randomization, the clinical and cardiac rhythm will be continuously registered for 30 days. PeakVO2 is assessed by cardiopulmonary exercise testing (CPET) at 15 and 30 days in both groups. Secondary endpoints include quality of life, cognitive, and safety assessment. Patients with stable HFpEF, functional class New York Heart Association (NYHA) II‐III, chronic treatment with beta‐blockers, and ChI will be enrolled. A sample size estimation [alfa: 0.05, power: 90%, a 20% loss rate, and delta change of mean peakVO2: +1.2 mL/kg/min (SD ± 2.0)] of 52 patients is necessary to test our hypothesis.

Results

Patients started enrolling in October 2018. As January 14th, 2020, 28 patients have been enrolled. It is projected to enroll the last patient at the end of July 2020.

Conclusions

Optimizing therapy that improves functional capacity remains an unmeet priority in HFpEF. Deprescribing beta‐blockers in patients with HFpEF and ChI seems a plausible intervention to improve functional capacity. This trial is an attempt towards precision medicine in this complex syndrome.

Trial registration

http://clinicaltrials.gov: NCT03871803.

Effect of Ivabradine on Left Ventricular Diastolic Function, Exercise Tolerance and Quality of Life in Patients With Heart Failure: A Systemic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Ivabradine is a heart rate-lowering drug that selectively inhibits the funny (If) current of the sinoatrial node. It is currently recommended in patients with heart failure (HF) with reduced ejection fraction (HFrEF) in sinus rhythm and a heart rate of ≥ 70 beats per minute (bpm) at rest. To investigate whether ivabradine has an effect on diastolic dysfunction, exercise tolerance and quality of life (QOL), we conducted a systemic review and meta-analysis of randomized controlled trials (RCTs).

METHODS

We searched PubMed, EMBASE and Cochrane Central Register of Clinical Trials for studies on the effect of ivabradine on left ventricular (LV) diastolic dysfunction, exercise tolerance, QOL, readmission for worsening HF and mortality in both patients with HF with preserved ejection fraction (HFpEF) and HFrEF.

RESULTS

Thirteen RCTs with 881 patients met the inclusion criteria. According to the pooled analysis, for the HFpEF subgroup, treatment with ivabradine resulted in a decrease in early diastolic mitral inflow to late diastolic flow ratio (E/A) (standardized mean difference (SMD): -0.53; 95% confidence interval (CI): -0.99, -0.07; P < 0.000) and increase in peak oxygen uptake during exercise (VO2) (SMD: 0.05; 95% CI: -0.35, 0.45; P < 0.00; I2 = 95.1%). Similar effect was seen in the HFrEF subgroup with decrease in E/A ratio (SMD: -0.33; 95% CI: -0.59, -0.06; P < 0.000) and early diastolic mitral inflow to annular velocity ratio (E/e') (SMD: -1.01; 95% CI: -1.49, -0.54; P < 0.012). Ivabradine therapy increased peak VO2 and 6-min walk test (6MWT) in HFrEF patients (SMD: 0.83; 95% CI: 0.35, 1.32; P < 0.00; I2 = 97.5% and SMD: 1.11; 95% CI: 0.82, 1.41; P < 0.000, respectively). There was also significant reduction in Minnesota Living with Heart Failure Questionnaire (MLHFQ) score (SMD: -0.68; 95% CI: -0.91, -0.45; P < 0.000). However, there was no significant difference in readmission for worsening HF and all-cause mortality between ivabradine and control (risk ratio (RR): 1.44; 95% CI: 0.73, 2.16; P < 0.148 and RR: 0.76; 95% CI: 0.19, 1.33; P < 0.907, respectively).

CONCLUSIONS

Ivabradine therapy is associated with improved LV diastolic function, increases exercise tolerance and hence QOL, but it has no significant effect on readmission for worsening HF and all-cause mortality.