Benefits of Heart Rate Slowing With Ivabradine in Patients With Systolic Heart Failure and Coronary Artery Disease

Effect of hypertriglyceridemia on left ventricular global longitudinal strain in patients with coronary heart disease in Jilin Province, China: a cross-sectional study

Aims

Using speckle tracking technology to investigate the effect of hypertriglyceridemia on the global longitudinal strain(GLS) of the left ventricle in patients with coronary heart disease in the early stage, and to explore the value of myocardial strain in early identification of cardiac dysfunction in patients with coronary heart disease in the pre-heart failure stage.

Methods

A cross-sectional study of 138 participants was conducted in Jilin Province, China. Basic clinical, biochemical, and echocardiographic data were obtained for all patients. Myocardial strain parameters were compared between the hypertriglyceridemia and normal triglyceride level groups and the effect of hypertriglyceridemia on early left ventricular global longitudinal strain impairment in coronary heart disease patients was evaluated.

Results

The overall longitudinal strain of the left ventricle was smaller in the hypertriglyceridemia group than in the normal triglyceride group. After the multivariate Logistic regression model adjusting for the influence of confounding factors, the results remained stable.

Conclusions

The risk of impairment of global longitudinal strain of the left ventricle in patients with coronary heart disease is positively correlated with triglyceride levels, and hypertriglyceridemia maybe an independent risk factor affecting early cardiac dysfunction in the pre-heart failure stage of patients with coronary heart disease.

In-hospital Heart Rate Reduction With Beta Blockers and Ivabradine Early After Recovery in Patients With Acute Decompensated Heart Failure Reduces Short-Term Mortality and Rehospitalization

Objective: In the past years, heart rate (HR) has emerged as a highly relevant modifiable risk factor for heart failure (HF) patients. However, most of the clinical trials so far evaluated the role of HR in stable chronic HF cohorts. The aim of this multi-center, prospective observational study was to assess the association between HR and therapy with HR modulators (beta blockers, ivabradine, or a combination of ivabradine and beta blockers) at hospital discharge with patients' cardiovascular mortality and re-hospitalization at 6 months in acutely decompensated HF patients.

Materials and Methods: We recruited 289 HF patients discharged alive after admission for HF decompensation from 10 centers in northern Italy over 9 months (from April 2017 to January 2018). The primary endpoint was the combination of cardiovascular mortality or re-hospitalizations for HF at 6 months.

Results: At 6 months after discharge, 64 patients were readmitted (32%), and 39 patients died (16%). Multivariate analysis showed that HR at discharge ≥ 90 bpm (OR = 8.47; p = 0.016) independently predicted cardiovascular mortality, while therapy with beta blockers at discharge was found to reduce the risk of the composite endpoint. In patients receiving HR modulators the event rates for the composite endpoint, all-cause mortality, and cardiovascular mortality were lower than in patients not receiving HR modulators.

Conclusions: Heart rate at discharge ≥90 bpm predicts cardiovascular mortality, while therapy with beta blockers is negatively associated with the composite endpoint of cardiovascular mortality and hospitalization at 6 months in acutely decompensated HF patients. Patients receiving a HR modulation therapy at hospital discharge showed the lowest rate of cardiovascular mortality and re-hospitalization.

Ivabradine improves survival and attenuates cardiac remodeling in isoproterenol-induced myocardial injury

This study investigated whether ivabradine, a selective I_f current inhibitor reducing heart rate (HR), is able to improve survival and prevent left ventricular (LV) remodeling in isoproterenol‐induced heart damage. Wistar rats were treated for 6 weeks: controls (n = 10), ivabradine (10 mg/kg/day orally; n = 10), isoproterenol (5 mg/kg/day intraperitoneally; n = 40), and isoproterenol plus ivabradine (n = 40). Isoproterenol increased mortality, induced hypertrophy of both ventricles and LV fibrotic rebuilding, and reduced systolic blood pressure (SBP). Ivabradine significantly increased survival rate (by 120%) and prolonged average survival time (by 20%). Furthermore, ivabradine reduced LV weight and hydroxyproline content in soluble and insoluble collagen fraction, reduced HR and attenuated SBP decline. We conclude that ivabradine improved survival in isoproterenol‐damaged hearts.

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.

Effect of ivabradine on major adverse cardiovascular events and mortality in critically ill patients: a systematic review and meta-analyses of randomised controlled trials with trial sequential analyses

BACKGROUND

Ivabradine lowers heart rate (HR) without affecting contractility or vascular tone. It is licensed for HR control in chronic heart diseases. We performed a systematic review and meta-analyses to examine whether ivabradine could decrease major adverse cardiovascular events (MACE) and mortality in critically ill patients.

METHODS

We searched Medline, Embase, Cochrane Library, and Web of Science for RCTs. Trial quality was assessed using the Cochrane risk of bias tool. Random-effects meta-analyses were performed if at least three trials or 100 patients were available. Results are reported as weighted mean difference (WMD), odds ratio (OR), and 95% confidence intervals (CIs). Trial sequential analyses were performed to estimate the sample size needed to reach definitive conclusions of efficacy or futility.

RESULTS

We included 13 RCTs (n=1497 patients). We found no evidence of an impact of ivabradine on MACE (three RCTs, 819 patients; OR=0.77; 95% CI, 0.53-1.11) or mortality (10 RCTs, 1356 patients; OR=1.07; 95% CI, 0.63-1.82), but sample sizes were not reached to allow definitive conclusions. Compared with placebo or standard care, ivabradine reduced HR (eight RCTs, 464 patients; WMD, -9.5 beats min^-1; 95% CI, -13.3 to -5.8). Risk of bradycardia was not different between ivabradine and control (five RCTs, 434 patients; OR=1.2; 95% CI, 0.60-2.38). Risk of bias was overall high or unclear.

CONCLUSIONS

Ivabradine reduces HR compared with placebo or standard care. The effect on MACE or mortality in acute care remains unclear. Further RCTs powered to detect changes in clinically relevant outcomes are warranted.

CLINICAL TRIAL REGISTRATION

Prospero CRD42018086109.

Optimization of Heart Failure Treatment by Heart Rate Reduction

Heart failure (HF) treatment should be optimized in addition to guideline-directed and recommended drugs to achieve an appropriate heart rate (i.e. 50−60 bpm) by ivabradine in patients with a heart rate >70 bpm in sinus rhythm and with an ejection fraction ≤35%. Heart rate reduction was to reduce cardiovascular death and HF hospitalization dependent on baseline resting heart rate. In particular in patients at a heart rate >75 bpm, a reduction in cardiovascular death, all-cause death, HF death, HF hospitalization and all-cause hospitalization has been observed. The optimal heart rate achieved appears to be between 50−60 bpm, if well tolerated as in these patients the lowest event rate is observed on treatment. Heart rate reduction is, therefore, a treatable risk factor in chronic HF. Observational studies support the concept that it is a risk indicator in other cardiovascular and non-cardiovascular conditions. Whether heart rate reduction is also modifying risk in other conditions than chronic HF should be explored in prospective clinical trials.

Pharmacology of Ivabradine and the Effect on Chronic Heart Failure

Chronic Heart Failure (CHF) is a complex clinical syndrome with a high incidence worldwide. Although various types of pharmacological and device therapies are available for CHF, the prognosis is not ideal, for which, the control of increased Heart Rate (HR) is critical. Recently, a bradycardic agent, ivabradine, is found to reduce HR by inhibiting the funny current (If). The underlying mechanism states that ivabradine can enter the Hyperpolarization-activated Cyclic Nucleotide-gated (HCN) channels and bind to the intracellular side, subsequently inhibiting the If. This phenomenon can prolong the slow spontaneous phase in the diastolic depolarization, and thus, reduce HR. The clinical trials demonstrated the significant effects of the drug on reducing HR and improving the symptoms of CHF with fewer adverse effects. This review primarily introduces the chemical features and pharmacological characteristics of ivabradine and the mechanism of treating CHF. Also, some expected therapeutic effects on different diseases were also concluded. However, ivabradine, as a typical If channel inhibitor, necessitates additional research to verify its pharmacological functions.

The Human Coronary Collateral Circulation, Its Extracardiac Anastomoses and Their Therapeutic Promotion

Cardiovascular disease remains the leading global cause of death, and the number of patients with coronary artery disease (CAD) and exhausted therapeutic options (i.e., percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG) and medical treatment) is on the rise. Therefore, the evaluation of new therapeutic approaches to offer an alternative treatment strategy for these patients is necessary. A promising research field is the promotion of the coronary collateral circulation, an arterio-arterial network able to prevent or reduce myocardial ischemia in CAD. This review summarizes the basic principles of the human coronary collateral circulation, its extracardiac anastomoses as well as the different therapeutic approaches, especially that of stimulating the extracardiac collateral circulation via permanent occlusion of the internal mammary arteries.

Atrial Fibrillation in Patients with Heart Failure: Current State and Future Directions

Heart failure affects nearly 26 million people worldwide. Patients with heart failure are frequently affected with atrial fibrillation, and the interrelation between these pathologies is complex. Atrial fibrillation shares the same risk factors as heart failure. Moreover, it is associated with a higher-risk baseline clinical status and higher mortality rates in patients with heart failure. The mechanisms by which atrial fibrillation occurs in a failing heart are incompletely understood, but animal studies suggest they differ from those that occur in a healthy heart. Data suggest that heart failure-induced atrial fibrosis and atrial ionic remodeling are the underlying abnormalities that facilitate atrial fibrillation. Therapeutic considerations for atrial fibrillation in patients with heart failure include risk factor modification and guideline-directed medical therapy, anticoagulation, rate control, and rhythm control. As recommended for atrial fibrillation in the non-failing heart, anticoagulation in patients with heart failure should be guided by a careful estimation of the risk of embolic events versus the risk of hemorrhagic episodes. The decision whether to target a rate-control or rhythm-control strategy is an evolving aspect of management. Currently, both approaches are good medical practice, but recent data suggest that rhythm control, particularly when achieved through catheter ablation, is associated with improved outcomes. A promising field of research is the application of neurohormonal modulation to prevent the creation of the "structural substrate" for atrial fibrillation in the failing heart.

Influences of Ivabradine treatment on serum levels of cardiac biomarkers sST2, GDF-15, suPAR and H-FABP in patients with chronic heart failure

Chronic heart failure (CHF) represents a major cause of hospitalization and death. Recent evidence shows that novel biomarkers such as soluble suppression of tumorigenicity (sST2), growth-differentiation factor-15 (GDF-15), soluble urokinase plasminogen activator receptor (suPAR) and heart-type fatty acid binding protein (H-FABP) are correlated with inflammatory and ischemic responses in CHF patients. In this study we examined the effects of Ivabradine that inhibited the hyperpolarization-activated cyclic nucleotide-gated channel (HCN channel, also called funny current I_f), thereby leading to selective heart rate reduction and improved myocardial oxygen supply on the cardiac biomarkers sST2, GDF-15, suPAR and H-FABP in 50 CHF patients at the University Hospital of Jena. Patients were divided into three groups based on the etiology of CHF: dilated cardiomyopathy (DCM, n=20), ischemic cardiomyopathy (ICM, n=20) and hypertensive cardiomyopathy (HCM, n=10). The patients were administered Ivabradine (5 mg, bid for 3 months, and 7.5 mg bid for further 3 months). Analyses of cardiovascular biomarkers were performed at baseline as well as at 3- and 6-month follow-ups. At 6-month follow-up, GDF-15 levels were significantly reduced compared to baseline levels (P=0.0215), indicating a reduction in the progress of cardiac remodeling. H-FABP concentration was significantly lower in DCM patients compared to ICM (1.89 vs 3.24 μg/mL) and HCM patients (1.89 vs 3.80 μg/mL), and decreased over the 6-month follow-up (P=0.0151). suPAR median levels remained elevated, implying major ongoing inflammatory processes. As shown by significant decreases in GDF-15 and H-FABP levels, a reduction in ventricular remodeling and sub-clinical ischemia could be assumed. However, markers of hemodynamic stress (sST2) and inflammation (suPAR) showed no change or progression after 6 months of Ivabradine treatment in CHF patients. Further studies are necessary to validate the clinical applicability of these novel cardiovascular biomarkers.

Increasing T-type calcium channel activity by β-adrenergic stimulation contributes to β-adrenergic regulation of heart rates

KEY POINTS

Cav3.1 T-type Ca2+ channel current (ICa-T ) contributes to heart rate genesis but is not known to contribute to heart rate regulation by the sympathetic/β-adrenergic system (SAS). We show that the loss of Cav3.1 makes the beating rates of the heart in vivo and perfused hearts ex vivo, as well as sinoatrial node cells, less sensitive to β-adrenergic stimulation; it also renders less conduction acceleration through the atrioventricular node by β-adrenergic stimulation. Increasing Cav3.1 in cardiomyocytes has the opposite effects. ICa-T in sinoatrial nodal cells can be upregulated by β-adrenergic stimulation. The results of the present study add a new contribution to heart rate regulation by the SAS system and provide potential new mechanisms for the dysregulation of heart rate and conduction by the SAS in the heart. T-type Ca2+ channel can be a target for heart disease treatments that aim to slow down the heart rate ABSTRACT: Cav3.1 (α1G ) T-type Ca2+ channel (TTCC) is expressed in mouse sinoatrial node cells (SANCs) and atrioventricular (AV) nodal cells and contributes to heart rate (HR) genesis and AV conduction. However, its role in HR regulation and AV conduction acceleration by the β-adrenergic system (SAS) is unclear. In the present study, L- (ICa-L ) and T-type (ICa-T ) Ca2+ currents were recorded in SANCs from Cav3.1 transgenic (TG) and knockout (KO), and control mice. ICa-T was absent in KO SANCs but enhanced in TG SANCs. In anaesthetized animals, different doses of isoproterenol (ISO) were infused via the jugular vein and the HR was recorded. The EC50 of the HR response to ISO was lower in TG mice but higher in KO mice, and the maximal percentage of HR increase by ISO was greater in TG mice but less in KO mice. In Langendorff-perfused hearts, ISO increased HR and shortened PR intervals to a greater extent in TG but to a less extent in KO hearts. KO SANCs had significantly slower spontaneous beating rates than control SANCs before and after ISO; TG SANCs had similar basal beating rates as control SANCs probably as a result of decreased ICa-L but a greater response to ISO than control SANCs. ICa-T in SANCs was significantly increased by ISO. ICa-T upregulation by β-adrenergic stimulation contributes to HR and conduction regulation by the SAS. TTCC can be a target for slowing the HR.

Defining the neural fulcrum for chronic vagus nerve stimulation: implications for integrated cardiac control

KEY POINTS

The evoked cardiac response to bipolar cervical vagus nerve stimulation (VNS) reflects a dynamic interaction between afferent mediated decreases in central parasympathetic drive and suppressive effects evoked by direct stimulation of parasympathetic efferent axons to the heart. The neural fulcrum is defined as the operating point, based on frequency-amplitude-pulse width, where a null heart rate response is reproducibly evoked during the on-phase of VNS. Cardiac control, based on the principal of the neural fulcrum, can be elicited from either vagus. Beta-receptor blockade does not alter the tachycardia phase to low intensity VNS, but can increase the bradycardia to higher intensity VNS. While muscarinic cholinergic blockade prevented the VNS-induced bradycardia, clinically relevant doses of ACE inhibitors, beta-blockade and the funny channel blocker ivabradine did not alter the VNS chronotropic response. While there are qualitative differences in VNS heart control between awake and anaesthetized states, the physiological expression of the neural fulcrum is maintained.

ABSTRACT

Vagus nerve stimulation (VNS) is an emerging therapy for treatment of chronic heart failure and remains a standard of therapy in patients with treatment-resistant epilepsy. The objective of this work was to characterize heart rate (HR) responses (HRRs) during the active phase of chronic VNS over a wide range of stimulation parameters in order to define optimal protocols for bidirectional bioelectronic control of the heart. In normal canines, bipolar electrodes were chronically implanted on the cervical vagosympathetic trunk bilaterally with anode cephalad to cathode (n = 8, 'cardiac' configuration) or with electrode positions reversed (n = 8, 'epilepsy' configuration). In awake state, HRRs were determined for each combination of pulse frequency (2-20 Hz), intensity (0-3.5 mA) and pulse widths (130-750 μs) over 14 months. At low intensities and higher frequency VNS, HR increased during the VNS active phase owing to afferent modulation of parasympathetic central drive. When functional effects of afferent and efferent fibre activation were balanced, a null HRR was evoked (defined as 'neural fulcrum') during which HRR ≈ 0. As intensity increased further, HR was reduced during the active phase of VNS. While qualitatively similar, VNS delivered in the epilepsy configuration resulted in more pronounced HR acceleration and reduced HR deceleration during VNS. At termination, under anaesthesia, transection of the vagi rostral to the stimulation site eliminated the augmenting response to VNS and enhanced the parasympathetic efferent-mediated suppressing effect on electrical and mechanical function of the heart. In conclusion, VNS activates central then peripheral aspects of the cardiac nervous system. VNS control over cardiac function is maintained during chronic therapy.