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Ivabradine, as a specific If current inhibitor, has been widely used in the treatment of chronic heart failure in adults due to its ability to reduce heart rate without affecting myocardial contractility and blood pressure. It has also shown good effects in various types of tachyarrhythmias. However, the application of ivabradine in pediatric cardiovascular diseases still faces many limitations. This article reviews the current research progress on the use of ivabradine in treating pediatric cardiovascular diseases both domestically and internationally, aiming to provide guidance for pediatric cardiologists. Citation:Chinese Journal of Contemporary Pediatrics, 2024, 26(7): 782-788.

Novel Therapies for the Treatment of Cardiovascular Disease.

Over the last decade, randomized clinical trials of several pharmacologic agents have demonstrated a reduction in cardiovascular mortality and other important secondary outcomes. Angiotensin-Neprilysin Inhibitors and Sodium-Glucose Co-transporter 2 inhibitors have now become pillars in the treatment of heart failure. Ivabradine is a negative chronotropic agent used as an adjunctive therapy in patients with heart failure. Two new hypertension therapies, zilebresiran and aprocitentan, are currently in investigational stages. Finally, mavacamten has emerged as a pharmacologic treatment for hypertrophic obstructive cardiomyopathy. Practitioners must be familiar with the indications and side effects of newer therapies as they are now frequently prescribed.

Structural determinants of ivabradine block of the open pore of HCN4.

HCN1-4 channels are the molecular determinants of the If/Ih current that crucially regulates cardiac and neuronal cell excitability. HCN dysfunctions lead to sinoatrial block (HCN4), epilepsy (HCN1), and chronic pain (HCN2), widespread medical conditions awaiting subtype-specific treatments. Here, we address the problem by solving the cryo-EM structure of HCN4 in complex with ivabradine, to date the only HCN-specific drug on the market. Our data show ivabradine bound inside the open pore at 3 Å resolution. The structure unambiguously proves that Y507 and I511 on S6 are the molecular determinants of ivabradine binding to the inner cavity, while F510, pointing outside the pore, indirectly contributes to the block by controlling Y507. Cysteine 479, unique to the HCN selectivity filter (SF), accelerates the kinetics of block. Molecular dynamics simulations further reveal that ivabradine blocks the permeating ion inside the SF by electrostatic repulsion, a mechanism previously proposed for quaternary ammonium ions.

Effect of ivabradine on structural and functional changes of myocardium and NT-proBNP levels in patients with stable coronary heart disease after coronary stenting.

OBJECTIVE: Aim: To investigate the effect of ivabradine on the hemodynamics and contractility of the myocardium and the features of NT-pro-BNP production in patients with stable ischemic heart disease after endovascular revascularization of the myocardium depending on the number of affected coronary arteries during 12 months of therapy. PATIENTS AND METHODS: Materials and Methods: The object of the study was 120 patients with stable coronary artery disease: angina pectoris of functional class III with heart failure IIA FC III with preserved and moderately reduced ejection fraction of the left ventricle, who underwent coronary artery stenting. The examined patients were randomized according to the number of affected coronary vessels and the method of treatment. RESULTS: Results: Ivabradine in patients with stable ischemic heart disease after 12 months of therapy had a significant beneficial effect on the structural and functional parameters of the myocardium (contributed to the reverse remodeling of the left ventricle), which did not depend on the number of stented coronary arteries (p<0.05). In patients with stented one coronary artery, all structural and functional indicators of the heart after 12 months of treatment reached the values of practically healthy individuals from the control group. The use of ivabradine in patients with stable ischemic heart disease with heart failure with preserved and intermediate ejection fraction of the left ventricle after coronary stenting made it possible to ensure the correction of a number of clinical and pathogenetic links of the disease, which generally contributed to the improvement of metric and volumetric parameters of the heart. CONCLUSION: Conclusions: Ivabradine made it possible to significantly increase the effectiveness of standard therapy, which was manifested by a faster recovery of the geometry and contractility of the left ventricle. Therefore, the use of ivabradine along with standard therapy was appropriate for such a contingent of patients. The management of patients with stable coronary heart disease should combine adequate (surgical and pharmacological) treatment of the underlying disease, further individual medication correction of symptoms and circulatory disorders inherent in coronary heart disease and heart failure.

Evaluating the role of ivabradine in acute decompensated heart failure: A systematic review and meta-analysis.

BACKGROUND: Acute decompensated heart failure (ADHF) presents a significant global health challenge, with high morbidity, mortality, and healthcare costs. The current therapeutic options for ADHF are limited. Ivabradine, a selective inhibitor of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, has emerged as a potential therapy for ADHF by reducing the heart rate (HR) without negatively affecting myocardial contractility. However, the evidence regarding the efficacy and safety of ivabradine in patients with ADHF is limited and inconsistent. This meta-analysis aimed to evaluate the efficacy and safety of ivabradine for ADHF based on observational studies. METHODS: A systematic literature search was conducted following PRISMA guidelines to identify relevant observational studies comparing ivabradine with placebo in adult patients with ADHF. Data were pooled using a random-effects model, and heterogeneity was assessed. The risk of bias was evaluated using the Newcastle-Ottawa Scale. RESULTS: Four observational studies comprising a total of 12034 patients. Meta-analysis revealed that ivabradine significantly reduced all-cause mortality (RR: 0.66, 95 % CI: 0.49-0.89, p < 0.01) and resting HR (MD: -12.54, 95 % CI: -21.66-3.42, p < 0.01) compared to placebo. However, no significant differences were observed in cardiovascular mortality, hospital readmission for all causes, changes in LVEF, or changes in LVEDD. Sensitivity and publication bias assessments were conducted for each outcome. CONCLUSION: Ivabradine may be beneficial for reducing mortality and HR in patients with ADHF. However, its impact on other clinical outcomes such as cardiovascular mortality, hospital readmission, and cardiac function remains inconclusive. Further research, particularly well-designed RCTs with larger sample sizes and longer follow-up durations, are warranted.

A Systematic Review and Meta-Analysis of Randomised Controlled Trials Assessing Clinical and Haemodynamic Outcomes of Ivabradine in Heart Failure With Reduced Ejection Fraction Patients.

BACKGROUND: Ivabradine, a pure bradycardic agent, can be given to heart failure reduced ejection fraction (HFrEF) patients with a sinus rhythm of ≥70 bpm on a maximum beta blocker dose, or when beta blockers are contraindicated. This study aimed to see how ivabradine affects the clinical and haemodynamic outcomes of HFrEF patients. METHODS: This systematic review and meta-analysis searched ClinicalTrials.gov, OpenMD, ProQuest, PubMed, and ScienceDirect for potential articles. All relevant data were extracted. For all pooled effects, the random effect model was applied. RESULTS: A total of 18,972 heart failure (HF) patients from nine randomised clinical trials (RCTs) were involved in this study. Ivabradine decreased the risk of HF mortality (RR 0.79; 95% CI 0.64-0.98; p=0.03) and HF hospitalisation (RR 0.80; 95% CI 0.65-0.97; p=0.03). Ivabradine was related to a greater reduction in heart rate (MD -12.21; 95% CI -15.47 - -8.96; p<0.01) and left ventricular ejection fraction (LVEF) improvement (MD 3.24; 95% CI 2.17-4.31; p <0.01) compared with placebo. Asymptomatic bradycardia (RR 4.25; 95% CI 3.36-5.39; p<0.01) and symptomatic bradycardia (RR 3.99; 95% CI 3.17-5.03; p<0.01) were higher in the ivabradine group. CONCLUSION: Ivabradine can reduce the risk of HF mortality and HF hospitalisation in HFrEF patients. Ivabradine also effectively reduces resting heart rate and improves LVEF. However, ivabradine is associated with a greater risk of symptomatic and asymptomatic bradycardia.

Ivabradine restores tonic cardiovascular autonomic control and reduces tachycardia, hypertension and left ventricular inflammation in post-weaning protein malnourished rats.

Malnutrition results in autonomic imbalance and heart hypertrophy. Overexpression of hyperpolarization-activated cyclic nucleotide-gated channels (HCN) in the left ventricles (LV) is linked to hypertrophied hearts and abnormal myocardium automaticity. Given that ivabradine (IVA) has emerging pleiotropic effects, in addition to the widely known bradycardic response, this study evaluated if IVA treatment could repair the autonomic control and cardiac damages in malnourished rats. AIM: Assess the impact of IVA on tonic cardiovascular autonomic control and its relationship with hemodynamics regulation, LV inflammation, and HCN gene expression in post-weaning protein malnutrition condition. MAIN METHODS: After weaning, male rats were divided into control (CG; 22 % protein) and malnourished (MG; 6 % protein) groups. At 35 days, groups were subdivided into CG-PBS, CG-IVA, MG-PBS and MG-IVA (PBS 1 ml/kg or IVA 1 mg/kg) received during 8 days. We performed jugular vein cannulation and electrode implant for drug delivery and ECG registration to assess tonic cardiovascular autonomic control; femoral cannulation for blood pressure (BP) and heart rate (HR) assessment; and LV collection to evaluate ventricular remodeling and HCN gene expression investigation. KEY FINDINGS: Malnutrition induced BP and HR increases, sympathetic system dominance, and LV remodeling without affecting HCN gene expression. IVA reversed the cardiovascular autonomic imbalance; prevented hypertension and tachycardia; and inhibited the LV inflammatory process and fiber thickening caused by malnutrition. SIGNIFICANCE: Our findings suggest that ivabradine protects against malnutrition-mediated cardiovascular damage. Moreover, our results propose these effects were not attributed to HCN expression changes, but rather to IVA pleiotropic effects on autonomic control and inflammation.

Efficacy and Tolerability of Ivabradine for Cardiomyopathy in Patients with Duchenne Muscular Dystrophy.

Duchenne muscular dystrophy (DMD) is an intractable X-linked myopathy caused by dystrophin gene mutations. Patients with DMD suffer from progressive muscle weakness, inevitable cardiomyopathy, increased heart rate (HR), and decreased blood pressure (BP). The aim of this study was to clarify the efficacy and tolerability of ivabradine treatment for DMD cardiomyopathy.A retrospective analysis was performed in 11 patients with DMD, who received ivabradine treatment for more than 1 year. Clinical results were analyzed before (baseline), 6 months after, and 12 months after the ivabradine administration.The initial ivabradine dose was 2.0 ± 1.2 mg/day and the final dose was 5.6 ± 4.0 mg/day. The baseline BP was 95/64 mmHg. A non-significant BP decrease to 90/57 mmHg was observed at 1 month but it recovered to 97/62 mmHg at 12 months after ivabradine administration. The baseline HR was 93 ± 6 bpm and it decreased to 74 ± 12 bpm at 6 months (P = 0.011), and to 77 ± 10 bpm at 12 months (P = 0.008). A linear correlation (y = 2.2x + 5.1) was also observed between the ivabradine dose (x mg/day) and HR decrease (y bpm). The baseline LVEF was 38 ± 12% and it significantly increased to 42 ± 9% at 6 months (P = 0.011) and to 41 ± 11% at 12 months (P = 0.038). Only 1 patient with the lowest BMI of 11.0 kg/m2 and BP of 79/58 mmHg discontinued ivabradine treatment at 6 months, while 1-year administration was well-tolerated in the other 10 patients.Ivabradine decreased HR and increased LVEF without lowering BP, suggesting it can be a treatment option for DMD cardiomyopathy.

Clinical Implications of Ivabradine in the Contemporary Era.

Ivabradine is a recently introduced inhibitor of the If ion channel, which exhibits the capacity to reduce heart rate while preserving hemodynamic stability. At present, ivabradine finds its clinical indication in patients suffering from heart failure with reduced ejection fraction and maintaining a relative sinus rhythm refractory to beta-blockers. To optimize heart rate control, it is recommended to pursue an aggressive up-titration of ivabradine. This approach may ameliorate tachycardia-induced hypotension by incrementally enhancing cardiac output and allow further up-titration of agents aimed at ameliorating heart failure, such as beta-blockers. Both the modulation of heart rate itself and the up-titration of agents targeting heart failure lead to cardiac reverse remodeling, consequently culminating in a subsequent reduction in mortality and morbidity. A novel overlap theory that our team proposed recently has emerged in recent times. Under trans-mitral Doppler echocardiography, the E-wave and A-wave closely juxtapose one another without any overlapping at the optimal heart rate. Employing echocardiography-guided ivabradine for heart-rate modulation to minimize the overlap between the E-wave and A-wave appears to confer substantial benefits to patients with heart failure. This approach facilitates superior cardiac reverse remodeling and yields more favorable clinical outcomes when compared to those patients who do not receive echocardiography-guided care. The next pertinent issue revolves around the potential expansion of ivabradine's clinical indications to encompass a broader spectrum of diseases. It is imperative to acknowledge that ivabradine may not yield clinically significant benefits in patients afflicted by heart failure with preserved ejection fraction, acute heart failure, sepsis, or stable angina. An important fact yet to be explored is the clinical applicability of ivabradine in patients with atrial fibrillation, a concern that beckons future investigation. In this review, the concept of overlap theory it introduced, along with its application to expand the indication of ivabradine and the overlap theory-guided optimal ivabradine therapy.

Detection of retinal dysfunction induced by HCN channel inhibitors using multistep light stimulus and long-duration light stimulus ERG in rats.

Ivabradine, a hyperpolarization-activated cyclic nucleotide-gated (HCN) channel inhibitor, has been reported to induce photosensitivity-related visual disturbances such as phosphene in humans. Ivabradine-induced visual disturbances are caused by inhibition of HCN channels in the retina, and the mechanisms have been verified using HCN channel knockout mice and electroretinography (ERG). However, in rats, classical ERG using single flash light stimulus with standard analyses of waveform amplitude and latency has not revealed abnormal retinal function after administration of ivabradine. To verify whether retinal dysfunction after ivabradine administration was detectable in rats, we performed ERG using multistep flash light stimulation at the time when plasma concentration of ivabradine was high. Furthermore, the mechanism of the change in the waveform that appeared after the b-wave was investigated. Ivabradine and cilobradine, a selective HCN channel inhibitor, were administered subcutaneously to rats at 4-40 mg/kg as a single dose, and flash or long-duration ERG recordings at each light stimulus luminance were conducted 1.5 h after administration. Plasma and retinal concentrations of both compounds were measured immediately after the ERG recordings. In the flash ERG, prolongation of a- and/or b-wave latencies were detected at each light stimulus, and dose-dependent waveform changes after the b-wave were recorded at the specific light stimulus luminance for both compounds. These ERG changes increased in response to increasing plasma and retinal concentrations for both ivabradine and cilobradine. In the long-duration light stimulus ERG, a change in the waveform of the b-wave trough and attenuation of the c-wave were recorded, suggesting that the feedback control in the photoreceptor cells may be inhibited. This study revealed that the retinal dysfunction by HCN channel inhibitors in rats can be detected by multistep light stimulus ERG. Additionally, we identified that the inhibition of feedback current and the sustained responses in the photoreceptor cells cause the retinal dysfunction of HCN channel inhibitors in rats.

Hyperpolarization-activated cyclic nucleotide-gated channel inhibitor in myocardial infarction: Potential benefits beyond heart rate modulation.

Myocardial infarction (MI) and its associated complications including ventricular arrhythmias and heart failure are responsible for a significant incidence of morbidity and mortality worldwide. The ensuing cardiomyocyte loss results in neurohormone-driven cardiac remodeling, which leads to chronic heart failure in MI survivors. Ivabradine is a heart rate modulation agent currently used in treatment of chronic heart failure with reduced ejection fraction. The canonical target of ivabradine is the hyperpolarization-activated cyclic nucleotide-gated channels (HCN) in cardiac pacemaker cells. However, in post-MI hearts, HCN can also be expressed ectopically in non-pacemaker cardiomyocytes. There is an accumulation of intriguing evidence to suggest that ivabradine also possesses cardioprotective effects that are independent of heart rate reduction. This review aims to summarize and discuss the reported cardioprotective mechanisms of ivabradine beyond heart rate modulation in myocardial infarction through various molecular mechanisms including the prevention of reactive oxygen species-induced mitochondrial damage, improvement of autophagy system, modulation of intracellular calcium cycling, modification of ventricular electrophysiology, and regulation of matrix metalloproteinases.

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.

Effectiveness and safety of ivabradine in Chinese patients with chronic heart failure: an observational study.

AIMS: A therapeutic strategy for chronic heart failure (HF) is to lower resting heart rate (HR). Ivabradine is a well-known HR-lowering agent, but limited prospective data exist regarding its use in Chinese patients. This study aimed to evaluate the effectiveness and safety of ivabradine in Chinese patients with chronic HF. METHODS AND RESULTS: This multicentre, single-arm, prospective, observational study enrolled Chinese patients with chronic HF. The primary outcome was change from baseline in HR at 1 and 6 months, measured by pulse counting. Effectiveness was also evaluated using laboratory tests, the Kansas City Cardiomyopathy Questionnaire (KCCQ) clinical summary score (CSS) and overall summary score (OSS), and New York Heart Association (NYHA) class. Treatment-emergent adverse events (TEAEs) were assessed. A post hoc analysis examined the effectiveness and safety of ivabradine combined with an angiotensin receptor-neprilysin inhibitor (ARNI) or beta-blocker. A total of 1003 patients were enrolled [mean age 54.4 ± 15.0 years, 773 male (77.1%), mean baseline HR 88.5 ± 11.3 b.p.m., mean blood pressure 115.7/74.4 ± 17.2/12.3 mmHg, mean left ventricular ejection fraction 30.9 ± 7.6%, NYHA Classes III and IV in 48.8% and 22.0% of patients, respectively]. HR decreased by a mean of 12.9 and 16.1 b.p.m. after 1 and 6 months, respectively (both P < 0.001). At Month 6, improvements in the KCCQ CSS and OSS of ≥5 points were observed in 72.1% and 74.1% of patients, respectively (both P < 0.001). Left ventricular ejection fraction increased by 12.1 ± 11.6 (P < 0.001), and 66.7% of patients showed improvement in NYHA class (P < 0.001). At Month 6, the overall proportion of patients in NYHA Classes III and IV was reduced to 13.5% and 2.1%, respectively. Serum brain natriuretic peptide (BNP) and N-terminal pro-BNP changed by -331.9 ng/L (-1238.6, -134.0) and -1113.8 ng/L (-2202.0, -297.2), respectively (P < 0.001). HR reductions and improvements in NYHA and KCCQ scores with ivabradine were similar with and without use of ARNIs or beta-blockers. Of 498 TEAEs in 296 patients (29.5%), 73 TEAEs in 55 patients (5.5%) were considered related to ivabradine [most frequent sinus bradycardia (n = 7) and photopsia (n = 7)]. TEAEs were reported in a similar number of patients in ARNI and beta-blocker subgroups (21.9-35.6%). CONCLUSIONS: Ivabradine treatment reduced HR and improved cardiac function and health-related quality of life in Chinese patients with chronic HF. Benefits were seen irrespective of whether or not patients were also taking ARNIs or beta-blockers. Treatment was well tolerated with a similar profile to previous ivabradine studies.