Favourable effects of heart rate reduction with intravenous administration of ivabradine in patients with advanced heart failure☆

Heart Rate Reduction and the Prognosis of Heart Failure Focused on Ivabradine

Cardioprotective medications referred to as the fantastic four are used to treat heart failure (HF). Additionally, ivabradine can also be used if the heart rate (HR) is elevated. An elevated HR is a prognostic factor in HF patients, as well as in the general population. In both HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF), an elevated HR is associated with all-cause mortality, whereas cardiovascular death is only associated with the former. In addition, previous clinical trials revealed that ivabradine was useful only in HFrEF but not in HFpEF. Therefore, ivabradine is indicated for patients only with HFrEF. Moreover, ivabradine increases the stroke volume by ensuring an effective diastolic time as a result of the decreased HR. Including this effect, the introduction of ivabradine allowed for the discontinuation of dobutamine infusion used in HF patients and the uptitration of β-blockers in other reports. Additionally, ivabradine improves exercise tolerance and the subjective symptoms of HF. However, the effects of ivabradine on exercise tolerance remain poorly understood, and prospective clinical trials are underway. While these beneficial effects have been reported, side effects such as photopsia and atrial fibrillation have also been reported. It is important to use ivabradine appropriately in conjunction with standard HF treatment, including quadruple therapy.

Assessment of safety profile of ivabradine in real-world scenario using FDA adverse event reporting system database

BACKGROUND

Ivabradine is primarily indicated for patients with sinus rhythm and a heart rate ≥ 75 beats/min, who have NYHA class II-IV chronic heart failure with systolic dysfunction. There is currently a lack of large-scale, real-world studies concerning its drug adverse reactions.

RESEARCH DESIGN & METHODS

This research assesses the side effects of ivabradine by analyzing reports of adverse events (AEs) from the FDA's Adverse Event Reporting System (FAERS) database. To evaluate the importance of these AEs, four sequential analytic strategies were utilized.

RESULTS

In total, 2,701 ivabradine-related AE reports were identified in the FAERS database. We identified 26 ivabradine-induced AEs, each with more than 20 reports, including some significant AEs not mentioned on the product label. The timing of AEs was also analyzed, with the majority of AEs occurring within the first month of ivabradine use. Gender-specific analysis indicates that female have a higher risk of AEs, such as off-label use, tachycardia, drug effectiveness for unapproved indications, and rash compared to male.

CONCLUSION

This study provides important information for maximizing the usage of ivabradine, increasing its efficacy, and reducing any possible negative effects. The actual clinical use of the medication will be greatly aided by this knowledge.

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.

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.

Effect of preoperative ivabradine on hemodynamics during elective off-pump CABG

Background

Ivabradine is a specific heart rate (HR)-lowering agent which blocks the cardiac pacemaker If channels. It reduces the HR without causing a negative inotropic or lusitropic effect, thus preserving ventricular contractility. The authors hypothesized that its usefulness in lowering HR can be utilized in patients undergoing off-pump coronary artery bypass (OPCAB) surgery.

Objective

To study the effects of preoperative ivabradine on hemodynamics (during surgery) in patients undergoing elective OPCAB surgery.

Methods

Fifty patients, New York Heart Association (NYHA) class I and II, were randomized into group I (control, n = 25) and group II (ivabradine group, n = 25). In group I, patients received the usual anti-anginal medications in the preoperative period, as per the institutional protocol. In group II, patients received ivabradine 5 mg twice daily for 3 days before surgery, in addition to the usual anti-anginal medications. Anesthesia was induced with fentanyl, thiopentone sodium, and pancuronium bromide as a muscle relaxant and maintained with fentanyl, midazolam, pancuronium bromide, and isoflurane. The hemodynamic parameters [HR and mean arterial pressure (MAP)] and pulmonary artery (PA) catheter-derived data were recorded at the baseline (before induction), 3 min after the induction of anesthesia at 1 min and 3 min after intubation and at 5 min and 30 min after protamine administration. Intraoperatively, hemodynamic data (HR and MAP) were recorded every 10 min, except during distal anastomosis of the coronary arteries when it was recorded every 5 min. Post-operatively, at 24 hours, the levels of troponin T and brain natriuretic peptide (BNP) were measured. This trial's CTRI registration number is CTRI/005858.

Results

The HR in group II was lower when compared to group I (range 59.6-72.4 beats/min and 65.8-80.2 beats/min, respectively) throughout the study period. MAP was comparable [range (78.5-87.8 mm Hg) vs. (78.9-88.5 mm Hg) in group II vs. group I, respectively] throughout the study period. Intraoperatively, 5 patients received metoprolol in group I to control the HR, whereas none of the patients in group II required metoprolol. The incidence of preoperative bradycardia (HR <60 beats/min) was higher in group II (20%) vs. group I (8%). There was no difference in both the groups in terms of troponin T and BNP level after 24 hours, time to extubation, requirement of inotropes, incidence of arrhythmias, in-hospital morbidity, and 30-day mortality.

Conclusion

Ivabradine can be safely used along with other anti-anginal agents during the preoperative period in patients undergoing OPCAB surgery. It helps to maintain a lower HR during surgery and reduces the need for beta-blockers in the intraoperative period, a desirable and beneficial effect in situations where the use of beta-blockers may be potentially harmful. Further studies are needed to evaluate the beneficial effects of perioperative Ivabradine in patients with moderate-to-severe left ventricular dysfunction.

[Mechano-energetic defects in heart failure]

Heart failure is characterized by defects in excitation-contraction coupling, energetic deficit and oxidative stress. The energy for cardiac contraction and relaxation is provided in mitochondria, whose function is tightly regulated by excitation-contraction coupling in cardiac myocytes. In heart failure with reduced ejection fraction (HFrEF), alterations in the ion balance in cardiac myocytes impair mitochondrial Ca²⁺ uptake, which is required for activation of the Krebs cycle, causing an energetic deficit and oxidative stress in mitochondria. Recent clinical studies suggest that in heart failure with preserved ejection fraction (HFpEF), in stark contrast to HFrEF, hypercontractility often occurs as an attempt to compensate for a pathological increase in systemic and pulmonary vascular resistance. This hypercontractility increases cardiac energy and oxygen demands at rest and reduces the contractile, diastolic and coronary reserves, preventing an adequate increase in cardiac output during exercise. Moreover, increased contractility causes long-term maladaptive remodeling processes due to oxidative stress and redox-sensitive prohypertrophic signaling pathways. As overweight and diabetes, particularly in the interplay with hemodynamic stress, are important risk factors for the development of HFpEF, interventions targeting metabolism in particular could ameliorate the development and progression of HFpEF.

Therapeutic Use and Molecular Aspects of Ivabradine in Cardiac Remodeling: A Review

Cardiac remodeling can cause ventricular dysfunction and progress to heart failure, a cardiovascular disease that claims many lives globally. Ivabradine, a funny channel (I_f) inhibitor, is used in patients with chronic heart failure as an adjunct to other heart failure medications. This review aims to gather updated information regarding the therapeutic use and mechanism of action of ivabradine in heart failure. The drug reduces elevated resting heart rate, which is linked to increased morbidity and mortality in patients with heart failure. Its use is associated with improved cardiac function, structure, and quality of life in the patients. Ivabradine exerts several pleiotropic effects, including an antiremodeling property, which are independent of its principal heart-rate-reducing effects. Its suppressive effects on cardiac remodeling have been demonstrated in animal models of cardiac remodeling and heart failure. It reduces myocardial fibrosis, apoptosis, inflammation, and oxidative stress as well as increases autophagy in the animals. It also modulates myocardial calcium homeostasis, neurohumoral systems, and energy metabolism. However, its role in improving heart failure remains unclear. Therefore, elucidating its molecular mechanisms is imperative and would aid in the design of future studies.

Hemodynamic effects of heart rate lowering in patients admitted for acute heart failure: the RedRate-HF Study (Reduction of heart Rate in Heart Failure)

BACKGROUND

In patients admitted for acute heart failure (HF) indication for drugs which reduce the heart rate (HR) is debated. The multicentre prospective study Reduction of heart Rate in Heart Failure (RedRate-HF) was designed to analyse the hemodynamic effects of an early reduction of HR in acute HF.

METHODS

Hemodynamic parameters were recorded by using the bioimpedance technique, which was shown to be accurate, highly reproducible and sensitive to intra-observer changes. Lowering HR was obtained by ivabradine 5 mg bd, given 48-72 h after admission on the top of optimized treatment. Patients were followed at 24, 48, 72 h after drug assumption and at hospital discharge.

RESULTS

Twenty patients of a mean age of 67 ± 15 years, BNP at entry 1348 ± 1198 pg/ml were enrolled. Despite a clinical stabilization, after 48-72 h from admission, HR was persistently >70 bpm. Ivabradine was well tolerated in all patients with a significant increase in RR interval from 747 ± 69 ms at baseline to 948 ± 121 ms at discharge, P < 0.0001. Change in HR was associated with a significant increase in stroke volume (baseline 73 ± 22 vs. 84 ± 19 ml at discharge, P = 0.03), and reduction in left cardiac work index (baseline 3.6 ± 1.2 vs. 3.1 ± 1.1 kg/m2 at discharge, P = 0.04). Other measures of heart work were also significantly affected while cardiac output remained unchanged.

CONCLUSION

The strategy of an early lowering of HR in patients admitted for acute HF on top of usual care is feasible and safe. The HR reduction causes a positive increase in stroke volume and may contribute to saving energy without affecting cardiac output.

Relationships Among Heart Rate, β-Blocker Dosage, and Prognosis in Patients With Coronary Artery Disease in a Real-World Database Using a Multimodal Data Acquisition System

BACKGROUND

The optimal heart rate (HR) and optimal dose of β-blockers (BBs) in patients with coronary artery disease (CAD) have been unclear. We sought to clarify the relationships among HR, BB dose, and prognosis in patients with CAD using a multimodal data acquisition system.

METHODS AND RESULTS

We evaluated the data for 8,744 CAD patients who underwent cardiac catheterization from 6 university hospitals and the National Cerebral and Cardiovascular Center and who were registered using the Clinical Deep Data Accumulation System. Patients were divided into quartile groups based on their HR at discharge: Q1 (HR <60 beats/min), Q2 (HR 60-66 beats/min), Q3 (HR 67-74 beats/min), and Q4 (HR ≥75 beats/min). Among patients with acute coronary syndrome (ACS) and patients with chronic coronary syndrome (CCS), those in Q4 (HR ≥75 beats/min) had a significantly greater incidence of major adverse cardiac and cerebral events (MACCE) compared with those in Q1 (ACS patients: hazard ratio 1.65, P=0.001; CCS patients: hazard ratio 1.45, P=0.019). Regarding the use of BBs (n=4,964), low-dose administration was significantly associated with MACCE in the ACS group (hazard ratio 1.41, P=0.012), but not in patients with CCS after adjustment for covariates.

CONCLUSIONS

HR ≥75 beats/min was associated with worse outcomes in patients with CCS or ACS.

Clinical trials on the pharmacological treatment of long COVID: A systematic review

The postacute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (PASC), also known as post-acute coronavirus disease 19 (COVID-19) or the long COVID syndrome (long COVID) is an emerging public health concern. A substantial proportion of individuals may remain symptomatic months after initial recovery. An updated review of published and ongoing trials focusing on managing long COVID will help identify gaps and address the unmet needs of patients suffering from this potentially debilitating syndrome. A comprehensive literature search was conducted on the international databases and clinical trial registries from inception to 31 July 2022. This review included 6 published trials and 54 trial registration records. There is significant heterogeneity in the characterization of long COVID and ascertainment of primary outcomes. Most of the trials are focused on individual symptoms of long COVID or isolated organ dysfunction, classified according to cardiovascular, respiratory and functional capacity, neurological and psychological, fatigue, and olfactory dysfunction. Most of the interventions are related to the mechanisms causing the individual symptoms. Although the six published trials showed significant improvement in the symptoms or organ dysfunction studied, these initial studies lack internal and external validity limiting the generalizability. This review provides an update of the pharmacological agents that could be used to treat long COVID. Further standardization of the diagnostic criteria, inclusion of participants with concomitant chronic cardiometabolic diseases and standardization of outcomes will be essential in future clinical trials.

Heart rate control and haemodynamic improvement with ivabradine in cardiogenic shock patient on mechanical circulatory support

AIMS

Cardiogenic shock (CS) is a life-threatening condition due to primary cardiac dysfunction. First-line therapy involves drug administration (including inotropes and/or vasopressors) up to mechanical circulatory support. Tachycardia is a frequent compensatory mechanism in response to hypotension and low cardiac output or a side effect related to inotropic drugs. Ivabradine selectively acts on the IKf channel in the sinoatrial node to reduce sinus heart rate without affecting inotropism. Its use, in small non-randomized series of patients with CS without mechanical circulatory support, was safe and well tolerated.

METHODS AND RESULTS

We present the use of ivabradine in six patients with CS undertaking veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and a matched cohort of selected patients with similar features who did not receive ivabradine. Data regarding haemodynamic and echocardiographic monitoring, oxygenation, renal function, mechanical circulatory support, inotropes, and vasopressors doses were collected before (t0), at 12 (t1), 24 (t2), and 48 (t3) h after ivabradine administration. Ivabradine administration led to a significant heart rate reduction of 20.83 [95% confidence interval (CI) -27.2 to -14.4] b.p.m. (<0.01). Echo-derived left ventricular native stroke volume (SV) significantly increased by +7.83 (95% CI 4.74-10.93) mL (P < 0.001) with a parallel reduction of VA-ECMO support [-170 (95% CI -225.05 to -114.95)]. Noradrenaline was down-titrated over the observation period in all patients (P = 0.016).

CONCLUSION

A significant reduction in heart rate was observed after ivabradine administration. This was associated with a native ventricular SV improvement allowing the reduction of extracorporeal flow support and vasopressors administration.

Early administration of ivabradine in patients admitted for acute decompensated heart failure

BACKGROUND

Heart rate (HR) control is important in heart failure (HF) patients with reduced ejection fraction, and ivabradine is indicated for patients with chronic HF and sinus rhythm. However, ivabradine is limited in initiation of ivabradine at acute stage of HF.

MATERIALS AND METHODS

This multi-institutional retrospective study enrolled 30,639 patients who were admitted for HF from January 01, 2013 to December 31, 2018 at Chang Gung Memorial Hospitals. After applying selection criteria, the eligible patients were divided into ivabradine and non-ivabradine groups according to the initiation of ivabradine at the index hospitalization. HR, clinical outcomes including HF hospitalization, all-cause hospitalization, mortality, the composite of cardiovascular (CV) death or HF hospitalization and newly developed atrial fibrillation, and left ventricular ejection fraction (LVEF) and left atrium size were compared between the ivabradine and non-ivabradine groups after inverse probability of treatment weighting (IPTW) analysis after 12 months.

RESULTS

The HR at admission in the ivabradine group (n = 433) was 99.04 ± 20.69/min, compared to 86.99 ± 20.34/min in the non-ivabradine group (n = 9,601). After IPTW, HR was lower in the ivabradine group than that in the non-ivabradine group after 12 months (74.14 ± 8.53 vs. 81.23 ± 16.79 bpm, p = 0.079). However, there were no significant differences in HF hospitalization (HR = 1.02; 95% CI, 0.38-2.79), all-cause hospitalization (HR = 0.95; 95% CI, 0.54-1.68), mortality (HR = 0.87; 95% CI, 0.69-1.08), the composite of CV death or HF hospitalization (HR = 0.87; 95% CI, 0.69-1.08) and newly developed AF between the two groups. In addition, LVEF increased with time in both groups, but there were no significant differences during the observation period.

CONCLUSION

Ivabradine was beneficial in controlling HR when initiated in patients with acute stage of HF, but it did not seem to provide any benefits in reducing HF hospitalization, all-cause hospitalization, and mortality in 1 year after discharge.

Slowing Heart Rate Protects Against Pathological Cardiac Hypertrophy

We aimed to determine the pathophysiological impact of heart rate (HR) slowing on cardiac function. We have recently developed a murine model in which it is possible to conditionally delete the stimulatory heterotrimeric G-protein (Gα_s) in the sinoatrial (SA) node after the addition of tamoxifen using cre-loxP technology. The addition of tamoxifen leads to bradycardia. We used this approach to examine the physiological and pathophysiological effects of HR slowing. We first looked at the impact on exercise performance by running the mice on a treadmill. After the addition of tamoxifen, mice with conditional deletion of Gα_s in the SA node ran a shorter distance at a slower speed. Littermate controls preserved their exercise capacity after tamoxifen. Results consistent with impaired cardiac capacity in the mutants were also obtained with a dobutamine echocardiographic stress test. We then examined if HR reduction influenced pathological cardiac hypertrophy using two models: ligation of the left anterior descending coronary artery for myocardial infarction and abdominal aortic banding for hypertensive heart disease. In littermate controls, both procedures resulted in cardiac hypertrophy. However, induction of HR reduction prior to surgical intervention significantly ameliorated the hypertrophy. In order to assess potential protein kinase pathways that may be activated in the left ventricle by relative bradycardia, we used a phospho-antibody array and this revealed selective activation of phosphoinositide-3 kinase. In conclusion, HR reduction protects against pathological cardiac hypertrophy but limits physiological exercise capacity.

Stroke Severity in Ischemic Stroke Patients with a History of Diastolic Blood Pressure Treated in a Telestroke Network

Background: The relationship between diastolic blood pressure (DBP), risk factors, and stroke severity in acute ischemic stroke (AIS) patients treated in a telestroke network is not fully understood. The present study aims to determine the effect of risk factors on stroke severity in AIS patients with a history of elevated DBP. Material and Methods: We retrospectively analyzed data on stroke severity for AIS patients treated between January 2014 and June 2016 treated in the PRISMA Health telestroke network. Data on the severity of stroke on admission were evaluated using NIHSS scores ≤7 for reduced, and >7 for increased, stroke severity. DBP was stratified as ≤80 mmHg for reduced DBP and >80 mmHg for elevated DBP. The study’s primary outcomes were risk factors associated with improving neurologic functions or reduced stroke severity and deteriorating neurologic functions or increased stroke severity. The associations between risk factors and stroke severity for AIS with elevated DBP were determined using multi-level logistic and regression models. Results: In the adjusted analysis, AIS patients with a DBP ≤ 80 mmHg, obesity (OR = 0.388, 95% Cl, 0.182−0.828, p = 0.014) was associated with reduced stroke severity, while an increased heart rate (OR = 1.025, 95% Cl, 1.001−1.050, p = 0.042) was associated with higher stroke severity. For AIS patients with a DBP > 80 mmHg, hypertension (OR = 3.453, 95% Cl, 1.137−10.491, p = 0.029), history of smoking (OR = 2.55, 95% Cl, 1.06−6.132, p = 0.037), and heart rate (OR = 1.036, 95% Cl, 1.009−1.064, p = 0.009) were associated with higher stroke severity. Caucasians (OR = 0.294, 95% Cl, 0.090−0.964, p = 0.002) and obesity (OR = 0.455, 95% Cl, 0.207−1.002, p = 0.05) were more likely to be associated with reduced stroke severity. Conclusions: Our findings reveal specific risk factors that can be managed to improve the care of AIS patients with elevated DBP treated in the telestroke network.

The Bradycardic Agent Ivabradine Acts as an Atypical Inhibitor of Voltage-Gated Sodium Channels

Background and purpose: Ivabradine is clinically administered to lower the heart rate, proposedly by inhibiting hyperpolarization-activated cyclic nucleotide-gated cation channels in the sinoatrial node. Recent evidence suggests that voltage-gated sodium channels (VGSC) are inhibited within the same concentration range. VGSCs are expressed within the sinoatrial node and throughout the conduction system of the heart. A block of these channels thus likely contributes to the established and newly raised clinical indications of ivabradine. We, therefore, investigated the pharmacological action of ivabradine on VGSCs in sufficient detail in order to gain a better understanding of the pro- and anti-arrhythmic effects associated with the administration of this drug. Experimental Approach: Ivabradine was tested on VGSCs in native cardiomyocytes isolated from mouse ventricles and the His-Purkinje system and on human Nav1.5 in a heterologous expression system. We investigated the mechanism of channel inhibition by determining its voltage-, frequency-, state-, and temperature-dependence, complemented by a molecular drug docking to the recent Nav1.5 cryoEM structure. Automated patch-clamp experiments were used to investigate ivabradine-mediated changes in Nav1.5 inactivation parameters and inhibition of different VGSC isoforms. Key results: Ivabradine inhibited VGSCs in a voltage- and frequency-dependent manner, but did not alter voltage-dependence of activation and fast inactivation, nor recovery from fast inactivation. Cardiac (Nav1.5), neuronal (Nav1.2), and skeletal muscle (Nav1.4) VGSC isoforms were inhibited by ivabradine within the same concentration range, as were sodium currents in native cardiomyocytes isolated from the ventricles and the His-Purkinje system. Molecular drug docking suggested an interaction of ivabradine with the classical local anesthetic binding site. Conclusion and Implications: Ivabradine acts as an atypical inhibitor of VGSCs. Inhibition of VGSCs likely contributes to the heart rate lowering effect of ivabradine, in particular at higher stimulation frequencies and depolarized membrane potentials, and to the observed slowing of intra-cardiac conduction. Inhibition of VGSCs in native cardiomyocytes and across channel isoforms may provide a potential basis for the anti-arrhythmic potential as observed upon administration of ivabradine.

Real-World Effectiveness of Ivabradine in Chinese Patients with Chronic Heart Failure: Interim Analysis of the POSITIVE Study

Background

Ivabradine improves cardiac function and clinical outcomes in chronic heart failure (HF) by reducing heart rate (HR), but there is a lack of real-world data on its effectiveness and safety in Chinese patients.

Methods

We designed a prospective, multicenter, observational study of Chinese adults with HF and left ventricular systolic dysfunction, resting HR ≥ 75 beats per minute (bpm), and an indication for ivabradine treatment. An interim analysis was performed using a cut-off date of 31 October 2019. The primary outcome was change in HR at 6 months after the initiation of ivabradine. Secondary endpoints included change in New York Heart Association (NYHA) functional class; quality of life (QoL), measured using the Kansas City Cardiomyopathy Questionnaire (KCCQ); and adverse events (AEs).

Results

Overall, 655 subjects were included in the interim analysis. Mean reduction in HR from baseline was 13.2 (95% confidence interval [CI] 11.2–15.2) bpm at Month 1, and 14.5 (95% CI 11.8–17.2) bpm at Month 6 (p < 0.001 for both changes). NYHA functional class and KCCQ scores improved significantly over time (p < 0.001 for all comparisons with baseline), indicating amelioration of symptoms and better QoL, respectively. Forty-four subjects (6.7%) reported a total of 60 ivabradine-related AEs, most frequently phosphenes and bradycardia (both n = 6, 0.9%).

Conclusion

Treatment with ivabradine for 6 months effectively reduced HR and improved functional class and QoL in Chinese patients with chronic HF. Treatment was well tolerated.

Clinical Trial Registration

ISRCTN11703380; registered on 8 November 2016.

Clinical comparative study assessing the effect of ivabradine on neopterin and NT-Pro BNP against standard treatment in chronic heart failure patients

Purpose

Heart rate reduction (HR) is a cornerstone in heart failure therapy as it improves patient outcomes. The aim of this study is to evaluate short-term effect of ivabradine on NT-Pro BNP and neopterin in heart failure patients and assess the association between HR and these biomarkers.

Methods

Sixty patients on standard heart failure therapy were randomly allocated into ivabradine group (n = 30) and non-ivabradine group (n = 30). Ivabradine 5 mg twice daily was given for 3 months. Lipid profile and kidney functions were performed and blood samples for NT-Pro BNP and neopterin were analysed at baseline and after 3 months of intervention in both groups.

Results

There was a significant improvement in NYHA class in ivabradine group (p < 0.001). Ejection fraction was improved in ivabradine and non-ivabradine groups after intervention (p < 0.001), with a greater improvement in ivabradine group (p = 0.026). Heart rate was reduced in ivabradine group (p < 0.001) and non-ivabradine group (p < 0.001) yet greater reduction was seen in ivabradine group (p < 0.001). Serum creatinine and blood urea nitrogen were reduced in ivabradine group (Scr: p = 0.001, BUN: p = 0.001). NT-Pro BNP and neopterin levels significantly decreased in ivabradine group (NT-Pro BNP: p < 0.001, neopterin p < 0.001). Significant positive correlation was found between HR and biomarker levels after intervention (NT-Pro BNP: r = 0.475, p < 0.001, neopterin: r = 0.384, p = 0.002).

Conclusion

Ivabradine therapy reduced levels of both biomarkers which correlated well with HR. Biomarker levels might provide a tool for assessing ivabradine effectiveness in HF.

Trial registration

Date: June 26, 2020. Identifier: NCT04448899. Link: Ivabradine in Patients with Congestive Heart Failure—Full Text View—ClinicalTrials.gov.

Effects of ivabradine on the prevention of intradialytic hypotension in a dialytic patient with heart failure with reduced ejection fraction

A 65-year-old man with a history of heart failure with reduced ejection fraction (HFrEF) and renal failure was admitted due to difficulty in fluid volume control during haemodialysis. He had frequent episodes of intradialytic hypotension (IDH) with presyncope during haemodialysis despite using a vasopressor agent. Before haemodialysis, his blood pressure was 130-150/60-70 mm Hg, and his heart rate was 80-100 beats/min. There were no specific causes of IDH. For refractory IDH, he was treated with oral ivabradine (2.5 mg two times per day), which resulted in reduced heart rate and decreased occurrence of IDH. This is the first report to describe a dialysis case with HFrEF presenting with an elevated heart rate and impaired fluid management as manifested by recurring IDH, which improved after ivabradine treatment. Ivabradine therapy may assist in increasing stroke volume by lowering the sinus heart rate, thus resulting in the prevention of IDH.

Torsadogenic Potential of HCN Channel Blocker Ivabradine Assessed in the Rabbit Proarrhythmia Model

Torsadogenic effects of ivabradine, an inhibitor of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, were assessed in an in vivo proarrhythmia model of acute atrioventricular block rabbit. Ivabradine at 0.01, 0.1, and 1 mg/kg was intravenously administered to isoflurane-anesthetized rabbits (n = 5) in the stable idioventricular rhythm. Ivabradine at 0.01 and 0.1 mg/kg hardly affected the atrial and ventricular automaticity, QT interval, or the monophasic action potential duration of the ventricle. Additionally administred ivabradine at 1 mg/kg decreased the atrial and ventricular rate significantly but increased the QT interval and duration of the monophasic action potential. Meanwhile, torsade de pointes arrhythmias were detected in 1 out of 5 animals and in 2 out of 5 animals after the administration of 0.1 and 1 mg/kg, respectively. Importantly, torsade de pointes arrhythmias could be observed only in 2 rabbits showing more potent suppressive effects on ventricular automaticity. These results suggest that the torsadogenic potential of ivabradine may become evident when its expected bradycardic action appears more excessively.

Disease-modifier Drugs in Patients with Advanced Heart Failure: How to Optimize Their Use?

Therapy based on disease-modifier drugs is among the required criteria to diagnose advanced heart failure (AdvHF). Nevertheless, several conditions, such as hospitalization, hypotension, renal dysfunction, electrolyte abnormalities, medical inertia, and patients' adherence, can make the maintenance of optimal medical therapy in patients with AdvHF challenging. Moreover, in recent years, new classes of drugs able have been shown to be able to further modify the natural history of heart failure with reduced ejection fraction, but they are still not widely adopted. This article discusses the optimal use of disease-modifier drugs in patients with AdvHF as well as the possible usefulness of the new therapeutic opportunities.

The association between ivabradine and adverse cardiovascular events in acute decompensated HFrEF patients

AIMS

Ivabradine has been used in patients who have chronic heart failure (HF) with reduced ejection fraction (HFrEF) and concomitant sinus heart rate ≥70 bpm. This administration for acute HFrEF remains a concern. This study used a real-world multicentre database to investigate the effects of ivabradine among patients with acute decompensated HFrEF before discharge.

METHODS AND RESULTS

This study retrospectively identified patients with acute decompensated HFrEF who were administered ivabradine at discharge from two multicentre HF databases. Propensity score matching was performed to adjust for confounders. Cardiovascular mortality, all-cause mortality, and recurrent HF rehospitalization risks were then compared between those with and without ivabradine treatment. After 1:2 propensity score matching, 876 patients (age, 60.7 ± 14.6 years; female, 23.2%; left ventricular ejection fraction, 28.2% ± 7.8%; and heart rate at discharge, 84.3 ± 13.8 bpm) were included in the final analysis, including 292 and 584 patients with and without ivabradine treatment at discharge, respectively. No significant differences were observed in baseline characteristics between the two groups. At 1 year follow-up, patients in the ivabradine group had significantly lower heart rates (77.6 ± 14.7 vs. 81.1 ± 16.3 bpm; P = 0.005) and lower HF severity symptoms (New York Heart Association Functional class, 2.1 ± 0.7 vs. 2.3 ± 0.9; P < 0.001) than those from the non-ivabradine group. Ivabradine users had significantly lower risks of 1 year cardiovascular mortality (5.8 vs. 12.2 per 100-person year; P = 0.003), all-cause mortality (7.2 vs. 14.0 per 100-person year; P = 0.003), and total HF rehospitalization (42.3 vs. 72.6 per 100-person year; P < 0.001) than non-ivabradine users. Following multivariate analysis, the predischarge prescription of ivabradine remained independently associated with lower 1 year all-cause mortality (hazard ratio, 0.45; 95% confidence interval, 0.28-0.74; P = 0.002) and cardiovascular mortality (hazard ratio, 0.41; 95% confidence interval, 0.24-0.72; P = 0.002).

CONCLUSIONS

The current study findings suggest that ivabradine treatment is associated with reduced risks of cardiovascular mortality, all-cause mortality, and HF rehospitalization within 1 year among patients with acute decompensated HFrEF in real-world populations.

Impact of ivabradine in decompensated heart failure due to cancer therapy-related cardiac dysfunction

In cases of decompensated heart failure related to cancer therapy-related cardiac dysfunction, ivabradine administration could lead to an increased stroke volume by reducing the sinus heart rate, resulting in favorable hemodynamics. Assessment of the overlap between the E- and A-waves facilitates understanding the effects of ivabradine in such cases.

Efficacy of early initiation of ivabradine treatment in patients with acute heart failure: rationale and design of SHIFT-AHF trial

AIMS

Elevated heart rate (HR) in heart failure (HF) is associated with worse outcomes, particularly in acute HF (AHF). HR reduction with ivabradine reduces cardiovascular events in HF patients with reduced ejection fraction. The present trial aimed to test the hypothesis that the early HR reduction using ivabradine improves clinical outcomes in patients with AHF.

METHODS AND RESULTS

SHIFT-AHF is a prospective, multi-centre, double-blind, randomized, placebo-controlled trial to evaluate the efficacy and safety of ivabradine when adding to standard therapy in AHF patients (SHIFT-AHF). The trial will include 674 AHF patients with left ventricular ejection fraction < 45% and New York Heart Association functional classes III-IV. Participants were enrolled from March 2020 and will be followed up until December 2022. Patients are randomized to treatment with ivabradine or placebo (randomization 1:1). After allocation, the dose of ivabradine is titrated according to HR. Six months' follow-up and three control visits (7, 90, and 180 days after enrolment) are required for every participant. Assessment involves clinical examination, laboratory tests, echocardiography, electrocardiography, heart rhythm, cardiac function, and quality of life. The primary endpoint is a composite of all-cause mortality or re-admission due to worsening HF. Secondary endpoints include the assessments of cardiac remodelling, cardiac functional capacity, and quality of life.

CONCLUSIONS

The SHIFT-AHF trial will shed further light on the role of early HR reduction using ivabradine in patients with AHF.

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.

Hemodynamic effects of ivabradine use in combination with intravenous inotropic therapy in advanced heart failure

Intravenous inotropic therapy can be used in patients with advanced heart failure, as palliative therapy or as a bridge to cardiac transplantation or mechanical circulatory support, as well as in cardiogenic shock. Their use is limited to increasing cardiac output in low cardiac output states and reducing ventricular filling pressures to alleviate patient symptoms and improve functional class. Many advanced heart failure patients have sinus tachycardia as a compensatory mechanism to maintain cardiac output. However, excessive sinus tachycardia caused by intravenous inotropes can increase myocardial oxygen consumption, decrease coronary perfusion, and at extreme heart rates decrease ventricular filling and stroke volume. The limited available hemodynamic studies support the hypothesis that adding ivabradine, a rate control agent without negative inotropic effect, may blunt inotrope-induced tachycardia and its associated deleterious effects, while optimizing cardiac output by increasing stroke volume. This review analyzes the intriguing pathophysiology of combined intravenous inotropes and ivabradine to optimize the hemodynamic profile of patients in advanced heart failure. Graphical abstract Illustration of the beneficial and deleterious hemodynamic effects of intravenous inotropes in advanced heart failure, and the positive effects of adding ivabradine.

Ivabradine and endothelium: an update

Ivabradine is a pure heart-rate lowering drug that is nowadays used, accordingly to the last ESC Guidelines, to reduce mortality and heart failure (HF) hospitalization in patients with HF with reduced ejection fraction and in symptomatic patiens with inappropriate sinus tachycardia. Moreover, interesting effect of ivabradine on endothelial and myocardial function and on oxidative stress and inflamation pathways are progressively emerging. The aim of this paper is to highlight newer evidences about ivabradine effect (and consequently possible future application of the drug) in pathological settings different from guidelines-based clinical practice.

Old and New Drugs for Treatment of Advanced Heart Failure

BACKGROUND

Advanced heart failure (HF) is a progressive disease with high mortality and limited medical therapeutic options. Long-term mechanical circulatory support and heart transplantation remain goldstandard treatments for these patients; however, access to these therapies is limited by the advanced age and multiple comorbidities of affected patients, as well as by the limited number of organs available.

METHODS

Traditional and new drugs available for the treatment of advanced HF have been researched.

RESULTS

To date, the cornerstone for the treatment of patients with advanced HF remains water restriction, intravenous loop diuretic therapy and inotropic support. However, many patients with advanced HF experience loop diuretics resistance and alternative therapeutic strategies to overcome this problem have been developed, including sequential nephron blockade or use of the hypertonic saline solution in combination with high-doses of furosemide. As classic inotropes augment myocardial oxygen consumption, new promising drugs have been introduced, including levosimendan, istaroxime and omecamtiv mecarbil. However, pharmacological agents still remain mainly short-term or palliative options in patients with acute decompensation or excluded from mechanical therapy.

CONCLUSION

Traditional drugs, especially when administered in combination, and new medicaments represent important therapeutic options in advanced HF. However, their impact on prognosis remains unclear. Large trials are necessary to clarify their therapeutic potential and prognostic role in these fragile patients.

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.

Ivabradine and metoprolol in fixed dose combination: When, why and how to use it

Heart rate is an important factor in coronary artery disease and its manifestations, and as such has been considered as a possible target for therapy. Although in epidemiological, and in less degree, in clinical studies derived indications of a possible pathogenetic role of heart rate in major cardiac diseases, clinical trials did not provided any strong evidence. However, even as a simple risk marker, remains important in the treatment of coronary artery disease and heart failure. Beta-blockers are the drugs most frequently used for heart rate control. However, recent studies constantly find insufficient effectiveness of beta-blockers in heart rate control and go further to question their efficacy on outcomes, making clear the need for an additional therapy. Ivabradine, a pure heart rate inhibitor, added to classic beta-blocker treatment represent the new therapeutic option in stable coronary disease and heart failure.

Initiation of ivabradine in cardiogenic shock

AIMS

Ivabradine is a selective sinus node inhibitor indicated in patients with symptomatic chronic heart failure on stable guideline-recommended heart failure therapy including appropriate doses of beta-blockers. The use in cardiogenic shock remains off label and has been considered a contraindication due to the theoretical risk of attenuating compensatory tachycardia. Tachycardia, especially in the context of inotropic therapy, may be deleterious, resulting in increased myocardial oxygen consumption and reduction in diastolic filling. As ivabradine does not have negative inotropic action, it may present a potential means to manage tachycardia in cardiogenic shock. We present a case series of four patients with cardiogenic shock started on ivabradine who were unable to tolerate beta-blockers.

METHODS AND RESULTS

Five patients identified with cardiogenic shock defined as a severe reduction in cardiac index (<2.0 L/min/m² ) and elevated filling pressures on inotropic therapy were started on ivabradine in patients with sinus tachycardia [heart rate (HR) >100] who were intolerant to beta-blockers. Each patient had a cardiac magnetic resonance imaging, echocardiogram, and coronary angiogram for determination of aetiology. Invasive haemodynamics via pulmonary artery catheterization were measured during initiation and titration of ivabradine (baseline, 6, 12, 24, and 48 h after ivabradine administration) with continuous telemetry monitoring for any dysrhythmia or bradyarrhythmias. All patients tolerated ivabradine initiation, and at 24 h, an observed decrease in HR (106 ± 6.8 vs. 91.6 ± 6.4 b.p.m., P = 0.04), pulmonary arterial occlusion pressure (30.4 ± 4.8 vs. 24 ± 5.1 mmHg, P = 0.04), and right atrial pressure (16.8 ± 6.2 vs. 9 ± 4.3 mmHg, P = 0.0002). An improvement was observed in mixed venous oxygen saturation (SvO₂ ) (51 ± 8.8 vs. 64.8 ± 5.3%, P < 0.04), stroke volume (37.2 ± 7.6 vs. 49.2 ± 12.9 mL, P < 0.04), and right and left ventricular stroke work index (Table 1). No significant changes were observed with mean arterial pressure (73.4 ± 7.5 vs. 75.8 ± 5.0 mmHg, P = 0.81) and thermodilution-derived cardiac index (1.7 ± 0.2 vs. 2.5 ± 0.7 L/min/m² , P = 0.58). Inotropic support was weaned successfully in three of five patients (88 ± 30 h) with subsequent titration of beta-blocker therapy. Two patients improved clinically but ultimately required left ventricular assist device implantation. All patients were discharged alive from hospital at 17 ± 7.9 days following ivabradine initiation.

CONCLUSIONS

In our small non-randomized series of patients in cardiogenic shock, ivabradine was safely used to reduce HR in patients previously intolerant of beta-blockade. There are limited data surrounding the use of ivabradine in cardiogenic shock, and future studies should be undertaken to determine the optimal HR in humans with cardiogenic shock and whether systematic limitation of peak HR may improve outcomes.

Study of Attenuation of Hemodynamic Response to Laryngoscopy and Endotracheal Intubation using Intra-oral Ivabradine

Context

Endotracheal intubation is one of the most commonly performed procedures, where rapid and dramatic hemodynamic changes which adversely affect the patient may occur during the perioperative period. Various strategies have been applied to attenuate these responses in high-risk individuals. Ivabradine is a very unique cardiotonic drug in the medical literature which reduces the heart rate without jeopardizing hemodynamics in unhealthy, compromised patients.

Aims and Objective

The aim of this study is to evaluate the effect of oral ivabradine on the hemodynamics during laryngoscopy and endotracheal intubation in patients undergoing surgical procedure under general anesthesia and to note the side effects and complications.

Settings and Design

This was a prospective, randomized, and double-blind controlled study.

Subjects and Methods

A total of 50 American Society of Anesthesiologists physical status I patients between 20 and 50 years age comparable in demographic variables of either sex, undergoing surgery under general anesthesia were randomized into two groups, namely, Group T and Group C of 25 each. Group T (test group) received tablet ivabradine 5 mg 1 h before intubation. Group C (control group) received placebo 1 h before intubation. The pulse rate, systolic and diastolic blood pressures, and mean arterial pressure were recorded for around 10 min and surgery was not allowed to commence. These hemodynamic variables were measured preoperatively, at intubation, after 1 min, 5 min, 8 min and 10 min postintubation.

Statistical Analysis Used

The Chi-square test and ANOVA test using INDOSTAT software for hemodynamics were used in this study.

Results

There was an increase in all parameters in the control group during and postintubation and was undisturbed in the test group as compared to base line. The increase was constant up to 3 min and got settled within 5 min in the control group.

Conclusion

Ivabradine had better patient compliance in terms of blunting laryngoscopic pressor.

Ivabradine for the Treatment of Cardiovascular Diseases

Higher heart rate (HR) is independently related to worse outcomes in various cardiac diseases, including hypertension, coronary artery disease, and heart failure (HF). HR is determined by the pacemaker activity of cells within the sinoatrial node. The hyperpolarization-activated cyclic nucleotide-gated (HCN) 4 channel, one of 4 HCN isoforms, generates the I_f current and plays an important role in the regulation of pacemaker activity in the sinoatrial node. Ivabradine is a novel and only available HCN inhibitor, which can reduce HR and has been approved for stable angina and chronic HF in many countries other than Japan. In this review, we summarize the current knowledge of the HCN4 channel and ivabradine, including the function of HCN4 in cardiac pacemaking, the mechanism of action of I_f inhibition by ivabradine, and the pharmacological and clinical effects of ivabradine in cardiac diseases as HF, coronary artery disease, and atrial fibrillation.

Acute Heart Rate-Dependent Hemodynamic Function of the Heart in the Post-Myocardial Infarction Rat Model: Change Over Time

BACKGROUND

Optimal heart rate (HR) for acute hemodynamic efficiency in heart failure (HF) is unknown.

METHODS

Wistar-Kyoto rats were followed-up for 3 and 7 days, 1 or 2 months after myocardial infarction (MI) or sham operation (ShO) and left ventricle (LV) pressure-volume (PV) loops were obtained at various HRs: baseline 400 beats per minute (bpm), reduced by ivabradine to 320 bpm, increased by atrial pacing to 480 bpm, under normal conditions and after preload increase (PI).

RESULTS

In the ShO group, PI augmented cardiac output (CO) by 55%, 67%, 84% at reduced, baseline, and increased HR, respectively. In post-MI rats, PI augmented CO 3 and 7 days, but not 1 and 2 months after MI. At increased HR, in response to PI, CO increased 3 and 7 days, tended to fall 1 and 2 months after MI; this hemodynamic response was salvaged by HR reduction. Further beneficial effects of HR reduction included reduction of LV end-diastolic pressure, increase of ejection fraction, contractility and relaxation velocity 1 and 2 months after MI.

CONCLUSIONS

In a rat HF model, optimal HR with regard to acute hemodynamic performance is shifted. Whereas in ShO rats increased HR facilitates CO increase induced by PI, in HF rats, such increase reduces CO, and HR reduction has beneficial effects. Thus, besides reducing progression of HF, HR-reducing interventions also offer immediate hemodynamic benefits.

Intravenous ivabradine versus placebo in patients with low cardiac output syndrome treated by dobutamine after elective coronary artery bypass surgery: a phase 2 exploratory randomized controlled trial

BACKGROUND

Low cardiac output syndrome (LCOS) is a severe condition which can occur after cardiac surgery, especially among patients with pre-existing left ventricular dysfunction. Dobutamine, its first-line treatment, is associated with sinus tachycardia. This study aims to assess the ability of intravenous ivabradine to decrease sinus tachycardia associated with dobutamine infused for LCOS after coronary artery bypass graft (CABG) surgery.

METHODS

In a phase 2, multi-center, single-blind, randomized controlled trial, patients with left ventricular ejection fraction below 40% presenting sinus tachycardia of at least 100 beats per minute (bpm) following dobutamine infusion for LCOS after CABG surgery received either intravenous ivabradine or placebo (three ivabradine for one placebo). Treatment lasted until dobutamine weaning or up to 48 h. The primary endpoint was the proportion of patients achieving a heart rate (HR) in the 80- to 90-bpm range. Secondary endpoints were invasive and non-invasive hemodynamic parameters and arrhythmia events.

RESULTS

Nineteen patients were included. More patients reached the primary endpoint in the ivabradine than in the placebo group (13 (93%) versus 2 (40%); P = 0.04). Median times to reach target HR were 1.0 h in the ivabradine group and 5.7 h in the placebo group. Ivabradine decreased HR (112 to 86 bpm, P <0.001) while increasing cardiac index (P = 0.02), stroke volume (P <0.001), and systolic blood pressure (P = 0.03). In the placebo group, these parameters remained unchanged from baseline. In the ivabradine group, five patients (36%) developed atrial fibrillation (AF) and one (7%) was discontinued for sustained AF; two (14%) were discontinued for bradycardia.

CONCLUSION

Intravenous ivabradine achieved effective and rapid correction of sinus tachycardia in patients who received dobutamine for LCOS after CABG surgery. Simultaneously, stroke volume and systolic blood pressure increased, suggesting a beneficial effect of this treatment on tissue perfusion.

TRIAL REGISTRATION

European Clinical Trials Database: EudraCT 2009-018175-14 . Registered February 2, 2010.

The effects of heart rate control in chronic heart failure with reduced ejection fraction

Elevated heart rate has been associated with worse prognosis both in the general population and in patients with heart failure. Heart rate is finely modulated by neurohormonal signals and it reflects the balance between the sympathetic and the parasympathetic limbs of the autonomic nervous system. For this reason, elevated heart rate in heart failure has been considered an epiphenomenon of the sympathetic hyperactivation during heart failure. However, experimental and clinical evidence suggests that high heart rate could have a direct pathogenetic role. Consequently, heart rate might act as a pathophysiological mediator of heart failure as well as a marker of adverse outcome. This hypothesis has been supported by the observation that the positive effect of beta-blockade could be linked to the degree of heart rate reduction. In addition, the selective heart rate control with ivabradine has recently been demonstrated to be beneficial in patients with heart failure and left ventricular systolic dysfunction. The objective of this review is to examine the pathophysiological implications of elevated heart rate in chronic heart failure and explore the mechanisms underlying the effects of pharmacological heart rate control.

Effects of ivabradine on endothelial function, aortic properties and ventricular-arterial coupling in chronic systolic heart failure patients

AIM

Heart rate (HR) is an important prognostic factor in patients affected by chronic heart failure (CHF); ivabradine has been demonstrated to significantly reduce nonfatal myocardial infarction and hospitalization rate for acute heart failure and to improve left ventricular (LV) reverse remodeling, quality of life, exercise capacity, and arterial elastance (Ea) in these patients. We aimed at evaluating the short-term effects of ivabradine on ventricular-arterial coupling (VAC), aortic stiffness, and endothelial function in stable patients with CHF.

METHODS

We evaluated 30 consecutive CHF patients (LVEF≤ 35%, NYHA class II) with sinus rhythm and HR ≥ 70 bpm on optimized pharmacological therapy. All of them underwent both transthoracic echocardiogram to assess aortic elastic properties (aortic distensibility, AD; aortic stiffness index, ASI; systolic aortic strain, SAS) and VAC, and peripheral arterial tonometry to measure endothelial function. Therapy with ivabradine 5 mg bid was added and each patient was evaluated with the same examinations after 4 months.

RESULTS

At the baseline, 73% of patients had impaired VAC and 63% endothelial dysfunction. After 4 months, there was a significant improvement in the VAC value (ΔVAC -0.10 ± 0.18, P = .021), mainly linked to Ea (ΔEa -0.40 ± 0.23 mm Hg/mL; P = .003). All the parameters of aortic elasticity underwent significant improvement (ΔAD 1.82 ± 1.43 cm² × dyn^- ¹, P = .004; ΔASI -4.73 ± 6.07, P = .033; ΔSAS -7.98 ± 4.37%, P = .003). Lastly, we also noted a significant improvement of endothelial function (Δ RHI 0.35 ± 0.35; P < .001). At follow-up 40% of patients had impaired VAC (P = .018) and 33% endothelial dysfunction (P = .038).

CONCLUSION

In patients with CHF adding ivabradine on top to the standard optimized medical therapy, when indicated, seems to improve endothelial function, aortic properties, and VAC.

Emerging role of ivabradine for rate control in atrial fibrillation

Control of ventricular rate is recommended for patients with paroxysmal, persistent, or permanent atrial fibrillation (AF). Existing rate-control options, including beta-blockers, nondihydropyridine calcium channel blockers, and digoxin, are limited by adverse hemodynamic effects and their ability to attain target heart rate (HR). Ivabradine, a novel HR-controlling agent, decreases HR through deceleration of conduction through If ('funny') channels, and is approved for HR reduction in heart failure patients with ejection fraction less than 35% and elevated HR, despite optimal pharmacological treatment. Because If channels were thought to be expressed solely in sinoatrial (SA) nodal tissue, ivabradine was not investigated in heart failure patients with concomitant AF. Subsequent identification of hyperpolarization-activated cyclic nucleotide-gated cation channel 4 (HCN4), the primary gene responsible for If current expression throughout the myocardium, stimulated interest in the potential role of ivabradine for ventricular rate control in AF. Preclinical studies of ivabradine in animal models with induced AF demonstrated a reduction in HR, with no significant worsening of QT interval or mean arterial pressure. Preliminary human data suggest that ivabradine provides HR reduction without associated hemodynamic complications in patients with AF. Questions remain regarding efficacy, safety, optimal dosing, and length of therapy in these patients. Prospective, randomized studies are needed to determine if ivabradine has a role as a rate-control treatment in patients with AF.

Advances in the management of heart failure: the role of ivabradine

A high resting heart rate (≥70–75 b.p.m.) is a risk factor for patients with heart failure (HF) with reduced ejection fraction (EF), probably in the sense of accelerated atherosclerosis, with an increased morbidity and mortality. Beta-blockers not only reduce heart rate but also have negative inotropic and blood pressure-lowering effects, and therefore, in many patients, they cannot be given in the recommended dose. Ivabradine specifically inhibits the pacemaker current (funny current, I_f) of the sinoatrial node cells, resulting in therapeutic heart rate lowering without any negative inotropic and blood pressure-lowering effect. According to the European Society of Cardiology guidelines, ivabradine should be considered to reduce the risk of HF hospitalization and cardiovascular death in symptomatic patients with a reduced left ventricular EF ≤35% and sinus rhythm ≥70 b.p.m. despite treatment with an evidence-based dose of beta-blocker or a dose below the recommended dose (recommendation class “IIa” = weight of evidence/opinion is in favor of usefulness/efficacy: “should be considered”; level of evidence “B” = data derived from a single randomized clinical trial or large nonrandomized studies). Using a heart rate cutoff of ≥ 75 b.p.m., as licensed by the European Medicines Agency, treatment with ivabradine 5–7.5 mg b.i.d. reduces cardiovascular mortality by 17%, HF mortality by 39% and HF hospitalization rate by 30%. A high resting heart rate is not only a risk factor in HF with reduced EF but also at least a risk marker in HF with preserved EF, in acute HF and also in special forms of HF. In this review, we discuss the proven role of ivabradine in the validated indication “HF with reduced EF” together with interesting preliminary findings, and the potential role of ivabradine in further, specific forms of HF.

Acute ivabradine treatment reduces heart rate without increasing atrial fibrillation inducibility irrespective of underlying vagal activity in dogs

Ivabradine, a bradycardic agent, has been shown to stably reduce patient's heart rate (HR) in the setting of acute cardiac care. However, an association between atrial fibrillation (AF) risk and acute ivabradine treatment remains a controversial clinical issue, and has not been thoroughly investigated. Bradycardia and abnormal atrial refractoriness induced by ivabradine treatment may enhance vulnerability to AF induction, especially when vagal nerve is concurrently activated. We aimed to experimentally investigate the effects of acute ivabradine treatment with/without concurrent vagal activation on AF inducibility. In 16 anesthetized dogs, cervical vagal nerves were prepared for electrical stimulation (VS). AF induction rate (AFIR) was determined by atrial burst pacing. HR, atrial action potential duration (APD), atrial effective refractory period (ERP), and AFIR were obtained consecutively at baseline, during delivery of VS (VS alone), after intravenous injection of ivabradine 0.5 mg/kg (n = 8, ivabradine group) or saline (n = 8, saline group), and again during VS delivery (drug+VS). In the ivabradine group, ivabradine alone significantly lowered HR compared to baseline, while ivabradine+VS significantly lowered HR compared to VS alone. Contrary to expectations, there were no significant differences in trends of APD, temporal dispersion of APD, ERP, and AFIR between ivabradine and saline groups. Irrespective of whether ivabradine or saline was injected, VS significantly shortened APD and ERP, and increased AFIR. Interestingly, although bradycardia in response to ivabradine injection was more intense than that to VS alone, AFIR was significantly lower after ivabradine injection than during VS alone. We conclude that, despite its intense bradycardic effect, acute ivabradine treatment does not increase AF inducibility irrespective of underlying vagal activity. This study may constitute support for the safety of using ivabradine in the setting of acute cardiac care.

Reversing dobutamine-induced tachycardia using ivabradine increases stroke volume with neutral effect on cardiac energetics in left ventricular post-ischaemia dysfunction

AIM

Compensatory tachycardia can potentially be deleterious in acute heart failure. In this study, we tested a therapeutic strategy of combined inotropic support (dobutamine) and selective heart rate (HR) reduction through administration of ivabradine.

METHODS

In an open-chest pig model (n = 12) with left ventricular (LV) post-ischaemia dysfunction, cardiac function was assessed by LV pressure catheter and sonometric crystals. Coronary flow and blood samples from the coronary sinus were used to measure myocardial oxygen consumption (MVO2 ). LV energetics was assessed by comparing MVO2 with cardiac work at a wide range of workloads.

RESULTS

In the post-ischaemia heart, dobutamine (5 μg kg(-1)  min(-1) ) increased cardiac output (CO) by increasing HR from 102 ± 21 to 131 ± 16 bpm (beats per min; P < 0.05). Adding ivabradine (0.5 mg kg(-1) ) slowed HR back to 100 ± 9 bpm and increased stroke volume from 30 ± 5 to 36 ± 5 mL (P < 0.05) by prolonging diastolic filling time and increasing end-diastolic dimensions. Adding ivabradine had no adverse effects on CO, mean arterial pressure and cardiac efficiency. Similar findings on efficiency and LV function were also seen using an ex vivo working mouse heart protocol.

CONCLUSIONS

A combined infusion of dobutamine and ivabradine had a neutral effect on post-ischaemia LV efficiency and increased left ventricular output without an increase in HR.

Is Heart Rate a Norepiphenomenon in Heart Failure?

There has been an increased focus on heart rate as a target in the management of cardiovascular disease and more specifically in heart failure with preserved ejection fraction in recent years with several studies showing the benefit of a lower resting heart rate on outcomes. This review paper examines the pathophysiology behind the benefits of lowering heart rate in heart failure and also the evidence for and against the pharmacological agents available to achieve this.

Chronic exposure to ivabradine reduces readmissions in the vulnerable phase after hospitalization for worsening systolic heart failure: a post-hoc analysis of SHIFT

AIMS

During the post-discharge phase following a heart failure hospitalization (HFH), patients are at high risk of early readmission despite standard of care therapy. We examined the impact of chronic exposure to ivabradine on early readmissions in patients hospitalized for heart failure during the course of the SHIFT study (Systolic Heart Failure treatment with the If inhibitor ivabradine Trial).

METHODS AND RESULTS

A total of 1186 of the 6505 randomized patients experienced at least one HFH during the study, and had a more severe profile than those without HFH. Of these 1186 patients, 334 patients (28%) were rehospitalized within 3 months for any reason, mostly for cardiovascular causes (86%), including HFH (61%). Ivabradine was associated with fewer all-cause hospitalizations at 1 month [incidence rate ratio (IRR) 0.70, 95% confidence interval (CI) 0.50-1.00, P < 0.05], 2 months (IRR 0.75, 95% CI 0.58-0.98, P = 0.03), and 3 months (IRR 0.79, 95% CI 0.63-0.99, P = 0.04). A trend for a reduction in cardiovascular and HF hospitalizations was also observed in ivabradine-treated patients.

CONCLUSION

We demonstrate in this post-hoc analysis that chronic exposure to ivabradine reduces the incidence of all-cause hospitalizations during the vulnerable phase after a HFH. Further studies are needed to investigate if in-hospital or early post-discharge initiation of ivabradine could be useful to improve early outcomes in patients hospitalized for HF.