Long-Term Safety and Efficacy of Ivabradine in Patients with Chronic Stable Angina

Ivabradine in Cardiovascular Disease Management Revisited: a Review

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

Effects of adding ivabradine to usual care in patients with angina pectoris: a systematic review of randomised clinical trials with meta-analysis and Trial Sequential Analysis

OBJECTIVE

To determine the impact of ivabradine on outcomes important to patients with angina pectoris caused by coronary artery disease.

METHODS

We conducted a systematic review. We included randomised clinical trials comparing ivabradine versus placebo or no intervention for patients with angina pectoris due to coronary artery disease published prior to June 2020. We used Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, Cochrane methodology, Trial Sequential Analysis, Grading of Recommendations Assessment, Development, and Evaluation, and our eight-step procedure. Primary outcomes were all-cause mortality, serious adverse events and quality of life.

RESULTS

We included 47 randomised clinical trials enrolling 35 797 participants. All trials and outcomes were at high risk of bias. Ivabradine compared with control did not have effects when assessing all-cause mortality (risk ratio [RR] 1.04; 95% CI 0.96 to 1.13), quality of life (standardised mean differences -0.05; 95% CI -0.11 to 0.01), cardiovascular mortality (RR 1.07; 95% CI 0.97 to 1.18) and myocardial infarction (RR 1.03; 95% CI 0.91 to 1.16). Ivabradine seemed to increase the risk of serious adverse events after removal of outliers (RR 1.07; 95% CI 1.03 to 1.11) as well as the following adverse events classified as serious: bradycardia, prolonged QT interval, photopsia, atrial fibrillation and hypertension. Ivabradine also increased the risk of non-serious adverse events (RR 1.13; 95% CI 1.11 to 1.16). Ivabradine might have a statistically significant effect when assessing angina frequency (mean difference (MD) 2.06; 95% CI 0.82 to 3.30) and stability (MD 1.48; 95% CI 0.07 to 2.89), but the effect sizes seemed minimal and possibly without any relevance to patients, and we identified several methodological limitations, questioning the validity of these results.

CONCLUSION

Our findings do not support that ivabradine offers significant benefits on patient important outcomes, but rather seems to increase the risk of serious adverse events such as atrial fibrillation and non-serious adverse events. Based on current evidence, guidelines need reassessment and the use of ivabradine for angina pectoris should be reconsidered.

PROSPERO REGISTRATION NUMBER

CRD42018112082.

A possible key role of vision in the development of schizophrenia

Based on a brief overview of the various aspects of schizophrenia reported by numerous studies, here we hypothesize that schizophrenia may originate (and in part be performed) from visual areas. In other words, it seems that a normal visual system or at least an evanescent visual perception may be an essential prerequisite for the development of schizophrenia as well as of various types of hallucinations. Our study focuses on auditory and visual hallucinations, as they are the most prominent features of schizophrenic hallucinations (and also the most studied types of hallucinations). Here, we evaluate the possible key role of the visual system in the development of schizophrenia.

Ivabradine in Congestive Heart Failure: Patient Selection and Perspectives

Heart failure (HF) is the fourth-most frequent cause of death and remains a challenge for public health. Therapy goals for HF with reduced ejection fraction (HFrEF) are the improvement in the quality of life, prolonged survival, a reduction of signs and symptoms, and the prevention of hospitalization. Angiotensin-converting enzyme inhibitors, beta‐blockers, and mineralocorticoid receptor antagonists are the treatments of choice for HFrEF. Although ivabradine is not available in all countries, it is likely a new promising approach to improve outcomes in patients with HFrEF, either alone or with beta-blockers. Here, we review the current knowledge about ivabradine in HFrEF and assess its effect on outcomes in HF.

Ivabradine for coronary artery disease and/or heart failure-a protocol for a systematic review of randomised clinical trials with meta-analysis and Trial Sequential Analysis

BACKGROUND

Coronary artery disease and heart failure are both highly prevalent diseases with a global prevalence of 93 million and 40 million. These patients are at increased risk of morbidity and mortality. The management of these patients involves medical therapy, and both diseases can be treated using the heart rate-lowering drug ivabradine. However, the evidence regarding the use of ivabradine in the treatment of coronary artery disease and/or heart failure is unclear. Our objective is to assess the beneficial and harmful effects of ivabradine in the treatment of coronary artery disease and/or heart failure.

METHODS

This protocol for a systematic review was undertaken using the recommendations of The Cochrane Collaboration, the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P), and the eight-step assessment procedure suggested by Jakobsen and colleagues. We plan to include all relevant randomised clinical trials assessing the use of ivabradine in the treatment of coronary artery disease and/or heart failure. We will search the Cochrane Central Register of Controlled Trials (CENTRAL), Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica database (EMBASE), Latin American and Caribbean Health Sciences Literature (LILACS), Science Citation Index Expanded on Web of Science, Chinese Biomedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), Chinese Science Journal Database (VIP), and BIOSIS in order to identify relevant trials. We will begin the searches in February 2019. All included trials will be assessed and classified at low risk of bias or at high risk of bias. Our primary conclusions will be based on the results from the primary outcomes at low risk of bias. Extracted data will be analysed using Review Manager 5.3 and Trial Sequential Analysis 0.9.5.10. We will create a 'Summary of Findings' table in which we will present our primary and secondary outcomes, and we will assess the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

DISCUSSION

The systematic review will have the potential to aid clinicians in decision-making regarding ivabradine and to benefit patients with coronary artery disease and/or heart failure.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018112082.

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.

Role of ivabradine in management of stable angina in patients with different clinical profiles

In chronic stable angina, elevated heart rate contributes to the development of symptoms and signs of myocardial ischaemia by increasing myocardial oxygen demand and reducing diastolic perfusion time. Accordingly, heart rate reduction is a well-known strategy for improving both symptoms of myocardial ischaemia and quality of life (QOL). The heart rate-reducing agent ivabradine, a direct and selective inhibitor of the I_f current, decreases myocardial oxygen consumption while increasing diastolic time, without affecting myocardial contractility or coronary vasomotor tone. Ivabradine is indicated for treatment of stable angina and chronic heart failure (HF). This review examines available evidence regarding the efficacy and safety of ivabradine in stable angina, when used as monotherapy or in combination with beta-blockers, in particular angina subgroups and in patients with stable angina with left ventricular systolic dysfunction (LVSD) or HF. Trials involving more than 45 000 patients receiving treatment with ivabradine have shown that this agent has antianginal and anti-ischaemic effects, regardless of age, sex, severity of angina, revascularisation status or comorbidities. This heart rate-lowering agent might also improve prognosis, reduce hospitalisation rates and improve QOL in angina patients with chronic HF and LVSD.

Treatment of Stable Angina with a New Fixed-Dose Combination of Ivabradine and Metoprolol: Effectiveness and Tolerability in Routine Clinical Practice

Introduction

In this prospective, multicenter, observational cohort study, the effectiveness and tolerability of the first fixed-dose combination (FDC) formulation of the selective heart rate reducing agent ivabradine and the beta-blocker metoprolol was evaluated in stable angina pectoris (AP) patients in a clinical practice setting.

Methods

Stable AP outpatients received a FDC of ivabradine and metoprolol (b.i.d.) for 4 months, in addition to cardiovascular standard therapy. Resting heart rate (HR), number of angina attacks, short-acting nitrate consumption, severity of symptoms (assessed by patient judgment and documented by CCS score) and tolerability were documented. Medication adherence was assessed by a modified four-item Morisky questionnaire. Descriptive statistics were performed on all data.

Results

A total of 747 stable AP patients (mean age, 66.4 years, 62% male, 50% and 31% with previous PCI and myocardial infarction, respectively) were included. Apart from ivabradine and beta-blockers as free combination, most frequently used concomitant standard medications at baseline were aspirin (68%), statins (71%), ACEI/AT1-blockers (76%), diuretics (35%), and calcium antagonists (15%). Highly prevalent comorbidities were hypertension (86%), hyperlipidemia (65%), and diabetes (35%). After 4 months, switch to treatment with the FDC was associated with a significant reduction in mean HR by 10 bpm. Proportion of patients with ≥ 1 angina attacks/week decreased from 38 to 7%. Patients in CCS class 1 increased (25 to 63%), while they decreased in CCS class 3 (19 to 5%). Medication adherence was also significantly improved (p < 0.001 for all changes from baseline). Mostly mild adverse events were documented in 5.4% of patients.

Conclusions

In these stable AP patients in a real-life setting, treatment with a FDC of ivabradine and metoprolol was associated with reduced HR and angina symptoms, while exercise capacity (CCS score) was improved. These effects may be mainly mediated by the increased medication adherence of patients observed with use of the FDC formulation.

Funding

Servier

Trial registration number

ISRCTN51906157

Management standards for stable coronary artery disease in India

Coronary artery disease (CAD) is one of the important causes of cardiovascular morbidity and mortality globally, giving rise to more than 7 million deaths annually. An increasing burden of CAD in India is a major cause of concern with angina being the leading manifestation. Stable coronary artery disease (SCAD) is characterised by episodes of transient central chest pain (angina pectoris), often triggered by exercise, emotion or other forms of stress, generally triggered by a reversible mismatch between myocardial oxygen demand and supply resulting in myocardial ischemia or hypoxia. A stabilised, frequently asymptomatic phase following an acute coronary syndrome (ACS) is also classified as SCAD. This definition of SCAD also encompasses vasospastic and microvascular angina under the common umbrella.

Effectiveness of Ivabradine Treatment in Different Subpopulations with Stable Angina in Clinical Practice: A Pooled Analysis of Observational Studies

Objectives: The efficacy of ivabradine has been demonstrated in different subpopulations of stable angina patients in randomized clinical trials. This study explored its effectiveness in subpopulations seen in clinical practice as they often differ from those of randomized trials. Methods: Data were pooled from three German observational studies with similar inclusion criteria (stable angina and heart rate ≥60 bpm). All patients received 2.5, 5, or 7.5 mg b.i.d. of ivabradine for 4 months, with or without concomitant beta-blocker. Antianginal effectiveness was analyzed in subpopulations defined by gender, age, heart rate, angina severity, use of concomitant beta-blocker, previous percutaneous coronary intervention procedure, and comorbidities (including previous myocardial infarction and diabetes). Results: Treatment data were available on 8,555 patients, where therapy with ivabradine was associated with a significant reduction in the frequency of angina attacks and consumption of short-acting nitrates of 87%. Effectiveness was maintained in all investigated subpopulations, with a reduction in antianginal parameters of 82-90%. Clinical status (Canadian Cardiovascular Society class) and quality of life were also improved. Ivabradine was well tolerated in all subgroups. Conclusions: Ivabradine is effective and safe in all subpopulations of angina patients seen in clinical practice, independent of age, comorbidities, and use of beta-blocker.

Effectiveness of Ivabradine in Treating Stable Angina Pectoris

Many studies show that ivabradine is effective for stable angina.This meta-analysis was performed to determine the effect of treatment duration and control group type on ivabradine efficacy in stable angina pectoris.Relevant articles in the English language in the PUBMED and EMBASE databases and related websites were identified by using the search terms "ivabradine," "angina," "randomized controlled trials," and "Iva." The final search date was November 2, 2015.Articles were included if they were published randomized controlled trials that related to ivabradine treatment of stable angina pectoris.Patients with stable angina pectoris were included.The patients were classified according to treatment duration (<3 vs ≥3 months) or type of control group (placebo vs beta-receptor blocker). Angina outcomes were heart rate at rest or peak, exercise duration, and time to angina onset.Seven articles were selected. There were 3747 patients: 2100 and 1647 were in the ivabradine and control groups, respectively. The ivabradine group had significantly longer exercise duration when they had been treated for at least 3 months, but not when treatment time was less than 3 months. Ivabradine significantly improved time to angina onset regardless of treatment duration. Control group type did not influence the effect of exercise duration (significant) or time to angina onset (significant).Compared with beta-blocker and placebo, ivabradine improved exercise duration and time to onset of angina in patients with stable angina. However, its ability to improve exercise duration only became significant after at least 3 months of treatment.

Ivadradine

Each month, subscribers to The Formulary Monograph Service receive 5 to 6 well-documented monographs on drugs that are newly released or are in late phase 3 trials. The monographs are targeted to Pharmacy & Therapeutics Committees. Subscribers also receive monthly 1-page summary monographs on agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation/medication use evaluation (DUE/MUE) is also provided each month. With a subscription, the monographs are sent in print and are also available on-line. Monographs can be customized to meet the needs of a facility. A drug class review is now published monthly with The Formulary Monograph Service. Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. For more information about The Formulary Monograph Service, call The Formulary at 800-322-4349. The October 2015 monograph topics are sacubitril/valsartan, daclatasvir, sonidegib, alirocumab, and sodium zirconium cyclosilicate. The Safety MUE is on sacubitril/valsartan.

Pleiotropic, heart rate-independent cardioprotection by ivabradine

BACKGROUND AND PURPOSE

In pigs, ivabradine reduces infarct size even when given only at reperfusion and in the absence of heart rate reduction. The mechanism of this non-heart rate-related cardioprotection is unknown. Hence, in the present study we assessed the pleiotropic action of ivabradine in more detail.

EXPERIMENTAL APPROACH

Anaesthetized mice were pretreated with ivabradine (1.7 mg · kg(-1) i.v.) or placebo (control) before a cycle of coronary occlusion/reperfusion (30/120 min ± left atrial pacing). Infarct size was determined. Isolated ventricular cardiomyocytes were exposed to simulated ischaemia/reperfusion (60/5 min) in the absence and presence of ivabradine, viability was then quantified and intra- and extracellular reactive oxygen species (ROS) formation was detected. Mitochondria were isolated from mouse hearts and exposed to simulated ischaemia/reperfusion (6/3 min) in glutamate/malate- and ADP-containing buffer in the absence and presence of ivabradine respectively. Mitochondrial respiration, extramitochondrial ROS, mitochondrial ATP production and calcium retention capacity (CRC) were assessed.

KEY RESULTS

Ivabradine decreased infarct size even with atrial pacing. Cardiomyocyte viability after simulated ischaemia/reperfusion was better preserved with ivabradine, the accumulation of intra- and extracellular ROS decreased in parallel. Mitochondrial complex I respiration was not different without/with ivabradine, but ivabradine significantly inhibited the accumulation of extramitochondrial ROS, increased mitochondrial ATP production and increased CRC.

CONCLUSION AND IMPLICATIONS

Ivabradine reduces infarct size independently of a reduction in heart rate and improves ventricular cardiomyocyte viability, possibly by reducing mitochondrial ROS formation, increasing ATP production and CRC.

Ivabradine: a new rate-limiting therapy for coronary artery disease and heart failure

Ivabradine is a new bradycardic agent acting on the I f channels of sinoatrial nodal cells to decrease the rate of diastolic depolarization and thus heart rate. The benefit of ivabradine over other negatively chronotropic agents is its absence of negative inotropy. Effective management of coronary artery disease, in terms of reducing morbidity and mortality, is reliant on controlling heart rate. Ivabradine has been shown to safely and effectively reduce heart rate without compromising cardiac function in patients with coronary artery disease and more recently in patients with heart failure and raised heart rate. Furthermore, ivabradine has been shown to have a favourable side-effect profile compared with alternative bradycardic agents. This article reviews the evidence for ivabradine in coronary artery disease and heart failure and compares its safety with alternative bradycardic agents for these conditions.

Selective and specific inhibition of If with ivabradine for the treatment of coronary artery disease or heart failure

Heart rate is an important contributor in the pathophysiology of both coronary artery disease (CAD) and heart failure (HF). Ivabradine is an anti-anginal and anti-ischaemic agent, which selectively and specifically inhibits the I_f current in the sino-atrial node and provides pure heart rate reduction without altering other cardiac parameters, including conduction, and without directly affecting other haemodynamic parameters. It is approved for the treatment of CAD and HF. This article summarises the pharmacological properties, pharmacokinetics, clinical efficacy and tolerability of ivabradine in the treatment of CAD and HF, and presents evidence demonstrating that the pharmacological and clinical properties and clinical efficacy of ivabradine make it an important therapeutic choice for patients with stable CAD or HF. The positive effect of ivabradine on angina pectoris symptoms and its ability to reduce myocardial ischemia make it an important agent in the management of patients with stable CAD or chronic HF. Further studies are underway to add to the already robust evidence of ivabradine for the prevention of cardiovascular events in patients with CAD but without clinical HF. The SIGNIFY (Study assessInG the morbidity–mortality beNefits of the I_f inhibitor ivabradine in patients with coronarY artery disease) trial includes patients with stable CAD and an LVEF above 40 %, with no clinical sign of HF, and is investigating the long-term effects (over a period of 48 months) of ivabradine in a large study population. So far, this study has included more than 19,000 patients from 51 countries.

An evaluation of the pharmacokinetics and pharmacodynamics of ivabradine for the treatment of heart failure

INTRODUCTION

Ivabradine is a new heart-rate-lowering drug; the aim of this review was to analyze its role in heart failure (HF).

AREAS COVERED

This systematic review on the role of ivabradine in HF is based on material searched and obtained through Pubmed and Medline up to September 2013.

EXPERT OPINION

Heart rate (HR) is a risk factor in patients with HF, and its reduction is considered an important goal of therapy. The BEAUTIFUL trial demonstrated the benefits of ivabradine on prognosis (only on ischemic endpoints) in patients with coronary artery disease (CAD) and left ventricular systolic dysfunction (LVSD) and HR ≥ 60 bpm. In the SHIFT trial, which enrolled patients with LVSD, HF and HR ≥ 70 bpm, ivabradine administration (on top of guideline-based therapy, including β-blockers [BB]) was associated with a reduction of cardiovascular death and hospitalizations for HF, but BB were underutilized. Further studies are needed to test the efficacy of ivabradine in CAD patients with high HR and to shed light on the comparison between ivabradine and a more aggressive therapy with higher doses of BB in HF patients.

'Inappropriate' sinus tachycardia: does the 100 beats per min cut-off matter?

Sinus tachycardia is commonly encountered in clinical practice and when persistent, can result in significant symptoms and impaired quality of life, warranting further evaluation. On the other hand, a growing body of epidemiological and clinical evidence has shown that high resting heart rate (HR) within the accepted normal range is independently associated with increased risk of all-cause and cardiovascular mortality. However, higher HR as a risk factor for adverse cardiovascular outcomes is frequently underappreciated. In this review, we focus on two challenging problems that span the spectrum of abnormally fast sinus HR. The first section reviews inappropriate sinus tachycardia, a complex disorder characterized by rapid sinus HR without a clear underlying cause, with particular emphasis on current management options. The latter section discusses the prognostic significance of elevated resting HR and reviews clinical evidence aimed at modifying this simple, yet highly important risk factor.

Pharmacodynamic effects of ivabradine, a negative chronotropic agent, in healthy cats

OBJECTIVE

To determine the pharmacodynamic effects of oral ivabradine in cats.

ANIMALS

Eight healthy, adult domestic short hair cats.

METHODS

Each cat underwent four study periods of 24 h, receiving either one dose of placebo or ivabradine (0.1 mg/kg, 0.3 mg/kg, and 0.5 mg/kg) in a single-blind randomized crossover study. Clinical tolerance was assessed hourly for the first 8 h, at 12 h, and at the end of the 24-h study period. Heart rate and blood pressure were monitored continuously for 18-24 h via radiotelemetry after each treatment. Response to stress (acoustic startle) was studied before (t = 0) and after treatment (t = 4 h). Statistical comparisons were made using a linear mixed models and 1-way and 2-way repeated measures ANOVA.

RESULTS

Heart rate (min(-1)) decreased significantly (P < 0.05) in a dose-dependent manner with peak negative chronotropic effects observed 3 h after ivabradine (mean ± SD; placebo, 144 ± 20; ivabradine 0.1 mg/kg, 133 ± 22; ivabradine 0.3 mg/kg, 112 ± 20; and ivabradine 0.5 mg/kg, 104 ± 11). Heart rate (min(-1)) was still reduced (P < 0.05) 12 h after ivabradine (0.3 mg/kg; 128 ± 18 and 0.5 mg/kg; 124 ± 16) compared to placebo (141 ± 21). The tachycardic response to acoustic startle was significantly (P < 0.01) blunted at all 3 doses of ivabradine. Myocardial oxygen consumption estimated by the rate-pressure product was significantly reduced (P < 0.05) for all doses of ivabradine. No effect of ivabradine on systolic, diastolic, and mean blood pressure was identified and no clinically discernable side effects were observed.

CONCLUSION

These findings indicate that a single oral dose of ivabradine predictably lowers heart rate, blunts the chronotropic response to stress, and is clinically well tolerated in healthy cats. This makes ivabradine potentially interesting in the treatment of feline heart disease where ischemia is of pathophysiologic importance.

Innovation in coronary artery disease and heart failure: clinical benefits of pure heart rate reduction with ivabradine

The link between elevated heart rate and cardiovascular events is established in healthy individuals and in patients with cardiovascular disease. The new agent, ivabradine, specifically and selectively inhibits the I(f) current, with the sole action of heart rate reduction, with no impact on any other cardiac parameters. The benefits of "pure" heart rate reduction with ivabradine have been the focus of one of the largest clinical development programs ever performed, involving >20,000 individuals. Ivabradine has anti-ischemic and antianginal efficacy in monotherapy, as well as in combination with other antianginals, such as beta-blockers, and is safe and well tolerated. Two major morbidity-mortality trials, BEAUTIFUL and SHIFT, showed that heart rate reduction with ivabradine dramatically improves prognosis in patients with coronary artery disease and left ventricular dysfunction, symptomatic angina, or chronic heart failure. The development of ivabradine represents a clear innovation in the management of cardiovascular disease.

Safety of ivabradine in patients with coronary artery disease and left ventricular systolic dysfunction (from the BEAUTIFUL Holter Substudy)

The BEAUTIFUL Holter substudy explored the cardiac safety of the I(f) inhibitor ivabradine in patients with stable coronary artery disease and left ventricular systolic dysfunction receiving optimal background therapy. The Holter substudy included 840 patients (ivabradine 5 or 7.5 mg/day, n = 421; placebo, n = 419), and the safety set consisted of 807 patients (ivabradine, n = 408; placebo, n = 399). Ambulatory 24-hour electrocardiographic Holter monitoring was performed at baseline and after 1 month and 6 months. There were no relevant between-group differences in baseline characteristics; 93% were receiving concomitant β blocker. Treatment with ivabradine was associated with a decrease in 24-hour heart rate of 6.3 ± 9.5 beats/min at last assessment versus no change with placebo (0.4 ± 7.2 beats/min, p <0.001, between-group difference), with a greater decrease in waking heart rate with ivabradine than during sleep (6.8 ± 10.4 vs 5.2 ± 8.9 beats/min, respectively, at last visit). Incidence of episodes of heart rate <30 beats/min during waking hours or during sleep was ≤1% in the 2 groups. Although there were more patients with heart rates <40 or <50 beats/min with ivabradine than with placebo (awake 12% vs 4% for <40 beats/min and 68% vs 36% for <50 beats/min, respectively; asleep 22% vs 5% for <40 beats/min and 77% vs 50% for <50 beats/min, respectively), there was no between-group difference in episode severity. There was no increase in incidence of conduction and rhythm disturbances. In conclusion, our results confirm that ivabradine significantly lowers heart rate without raising concern for cardiac safety. Our observations strongly support the safety of combining ivabradine with β blockers in patients with coronary artery disease.

[Ivabradine in coronary heart disease: experimental and clinical pharmacology]

The present paper reviews clinical evidence underlining the role of ivabradine in the management of patient with ischemic heart disease. Reduction in heart rate mediated by this selective I(f) current inhibitor has been associated with anti-ischemic efficacy without any effect on haemodynamic or myocardial contractility. The antianginal efficacy of ivabradine is similar or superior to that of conventional anti-ischemic agents. Moreover combination therapy with ivabradine provides substantial benefit in patients already receiving beta-blocker. Prognostic efficacy of ivabradine is evaluated in a large program of studies, among which BEAUTIFUL in coronary patients with left ventricular dysfunction. The SIGNIFY study is ongoing in stable coronary patients without ventricular dysfunction. Furthermore the SHIFT trial will evaluate ivabradine benefits in heart failure patients, whatever the origin, ischemic or not.

Recent advances in the management of chronic stable angina II. Anti-ischemic therapy, options for refractory angina, risk factor reduction, and revascularization

The objectives in treating angina are relief of pain and prevention of disease progression through risk reduction. Mechanisms, indications, clinical forms, doses, and side effects of the traditional antianginal agents - nitrates, β-blockers, and calcium channel blockers - are reviewed. A number of patients have contraindications or remain unrelieved from anginal discomfort with these drugs. Among newer alternatives, ranolazine, recently approved in the United States, indirectly prevents the intracellular calcium overload involved in cardiac ischemia and is a welcome addition to available treatments. None, however, are disease-modifying agents. Two options for refractory angina, enhanced external counterpulsation and spinal cord stimulation (SCS), are presented in detail. They are both well-studied and are effective means of treating at least some patients with this perplexing form of angina. Traditional modifiable risk factors for coronary artery disease (CAD) - smoking, hypertension, dyslipidemia, diabetes, and obesity - account for most of the population-attributable risk. Individual therapy of high-risk patients differs from population-wide efforts to prevent risk factors from appearing or reducing their severity, in order to lower the national burden of disease. Current American College of Cardiology/American Heart Association guidelines to lower risk in patients with chronic angina are reviewed. The Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial showed that in patients with stable angina, optimal medical therapy alone and percutaneous coronary intervention (PCI) with medical therapy were equal in preventing myocardial infarction and death. The integration of COURAGE results into current practice is discussed. For patients who are unstable, with very high risk, with left main coronary artery lesions, in whom medical therapy fails, and in those with acute coronary syndromes, PCI is indicated. Asymptomatic patients with CAD and those with stable angina may defer intervention without additional risk to see if they will improve on optimum medical therapy. For many patients, coronary artery bypass surgery offers the best opportunity for relieving angina, reducing the need for additional revascularization procedures and improving survival. Optimal medical therapy, percutaneous coronary intervention, and surgery are not competing therapies, but are complementary and form a continuum, each filling an important evidence-based need in modern comprehensive management.

Ivabradine: from molecular basis to clinical effectiveness

Ivabradine (IVA) is a novel, specific, heart rate (HR)-lowering agent that acts in sinoatrial node (SAN) cells by selectively inhibiting the pacemaker If current in a dose-dependent manner by slowing the diastolic depolarization slope of SAN cells, and reducing HR at rest and during exercise with minimal effect on myocardial contractility, blood pressure, and intracardiac conduction. Many published studies have demonstrated that HR reduction with IVA is beneficial in patients with chronic stable angina. IVA has been shown to be noninferior to beta-blocker and calcium antagonist drugs in HR reduction. The specific pharmacodynamic and pharmacokinetic properties of IVA make it an important agent in the management of patients with coronary artery disease, particularly in those patients with an elevated HR. The aim of this short review is to describe the regulation of HR and If current with IVA, and some beneficial effects of this medication in patients with coronary artery disease.

The usefulness of chronic heart failure treatments in chronic cardiac graft failure

Following cardiac transplantation, registry data has demonstrated a gradual improvement in survival over the last several decades, which is testament to continual improvement in aftercare strategy. However, a significant number of patients will eventually develop a new syndrome of chronic heart failure, owing to the multitude of physiological processes that occur after transplantation. This condition, referred to as chronic graft failure (CGF) should be regarded as a unique illness rather than one that is simply analogous with chronic heart failure. In particular, the unique pathophysiological (and pharmacological) environment in the setting of CGF presents a challenging situation to the transplant physician. There is uncertainty over which treatments to offer given a paucity of clinical trial data to support the use of standard heart failure treatments in CGF. In this review, we discuss which chronic heart failure treatments could be considered in the setting of CGF based on their mechanisms of action, benefits within the native heart failure setting, and the relevant issues within the posttransplant environment.

I(f) inhibition in cardiovascular diseases

Heart rate (HR) is determined by the pacemaker activity of cells from the sinoatrial node (SAN), located in the right atria. Spontaneous electrical activity of SAN cells results from a diastolic depolarization (DD). Despite controversy in the exact contribution of funny current (I(f)) in pacemaking, it is a major contributor of DD. I(f) is an inward Na(+)/K(+) current, activated upon hyperpolarization and directly modulated by cyclic adenosine monophosphate. The f-proteins are hyperpolarization-activated cyclic nucleotide-gated channels, HCN4 being the main isoform of SAN. Ivabradine (IVA) decreases DD and inhibits I(f) in a use-dependent manner. Under normal conditions IVA selectively reduces HR and limits exercise-induced tachycardia, in animals and young volunteers. Reduction in HR with IVA both decreases myocardial oxygen consumption and increases its supply due to prolongation of diastolic perfusion time. In animal models and in human with coronary artery disease (CAD), IVA has anti-anginal and anti-ischemic efficacy, equipotent to classical treatments, β-blockers, or calcium channel blockers. As expected from its selectivity for I(f), the drug is safe and well tolerated with minor visual side effects. As a consequence, IVA is the first inhibitor of I(f) approved for the treatment of stable angina. Available clinical data indicate that IVA could improve the management of stable angina in all patients including those treated with β-blockers. As chronic elevation of resting HR is an independent predictor of mortality, pure HR reduction by inhibition of I(f) could, beyond the control of anti-anginal symptoms, improve the prognosis of CAD and heart failure; this therapeutic potential is currently under evaluation with IVA.

Control of risk factors in and treatment of patients with coronary heart disease: the TRECE study

The aim of the TRECE study was to describe treatment in patients with coronary heart disease (CHD). It was an observational, cross-sectional multicenter study of patients who were treated in either an internal medicine (n=50) or cardiology (n=50) department or in primary care (n=100) during 2006. The patients' history, risk factors and treatment were recorded, and noncardiac disease was evaluated using the Charlson index. Optimal medical treatment (OMT) was regarded as comprising combined administration of antiplatelet agents, statins, beta-blockers, and renin-angiotensin-aldosterone system blockers. In total, data on 2897 patients were analyzed; their mean age was 67.4 years and 71.5% were male. Overall, 25.9% (95% confidence interval, 25.6-26.2%) received OMT. Multivariate analysis showed that prescription of OMT was independently associated with hypertension, diabetes, current smoking, myocardial infarction and angina. In contrast, nonprescription of OMT was associated with atrial fibrillation, chronic obstructive pulmonary disease and a Charlson index>/=4. The main findings were that few CHD patients were prescribed OMT and that its prescription was determined by the presence of symptoms and comorbid conditions.

Treatment of stable angina pectoris by ivabradine in every day practice: the REDUCTION study

BACKGROUND

The antianginal efficacy of ivabradine was studied in controlled clinical trials. Strict patient selection criteria may cause a discrepancy between the results of highly controlled clinical trials and everyday routine practice. The objective of this study was to evaluate the efficacy and safety of ivabradine in everyday routine practice.

METHODS

In this multicenter study, 4,954 patients with stable angina pectoris received ivabradine in everyday routine practice and underwent follow-up for 4 months. The heart rate (HR), angina pectoris attacks, nitrate consumption, overall efficacy, and tolerance were evaluated.

RESULTS

Within 4 months of treatment with ivabradine, HR was reduced by 12.4 +/- 12.2 beat/min from 82.9 +/- 15.3 to 70.4 +/- 9.2 beat/min (P < .0001). Angina pectoris attacks were reduced from 2.4 +/- 3.1 to 0.4 +/- 1.5 per week (P < .0001). Consumption of short-acting nitrates was reduced from 3.3 +/- 4.4 to 0.6 +/- 1.6 U/wk (P < .0001). Seventy-eight cases of adverse drug reactions were reported. The most common adverse drug reactions were nausea (n = 11, 0.22%) and dizziness (n = 9, 0.18%). Efficacy and tolerance were graded by physicians as being "excellent/very good" for 97% and 98% of the patients treated.

CONCLUSION

Ivabradine reduces the HR and is highly effective and well tolerated in the treatment of patients with symptomatic coronary artery disease. The results confirm the findings of controlled clinical trials in a broad patient population in everyday routine practice.

The cardiac pacemaker current

In mammals cardiac rate is determined by the duration of the diastolic depolarization of sinoatrial node (SAN) cells which is mainly determined by the pacemaker I(f) current. f-channels are encoded by four members of the hyperpolarization-activated cyclic nucleotide-gated gene (HCN1-4) family. HCN4 is the most abundant isoform in the SAN, and its relevance to pacemaking has been further supported by the discovery of four loss-of-function mutations in patients with mild or severe forms of cardiac rate disturbances. Due to its selective contribution to pacemaking, the I(f) current is also the pharmacological target of a selective heart rate-reducing agent (ivabradine) currently used in the clinical practice. Albeit to a minor extent, the I(f) current is also present in other spontaneously active myocytes of the cardiac conduction system (atrioventricular node and Purkinje fibres). In working atrial and ventricular myocytes f-channels are expressed at a very low level and do not play any physiological role; however in certain pathological conditions over-expression of HCN proteins may represent an arrhythmogenic mechanism. In this review some of the most recent findings on f/HCN channels contribution to pacemaking are described.

A practical synthesis of 1-cyano-4,5-dimethoxybenzocyclobutene

A practical synthesis of 1-cyano-4,5-dimethoxybenzocyclobutene, the key intermediate of Ivabradine, was developed in four or five steps using two different routes. 2-Bromo-4,5-dimethoxyhydrocinnamonitrile was produced via the condensation of 2-bromo-4,5-dimethoxybenzaldehyde with acetonitrile or cyanoacetic acid and reduction by NaBH4. Cyclisation gave 1-cyano-4,5-dimethoxybenzocyclobutene. Overall yields of the routes A and B were 30% and 37% respectively. Route B is a short and simple route, permitting the synthesis of 1-cyano-4,5-dimethoxybenzocyclobutene on a large scale.

Ca2+: is there something new for the cardiovascular anesthesiologist?

PURPOSE OF REVIEW

Anesthesiologists are frequently called upon to treat abnormalities of heart rhythm or pumping ability. Intracellular Ca is crucial for normal excitation-contraction coupling in the heart and plays a major role in the sequence of events that starts with an electrical signal generated in the atria and ends with myocardial contraction.

RECENT FINDINGS

From controlled diffusion within the cell to a potential role as a biological clock, intracellular Ca is receiving a great deal of attention. For example, the pacemaking electrical signal is known to originate in the sinoatrial node myocyte, but exactly what role Ca plays is controversial despite the fact that the sinoatrial node was discovered over 100 years ago. Basic mechanisms involved in disease processes such as atrial fibrillation and new interventions for heart rate control are beginning to emerge. New discoveries in ventricular myocytes are also stimulating the development of promising therapeutic interventions to safely increase the pumping ability of the heart.

SUMMARY

As our understanding of cardiac physiology and pharmacology progresses at the subcellular and molecular levels, new therapies will continue to emerge and the practice of anesthesia will benefit greatly.

Pacemaker activity of the human sinoatrial node: role of the hyperpolarization-activated current, I(f)

The mechanism of primary, spontaneous cardiac pacemaker activity of the sinoatrial node (SAN) has extensively been studied in several animal species, but is virtually unexplored in man. Understanding the mechanisms of human SAN pacemaker activity is important for developing new therapeutic approaches for controlling the heart rate in the sick sinus syndrome and in diseased myocardium. Here we review the functional role of the hyperpolarization-activated 'funny' current, I(f), in human SAN pacemaker activity. Despite the many animal studies performed over the years, the contribution of I(f) to pacemaker activity is still controversial and not fully established. However, recent clinical data on mutations in the I(f) encoding HCN4 gene, which is thought to be the most abundant isoform of the HCN gene family in SAN, suggest a functional role of I(f) in human pacemaker activity. These clinical findings are supported by recent experimental data from single isolated human SAN cells that provide direct evidence that I(f) contributes to human SAN pacemaker activity. Therefore, controlling heart rate in clinical practice via I(f) blockers offers a valuable approach to lowering heart rate and provides an attractive alternative to conventional treatment for a wide range of patients with confirmed stable angina, while upregulation or artificial expression of I(f) may relieve disease-causing bradycardias.

Effects of ivabradine on allograft function and exercise performance in heart transplant recipients with permanent sinus tachycardia

Aim of this retrospective analysis was to evaluate the effects of ivabradine given primarily as a heart rate-lowering agent on allograft function and cardiopulmonary performance in heart transplant recipients with permanent sinus tachycardia. Starting May 2006, 26 heart transplant recipients with permanent sinus tachycardia received ivabradine (5 mg bid). It was discontinued early in 3 patients (11.5%) due to adverse events. In the remaining 23 patients, resting heart rate (HR) was significantly lowered from 106.3 +/- 9.1 to 82.2 +/- 6.3 bpm after 3 weeks of treatment. The effect remained constant during the remaining treatment period, whereas resting blood pressure was not affected. After 12 weeks of ivabradine treatment, the corrected QT interval was significantly reduced into the range seen in normal individuals. Left ventricular (LV) end-diastolic posterior wall thickness, LV mass and LV mass index were also found to have decreased significantly. There was a trend to improvement of cardiopulmonary performance and LV ejection fraction, both of which did not reach statistical significance, however. It may be concluded that ivabradine successfully reduced the resting HR of heart transplant recipients with sinus tachycardia without negatively influencing the blood pressure. The definitive impact of ivabradine on LV mass regression and cardiopulmonary performance require further prospective, randomized and controlled trials.

Current awareness: Pharmacoepidemiology and drug safety

In order to keep subscribers up‐to‐date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of pharmacoepidemiology and drug safety. Each bibliography is divided into 20 sections: 1 Reviews; 2 General; 3 Anti‐infective Agents; 4 Cardiovascular System Agents; 5 CNS Depressive Agents; 6 Non‐steroidal Anti‐inflammatory Agents; 7 CNS Agents; 8 Anti‐neoplastic Agents; 9 Haematological Agents; 10 Neuroregulator‐Blocking Agents; 11 Dermatological Agents; 12 Immunosuppressive Agents; 13 Autonomic Agents; 14 Respiratory System Agents; 15 Neuromuscular Agents; 16 Reproductive System Agents; 17 Gastrointestinal System Agents; 18 Anti‐inflammatory Agents ‐ Steroidal; 19 Teratogens/fetal exposure; 20 Others. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted.