Efficacy of ivabradine, a selective I(f) inhibitor, in patients with chronic stable angina pectoris and diabetes mellitus

Diabetes leading to heart failure and heart failure leading to diabetes: epidemiological and clinical evidence

Type 2 diabetes mellitus (T2DM) is a risk factor that plays a major role in the onset of heart failure (HF) both directly, by impairing cardiac function, and indirectly, through associated diseases such as hypertension, coronary disease, renal dysfunction, obesity, and other metabolic disorders. In a population of HF patients, the presence of T2DM ranged from 20 to 40%, according to the population studied, risk factor characteristics, geographic area, and age, and it is associated with a worse prognosis. Finally, patients with HF, when compared with those without HF, show an increased risk for the onset of T2DM due to several mechanisms that predispose the HF patient to insulin resistance. Despite the epidemiological data confirmed the relationship between T2DM and HF, the exact prevalence of HF in T2DM comes from interventional trials rather than from observational registries aimed to prospectively evaluate the risk of HF occurrence in T2DM population. This review is focused on the vicious cycle linking HF and T2DM, from epidemiological data to prognostic implications.

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 Na_v1.5 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 Na_v1.5 cryoEM structure. Automated patch-clamp experiments were used to investigate ivabradine-mediated changes in Na_v1.5 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 (Na_v1.5), neuronal (Na_v1.2), and skeletal muscle (Na_v1.4) 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.

Ivabradine in the management of COVID-19-related cardiovascular complications: A perspective

Abstract:

Besides acute respiratory distress syndrome, acute cardiac injury is a major complication in severe coronavirus disease 2019 (COVID-19) and associates with a poor clinical outcome. Acute cardiac injury with COVID-19 can be of various etiologies, including myocardial ischemia or infarction and myocarditis, and may compromise cardiac function, resulting in acute heart failure or cardiogenic shock. Systemic inflammatory response increases heart rate (HR), which disrupts the myocardial oxygen supply/demand balance and worsens cardiac energy efficiency, thus further deteriorating the cardiac performance of the injured myocardium. In fact, the combination of elevated resting HR and markers of inflammation synergistically predicts adverse cardiovascular prognosis. Thus, targeted HR reduction may potentially be of benefit in cardiovascular pathologies associated with COVID-19. Ivabradine is a drug that selectively reduces HR via If current inhibition in the sinoatrial node without a negative effect on inotropy. Besides selective HR reduction, ivabradine was found to exert various beneficial pleiotropic effects, either HR-dependent or HR-independent, including anti-inflammatory, anti-atherosclerotic, anti-oxidant and antiproliferative actions and the attenuation of endothelial dysfunction and neurohumoral activation. Cardioprotection by ivabradine has already been indicated in cardiovascular pathologies that are prevalent with COVID-19, including myocarditis, acute coronary syndrome, cardiogenic shock or cardiac dysautonomia. Here, we suggest that ivabradine may be beneficial in the management of COVID-19-related cardiovascular complications.

Comparative effectiveness of metoprolol, ivabradine, and its combination in the management of inappropriate sinus tachycardia in coronary artery bypass graft patients

BACKGROUND:

Inappropriate sinus tachycardia (IST) is an arrhythmic complication observed after coronary artery bypass graft (CABG) surgery which left untreated, commonly increases chances of postoperative stroke. The primary study objective was comparing effectiveness of beta blocker-metoprolol; a specific I_f blocker-ivabradine and its combination in patients who develop IST as a complication following CABG.

MATERIALS AND METHODS:

An open-labeled, investigator initiated, clinical study was conducted on 150 patients who developed IST (heart rate [HR] >100 beats/min) following elective CABG surgery. The patients were randomized into three treatment groups. Group I – received ivabradine (5 mg), Group II – metoprolol (25 mg), and Group III – ivabradine (5 mg) and metoprolol (25 mg). Treatment was given orally, twice a day for 7 days in all the three groups postoperatively. Primary endpoints were comparative effectiveness in HR and blood pressure reduction following treatment.

RESULTS:

IST was diagnosed by an electrocardiogram (12-lead) considering morphological features of P-wave and with 32% increase from baseline HR in all the three groups. Compared to IST arrthymic rate, HR was reduced in all groups following respective treatment (P = 0.05). Reduction in HR was significant (P < 0.05) in combination group followed by ivabradine which was significantly greater than metoprolol treated group. None of the treatments clinically changed the systolic, diastolic and mean blood pressure till discharge. No surgery/treatment-related complications were observed in any groups.

CONCLUSION:

Ivabradine stands as a pharmacological option for controlling HR and rhythm without associated side effects in postoperative CABG patients with IST.

Use of Preoperative Single Dose Ivabradine for Perioperative Hemodynamic Stabilization During Non-Cardiac Elective Surgery Under General Anaesthesia: A Pilot Study

Background

Peri-anesthetic hemodynamic fluctuations during non-cardiac surgeries are sometimes of serious consequences and associated with increased morbidity and mortality, especially in undiagnosed vulnerable patients. Currently used drugs like β-blocker, α2 agonist or sedative analgesic have their own limitations like combined negative ionotropic and chronotropic action, and unwanted bradycardia associated with hypotension, respectively. In this context, ivabradine has been used extensively in cases of cardiac failure, myocardial ischemia and cardiomyopathies for its funny channel associated dependable heart rate reducing property. Hence, for the first time, in search of a better agent for perioperative hemodynamic stabilization, the present study evaluated the role of ivabradine in patients undergoing non-cardiac surgeries.

Methods

This was a prospective, observer blind, randomized, interventional pilot study, conducted among 50 patients belonging undergoing elective abdominal laparoscopic surgeries, under general anesthesia. The study group patients received ivabradine tablet 7.5 mg, 2 h before scheduled time of surgery with a sip of water. All the patients received standardized balanced general anesthesia as practiced in our institute with all standard monitoring with additional minimum alveolar concentration (MAC) monitoring to ensure an adequate depth of anesthesia, and neuromuscular monitoring to ensure adequate and standard muscle relaxation. Hemodynamic stability of the groups was tested by comparing them at time points like induction, incision and operation, and extubation. Mean values of heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) were compared between groups, and also for variation with lapse of time, using RMANOVA analysis, using baseline parameters as covariate so as to standardize them.

Results

On multivariate analysis using Wilk’s lambda multivariate test, there was a statistically significant difference (F = 3.587, P = 0.036) in HR between the groups with time, while no significant difference of SBP, DBP and MAP between the groups with time.

Conclusions

The study revealed a significant attenuation of HR response to stressful events like laryngoscopy, intubation and surgical incision with ivabradine. Also, a good intraoperative protection against cardiovascular ischemic and arrhythmic episodes in perioperative period was achieved with this drug ivabradine.

Effectiveness and Impact on Adherence of a New Fixed-Dose Combination of Ivabradine and Metoprolol in a Wide Range of Stable Angina Patients in Real-Life Practice

INTRODUCTION

The antianginal effectiveness of ivabradine administration in addition to beta-blockers has been shown in patients with stable angina. The first fixed-dose combination (FDC) of ivabradine and metoprolol is now available and its evaluation in various stable angina patient populations relevant to clinical practice would be useful.

METHODS

In this 4-month, prospective, multicenter, observational study, the effectiveness and tolerability of the metoprolol/ivabradine FDC was assessed in patient subgroups specified according to age, coronary artery disease (CAD) duration, Canadian Cardiovascular Society (CCS) class, co-morbidities, and previous myocardial infarction (MI) or revascularization. Heart rate (HR), angina attack frequency, short-acting nitrate (SAN) consumption, functional status, and medication adherence were documented at baseline and after 4 months of follow-up.

RESULTS

A total of 747 stable angina patients were included and divided into subgroups. At 4 months, a significant decrease in HR, angina attack frequency, and SAN consumption per week was consistently observed across all patient subgroups. The proportion of CCS class I patients increased significantly from baseline to month 4. In all patient subgroups, at 4 months, a significant increase was observed in the proportion of patients with self-reported complete adherence. Complete adherence at the final visit was found to decrease with an increasing number of medications. Physicians evaluated the effectiveness and tolerability of the FDC as 'very good' and 'good' for more than 96% of patients in all analyzed patient subgroups.

CONCLUSIONS

Treatment with metoprolol/ivabradine FDC significantly improved angina symptoms and adherence, with an excellent tolerability profile, in stable angina patient subgroups relevant to real-life clinical practice, regardless of age, CAD duration, CCS class, comorbidities, previous MI, or history of revascularization.

TRIAL REGISTRATION

ISRCTN51906157.

FUNDING

This study was sponsored by Servier Deutschland GmbH. Editorial assistance and the Rapid Service Fee were funded by Servier, France. Plain language summary available for this article.

Type 2 Diabetes Mellitus and Heart Failure: A Scientific Statement From the American Heart Association and the Heart Failure Society of America: This statement does not represent an update of the 2017 ACC/AHA/HFSA heart failure guideline update

Type 2 diabetes mellitus is a risk factor for incident heart failure and increases the risk of morbidity and mortality in patients with established disease. Secular trends in the prevalence of diabetes mellitus and heart failure forecast a growing burden of disease and underscore the need for effective therapeutic strategies. Recent clinical trials have demonstrated the shared pathophysiology between diabetes mellitus and heart failure, the synergistic effect of managing both conditions, and the potential for diabetes mellitus therapies to modulate the risk of heart failure outcomes. This scientific statement on diabetes mellitus and heart failure summarizes the epidemiology, pathophysiology, and impact of diabetes mellitus and its control on outcomes in heart failure; reviews the approach to pharmacological therapy and lifestyle modification in patients with diabetes mellitus and heart failure; highlights the value of multidisciplinary interventions to improve clinical outcomes in this population; and outlines priorities for future research.

Type 2 Diabetes Mellitus and Heart Failure, A Scientific Statement From the American Heart Association and Heart Failure Society of America

Type 2 diabetes mellitus is a risk factor for incident heart failure and increases the risk of morbidity and mortality in patients with established disease. Secular trends in the prevalence of diabetes mellitus and heart failure forecast a growing burden of disease and underscore the need for effective therapeutic strategies. Recent clinical trials have demonstrated the shared pathophysiology between diabetes mellitus and heart failure, the synergistic effect of managing both conditions, and the potential for diabetes mellitus therapies to modulate the risk of heart failure outcomes. This scientific statement on diabetes mellitus and heart failure summarizes the epidemiology, pathophysiology, and impact of diabetes mellitus and its control on outcomes in heart failure; reviews the approach to pharmacological therapy and lifestyle modification in patients with diabetes mellitus and heart failure; highlights the value of multidisciplinary interventions to improve clinical outcomes in this population; and outlines priorities for future research.

Hyperpolarization-activated cyclic nucleotide-gated 2 (HCN2) ion channels drive pain in mouse models of diabetic neuropathy

Diabetic patients frequently suffer from continuous pain that is poorly treated by currently available analgesics. We used mouse models of type 1 and type 2 diabetes to investigate a possible role for the hyperpolarization-activated cyclic nucleotide-gated 2 (HCN2) ion channels as drivers of diabetic pain. Blocking or genetically deleting HCN2 channels in small nociceptive neurons suppressed diabetes-associated mechanical allodynia and prevented neuronal activation of second-order neurons in the spinal cord in mice. In addition, we found that intracellular cyclic adenosine monophosphate (cAMP), a positive HCN2 modulator, is increased in somatosensory neurons in an animal model of painful diabetes. We propose that the increased intracellular cAMP drives diabetes-associated pain by facilitating HCN2 activation and consequently promoting repetitive firing in primary nociceptive nerve fibers. Our results suggest that HCN2 may be an analgesic target in the treatment of painful diabetic neuropathy.

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.

The Role of Ivabradine in the Management of Angina Pectoris

Stable angina pectoris affects 2–4 % of the population in Western countries and entails an annual risk of death and nonfatal myocardial infarction of 1–2 % and 3 %, respectively. Heart rate (HR) is linearly related to myocardial oxygen consumption and coronary blood flow, both at rest and during stress. HR reduction is a key target for the prevention of ischemia/angina and is an important mechanism of action of drugs which are recommended as first line therapy for the treatment of angina in clinical guidelines. However, many patients are often unable to tolerate the doses of beta blocker or non-dihydropyridine calcium antagonists required to achieve the desired symptom control. The selective pacemaker current inhibitor ivabradine was developed as a drug for the management of patients with angina pectoris, through its ability to reduce HR specifically. The available data suggest that ivabradine is a well-tolerated and effective anti-anginal agent and it is recommended as a second-line agent for relief of angina in guidelines. However, recent clinical trials of ivabradine have failed to show prognostic benefit and have raised potential concerns about safety. This article will review the available evidence base for the current role of ivabradine in the management of patients with symptomatic angina pectoris in the context of stable coronary artery disease.

Pharmacologic management of chronic stable angina

Chronic stable angina is a significant problem in older adults. The goal of therapy is to provide symptomatic relief, improve patient quality of life, and prevent subsequent angina or myocardial infarction that could lead to sudden death. The efficacy and safety of drugs such as beta-blockers and calcium channel blockers for managing chronic stable angina in older adults has not been rigorously investigated. Drug selection should be based on physiologic alterations, patient comorbidities, adverse reaction profile, and cost.

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.

Noncoronary Collateral Myocardial Blood Flow: The Human Heart's Forgotten Blood Supply

The “noncoronary collateral circulation” (NCCC) or “noncoronary collateral myocardial blood flow” (NCCMBF), reaches the heart through a micro-vascular network arising from the bronchial, esophageal, pericardial, diaphragmatic, and aortic arteries. The left and right internal thoracic arteries (ITAs) along with their collateral branches also serve as a source of NCCMBF-a feature seen in other mammals. Under certain circumstances the ITAs have a high potential for developing collateral branches. In the case of severe Leriche syndrome or with chronic obstruction of the abdominal aorta, the ITAs can serve as the main or even sole source of blood supply to the lower limbs. It is also possible for the ITAs to develop angiographically visible branches that directly connect with the coronary arteries. In ischemic conditions there is a functional, ischemia-reducing extracardiac coronary artery supply via natural ipsilateral ITA anastomosis. To date we know little about NCCMBF and its potential benefits in clinical applications, which makes this a challenging and intriguing field of research. This paper reviews all available data on noncoronary collateral blood supply to the human heart.

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.

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.

Evaluation of pharmacokinetic and pharmacodynamic profiles and tolerability after single (2.5, 5, or 10 mg) and repeated (2.5, 5, or 10 mg bid for 4.5 days) oral administration of ivabradine in healthy male Korean volunteers

BACKGROUND

Ivabradine, a selective inhibitor of the pacemaker current in the sinoatrial node, has shown pure heart rate (HR)-reducing effects with anti-ischemic efficacy as well as improvement in heart failure outcomes.

OBJECTIVE

The purpose of this study was to explore pharmacokinetic (PK) and pharmacodynamic (PD) characteristics and tolerability in healthy male Korean volunteers, as well as to compare them with PK/PD profiles of white subjects.

METHODS

This was a randomized, double-blind, placebo-controlled Phase I study conducted in healthy male subjects. For each of the 3 dosing groups, 9 subjects were randomized to receive ivabradine and 3 to receive placebo. Subjects received a single oral dose of ivabradine 2.5, 5, or 10 mg and after a 3-day washout period, repeat doses of 2.5, 5, or 10 mg BID for 4.5 days. Blood and urine samples were collected over 72 hours during each period, and levels of ivabradine and its metabolite S18982 were determined by using validated LC-MS/MS, followed by noncompartmental PK analysis. For PD properties and tolerability, 24-hour Holter recordings were obtained: at baseline, after a single dose, after repeated doses, and after the last dose. Serial resting 12-lead ECG assessments were also performed throughout the study.

RESULTS

Forty-eight subjects were enrolled, and 45 completed the study. After single doses of 2.5, 5, and 10 mg, respective mean Cmax levels of ivabradine were 9, 15, and 39 ng/mL, and mean AUC0-last values were 30, 52, and 121 ng h/mL. At steady state, mean Cmax,ss levels were 11, 19, and 42 ng/mL, reached at a median Tmax of 0.67 hour for all 3 doses. The mean AUC0-τ levels were 43, 58, and 139 ng h/mL, respectively. The PK findings were linear with dose and time. Decreases in mean HR on both the Holter recordings and ECGs were observed in all of the ivabradine groups compared with placebo. After the repeated doses, mean decreases in HR were greater than those for the single doses for the same period. Statistically significant differences were observed between the 5- and 10-mg ivabradine groups and placebo. A total of 3 adverse events were reported in 2 subjects receiving ivabradine; both fully recovered without sequelae.

CONCLUSIONS

Single and repeated administration of ivabradine were generally well tolerated in these healthy male Korean volunteers. Ivabradine induced significant reductions in HR, especially at doses of 5 and 10 mg. PK/PD characteristics were similar to those found in white subjects, suggesting that the dose concentration-response relationship of ivabradine is similar between Korean and white subjects.

Ivabradine: an intelligent drug for the treatment of ischemic heart disease

Heart rate (HR) is a precisely regulated variable, which plays a critical role in health and disease. Elevated resting HR is a significant predictor of all-cause and cardiovascular mortality in the general population and patients with cardiovascular disease (CVD). β-blocking drugs exert negative effects on regional myocardial blood flow and function when HR reduction is eliminated by atrial pacing; calcium channel antagonists (CCAs) functionally antagonize coronary vasoconstriction mediated through α-adreno-receptors and are thus devoid of this undesired effect, but the compounds are nevertheless negative inotropes. From these observations derives the necessity to find alternative, more selective drugs to reduce HR through inhibition of specific electrical current (I(f)). Ivabradine (IVA) is a novel specific HR-lowering agent that acts in sinus atrial node (SAN) cells by selectively inhibiting the pacemaker I(f) current in a dose-dependent manner by slowing the diastolic depolarization slope of SAN cells, and by reducing HR at rest during exercise in humans. Coronary artery diseases (CAD) represent the most common cause of death in middle-aged and older adults in European Countries. Most ischemic episodes are triggered by an increase in HR, that induces an imbalance between myocardial oxygen delivery and consumption. IVA, a selective and specific inhibitor of the I(f) current which reduced HR without adverse hemodynamic effects, has clearly and unequivocally demonstrated its efficacy in the treatment of chronic stable angina pectoris (CSAP) and myocardial ischemia with optimal tolerability profile due to selective interaction with I(f) channels. The aim of this review is to point out the usefulness of IVA in the treatment of ischemic heart disease.

Treatment strategies for chronic stable angina

INTRODUCTION

Stable angina pectoris - generally the expression of an imbalance between myocardial oxygen demand and supply - is often the first manifestation of ischemic heart disease. The effective management of this highly prevalent condition is largely dependent on the identification of the prevailing pathogenic mechanism, the implementation of lifestyle changes and the appropriate use of pharmacological agents and revascularization techniques. There is abundant literature on management of chronic stable angina, but publications are generally devoted to focused areas. There is a need for a comprehensive review that addresses both the different types of angina and their pathogenic mechanisms, as well as rational approaches to patient management.

AREAS COVERED

This paper reviews the pathogenesis and pathophysiological mechanisms of myocardial ischemia, along with its consequences and current treatment options. Relevant papers in the English literature were identified via PubMed, using the following keywords relating to chronic stable angina: ischemic heart disease, coronary artery disease and antianginal therapy.

EXPERT OPINION

The treatment of chronic stable angina has improved in recent years as a result of a better understanding of its pathogenic mechanisms, the implementation of lifestyle changes and aggressive management of risk factors, as well as pharmacological advances and better revascularization techniques. Understanding the pathogenesis of the disease is important to identify effective treatment strategies. A careful clinical history, the implementation of appropriate diagnostic tests and a rational use of antianginal drugs and revascularization protocols often ensure the successful control of the patient's symptoms.

Electrophysiological effects of ivabradine in dog and human cardiac preparations: potential antiarrhythmic actions

Ivabradine is a novel antianginal agent which inhibits the pacemaker current. The effects of ivabradine on maximum rate of depolarization (V(max)), repolarization and spontaneous depolarization have not yet been reported in human isolated cardiac preparations. The same applies to large animals close to human in heart size and spontaneous frequency. Using microelectrode technique action potential characteristics and by applying patch-clamp technique ionic currents were studied. Ivabradine exerted concentration-dependent (0.1-10 μM) decrease in the amplitude of spontaneous diastolic depolarization and reduction in spontaneous rate of firing of action potentials and produced a concentration- and frequency-dependent V(max) block in dog Purkinje fibers while action potential duration measured at 50% of repolarization was shortened. In the presence of ivabradine, at 400 ms cycle length, V(max) block developed with an onset kinetic rate constant of 13.9 ± 3.2 beat(-1) in dog ventricular muscle. In addition to a fast recovery of V(max) from inactivation (τ=41-46 ms) observed in control, a second slow component for recovery of V(max) was expressed (offset kinetics of V(max) block) having a time constant of 8.76 ± 1.34 s. In dog after attenuation of the repolarization reserve ivabradine moderately but significantly lengthened the repolarization. In human, significant prolongation of repolarization was only observed at 10 μM ivabradine. Ivabradine in addition to the Class V antiarrhythmic effect also has Class I/C and Class III antiarrhythmic properties, which can be advantageous in the treatment of patients with ischemic heart disease liable to disturbances of cardiac rhythm.

Ivabradine: recent and potential applications in clinical practice

INTRODUCTION

published data indicate that heart rate is an independent strong predictor of cardiovascular and all-cause mortality in men and women of all ages, with and without cardiovascular disease, including atherosclerosis, ventricular arrhythmias, and left ventricular dysfunction. Ivabradine is a pure heart-rate-lowering agent with well-documented antianginal and anti-ischemic properties comparable to well-established anti-anginal agents.

AREAS COVERED

this short review explores recent results with ivabradine, a new medication that lowers heart rate by selectively inhibiting the I (f) current. This review also describes future potential applications.

EXPERT OPINION

measurement of heart rate represents an important component of the assessment of patients with coronary artery disease and chronic heart failure, and should be viewed in the same light as other risk factors, because a high heart rate has direct detrimental effects not only on myocardial ischemia but also on the progression of atherosclerosis, ventricular arrhythmias and left ventricular function. Ivabradine has anti-ischemic and antianginal efficacy equivalent to that of β-blockers and calcium channel antagonists in the treatment of chronic stable angina pectoris. Recently ivabradine has been shown to improve cardiac outcomes in stable coronary artery disease and left ventricular systolic dysfunction in patients who have heart rates of ≥ 70 bpm and in patients with stable angina.

Ivabradine reduces heart rate while preserving metabolic fluxes and energy status of healthy normoxic working hearts

Heart rate reduction (HRR) is an important target in the management of patients with chronic stable angina. Most available drugs for HRR, such as β-blockers, have adverse effects, including on cardiac energy substrate metabolism, a well-recognized determinant of cardiac homeostasis. This study aimed at 1) testing whether HRR by ivabradine (IVA) alters substrate metabolism in the healthy normoxic working heart and 2) comparing the effect of IVA with that of the β-blocker metoprolol (METO). This was assessed using our well-established model of ex vivo mouse heart perfusion in the working mode, which enables concomitant evaluation of myocardial contractility and metabolic fluxes using (13)C-labeled substrates. Hearts were perfused in the absence (controls; n = 10) or presence of IVA (n = 10, 3 μM) with or without atrial pacing to abolish HRR in the IVA group. IVA significantly reduced HR (35 ± 5%) and increased stroke volume (39 ± 9%) while maintaining similar cardiac output, contractility, power, and efficiency. Effects of IVA on HR and stroke volume were reversed by atrial pacing. At the metabolic level, IVA did not impact on substrate selection to citrate formation, rates of glycolysis, or tissue levels of high-energy phosphates. In contrast, METO, at concentrations up to 40 μM, decreased markedly cardiac function (flow: 25 ± 6%; stroke volume: 30 ± 10%; contractility: 31 ± 9%) as well as glycolysis (2.9-fold) but marginally affected HR. Collectively, these results demonstrate that IVA selectively reduces HR while preserving energy substrate metabolism of normoxic healthy working mouse hearts perfused ex vivo, a model that mimics to some extent the denervated transplanted heart. Our results provide the impetus for testing selective HRR by IVA on cardiac substrate metabolism in pathological models.

[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.

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.