Antianginal and antiischemic effects of ivabradine, an I(f) inhibitor, in stable angina: a randomized, double-blind, multicentered, placebo-controlled trial

Coronary sinus reducer for the treatment of refractory angina (ORBITA-COSMIC): a randomised, placebo-controlled trial

BACKGROUND

The coronary sinus reducer (CSR) is proposed to reduce angina in patients with stable coronary artery disease by improving myocardial perfusion. We aimed to measure its efficacy, compared with placebo, on myocardial ischaemia reduction and symptom improvement.

METHODS

ORBITA-COSMIC was a double-blind, randomised, placebo-controlled trial conducted at six UK hospitals. Patients aged 18 years or older with angina, stable coronary artery disease, ischaemia, and no further options for treatment were eligible. All patients completed a quantitative adenosine-stress perfusion cardiac magnetic resonance scan, symptom and quality-of-life questionnaires, and a treadmill exercise test before entering a 2-week symptom assessment phase, in which patients reported their angina symptoms using a smartphone application (ORBITA-app). Patients were randomly assigned (1:1) to receive either CSR or placebo. Both participants and investigators were masked to study assignment. After the CSR implantation or placebo procedure, patients entered a 6-month blinded follow-up phase in which they reported their daily symptoms in the ORBITA-app. At 6 months, all assessments were repeated. The primary outcome was myocardial blood flow in segments designated ischaemic at enrolment during the adenosine-stress perfusion cardiac magnetic resonance scan. The primary symptom outcome was the number of daily angina episodes. Analysis was done by intention-to-treat and followed Bayesian methodology. The study is registered with ClinicalTrials.gov, NCT04892537, and completed.

FINDINGS

Between May 26, 2021, and June 28, 2023, 61 patients were enrolled, of whom 51 (44 [86%] male; seven [14%] female) were randomly assigned to either the CSR group (n=25) or the placebo group (n=26). Of these, 50 patients were included in the intention-to-treat analysis (24 in the CSR group and 26 in the placebo group). 454 (57%) of 800 imaged cardiac segments were ischaemic at enrolment, with a median stress myocardial blood flow of 1·08 mL/min per g (IQR 0·77-1·41). Myocardial blood flow in ischaemic segments did not improve with CSR compared with placebo (difference 0·06 mL/min per g [95% CrI -0·09 to 0·20]; Pr(Benefit)=78·8%). The number of daily angina episodes was reduced with CSR compared with placebo (OR 1·40 [95% CrI 1·08 to 1·83]; Pr(Benefit)=99·4%). There were two CSR embolisation events in the CSR group, and no acute coronary syndrome events or deaths in either group.

INTERPRETATION

ORBITA-COSMIC found no evidence that the CSR improved transmural myocardial perfusion, but the CSR did improve angina compared with placebo. These findings provide evidence for the use of CSR as a further antianginal option for patients with stable coronary artery disease.

FUNDING

Medical Research Council, Imperial College Healthcare Charity, National Institute for Health and Care Research Imperial Biomedical Research Centre, St Mary's Coronary Flow Trust, British Heart Foundation.

Localization of hyperpolarization-activated cyclic nucleotide-gated channels in the vertebrate retinas across species and their physiological roles

Transmembrane proteins known as hyperpolarization-activated cyclic nucleotide-gated (HCN) channels control the movement of Na+ and K+ ions across cellular membranes. HCN channels are known to be involved in crucial physiological functions in regulating neuronal excitability and rhythmicity, and pacemaker activity in the heart. Although HCN channels have been relatively well investigated in the brain, their distribution and function in the retina have received less attention, remaining their physiological roles to be comprehensively understood. Also, because recent studies reported HCN channels have been somewhat linked with the dysfunction of photoreceptors which are affected by retinal diseases, investigating HCN channels in the retina may offer valuable insights into disease mechanisms and potentially contribute to identifying novel therapeutic targets for retinal degenerative disorders. This paper endeavors to summarize the existing literature on the distribution and function of HCN channels reported in the vertebrate retinas of various species and discuss the potential implications for the treatment of retinal diseases. Then, we recapitulate current knowledge regarding the function and regulation of HCN channels, as well as their relevance to various neurological disorders.

A Placebo-Controlled Trial of Percutaneous Coronary Intervention for Stable Angina

BACKGROUND

Percutaneous coronary intervention (PCI) is frequently performed to reduce the symptoms of stable angina. Whether PCI relieves angina more than a placebo procedure in patients who are not receiving antianginal medication remains unknown.

METHODS

We conducted a double-blind, randomized, placebo-controlled trial of PCI in patients with stable angina. Patients stopped all antianginal medications and underwent a 2-week symptom assessment phase before randomization. Patients were then randomly assigned in a 1:1 ratio to undergo PCI or a placebo procedure and were followed for 12 weeks. The primary end point was the angina symptom score, which was calculated daily on the basis of the number of angina episodes that occurred on a given day, the number of antianginal medications prescribed on that day, and clinical events, including the occurrence of unblinding owing to unacceptable angina or acute coronary syndrome or death. Scores range from 0 to 79, with higher scores indicating worse health status with respect to angina.

RESULTS

A total of 301 patients underwent randomization: 151 to the PCI group and 150 to the placebo group. The mean (±SD) age was 64±9 years, and 79% were men. Ischemia was present in one cardiac territory in 242 patients (80%), in two territories in 52 patients (17%), and in three territories in 7 patients (2%). In the target vessels, the median fractional flow reserve was 0.63 (interquartile range, 0.49 to 0.75), and the median instantaneous wave-free ratio was 0.78 (interquartile range, 0.55 to 0.87). At the 12-week follow-up, the mean angina symptom score was 2.9 in the PCI group and 5.6 in the placebo group (odds ratio, 2.21; 95% confidence interval, 1.41 to 3.47; P<0.001). One patient in the placebo group had unacceptable angina leading to unblinding. Acute coronary syndromes occurred in 4 patients in the PCI group and in 6 patients in the placebo group.

CONCLUSIONS

Among patients with stable angina who were receiving little or no antianginal medication and had objective evidence of ischemia, PCI resulted in a lower angina symptom score than a placebo procedure, indicating a better health status with respect to angina. (Funded by the National Institute for Health and Care Research Imperial Biomedical Research Centre and others; ORBITA-2 ClinicalTrials.gov number, NCT03742050.).

Hypoxia-induced signaling in the cardiovascular system: pathogenesis and therapeutic targets

Hypoxia, characterized by reduced oxygen concentration, is a significant stressor that affects the survival of aerobic species and plays a prominent role in cardiovascular diseases. From the research history and milestone events related to hypoxia in cardiovascular development and diseases, The "hypoxia-inducible factors (HIFs) switch" can be observed from both temporal and spatial perspectives, encompassing the occurrence and progression of hypoxia (gradual decline in oxygen concentration), the acute and chronic manifestations of hypoxia, and the geographical characteristics of hypoxia (natural selection at high altitudes). Furthermore, hypoxia signaling pathways are associated with natural rhythms, such as diurnal and hibernation processes. In addition to innate factors and natural selection, it has been found that epigenetics, as a postnatal factor, profoundly influences the hypoxic response and progression within the cardiovascular system. Within this intricate process, interactions between different tissues and organs within the cardiovascular system and other systems in the context of hypoxia signaling pathways have been established. Thus, it is the time to summarize and to construct a multi-level regulatory framework of hypoxia signaling and mechanisms in cardiovascular diseases for developing more therapeutic targets and make reasonable advancements in clinical research, including FDA-approved drugs and ongoing clinical trials, to guide future clinical practice in the field of hypoxia signaling in cardiovascular diseases.

Effect of ivabradine on ventricular arrhythmias in heart failure patients with reduced ejection fraction

BACKGROUND/INTRODUCTION

Heart failure patients with reduced ejection fraction are at high risk for ventricular arrhythmias and sudden cardiac death. Ivabradine, a specific inhibitor of the If current in the sinoatrial node, provides heart rate reduction in sinus rhythm and angina control in chronic coronary syndromes.

OBJECTIVE

The effect of ivabradine on ventricular arrhythmias in heart failure patients with reduced ejection fraction patients has not been fully elucidated. The aim of this study was to investigate the effect of ivabradine use on life-threatening arrhythmias and long-term mortality in heart failure patients with reduced ejection fraction patients.

METHODS

In this retrospective study, 1,639 patients with heart failure patients with reduced ejection fraction were included. Patients were divided into two groups: ivabradine users and nonusers. Patients presenting with ventricular tachycardia, the presence of ventricular extrasystole, and ventricular tachycardia in 24-h rhythm monitoring, appropriate implantable cardioverter-defibrillator shocks, and long-term mortality outcomes were evaluated according to ivabradine use.

RESULTS

After adjustment for all possible variables, admission with ventricular tachycardia was three times higher in ivabradine nonusers (95% confidence interval 1.5-10.2). The presence of premature ventricular contractions and ventricular tachycardias in 24-h rhythm Holter monitoring was notably higher in ivabradine nonusers. According to the adjusted model for all variables, 4.1 times more appropriate implantable cardioverter-defibrillator shocks were observed in the ivabradine nonusers than the users (95%CI 1.8-9.6). Long-term mortality did not differ between these groups after adjustment for all covariates.

CONCLUSION

The use of ivabradine reduced the appropriate implantable cardioverter-defibrillator discharge in heart failure patients with reduced ejection fraction patients. Ivabradine has potential in the treatment of ventricular arrhythmias in heart failure patients with reduced ejection fraction patients.

Physiological effects of ivabradine in heart failure and beyond

Ivabradine is a pharmacologic agent that inhibits the funny current responsible for determining heart rate in the sinoatrial node. Ivabradine's clinical potential has been investigated in the context of heart failure since it is associated with reduced myocardial oxygen demand, enhanced diastolic filling, stroke volume, and coronary perfusion time; however, it is yet to demonstrate definitive mortality benefit. Alternative effects of ivabradine include modulation of the renin-angiotensin-aldosterone system, sympathetic activation, and endothelial function. Here, we review key clinical trials informing the clinical use of ivabradine and explore opportunities for leveraging its potential pleiotropic effects in other diseases, including treatment of hyperadrenergic states and mitigating complications of COVID-19 infection.

INOCA/ANOCA: Mechanisms and novel treatments

Angina or ischemia with no obstructive coronary disease (ANOCA/INOCA) is a common but under-treated condition due to poorly understood pathophysiologic mechanisms, limited diagnostic tools, and lack of proven targeted therapy. Coronary microvascular dysfunction (CMD) occurs when the microvasculature inadequately perfuses the myocardium under stress, or at rest in the case of microvascular spasm resulting in ANOCA/INOCA. Coronary functional angiography (CFA) measures endothelial independent microvascular dysfunction (coronary flow reduction <2.5) in response to adenosine and endothelial dependent microvascular dysfunction (lack of dilation and/or constriction) to acetylcholine testing as well as epicardial and microvascular spasm. Current treatment for coronary microvascular dysfunction is limited to renin-angiotensin system (RAS) inhibitors and statins as well as antianginal medications. Novel therapies targeting the underlying pathology are under development and include the coronary sinus reducer, CD34+ stem cell therapy, and novel pharmacologic agents such as sGC stimulators or endothelin-receptor blockers. We review the current understanding of pathophysiology, diagnostic tools, and novel therapies for coronary microvascular dysfunction in ANOCA/INOCA.

Effect of Coronary Sinus Reducer Implantation on Aerobic Exercise Capacity in Refractory Angina Patients-A CROSSROAD Study

Coronary sinus reducer (CSR) implantation is a new treatment option for patients with refractory angina pectoris. However, there is no evidence from a randomized trial that would show an improvement in exercise capacity after this treatment. The aim of this study was to evaluate the influence of CSR treatment on maximal oxygen consumption and compare it to a sham procedure. Twenty-five patients with refractory angina pectoris (Canadian Cardiovascular Society (CCS) class II-IV) were randomized to a CSR implantation (n = 13) or a sham procedure (n = 12). At baseline and after 6 months of follow-up, the patients underwent symptom-limited cardiopulmonary exercise testing with an adjusted ramp protocol and assessment of angina pectoris using the CCS scale and Seattle angina pectoris questionnaire (SAQ). In the CSR group, maximal oxygen consumption increased from 15.56 ± 4.05 to 18.4 ± 5.2 mL/kg/min (p = 0.03) but did not change in the sham group (p = 0.53); p for intergroup comparison was 0.03. In contrast, there was no difference in the improvement of the CCS class or SAQ domains. To conclude, in patients with refractory angina and optimized medical therapy, CSR implantation may improve oxygen consumption beyond that of optimal medical therapy.

Mechanisms of current therapeutic strategies for heart failure: more questions than answers?

Heart failure (HF) is a complex, multifactorial and heterogeneous syndrome with substantial mortality and morbidity. Over the last few decades, numerous attempts have been made to develop targeted therapies that may attenuate the known pathophysiological pathways responsible for causing the progression of HF. However, therapies developed with this objective have sometimes failed to show benefit. The pathophysiological construct of HF with numerous aetiologies suggests that interventions with broad mechanisms of action which simultaneously target more than one pathway maybe more effective in improving the outcomes of patients with HF. Indeed, current therapeutics with clinical benefits in HF have targeted a wider range of intermediate phenotypes. Despite extensive scientific breakthroughs in HF research recently, questions persist regarding the ideal therapeutic targets which may help achieve maximum benefit. In this review, we evaluate the mechanism of action of current therapeutic strategies, the pathophysiological pathways they target and highlight remaining knowledge gaps regarding the mode of action of these interventions.

Updates on Pharmacologic Management of Microvascular Angina

Microvascular angina (MVA), historically called cardiac syndrome X, refers to angina with nonobstructive coronary artery disease. This female-predominant cardiovascular disorder adds considerable health-related costs due to repeated diagnostic angiography and frequent hospital admissions. Despite the high prevalence of this diagnosis in patients undergoing coronary angiography, it is still a therapeutic challenge for cardiologists. Unlike obstructive coronary artery disease, with multiple evidence-based therapies and management guidelines, little is known regarding the management of MVA. During the last decade, many therapeutic interventions have been suggested for the treatment of MVA. However, there is a lack of summarization tab and update of current knowledge about pharmacologic management of MVA, mostly due to unclear pathophysiology. In this article, we have reviewed the underlying mechanisms of MVA and the outcomes of various medications in patients with this disease. Contrary to vasospastic angina in which normal angiogram is observed as well, nitrates are not effective in the treatment of MVA. Beta-blockers and calcium channel blockers have the strongest evidence of improving the symptoms. Moreover, the use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, statins, estrogen, and novel antianginal drugs has had promising outcomes. Investigations are still ongoing for vitamin D, omega-3, incretins, and n-acetyl cysteine, which have resulted in beneficial initial outcomes. We believe that the employment of the available results and results of the future large-scale trials into cardiac care guidelines would help reduce the global cost of cardiac care tremendously.

Association of resting heart rate with cognitive decline and dementia in older adults: A population-based cohort study

INTRODUCTION

Resting heart rate (RHR) predicts future risk for cardiovascular disease (CVD). However, longitudinal studies investigating the relationship of RHR with cognitive decline are scarce.

METHODS

This population-based cohort study included 2147 participants (age≥60) in SNAC-K who were free of dementia and regularly followed from 2001-2004 to 2013-2016. RHR was assessed with electrocardiogram. Dementia was diagnosed following the Diagnostic and Statistical Manual of Mental Disorders 4th Revision criteria. Global cognitive function was assessed using Mini-Mental State Examination (MMSE). Data were analyzed using Cox and linear mixed-effects models.

RESULTS

RHR≥80 (vs. 60-69) bpm was associated with a multi-adjusted hazard ratio of 1.55 (95% confidence interval 1.06-2.27) for dementia. The association remained significant after excluding participants with prevalent and incident CVDs. Similarly, RHR≥80 bpm was associated with a multi-adjusted β-coefficient of -0.13 (-0.21 to -0.04) for MMSE score.

DISCUSSION

Higher RHR is associated with increased risk for dementia and faster cognitive decline independent of CVDs in a general population of elderly people.

Sustained-Release Ivabradine Hemisulfate in Patients With Systolic Heart Failure

BACKGROUND

Ivabradine has potent actions in reducing heart rate and improving clinical outcomes of chronic heart failure with reduced ejection fraction (HFrEF). At present, only the short-acting formulation of ivabradine is available that needs to be administered twice daily.

OBJECTIVES

This study sought to evaluate the role of ivabradine hemisulfate sustained release (SR), a novel long-acting formulation of ivabradine dosed once daily, in stable patients with HFrEF.

METHODS

Patients with stabilized HFrEF in New York Heart Association functional class II-IV were enrolled and randomized to receive placebo or ivabradine SR in addition to standard medications. The primary endpoint was the change of left ventricular (LV) end-systolic volume index from baseline to week 32.

RESULTS

We randomly assigned 181 patients to placebo and 179 patients to ivabradine SR. After 32 weeks, a significant improvement of LV end-systolic volume index from baseline was observed in both arms with a greater effect in the ivabradine SR arm. Ivabradine SR therapy also exhibited superiority in improving LV end-diastolic volume index, LV ejection fraction, resting heart rate, the Kansas City Cardiomyopathy Questionnaire score, and hospital admission for heart failure worsening and cardiovascular disease in comparison to placebo. Overall adverse events showed no difference between the treatment arms. There were fewer occurrences of worsening heart failure in the ivabradine SR arm.

CONCLUSIONS

The present study demonstrates that ivabradine SR once daily in addition to optimum standard therapy improved heart function in patients with HFrEF. (Clinical Trial of Systolic Heart Failure Treatment of IvabRadine Hemisulfate Sustained-release Tablets [FIRST]; NCT02188082).

Ivabradine and Atrial Fibrillation: A Meta-analysis of Randomized Controlled Trials

ABSTRACT

This was a meta-analysis of randomized control trials (RCTs) to evaluate the effect of ivabradine on the risk of atrial fibrillation (AF) as well as its effect on the ventricular rate in patients with AF. The PubMed, EMBASE, Cochrane Controlled Trials Register, and other databases were searched for RCTs of ivabradine. Thirteen trials with 37,533 patients met the inclusion criteria. The incidence of AF was significantly higher in the ivabradine treatment group than in the control group (odds ratio (OR), 1.23; 95% confidence interval (CI), 1.08-1.41), although it was reduced after cardiac surgery (OR, 0.70; 95% CI, 0.23-2.12). Regarding left ventricular ejection fraction (LVEF), ivabradine increased the risk of AF in both LVEF >40% (OR, 1.42; 95% CI, 1.24 to 1.63) and LVEF ≤40% subgroups (OR, 1.16; 95% CI, 0.98-1.37). The risk of AF was increased by both small and large cumulative doses of ivabradine (small cumulative dose: OR, 3.00; 95% CI, 0.48 to 18.93; large cumulative dose: OR, 1.05; 95% CI, 0.83-1.34). Furthermore, ivabradine may reduce the ventricular rate in patients with AF. In conclusion, we found that both large and small cumulative doses of ivabradine were associated with an increased incidence of AF, and the effect was more marked in the LVEF >40% subgroup. Nevertheless, ivabradine therapy is beneficial for the prevention of post-operative AF. Furthermore, ivabradine may be effective in controlling the ventricular rate in patients with AF, although more RCTs are needed to support this conclusion.

Vasomotor Dysfunction in Patients with Ischemia and Non-Obstructive Coronary Artery Disease: Current Diagnostic and Therapeutic Strategies

Many patients who present with symptoms or objective evidence of ischemia have no or non-physiologically-significant disease on invasive coronary angiography. The diagnosis of ischemic heart disease is thus often dismissed, and patients receive false reassurance or other diagnoses are pursued. We now know that a significant proportion of these patients have coronary microvascular dysfunction and/or vasospastic disease as the underlying pathophysiology of their clinical presentation. Making the correct diagnosis of such abnormalities is important not only because they impact the quality of life, with recurring symptoms and unnecessary repeated testing, but also because they increase the risk for adverse cardiovascular events. The mainstay of diagnosis remains an invasive comprehensive physiologic assessment, which further allows stratifying these patients into appropriate “endotypes”. It has been shown that tailoring treatment to the patient’s assigned endotype improves symptoms and quality of life. In addition to the conventional drugs used in chronic stable angina, multiple newer agents are being investigated. Moreover, innovative non-pharmacologic and interventional therapies are emerging to provide a bail-out in refractory cases. Many of these novel therapies fail to show consistent benefits, but others show quite promising results.

Effect of ivabradine in heart failure: a meta-analysis of heart failure patients with reduced versus preserved ejection fraction

In clinical trials of heart failure reduced ejection fraction (HFrEF), ivabradine seemed to be an effective heart rate lowering agent associated with lower risk of cardiovascular death. In contrast, ivabradine failed to improve cardiovascular outcomes in heart failure preserved ejection fraction (HFpEF) despite the significant effect on heart rate. This meta-analysis is the first to compare the effects of ivabradine on heart rate and mortality parameters in HFpEF versus HFrEF. We screened three databases: PubMed, Embase, and Cochrane Library. The outcomes of these studies were mortality, reduction in heart rate, and left ventricular function improvement. We compared the efficacy of ivabradine treatment in HFpEF versus HFrEF. Heart rate analysis of pooled data showed decrease in both HFrEF (-17.646 beats/min) and HFpEF (-11.434 beats/min), and a tendency to have stronger bradycardic effect in HFrEF (p = 0.094) in randomized clinical trials. Left ventricular ejection fraction analysis revealed significant improvement in HFrEF (5.936, 95% CI: [4.199-7.672], p < 0.001) when compared with placebo (p < 0.001). We found that ivabradine significantly improves left ventricular performance in HFrEF, at the same time it exerts a tendency to have improved bradycardic effect in HFrEF. These disparate effects of ivabradine and the higher prevalence of non-cardiac comorbidities in HFpEF may explain the observed beneficial effects in HFrEF and the unchanged outcomes in HFpEF patients after ivabradine treatment.

HCN1 channels: A versatile tool for signal processing by primary sensory neurons

Most primary sensory neurons (PSNs) generate a slowly-activating inward current in response to membrane hyperpolarization (I_h) and express HCN1 along with additional isoforms coding for hyperpolarization-activated channels (HCN). Changes in HCN expression may affect the excitability and firing patterns of PSNs, but retinal and inner ear PSNs do not fire action potentials, suggesting HCN channel roles may extend beyond excitability and cell firing control. In patients taking I_h blockers, photopsia triggered in response to abrupt changes in luminance correlates with impaired visual signal processing via parallel rod and cone pathways. Furthermore, in a mouse model of inherited retinal degeneration, HCN blockers or Hcn1 genetic ablation may worsen photoreceptors' demise. PSN's use of HCN channels to adjust either their firing rate or process signals generated by sensory transduction in non-spiking PSNs indicates HCN1 channels as a versatile tool with a novel role in sensory processing beyond firing control.

Management of refractory angina: an update

Despite the use of anti-anginal drugs and/or percutaneous coronary interventions (PCI) or coronary artery bypass grafting, the proportion of patients with coronary artery disease who have daily or weekly angina ranges from 2% to 24%. Refractory angina refers to long-lasting symptoms (for >3 months) due to established reversible ischaemia, which cannot be controlled by escalating medical therapy with the use of 2nd- and 3rd-line pharmacological agents, bypass grafting, or stenting. While there is uncertain prognostic benefit, the treatment of refractory angina is important to improve the quality of life of the patients affected. This review focuses on conventional pharmacological approaches to treating refractory angina, including guideline directed drug combination and dosages. The symptomatic and prognostic impact of advanced and novel revascularization strategies such as chronic total occlusion PCI, transmyocardial laser revascularization, coronary sinus occlusion, radiation therapy for recurrent restenosis, and spinal cord stimulation are also covered and recommendations of the 2019 ESC Guidelines on the Diagnosis and Management of Chronic Coronary Syndromes discussed. Finally, the potential clinical use of current angiogenetic and stem cell therapies in reducing ischaemia and/or pain is evaluated.

Effect of ivabradine on heart rate, functional capacity and pulmonary artery pressure in patients of COPD with cor pulmonale

We studied the effects of heart rate reduction by ivabradine to the ongoing therapy in patients with chronic obstructive pulmonary disease (COPD) and cor pulmonale.100 patients of COPD with cor pulmonale with sinus heart rate ≥ 90 bpm were randomly assigned to either ivabradine 5 mg twice daily (50 patients) or placebo (50 patients) alongwith standard therapy. Assessment was done at baseline and after 6 months which included 6 min walk test (6MWT), dyspnea scoring by modified borg scale, Lung function test by forced expiratory volume in 1 s (FEV1) and pulmonary artery systolic pressure (PASP) by echocardiogram. The drug group showed a significant reduction in heart rate from 95.1 ± 8.2 bpm to 71.1 ± 6.2 bpm (p < 0.001). This group also showed significant improvement in 6-min walk distance and dyspnea on modified Borg scale (p < 0.001) at 6 months follow up. However no significant difference was found between both groups regarding PASP or FEV1 at 6 months.

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.

Effects of visualization of successful revascularization on chest pain and quality of life in chronic coronary syndrome: study protocol for the multi-center, randomized, controlled PLA-pCi-EBO-pilot-trial

Background

Stable coronary artery disease (CAD), recently termed chronic coronary syndrome (CCS), is a highly prevalent disease. Current treatment strategies often include a relevant placebo effect. The hypothesis is that visual angiographic demonstration of the coronary arteries before and after successful percutaneous coronary intervention (PCI) by itself reduces the symptom burden of stable CAD/CCS.

Design and methods

The PLA-pCi-EBO-pilot-trial is a prospective, multi-center, randomized, controlled investigator-initiated pilot trial to study the effect of visual demonstration of successful PCI on quality of life (QoL) and angina pectoris (AP) in patients with symptomatic stable CAD/CCS. All patients with stable CAD/CCS and successful PCI will be screened. One hundred forty four patients with a frequency of AP ≥ 2/week will be randomized 1:1 stratified for AP frequency > 1/day. The control group will receive the common written procedural report on the procedure. Patients in the intervention group will additionally be given a printout picture of their coronary angiogram both before and after PCI. Primary endpoints are change in the Seattle Angina Questionnaire (SAQ)-derived QoL score 1 and 6 months after PCI. Secondary endpoints are changes in other SAQ-derived scores and dyspnea (NYHA score) 1 and 6 months after PCI.

Discussion

The PLA-pCi-EBO-pilot-trial evaluates the effect of visual angiographic result demonstration on disease symptoms and QoL in patients with stable CAD/CCS on top of PCI. A positive outcome of our study would encourage the routine use of angiographic picture demonstration and has thus the potential to change daily routine in the catheterization laboratory.

Trial registration

German Clinical Trials Register DRKS00017524. Registered on 5 July 2019

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.

Lessons Learnt from Recent Trials in Ischemic Heart Disease

Four recently published randomized controlled trials have informed the care of patients with stable ischemic heart disease. The purpose of this clinical focus article is to offer a summary and critical appraisal of the recent evidence. We aim to aid clinicians in the translation of the trial evidence to patient care.

Ivabradine for the Therapy of Chronic Stable Angina Pectoris: a Systematic Review and Meta-Analysis

Background and Objectives

Coronary artery disease (CAD) is the number one cause of death worldwide. The I_f channel inhibitor ivabradine serves as second line medication for the CAD leading symptom angina pectoris. This systematic review and meta-analysis assess the existing evidence of ivabradine in angina pectoris.

Methods

We systematically searched MEDLINE, Embase, CENTRAL, and Web of Science (September 2019) for randomized controlled trials (RCTs) that compared ivabradine versus placebo, standard therapy (ST) or other anti-anginal drugs. Two review authors independently assessed trials for inclusion and performed data extraction. We completed a ‘risk of bias’ assessment for all studies and assessed quality of the trial evidence using the Grading of Recommendations Assessment, Development and Evaluation methodology. We meta-analysed data were applicable and calculated mean differences (MDs) and risk ratios using a random-effects model.

Results

A total of 11 RCTs (n=16,039) were included. Compared to placebo/ST, we found significant effects on the frequency of hospitalisation in a small cohort (n=90; hazard ratio [HR], 0.19; 95% confidence interval [CI], 0.04, −0.92; p=0.04), but no effects on cardiovascular mortality (n=19,102; HR, 1.10; 95% CI, 0.94, 1.28; p=0.25) or the frequency of angina pectoris episodes (n=167; weighted MD, −1.06; 95% CI, −2.74, −0.61; p=0.21).

Conclusions

The present work makes an important contribution to optimal patient care in angina pectoris by complementing the current European Society of Cardiology guideline—recommending class IIa with evidence level B—decisively with 8 further studies.

Gating mechanism of hyperpolarization-activated HCN pacemaker channels

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are essential for rhythmic activity in the heart and brain, and mutations in HCN channels are linked to heart arrhythmia and epilepsy. HCN channels belong to the family of voltage-gated K⁺ (Kv) channels. However, why HCN channels are activated by hyperpolarization whereas Kv channels are activated by depolarization is not clear. Here we reverse the voltage dependence of HCN channels by mutating only two residues located at the interface between the voltage sensor and the pore domain such that the channels now open upon depolarization instead of hyperpolarization. Our data indicate that what determines whether HCN channels open by hyperpolarizations or depolarizations are small differences in the energies of the closed and open states, due to different interactions between the voltage sensor and the pore in the different channels.

Treatment of coronary microvascular dysfunction

Contemporary data indicate that patients with signs and symptoms of ischaemia and non-obstructive coronary artery disease (INOCA) often have coronary microvascular dysfunction (CMD) with elevated risk for adverse outcomes. Coronary endothelial (constriction with acetylcholine) and/or microvascular (limited coronary flow reserve with adenosine) dysfunction are well-documented, and extensive non-obstructive atherosclerosis is often present. Despite these data, patients with INOCA currently remain under-treated, in part, because existing management guidelines do not address this large, mostly female population due to the absence of evidence-based data. Relatively small sample-sized, short-term pilot studies of symptomatic mostly women, with INOCA, using intense medical therapies targeting endothelial, microvascular, and/or atherosclerosis mechanisms suggest symptom, ischaemia, and coronary vascular functional improvement, however, randomized, controlled outcome trials testing treatment strategies have not been completed. We review evidence regarding CMD pharmacotherapy. Potent statins in combination with angiotensin-converting enzyme inhibitor (ACE-I) or receptor blockers if intolerant, at maximally tolerated doses appear to improve angina, stress testing, myocardial perfusion, coronary endothelial function, and microvascular function. The Coronary Microvascular Angina trial supports invasive diagnostic testing with stratified therapy as an approach to improve symptoms and quality of life. The WARRIOR trial is testing intense medical therapy of high-intensity statin, maximally tolerated ACE-I plus aspirin on longer-term outcomes to provide evidence for guidelines. Novel treatments and those under development appear promising as the basis for future trial planning.

Role of endothelial dysfunction in determining angina after percutaneous coronary intervention: Learning from pathophysiology to optimize treatment

Endothelial dysfunction (EnD) is a hallmark feature of coronary artery disease (CAD), representing the key early step of atherosclerotic plaque development and progression. Percutaneous coronary intervention (PCI) is performed daily worldwide to treat symptomatic CAD, however a consistent proportion of patients remain symptomatic for angina despite otherwise successful revascularization. EnD plays a central role in the mechanisms of post-PCI angina, as it is strictly associated with both structural and functional abnormalities in the coronary arteries that may persist, or even accentuate, following PCI. The assessment of endothelial function in patients undergoing PCI might help to identify those patients at higher risk of future cardiovascular events and recurrent/persistent angina who might therefore benefit more from an intensive treatment. In this review, we address the role of EnD in determining angina after PCI, discussing its pathophysiological mechanisms, diagnostic approaches and therapeutic perspectives.

[Cardiovascular pharmacotherapy and coronary revascularization in end-stage renal failure]

There is a close physiological relationship between the kidneys and the heart. Cardiovascular diseases are the most prevalent cause of death in patients with chronic kidney disease (CKD), whereas CKD may directly accelerate the progression of cardiovascular diseases and is considered to be a cardiovascular risk factor. In patients with mild CKD, i.e. an estimated glomerular filtration rate (eGFR) >60 ml/min/1.73 m², treatment of coronary artery disease and chronic heart failure is not essentially different from patients with preserved renal function; however, as most pivotal trials have systematically excluded patients with advanced renal failure, many treatment recommendations in this patient group are based on observational studies, post hoc subgroup analyses and meta-analyses or pathophysiological considerations, which are not supported by controlled studies. Therefore, prospective randomized studies on the management of heart failure and coronary artery disease are needed, which should specifically focus on the growing number of patients with advanced renal functional impairment.

Pharmacology of Ivabradine and the Effect on Chronic Heart Failure

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

Advances in small-molecule therapy for managing angina pectoris in the elderly

Introduction: As our population ages, the prevalence of angina is growing, leading to increased morbidity and decreased quality of life. The management of angina in the elderly is challenging due to drug intolerance and/or drug resistance as well as frailty. Over the past decades, many new therapeutic small molecules have been investigated for the management of angina. Although none of these studies have specifically focused on the therapies for the elderly, they offer promising new avenues for the treatment of angina in the elderly. Areas covered: Herein, the authors provide a review of the recently published literature on the use of small-molecule therapies for angina management in the elderly and provide a brief overview of these therapies. Expert opinion: A variety of therapeutic classes of existing and newer small molecules are emerging for the management of angina in the elderly. An individualized approach to the management of angina in this growing population is critical for good outcomes. Many small molecules are in their initial stages of clinical use, and further research should be conducted on their utility, especially in the elderly.

Stable Angina Medical Therapy Management Guidelines: A Critical Review of Guidelines from the European Society of Cardiology and National Institute for Health and Care Excellence

Most patients with stable angina can be managed with lifestyle changes, especially smoking cessation and regular exercise, along with taking antianginal drugs. Randomised controlled trials show that antianginal drugs are equally effective and none of them reduced mortality or the risk of MI, yet guidelines prefer the use of beta-blockers and calcium channel blockers as a first-line treatment. The European Society of Cardiology guidelines for the management of stable coronary artery disease provide classes of recommendation with levels of evidence that are well defined. The National Institute for Health and Care Excellence (NICE) guidelines for the management of stable angina provide guidelines based on cost and effectiveness using the terms first-line and second-line therapy. Both guidelines recommend using low-dose aspirin and statins as disease-modifying agents. The aim of this article is to critically appraise the guidelines’ pharmacological recommendations for managing patients with stable angina.

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.

Percutaneous coronary intervention for stable coronary artery disease

The adverse consequences of stable coronary artery disease (CAD) are death, myocardial infarction (MI) and angina. Trials in stable CAD show that percutaneous coronary intervention (PCI) does not reduce mortality. PCI does appear to reduce spontaneous MI rates but at the expense of causing some periprocedural MI. Therefore, the main purpose of PCI is to relieve angina. Indeed, patients and physicians often choose PCI rather than first attempting to control symptoms with anti-anginal medications as recommended by guidelines. Nevertheless, it is unclear how effective PCI is at relieving angina. This is because, whereas anti-anginal medications are universally required to be tested against placebo, there is no such requirement for procedural interventions such as PCI. The first placebo-controlled trial of PCI showed a surprisingly small effect size. This may be because it is overly simplistic to assume that the presence of a stenosis and inducible ischaemia in a patient means that the clinical chest pain they report is caused by ischaemia. In this article, we review the evidence base and argue that if we as a medical specialty wish to lead the science of procedures for symptom control, we should recognise the special merit of placebo-controlled experiments.

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.

Heart rate in patients with reduced ejection fraction: relationship between single time point measurement and mean heart rate on prolonged implantable cardioverter defibrillator monitoring

Background

Heart rate (HR) is a prognostic marker that is increasingly used as a therapeutic target in patients with cardiovascular disease. The association between resting and mean HR remains unclear. We therefore set out to determine the relationship between resting HR on the electrocardiogram (ECG) obtained at a single time point, and mean HR on implantable cardioverter defibrillator (ICD) interrogation amongst patients with a reduced left ventricular ejection fraction (LVEF).

Methods

Prospective ICD data were obtained from 54 patients with LVEF < 40%. Mean HR determined using the ICD HR histograms was compared with resting HR measured on the ECG performed in the clinic.

Results

Average resting and ICD mean HRs were 67.9 ± 10.1 and 67.8 ± 9.6 bpm respectively. There was good correlation in the overall cohort (r = 0.79), in those with resting ECG HRs ≤ 70 bpm (r = 0.62), and amongst the 27 patients on intermediate-to-high dose beta-blockers (r = 0.91). However, Bland-Altman analysis demonstrated wide limits of agreement in the overall cohort (− 12.5, 12.7 bpm), at resting HRs ≤ 70 bpm (− 12.7, 9.8 bpm), and on intermediate-to-high dose beta-blockers (− 8.9, 7.4 bpm). Moreover, resting HR did not predict the 10-bpm interval where the most time was spent.

Conclusions

While resting HR correlated with mean HR in patients with reduced LVEF, and in important subgroups, the limits of agreement were unacceptably wide raising concern over the use of single time point resting HR as a therapeutic target.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0751-2) contains supplementary material, which is available to authorized users.

Rethinking revascularization in patients with stable angina

INTRODUCTION

Traditional and current perception for benefit of percutaneous coronary intervention (PCI) is that patients with stable angina will obtain symptom relief as well as improved exercise capacity after percutaneous revascularization. This common clinical perception is put to test in the ORBITA trial, the first blinded, randomized placebo-controlled clinical study ever conducted.Areas covered: Coronary artery disease, percutaneous coronary intervention, medical therapy.Expert Commentary: The authors found no significant improvement in exercise time, functional status, angina relief and quality of life in the PCI group compared with placebo. A possible explanation for this neutral outcome is that PCI is overvalued in symptom relief and to some extent explained by placebo effects or transient non-cardiac causes of chest pain. However, the chosen exercise tolerance improvement may have been too optimistic in a population with good functional capacity. Also PCI was anatomic and not functional driven, and follow-up duration may have been to short to wear off the placebo effect. While the evidence is not sufficient to alter revascularization guidelines, the message of this 200-patient, high-quality study is potent and will reverberate throughout the cardiology community and warrants further study.

Percutaneous coronary intervention in stable angina (ORBITA): a double-blind, randomised controlled trial

BACKGROUND

Symptomatic relief is the primary goal of percutaneous coronary intervention (PCI) in stable angina and is commonly observed clinically. However, there is no evidence from blinded, placebo-controlled randomised trials to show its efficacy.

METHODS

ORBITA is a blinded, multicentre randomised trial of PCI versus a placebo procedure for angina relief that was done at five study sites in the UK. We enrolled patients with severe (≥70%) single-vessel stenoses. After enrolment, patients received 6 weeks of medication optimisation. Patients then had pre-randomisation assessments with cardiopulmonary exercise testing, symptom questionnaires, and dobutamine stress echocardiography. Patients were randomised 1:1 to undergo PCI or a placebo procedure by use of an automated online randomisation tool. After 6 weeks of follow-up, the assessments done before randomisation were repeated at the final assessment. The primary endpoint was difference in exercise time increment between groups. All analyses were based on the intention-to-treat principle and the study population contained all participants who underwent randomisation. This study is registered with ClinicalTrials.gov, number NCT02062593.

FINDINGS

ORBITA enrolled 230 patients with ischaemic symptoms. After the medication optimisation phase and between Jan 6, 2014, and Aug 11, 2017, 200 patients underwent randomisation, with 105 patients assigned PCI and 95 assigned the placebo procedure. Lesions had mean area stenosis of 84·4% (SD 10·2), fractional flow reserve of 0·69 (0·16), and instantaneous wave-free ratio of 0·76 (0·22). There was no significant difference in the primary endpoint of exercise time increment between groups (PCI minus placebo 16·6 s, 95% CI -8·9 to 42·0, p=0·200). There were no deaths. Serious adverse events included four pressure-wire related complications in the placebo group, which required PCI, and five major bleeding events, including two in the PCI group and three in the placebo group.

INTERPRETATION

In patients with medically treated angina and severe coronary stenosis, PCI did not increase exercise time by more than the effect of a placebo procedure. The efficacy of invasive procedures can be assessed with a placebo control, as is standard for pharmacotherapy.

FUNDING

NIHR Imperial Biomedical Research Centre, Foundation for Circulatory Health, Imperial College Healthcare Charity, Philips Volcano, NIHR Barts Biomedical Research Centre.

If Channel as an Emerging Therapeutic Target for Cardiovascular Diseases: A Review of Current Evidence and Controversies

In 2015, non-communicable diseases accounted for 39.5 million (70%) of the total 56.4 million deaths that occurred globally, of which 17.7 million (45%) were due to cardiovascular diseases. An elevated heart rate is considered to be one of the independent predictors and markers of future cardiovascular diseases. A variety of experimental and epidemiological studies have found that atherosclerosis, heart failure, coronary artery disease, stroke, and arrhythmia are linked to elevated heart rate. Although there are established drugs to reduce the heart rate, these drugs have undesirable side effects. Hence, the development of new drugs that selectively inhibit the heart rate is considered necessary. In the search for such drugs, almost four decades ago the I_f channel, also known as the “funny channel,” emerged as a novel site for the selective inhibition of heart rate. These I_f channels, with a mixed sodium and potassium inward current, have been identified in the sinoatrial node of the heart, which mediates the slow diastolic depolarization of the pacemaker of the spontaneous rhythmic cells. The hyperpolarization-activated cyclic nucleotide-gated (HCN) subfamily is primarily articulated in the heart and neurons that are encoded by a family of four genes (HCN1-4) and they identify the funny channel. Of these, HCN-4 is the principal protein in the sinoatrial node. Currently, funny channel inhibition is being targeted for the treatment and prevention of cardiovascular diseases such as atherosclerosis and stroke. A selective I_f channel inhibitor named ivabradine was discovered for clinical use in treating heart failure and coronary artery disease. However, inconsistencies regarding the clinical effects of ivabradine have been reported in the literature, suggesting the need for a rigorous analysis of the available evidence. The objective of this review is therefore to assess the current advances in targeting the I_f channel associated with ivabradine and related challenges.

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