Long-Term Heart Rate Reduction Induced by the Selective I f Current Inhibitor Ivabradine Improves Left Ventricular Function and Intrinsic Myocardial Structure in Congestive Heart Failure

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

BACKGROUND

Ivabradine, a pure bradycardic agent, can be given to heart failure reduced ejection fraction (HFrEF) patients with a sinus rhythm of ≥70 bpm on a maximum beta blocker dose, or when beta blockers are contraindicated. This study aimed to see how ivabradine affects the clinical and haemodynamic outcomes of HFrEF patients.

METHODS

This systematic review and meta-analysis searched ClinicalTrials.gov, OpenMD, ProQuest, PubMed, and ScienceDirect for potential articles. All relevant data were extracted. For all pooled effects, the random effect model was applied.

RESULTS

A total of 18,972 heart failure (HF) patients from nine randomised clinical trials (RCTs) were involved in this study. Ivabradine decreased the risk of HF mortality (RR 0.79; 95% CI 0.64-0.98; p=0.03) and HF hospitalisation (RR 0.80; 95% CI 0.65-0.97; p=0.03). Ivabradine was related to a greater reduction in heart rate (MD -12.21; 95% CI -15.47 - -8.96; p<0.01) and left ventricular ejection fraction (LVEF) improvement (MD 3.24; 95% CI 2.17-4.31; p <0.01) compared with placebo. Asymptomatic bradycardia (RR 4.25; 95% CI 3.36-5.39; p<0.01) and symptomatic bradycardia (RR 3.99; 95% CI 3.17-5.03; p<0.01) were higher in the ivabradine group.

CONCLUSION

Ivabradine can reduce the risk of HF mortality and HF hospitalisation in HFrEF patients. Ivabradine also effectively reduces resting heart rate and improves LVEF. However, ivabradine is associated with a greater risk of symptomatic and asymptomatic bradycardia.

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

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

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.

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

Background

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

Objective

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

Methods

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

Results

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

Conclusion

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

The Usefulness of Prioritization of Ivabradine Before Beta-Blockers in a Heart Failure Patient Suffering From Intra-hemodialysis Hypotension

Depressed cardiac systolic function in hemodialysis patients occurs for a variety of reasons and is a clinical problem. Beta-blockers are a key drug in the treatment of heart failure; however, hypotension may occur, particularly in dialysis patients, thereby complicating dialysis. Ivabradine has the unique property of a negative chronotropic effect only, without the negative inotropic effect. A 55-year-old woman who underwent dialysis presented with dyspnea and fatigue even at rest due to low cardiac systolic function. The left ventricular ejection fraction (LVEF) was 30%. Medications for heart failure, such as carvedilol and enalapril, were initiated; however, they were discontinued owing to intradialytic hypotension. Subsequently, her heart rate increased to over 100 beats per minute (bpm); therefore, we administered 2.5 mg of ivabradine before beta-blockers, which reduced her heart rate by approximately 30 bpm without a significant blood pressure decrease. Moreover, her blood pressure stabilized during dialysis. After two weeks, we added 1.25 mg of bisoprolol and adjusted the dose to 0.625 mg. After seven months of treatment with 2.5 mg ivabradine and 0.625 mg bisoprolol, systolic cardiac function significantly improved to 70% of LVEF. Prioritizing ivabradine over beta-blockers may not cause intradialytic hypotension; even low doses of ivabradine and bisoprolol were considered effective heart failure therapies.

Optimal rate control in dogs with atrial fibrillation-ORCA study-Multicenter prospective observational study: Prognostic impact and predictors of rate control

BACKGROUND

The optimal heart rate (HR) in dogs with atrial fibrillation (AF) is unknown. Impact of HR on survival needs elucidation.

HYPOTHESIS/OBJECTIVES

Dogs with a 24 hours Holter-derived meanHR ≤125 beats per minute (bpm; rate controlled) survive longer than dogs with higher meanHR. We further aimed to determine which variables predict ability to achieving rate control.

ANIMALS

Sixty dogs with AF.

METHODS

Holter-derived meanHR, clinical, echocardiographic, and biomarker variables were analyzed prospectively. Survival was recorded from time of rate control, with all-cause mortality as primary endpoint. Cox proportional hazards analysis identified variables independently associated with survival; Kaplan-Meier survival analysis estimated the median survival time of dogs with meanHR ≤125 bpm vs >125 bpm. Logistic regression explored baseline variables associated with inability to achieve rate control.

RESULTS

Structural heart disease was present in 56/60 dogs, 50/60 had congestive heart failure, and 45/60 died. Median time to all-cause death was 160 days (range, 88-303 days), dogs with meanHR >125 bpm (n = 27) lived 33 days (95% confidence interval [CI], 15-141 days), dogs with meanHR ≤125 bpm (n = 33) lived 608 days (95% CI, 155-880 days; P < .0001). Congenital heart disease and N-terminal pro-B-type natriuretic peptide were independently associated with higher risk of death (P < .01 and <.0001, respectively) whereas meanHR ≤125 bpm decreased the risk of death (P < .001). Increased left atrial size, increased C-reactive protein concentration and lower blood pressure at admission were associated with failure to achieve rate control.

CONCLUSIONS AND CLINICAL IMPORTANCE

Rate control affects survival; an optimal target meanHR <125 bpm should be sought in dogs with AF. Baseline patient variables can help predict if rate control is achievable.

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

BACKGROUND

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

CONCLUSIONS

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

Mitochondrial-Targeted Therapies Require Mitophagy to Prevent Oxidative Stress Induced by SOD2 Inactivation in Hypertrophied Cardiomyocytes

Heart failure, mostly associated with cardiac hypertrophy, is a major cause of illness and death. Oxidative stress causes accumulation of reactive oxygen species (ROS), leading to mitochondrial dysfunction, suggesting that mitochondria-targeted therapies could be effective in this context. The purpose of this work was to determine whether mitochondria-targeted therapies could improve cardiac hypertrophy induced by mitochondrial ROS. We used neonatal (NCMs) and adult (ACMs) rat cardiomyocytes hypertrophied by isoproterenol (Iso) to induce mitochondrial ROS. A decreased interaction between sirtuin 3 and superoxide dismutase 2 (SOD2) induced SOD2 acetylation on lysine 68 and inactivation, leading to mitochondrial oxidative stress and dysfunction and hypertrophy after 24 h of Iso treatment. To counteract these mechanisms, we evaluated the impact of the mitochondria-targeted antioxidant mitoquinone (MitoQ). MitoQ decreased mitochondrial ROS and hypertrophy in Iso-treated NCMs and ACMs but altered mitochondrial structure and function by decreasing mitochondrial respiration and mitophagy. The same decrease in mitophagy was found in human cardiomyocytes but not in fibroblasts, suggesting a cardiomyocyte-specific deleterious effect of MitoQ. Our data showed the importance of mitochondrial oxidative stress in the development of cardiomyocyte hypertrophy. We observed that targeting mitochondria by MitoQ in cardiomyocytes impaired the metabolism through defective mitophagy, leading to accumulation of deficient mitochondria.

Nano-ivabradine averts behavioral anomalies in Huntington's disease rat model via modulating Rhes/m-tor pathway

Huntington's disease (HD) is characterized by abnormal involuntary movements together with cognitive impairment and disrupted mood changes. 3-nitropropionic acid (3-NP) is one of the chemo-toxic models used to address the striatal neurotoxicity pattern encountered in HD. This study aims to explain the neuroprotective effect of nano-formulated ivabradine (nano IVA) in enhancing behavioral changes related to 3-NP model and to identify the involvement of ras homolog enriched striatum (Rhes)/mammalian target of rapamycin (m-Tor) mediated autophagy pathway. Rats were divided into 6 groups, the first 3 groups received saline (control), ivabradine (IVA), nano IVA respectively, the fourth received a daily dose of 3-NP (20 mg/kg, s.c) for 2 weeks, the fifth received 3-NP + IVA (1 mg/kg, into the tail vein, every other day for 1 week) and the last group received 3-NP + nano IVA (1 mg/kg, i.v, every other day for 1 week). Interestingly, nano IVA reversed motor disabilities, improved memory function and overcame the psychiatric changes. It boosted expression of autophagy markers combined with down regulation of Rhes, m-Tor and b-cell lymphoma 2 protein levels. Also, it restored the normal level of neurotransmitters and myocardial function related-proteins. Histopathological examination revealed a preserved striatal structure with decreased number of darkly-degenerated neurons. In conclusion, the outcomes of this study provide a well-recognized clue for the promising neuroprotective effect of IVA and the implication of autophagy and Rhes/m-Tor pathways in the 3-NP induced HD and highlight the fact that nano formulations of IVA would be an auspicious approach in HD therapy.

Heart failure and its treatment from the perspective of sympathetic nerve activity

Heart failure is the end-stage phenotype of several cardiac diseases. The number of heart failure patients is increasing in accordance with an increase in the number of elderly people. The prognosis of heart failure is poor and its 5-year death rate is comparable to that of stage III cancer. It is important to understand the essential mechanism of the worsening prognosis of heart failure and to practice effective treatment from the perspective of improving the prognosis of heart failure based on its essential mechanism. Plasma noradrenaline level is a good predictor of the survival rate of heart failure patients, and sympathetic nerve activity is augmented in patients with heart failure as evidenced by a higher noradrenaline release rate (spillover) from the sympathetic nerve endings especially in the heart and kidney. Noradrenaline release is regulated by presynaptic receptors at the sympathetic nerve endings, and the kidney affects the sympathetic nerve activity. Although the short-term reflex augmentation of sympathetic nerve activity caused by reduced cardiac function may help to improve cardiac function, long-term augmentation of sympathetic nerve activity damages the heart and deteriorates the prognosis of heart failure. Currently, drugs such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, β-blockers, mineralocorticoid antagonists, ivabradine, angiotensin receptor-neprilysin inhibitor, and sodium-glucose transport protein 2 inhibitors, are used for the treatment of heart failure, and had a good prognosis in large randomized, controlled clinical trials. Interestingly, the same characteristics in common of these drugs is the ability to optimize excessively augmented sympathetic nerve activity. This review discusses insights into essential mechanism of heart failure that determines the prognosis of heart failure, focusing on the interaction between sympathetic nerve activity and anti-heart failure drugs currently recommended by the 2021 guidelines of the Japanese Circulation Society and the Japanese Heart Failure Society for heart failure treatment.

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

Aims

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

Methods and results

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

Conclusions

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

Heart failure and atrial fibrillation: tachycardia-mediated acute decompensation

Aims

Tachycardia is a reversible event that may cause hemodynamic decompensation but may not necessarily cause direct damages to the myocardium. To evaluate the clinical outcomes of patients with heart failure (HF) and atrial fibrillation (AF), whose acute decompensation was tachycardia mediated.

Methods and results

The Korean Acute Heart Failure registry was a prospective registry that consecutively enrolled 5625 patients with acute HF. Patients were classified into three groups according to the rhythm and aggravating factor: (i) 3664 (65.1%) patients with sinus rhythm (SR), (ii) 1033 (18.4%) patients with AF whose decompensation was tachycardia‐mediated, AF‐TM (+), and (iii) N = 928 (16.5%) patients with AF whose decompensation was not tachycardia‐mediated, AF‐TM (−). The primary outcomes were in‐hospital and post‐discharge 1 year all‐cause mortality. At admission, the mean heart rate was 90.8 ± 23.4, 86.8 ± 26.8, and 106.3 ± 29.7 beats per minute for the SR, AF‐TM (−), and AF‐TM (+) groups, respectively. The AF‐TM (+) group had more favourable characteristics such as de novo onset HF, less diabetes, ischaemic heart disease, and higher blood pressure than the AF‐TM (−) group. In‐hospital mortality rates were 5.1%, 6.5%, and 1.7% for SR, AF‐TM (−), and AF‐TM (+) groups, respectively. In logistic regression analysis, the AF‐TM (+) group had lower in‐hospital mortality after adjusting the significant covariates (odds ratio, 0.49; 95% confidence interval, 0.26–0.93). The mortality rate did not differ between SR and AF‐TM (−) groups. During 1 year follow‐up, 990 (18.5%) patients died. In univariate and multivariate Cox proportional regression analyses, there was no difference in 1‐year all‐cause mortality between the three groups.

Conclusions

In patients with HF and AF, patients whose acute decompensation is tachycardia‐mediated have better in‐hospital, but similar post‐discharge outcomes compared with those with SR or those with AF whose decompensation is not tachycardia‐mediated.

Clinical Trial Registration: ClinicalTrial.gov NCT01389843.

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

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

Effects of selective heart rate reduction with ivabradine on LV function and central hemodynamics in patients with chronic coronary syndrome

Objectives

We assessed left ventricular (LV) function and central hemodynamic effects in patients with a heart rate (HR) at rest of ≥70 beats per minute (bpm) and chronic coronary syndrome (CCS) after long-term treatment with ivabradine compared to placebo by cardiac magnetic resonance (CMR) imaging.

Methods and results

In a randomized, double-blinded, prospective cross-over design, 23 patients (18 male, 5 female) were treated with ivabradine (7.5 mg bid) or placebo for 6 months. CMR imaging was performed at baseline and after 6 and 12 months to determine LV functional parameters.Mean resting HR on treatment with ivabradine was 58 ± 8.2 bpm and 70.2 ± 8.3 bpm during placebo (p < 0.0001).There was no difference in systolic LV ejection fraction (ivabradine 57.4 ± 11.2% vs placebo 53.0 ± 10.9%, p = 0.18), indexed end-diastolic (EDVi) or end-systolic volumes (ESVi). Indexed stroke volume (SVi) (ml/m²) remained unchanged after treatment with ivabradine. Volume time curve parameters reflecting systolic LV function (peak ejection rate and time) were unaffected by ivabradine, while both peak filling rate (PFR) and PFR/EDV were significantly increased. Mean aortic velocity (cm/s) was significantly reduced during treatment with ivabradine (ivabradine 6.7 ± 2.7 vs placebo 9.0 ± 3.4, p = 0.01). Aortic flow parameters were correlated to parameters of vascular stiffness. The strongest correlation was revealed for mean aortic velocity with aortic distensibility (AD) (r = -0.86 [-0.90 to -0.85], p < 0.0001).

Conclusion

Long-term reduction of HR with ivabradine in patients with CCS improved diastolic function and reduced mean aortic flow velocity.

Using Tissue Doppler and Speckle Tracking Echocardiography to Assess if Ivabradine Improves Right Ventricular Function

Objective

To evaluate the mid-term effects of ivabradine on right ventricular functions in patients with heart failure.

Methods

A prospective study was conducted on 52 patients who had heart failure in normal sinus rhythm (59% male, age: 64.76 ±12.49 years). Right ventricular functions were measured at baseline, after one month and one year by conventional and tissue Doppler echocardiography imaging. The parameters, right ventricular (RV) longitudinal strain (LS), RV systolic longitudinal strain rate (LSRs), RV early diastolic longitudinal strain rate, and late diastolic longitudinal strain rate, were evaluated by apical four-chamber grayscale imaging through the free wall of RV in accordance with the automated function imaging protocol.

Results

During the follow-up, the pulmonary artery systolic pressure (PASP), RV fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE), myocardial performance index (MPI), E peak, and A peak values were similar to the basal values. While comparing the basal values of the global longitudinal systolic strain (GLS), LS, LSRs, longitudinal strain rate diastolic early filling (LSRe), and longitudinal strain rate diastolic late filling (LSRa), there were no differences in the first month but a significant increase was observed on one-year follow-up (p<0.001).

Conclusion

At the one-year follow-up, the heart failure patients who were given ivabradine treatment showed an improvement in the right ventricular function assessed by the new echocardiographic techniques.

Transient heart rate reduction improves acute decompensated heart failure-induced left ventricular and coronary dysfunction

Aims

Acute decompensated heart failure (ADHF), a live‐threatening complication of heart failure (HF), associates a further decrease of the already by HF‐impaired cardiac function with an increase in heart rate. We evaluated, using a new model of ADHF, whether heart rate reduction (HRR) opposes the acute decompensation‐related aggravation of cardiovascular dysfunction.

Methods and results

Cardiac output (echocardiography), cardiac tissue perfusion (magnetic resonance imaging), pulmonary wet weight, and in vitro coronary artery relaxation (Mulvany) were assessed 1 and 14 days after acute decompensation induced by salt‐loading (1.8 g/kg, PO) in rats with well‐established HF due to coronary ligation. HRR was induced by administration of the I_f current inhibitor S38844, 12 mg/kg PO twice daily for 2.5 days initiated 12 h or 6 days after salt‐loading (early or delayed treatment, respectively). After 24 h, salt‐loading resulted in acute decompensation, characterized by a reduction in cardiac output (HF: 130 ± 5 mL/min, ADHF: 105 ±  8 mL/min; P < 0.01), associated with a decreased myocardial perfusion (HF: 6.41 ± 0.53 mL/min/g, ADHF: 4.20 ± 0.11 mL/min/g; P < 0.01), a slight increase in pulmonary weight (HF: 1.68 ± 0.09 g, ADHF: 1.81 ± 0.15 g), and impaired coronary relaxation (HF: 55 ± 1% of pre‐contraction at acetylcholine 4.5 10⁻⁵ M, ADHF: 27 ± 7 %; P < 0.01). Fourteen days after salt‐loading, cardiac output only partially recovered (117 ± 5 mL/min; P < 0.05), while myocardial tissue perfusion (4.51 ± 0.44 mL/min; P < 0.01) and coronary relaxation (28 ± 4%; P < 0.01) remained impaired, but pulmonary weight further increased (2.06 ± 0.15 g, P < 0.05). Compared with untreated ADHF, HRR induced by S38844 improved cardiac output (125 ± 1 mL/min; P < 0.05), myocardial tissue perfusion (6.46 ± 0.42 mL/min/g; P < 0.01), and coronary relaxation (79 ± 2%; P < 0.01) as soon as 12 h after S38844 administration. These effects persisted beyond S38844 administration, illustrated by the improvements in cardiac output (130 ± 6 mL/min; P < 0.05), myocardial tissue perfusion (6.38 ± 0.48 mL/min/g; P < 0.01), and coronary relaxation (71 ± 4%; P < 0.01) at Day 14. S38844 did not modify pulmonary weight at Day 1 (1.78 ± 0.04 g) but tended to decrease pulmonary weight at Day 14 (1.80 ± 0.18 g). While delayed HRR induced by S38844 never improved cardiac function, early HRR rendered less prone to a second acute decompensation.

Conclusions

In a model mimicking human ADHF, early, but not delayed, transient HRR induced by the I_f current inhibitor S38844 opposes acute decompensation by preventing the decompensated‐related aggravation of cardiovascular dysfunction as well as the development of pulmonary congestion, and these protective effects persist beyond the transient treatment. Whether early transient HRR induced by I_f current inhibitors or other bradycardic agents, i.e. beta‐blockers, exerts beneficial effects in human ADHF warrants further investigation.

Heart Rate Reduction Improves Right Ventricular Function and Fibrosis in Pulmonary Hypertension

The potential benefit of heart rate reduction (HRR), independent of β-blockade, on right ventricular (RV) function in pulmonary hypertension (PH) remains undecided. We studied HRR effects on RV fibrosis and function in PH and RV pressure-loading models. Adult rats were randomized to 1) sham controls, 2) monocrotaline (MCT)-induced PH, 3) SU5416 + hypoxia (SUHX)-induced PH, or 4) pulmonary artery banding (PAB). Ivabradine (IVA) (10 mg/kg/d) was administered from 2 weeks after PH induction or PAB. Exercise tolerance, echocardiography, and pressure-volume hemodynamics were obtained at a terminal experiment 3 weeks later. RV myocardial samples were analyzed for putative mechanisms of HRR effects through fibrosis, profibrotic molecular signaling, and Ca⁺⁺ handling. The effects of IVA versus carvedilol on human induced pluripotent stem cell-derived cardiomyocytes beat rate and relaxation properties were evaluated in vitro. Despite unabated severely elevated RV systolic pressures, IVA improved RV systolic and diastolic function, profibrotic signaling, and RV fibrosis in PH/PAB rats. RV systolic-elastance (control, 121 ± 116; MCT, 49 ± 36 vs. MCT+IVA, 120 ± 54; PAB, 70 ± 20 vs. PAB+IVA, 168 ± 76; SUHX, 86 ± 56 vs. SUHX +IVA, 218 ± 111; all P < 0.05), the time constant of RV relaxation, echo indices of RV function, and fibrosis (fibrosis: control, 4.6 ± 1%; MCT, 13.4 ± 6.5 vs. MCT+IVA, 6.7 ± 2.6%; PAB, 11.4 ± 4.5 vs. PAB+IVA, 6.4 ± 5.1%; SUHX, 10 ± 4.6 vs. SUHX+IVA, 3.9 ± 2.2%; all P < 0.001) were improved by IVA versus controls. IVA had a dose-response effect on induced pluripotent stem cell-derived cardiomyocytes beat rate by delaying Ca⁺⁺ loss from the cytoplasm. In experimental PH or RV pressure loading, HRR improves RV fibrosis, function, and exercise endurance independent of β-blockade. The balance between adverse tachycardia and bradycardia requires further study, but judicious HRR may provide a promising strategy to improve RV function in clinical PH.

Effect of early use of ivabradine on left ventricular remodeling after primary percutaneous coronary intervention in patients with acute ST-segment elevation myocardial infarction: A pilot test

Objective

To investigate the effect of early use of ivabradine on left ventricular remodeling after primary percutaneous coronary intervention (PCI) in patients with acute ST‐segment elevation myocardial infarction (STEMI).

Methods

A total of 66 STEMI patients with sinus rhythm and the resting heart rate ≥80 bpm after successful emergency PCI were included. The patients in the test group were treated with ivabradine combined with metoprolol at 12 hr after PCI, while the control group was given only metoprolol orally. Their resting heart rate was controlled to <70 bpm at discharge and followed for 180 days. Heart rate and blood pressure were measured regularly. Echocardiogram was performed. N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP), high sensitivity troponin T, high sensitivity troponin I, and high sensitivity C‐reactive protein were measured. The major adverse cardiovascular events during hospitalization and follow‐up period were recorded.

Results

Compared with the control group, the heart rate of the test group decreased significantly (p < .05). Compared with the control group, the left ventricular end‐diastolic volume and left ventricular end‐systolic volume were significantly decreased while left ventricular ejection fraction was significantly increased in the test group at 90 days after operation. NT‐proBNP of the test group was significantly lower than that of the control group at 7 days after operation (p < .05).

Conclusion

For STEMI patients, early use of ivabradine combined with standard therapy such as β‐blocker after successful reperfusion can achieve effective heart rate control, with great safety and tolerance. But the effect of ivabradine on left ventricular remodeling is uncertain.

Effects of Ivabradine on Cardiac Remodeling in Patients With Stable Symptomatic Heart Failure: A Systematic Review and Meta-analysis

PURPOSE

Ivabradine reduces heart rate (HR) in patients with heart failure (HF). However, its effect on cardiac remodeling is not obvious. The goal of this study was to explore the extra effect of ivabradine on cardiac remodeling in patients with HF.

METHODS

We searched PubMed from database inception to January 31, 2020, Cochrane and Embase from database inception to February 2, 2020, and Web of Science and ClinicalTrials.gov from database inception to February 3, 2020, for randomized controlled trials on ivabradine treatments in patients with stable symptomatic HF, left ventricular ejection fraction (LVEF) < 45%, and resting HR ≥ 60 beats/min in sinus rhythm. We pooled the mean differences (MDs) or standardized mean differences and their 95% CIs. An inverse variance was used to combine data. Fixed- or random-effects models were used to outline the outcomes based on heterogeneity levels. We assessed the heterogeneity among studies according to the I² statistic. A sensitivity analysis for select results was performed to assess the robustness of the outcomes.

FINDINGS

Of 2277 trials, 9 trials fulfilled the inclusion criteria. A total of 1523 patients were enrolled in 9 studies. There were 796 participants in the ivabradine group and 727 participants in the control group. The duration of follow-up ranged from 6 weeks to 19.6 months. The mean (SD) age of the participants was 59.7 (11.2) years, and 1187 participants (77.9%) were men. Therapy with ivabradine was related to reversing cardiac remodeling with a significant increase in LVEF (MD = 3.04%; 95% CI, 2.07%-4.00%; p < 0.001), decrease in the left ventricular end-systolic volume index (LVESVI) (MD = -7.30 mL/m²; 95% CI, -12.94 to -1.66 mL/m²; p = 0.01), and reduction in the left ventricular end-diastolic volume index (LVEDVI) (MD = -7.27 mL/m²; 95% CI, -14.04 to -0.50 mL/m²; p = 0.04). In the subgroup of enrolled patients with a resting HR of ≥70 beats/min, greater progress in LVEF was detected in the ivabradine group (MD = 3.60%; 95% CI, 2.40%-4.81%; p < 0.001), and a higher improvement in LVESVI was identified in the ivabradine group (MD = -11.06 mL/m²; 95% CI, -21.15 to -0.98 mL/m²; p = 0.03).

IMPLICATIONS

In patients with stable symptomatic HF, LVEF <45%, and resting HR ≥ 60 beats/min in sinus rhythm, ivabradine use was associated with reversing cardiac remodeling with a significant increase in LVEF, a decrease in LVESVI, and a reduction in LVEDVI.

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

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

Evaluation of ivabradine in left ventricular dyssynchrony and reverse remodeling in patients with chronic heart failure

OBJECTIVES

Ivabradine is a pharmacological agent used in patients with heart failure and sinus rhythm. Its only known pharmacological effect is to slow the heart rate. In this study, we investigated the impact of ivabradine on dyssynchrony parameters in heart failure patients.

METHODS

In this study, we assigned 55 patients taking medication for heart failure to receive ivabradine in addition (Group I). Twenty healthy volunteers comprised Group II. Echocardiographic measurements (dyssynchrony, left ventricular volumes and left ventricular ejection fraction) were taken at baseline, 1 month, and 3 months.

RESULTS

A total of 32 heart failure patients in Group I completed the study. There was significant improvement in dyssynchrony parameters after ivabradine treatment in Group I. Interventricular dyssynchrony (IVD) decreased from 42.0 ± 24.4 milliseconds at baseline to 33.6 ± 20.7 milliseconds at 1 month (P = .001) and to 30.7 ± 19.4 milliseconds at 3 months (P < .001). Septal to posterior wall motion delay decreased from 90.3 ± 21.4 milliseconds to 83.9 ± 26.9 milliseconds (P = .011) at 1 month and to 81.5 ± 27.3 milliseconds at 3 months (P = .001). Septal to lateral Ts delay (Ts-SL) decreased from 42.7 ± 24.5 milliseconds to 35.8 ± 22.6 milliseconds at 1 month (P < .001) and to 34.8 ± 22.4 milliseconds at 3 months (P = .002). Left ventricular end-systolic volume (LVESV) decreased from 139.4 ± 42.2 mL to 135.3 ± 39.6 mL at 1 month (P = .006) and to 123.3 ± 39.5 mL at 3 months (P < .001).

CONCLUSION

The addition of ivabradine to heart failure treatment improves cardiac dyssynchrony parameters in chronic systolic heart failure patients with sinus rhythm.

Short-and long-term administration of imeglimin counters cardiorenal dysfunction in a rat model of metabolic syndrome

INTRODUCTION

Imeglimin, a glucose-lowering agent targeting mitochondrial bioenergetics, decreases reactive oxygen species (ROS) overproduction and improves glucose homeostasis. We investigated whether this is associated with protective effects on metabolic syndrome-related left ventricular (LV) and vascular dysfunctions.

METHODS

We used Zucker fa/fa rats to assess the effects on LV function, LV tissue perfusion, LV oxidative stress and vascular function induced by imeglimin administered orally for 9 or 90 days at a dose of 150 mg/kg twice daily.

RESULTS

Compared to untreated animals, 9- and 90-day imeglimin treatment decreased LV end-diastolic pressure and LV end-diastolic pressure-volume relation, increased LV tissue perfusion and decreased LV ROS production. Simultaneously, imeglimin restored acetylcholine-mediated coronary relaxation and mesenteric flow-mediated dilation. One hour after imeglimin administration, when glucose plasma levels were not yet modified, imeglimin reduced LV mitochondrial ROS production and improved LV function. Ninety-day imeglimin treatment reduced related LV and kidney fibrosis and improved kidney function.

CONCLUSION

In a rat model, mimicking Human metabolic syndrome, imeglimin immediately countered metabolic syndrome-related cardiac diastolic and vascular dysfunction by reducing oxidative stress/increased NO bioavailability and improving myocardial perfusion and after 90-day treatment myocardial and kidney structure, effects that are, at least in part, independent from glucose control.

Five-year results of heart rate control with ivabradine or metoprolol succinate in patients after heart transplantation

Background

Cardiac graft denervation causes inadequate sinus tachycardia in patients after heart transplantation (HTX) which is associated with reduced survival. This study investigated the 5-year results of heart rate control with ivabradine or metoprolol succinate in patients after HTX.

Methods

This registry study analyzed 104 patients receiving either ivabradine (n = 50) or metoprolol succinate (n = 54) within 5 years after HTX. Analysis included patient characteristics, medication, echocardiographic features, cardiac catheterization data, cardiac biomarkers, heart rates, and post-transplant survival including causes of death.

Results

Demographics and post-transplant medication revealed no significant differences except for ivabradine and metoprolol succinate use. At 5-year follow-up, patients with ivabradine had a significantly lower heart rate (73.3 bpm) compared to baseline (88.6 bpm; P < 0.01) and to metoprolol succinate (80.4 bpm; P < 0.01), a reduced left ventricular mass (154.8 g) compared to baseline (179.5 g; P < 0.01) and to metoprolol succinate (177.3 g; P < 0.01), a lower left ventricular end-diastolic pressure (LVEDP; 12.0 mmHg) compared to baseline (15.5 mmHg; P < 0.01) and to metoprolol succinate (17.1 mmHg; P < 0.01), and a reduced NT-proBNP level (525.4 pg/ml) compared to baseline (3826.3 pg/ml; P < 0.01) and to metoprolol succinate (1038.9 pg/ml; P < 0.01). Five-year post-transplant survival was significantly better in patients with ivabradine (90.0%) versus metoprolol succinate (68.5%; P < 0.01).

Conclusion

Patients receiving ivabradine showed a superior heart rate reduction and a better left ventricular diastolic function along with an improved 5-year survival after HTX.

β-Blockers and 1-Year Postdischarge Mortality for Heart Failure and Reduced Ejection Fraction and Slow Discharge Heart Rate

Background

Many hospitalized patients with heart failure and reduced ejection fraction (HFrEF) have a slow heart rate at discharge, and the effect of β‐blockers may be reduced in those patients. We sought to examine the variable effect of β‐blockers on clinical outcomes according to the discharge heart rate of hospitalized HFrEF patients.

Methods and Results

The KorAHF (Korean Acute Heart Failure) registry consecutively enrolled 5625 patients hospitalized for acute heart failure. In this analysis, we included patients with HFrEF (left ventricular ejection fraction ≤40%). Slow heart rate was defined as <70 beats per minute regardless of the use of β‐blockers. The primary outcome was 1‐year all‐cause postdischarge death according to heart rate. Among 2932 patients with HFrEF, 840 (29%) had a slow heart rate and 56% received β‐blockers at discharge. Patients with slow heart rates were older and had lower 1‐year mortality than those with high heart rates (P<0.001). A significant interaction between discharge heart rate and β‐blocker use was observed (P<0.001 for interaction). When stratified, only patients without a β‐blocker prescription and with a high heart rate showed higher 1‐year mortality. In a Cox‐proportional hazards regression analysis, β‐blocker prescription at discharge was associated with 24% reduced risk for 1‐year mortality in patients with high heart rates (hazard ratio: 0.76; 95% CI, 0.61–0.95) but not in those with slow heart rates (hazard ratio: 1.02; 95% CI, 0.68–1.55).

Conclusions

Many patients with acute heart failure have slow discharge heart rates, and β‐blockers may have a limited effect on HFrEF and slow discharge heart rate.

Clinical Trial Registration

URL: http://www.clinicaltrial.gov. Unique identifier: NCT01389843.

Intracerebroventricular infusion of donepezil prevents cardiac remodeling and improves the prognosis of chronic heart failure rats

Oral administration of donepezil, a centrally acting acetylcholinesterase inhibitor, improves the survival of rats with chronic heart failure (CHF). The mechanisms of cardioprotective effects of donepezil, however, remain totally unknown. To elucidate potential mechanisms, we examined whether central microinfusion of donepezil would exert cardioprotection. Intracerebroventricular microinfusion pumps with cerebroventricular cannula were implanted in rats with myocardial infarction. The rats were randomly divided into central saline treatment (CST) and central donepezil treatment (CDT) groups. We evaluated cardiac remodeling and function after a 6-week treatment and examined the 160-day survival rate. Compared to the CST, the CDT markedly improved the 160-day survival rate (68% vs. 32%, P = 0.002) through the prevention of cardiac remodeling and the lowering of plasma catecholamine, brain natriuretic peptide, and angiotensin II. These results suggest that the central mechanism plays an important role in the cardioprotective effects of donepezil.

Increased sarcoplasmic/endoplasmic reticulum calcium ATPase 2a activity underlies the mechanism of the positive inotropic effect of ivabradine

NEW FINDINGS

What is the central question of this study? The therapeutic effect of ivabradine on patients with chronic heart failure and chronic stable angina pectoris is mediated through a reduction in heart rate: what are the haemodynamic characteristics and the mechanism of the inotropic effect? What is the main finding and its importance? Ivabradine has a positive inotropic effect and lowers the heart rate both in vivo and in vitro. These effects are likely mediated by ivabradine's significant increase of the fast component rate constant mediated by sarcoplasmic/endoplasmic reticulum calcium ATPase 2a and decrease of the slow component rate constant that is mediated by the Na⁺ /Ca²⁺ exchanger and sarcolemmal Ca²⁺ -ATPase during the Ca²⁺ transient decay phase.

ABSTRACT

Ivabradine's therapeutic effect is mediated by a reduction of the heart rate; however, its haemodynamic characteristics and the mechanism of its inotropic effect are poorly understood. We aimed to investigate the positive inotropic effect of ivabradine and its underlying mechanism. The results demonstrated that ivabradine increased the positive inotropy of the rat heart in vivo by increasing the stroke work, cardiac output, stroke volume, end-diastolic volume, end-systolic pressure, ejection fraction, ±dP/dt_max , left ventricular end-systolic elastance and systolic blood pressure without altering the diastolic blood pressure and arterial elastance. This inotropic effect was observed in both non-paced and paced rat isolated heart. Ivabradine increased the Ca²⁺ transient amplitude and the reuptake rates of sarcoplasmic/endoplasmic reticulum calcium ATPase 2a (SERCA2a), lowered the diastolic Ca²⁺ level and suppressed the combined extrusion rate of the Na⁺ /Ca²⁺ exchanger and the sarcolemmal Ca²⁺ -ATPase. In addition, ivabradine widened the action potential duration, hyperpolarized the resting membrane potential, increased sarcoplasmic reticulum Ca²⁺ content and reduced Ca²⁺ leak. Overall, ivabradine had a positive inotropic effect brought about by enhanced SERCA2a activity, which might be mediated by increased phospholamban phosphorylation. The positive inotropic effect along with the lowered heart rate underlies ivabradine's therapeutic effect in heart failure.

Effect of Ivabradine on Left Ventricular Diastolic Function, Exercise Tolerance and Quality of Life in Patients With Heart Failure: A Systemic Review and Meta-Analysis of Randomized Controlled Trials

Background

Ivabradine is a heart rate-lowering drug that selectively inhibits the funny (I_f) current of the sinoatrial node. It is currently recommended in patients with heart failure (HF) with reduced ejection fraction (HFrEF) in sinus rhythm and a heart rate of ≥ 70 beats per minute (bpm) at rest. To investigate whether ivabradine has an effect on diastolic dysfunction, exercise tolerance and quality of life (QOL), we conducted a systemic review and meta-analysis of randomized controlled trials (RCTs).

Methods

We searched PubMed, EMBASE and Cochrane Central Register of Clinical Trials for studies on the effect of ivabradine on left ventricular (LV) diastolic dysfunction, exercise tolerance, QOL, readmission for worsening HF and mortality in both patients with HF with preserved ejection fraction (HFpEF) and HFrEF.

Results

Thirteen RCTs with 881 patients met the inclusion criteria. According to the pooled analysis, for the HFpEF subgroup, treatment with ivabradine resulted in a decrease in early diastolic mitral inflow to late diastolic flow ratio (E/A) (standardized mean difference (SMD): -0.53; 95% confidence interval (CI): -0.99, -0.07; P < 0.000) and increase in peak oxygen uptake during exercise (VO₂) (SMD: 0.05; 95% CI: -0.35, 0.45; P < 0.00; I² = 95.1%). Similar effect was seen in the HFrEF subgroup with decrease in E/A ratio (SMD: -0.33; 95% CI: -0.59, -0.06; P < 0.000) and early diastolic mitral inflow to annular velocity ratio (E/e’) (SMD: -1.01; 95% CI: -1.49, -0.54; P < 0.012). Ivabradine therapy increased peak VO₂ and 6-min walk test (6MWT) in HFrEF patients (SMD: 0.83; 95% CI: 0.35, 1.32; P < 0.00; I² = 97.5% and SMD: 1.11; 95% CI: 0.82, 1.41; P < 0.000, respectively). There was also significant reduction in Minnesota Living with Heart Failure Questionnaire (MLHFQ) score (SMD: -0.68; 95% CI: -0.91, -0.45; P < 0.000). However, there was no significant difference in readmission for worsening HF and all-cause mortality between ivabradine and control (risk ratio (RR): 1.44; 95% CI: 0.73, 2.16; P < 0.148 and RR: 0.76; 95% CI: 0.19, 1.33; P < 0.907, respectively).

Conclusions

Ivabradine therapy is associated with improved LV diastolic function, increases exercise tolerance and hence QOL, but it has no significant effect on readmission for worsening HF and all-cause mortality.

Differential Effect of β-Blockers According to Heart Rate in Acute Myocardial Infarction Without Heart Failure or Left Ventricular Systolic Dysfunction: A Cohort Study

OBJECTIVE

To evaluate the effect of β-blockers according to heart rate in patients with acute myocardial infarction (AMI) without heart failure (HF) or left ventricular systolic dysfunction (LVSD).

PATIENTS AND METHODS

We enrolled patients with AMI without HF or LVSD between June 1, 2003, and February 28, 2015, from Seoul National University Hospital Acute Myocardial Infarction Registry. Patients were categorized according to discharge heart rate recorded on electrocardiographs and β-blocker use. Low heart rate was defined as less than 75 beats/min. The primary end point was 5-year all-cause mortality according to discharge heart rate and β-blocker use.

RESULTS

Of 2271 patients, 1696 (74.7%) received β-blockers and 1427 (62.8%) had low heart rates. At 5 years after discharge, 205 patients died. Overall, patients with low heart rates (P<.001) and those with β-blocker treatment had lower mortality (P<.001). After adjustment for covariates, β-blocker use was associated with 48% reduced risk for 5-year mortality in patients with high heart rates (hazard ratio, 0.52; 95% CI, 0.35-0.76), but not in those with low heart rates (P=.97). In an inverse-probability treatment-weighted cohort, β-blocker use was also associated with improved mortality in those with a high heart rate. Findings were similar for 5-year cardiovascular mortality.

CONCLUSION

Among survivors with AMI without HF or LVSD, β-blocker use was associated with reduced 5-year all-cause mortality in patients who have high heart rates, but not in those with low heart rates.

Tachycardiomyopathy in Patients without Underlying Structural Heart Disease

Tachycardiomyopathy (TCM) is an underestimated cause of reversible left ventricle dysfunction. The aim of this study was to identify the predictors of recurrence and incidence of major cardiovascular events in TCM patients without underlying structural heart disease (pure TCM). The prospective, observational study enrolled all consecutive pure TCM patients. The diagnosis was suspected in patients admitted for heart failure (HF) with a reduced ejection fraction and concomitant persistent arrhythmia. Pure TCM was confirmed after the clinical and echocardiographic recovery during follow-up. From 107 pure TCM patients (9% of all HF admission, the median follow-up 22.6 months), 17 recurred, 51 were hospitalized for cardiovascular reasons, two suffered from thromboembolic events and one died. The diagnosis of obstructive sleep apnoea syndrome (OSAS, hazard ratio (HR) 5.44), brain natriuretic peptide on admission (HR 1.01 for each pg/mL) and the heart rate at discharge (HR 1.05 for each bpm) were all independent predictors of TCM recurrence. The left ventricular ejection fraction at discharge (HR 0.96 for each%) and the heart rate at discharge (HR 1.02 for each bpm) resulted as independent predictors of cardiovascular-related hospitalization. Pure TCM is more common than previously thought and associated with a good long-term survival but recurrences and hospitalizations are frequent. Reversing OSAS and controlling the heart rate could prevent TCM-related complications.

Use of low-dose β1-blocker for sinus tachycardia in patients with catecholamine support following cardiovascular surgery: a retrospective study

Background

Sinus tachycardia coupled with high-dose catecholamine is common after cardiopulmonary bypass (CPB). The present study assessed the hemodynamic efficacy and safety of combination therapy using low-dose β₁-selective adrenergic blocker (landiolol) and inotropes.

Methods

This was a retrospective, single center, self-comparison study at post-anesthesia care unit within a tertiary care center. The study included adults who underwent cardiac surgery with CPB and received landiolol between April 2007 and November 2011. We assessed hemodynamic data prior to and 1 h after initiation of landiolol therapy.

Results

We evaluated 11 patients who were administered 2.6 ± 1.3 μg/kg/min (mean ± SD) landiolol with sinus tachycardia and received catecholamine therapy after on-pump cardiovascular surgery. Landiolol administration led to a significant reduction in heart rate (HR; 112.4 ± 5.8 vs 126.0 ± 7.6 beats/min, p < 0.001), and a significant increase in stroke volume index (SVI) assessed by pulmonary artery catheterization (22.4 ± 5.4 vs. 18.9 ± 4.2 mL/m², p = 0.04). Only one patient showed no HR reduction, whereas seven patients showed decreased HR and increased SVI (64, 95% confidence interval: 30–98%). Moreover, all five patients who received high-dose catecholamine support showed improved hemodynamics. In terms of safety, no patients required cessation of landiolol therapy.

Conclusions

Low-dose landiolol therapy may safely decrease HR and improve hemodynamics among patients with sinus tachycardia receiving catecholamine treatment after cardiovascular surgery.

Trial registration

This study is retrospective. Registration number: 11. Duration of registration: April 2007~November 2011.

Ivabradine in Congestive Heart Failure: Patient Selection and Perspectives

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

Ivabradine reversed nondipping heart rate in rats with l-NAME-induced hypertension

We hypothesized that decreasing elevated night-time heart rate (HR) in hypertension by administering a bradycardic agent (ivabradine) at bedtime could bring cardiovascular benefit. Since rats are nocturnal animals, they exhibit circadian rhythms phase-shifted relative to humans. Sixty-six Wistar rats were divided into non-diseased controls and rats with l-NAME-induced hypertension to compare the haemodynamic effects of daytime-dosed and night-time-dosed ivabradine. l-NAME-induced hypertension inverted the physiological 5.6% night-to-day HR dip to an undesirable HR rise by 11.1%. Ivabradine dosed at daytime (the rat's resting phase) reverted a night-to-day HR rise to HR dip by 14.2%. These results suggest a cardiovascular benefit of ivabradine dosed at the human's resting phase (night-time) for hypertensive patients with nondipping HR.

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

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

Prognosis of heart failure treated with digoxin or with ivabradine: A cohort study in the community

BACKGROUND

Resting heart rate (HR) reduction with ivabradine (IVA) improves outcomes of patients with heart failure and reduced ejection fraction (HFrEF). Nevertheless, the best option to slow HR in patients with HFrEF treated with beta-blockers and a HR >70 bpm is unsettled.

AIMS

To evaluate whether, in patients with HFrEF, commencing therapy with digoxin (CT-DIG) is associated to a worse prognosis than commencing treatment with ivabradine (CT-IVA).

METHODS

Observational study over 10 years on 2364 patients with HFrEF in sinus rhythm and a HR >70 bpm. Main outcomes were mortality, hospitalisations and visits. We analyse the independent relationship of CT-DIG or CT-IVA with the prognosis, stratifying patients for cardiovascular comorbidity, and for other potential confounders (378 patients who CT-DIG vs another 355 patients who CT-IVA vs another 1631 patients non-exposed to IVA or DIG).

RESULTS

During a median follow-up of 57.5 months, 1751 patients (74.1%) died, and 2151 (91.0%) were hospitalised for HF. CT-DIG or CT-IVA was associated with a lower all-cause mortality (DIG: HR = 0.86 [95% CI, 0.82-0.90], and IVA: HR = 0.88 [0.83-0.93]), cardiovascular mortality (DIG: HR = 0.84 [0.80-0.89] and IVA: HR = 0.83 [0.78-0.89]), hospitalisation (DIG: HR = 0.86 [0.83-0.89] and IVA: HR = 0.87 [0.83-0.91]) and 30-day readmission (DIG: HR = 0.84 [0.79-0.90] and IVA: HR = 0.88 [0.79-0.95]), after adjustment for cardiovascular comorbidity, and other potential confounders. These associations with the prognosis of HFrEF did not differ between patients who CT-DIG and those who CT-IVA.

CONCLUSION

Commencing therapy with digoxin or with ivabradine is associated with an improved prognosis of patients with HFrEF.

Modernized Classification of Cardiac Antiarrhythmic Drugs

BACKGROUND

Among his major cardiac electrophysiological contributions, Miles Vaughan Williams (1918-2016) provided a classification of antiarrhythmic drugs that remains central to their clinical use.

METHODS

We survey implications of subsequent discoveries concerning sarcolemmal, sarcoplasmic reticular, and cytosolic biomolecules, developing an expanded but pragmatic classification that encompasses approved and potential antiarrhythmic drugs on this centenary of his birth.

RESULTS

We first consider the range of pharmacological targets, tracking these through to cellular electrophysiological effects. We retain the original Vaughan Williams Classes I through IV but subcategorize these divisions in light of more recent developments, including the existence of Na+ current components (for Class I), advances in autonomic (often G protein-mediated) signaling (for Class II), K+ channel subspecies (for Class III), and novel molecular targets related to Ca2+ homeostasis (for Class IV). We introduce new classes based on additional targets, including channels involved in automaticity, mechanically sensitive ion channels, connexins controlling electrotonic cell coupling, and molecules underlying longer-term signaling processes affecting structural remodeling. Inclusion of this widened range of targets and their physiological sequelae provides a framework for a modernized classification of established antiarrhythmic drugs based on their pharmacological targets. The revised classification allows for the existence of multiple drug targets/actions and for adverse, sometimes actually proarrhythmic, effects. The new scheme also aids classification of novel drugs under investigation.

CONCLUSIONS

We emerge with a modernized classification preserving the simplicity of the original Vaughan Williams framework while aiding our understanding and clinical management of cardiac arrhythmic events and facilitating future developments in this area.

Effects of Ivabradine on Left Ventricular Systolic Function and Cardiac Fibrosis in Rat Myocardial Ischemia-Reperfusion Model

We evaluated the effects of Ivabradine on left ventricle (LV) ejection fraction (EF) and LV infarcted tissue in the rat myocardial ischemia-reperfusion model. Twenty rats were randomly assigned to group 1 (ischemia-reperfusion, no treatment, n=10) and group 2 (ischemia-reperfusion + Ivabradine 10 mg/kg, n=10). Ivabradine was administered for 28 days. Echocardiography was performed at 7 days and at 28 days after the induction of ischemia-reperfusion injury. Cardiac fibrosis induced by ischemia-reperfusion injury was evaluated by Masson's trichrome staining. The infarct size was quantified using the Image J program. At the 28-day follow-up, LVEF was significantly higher (36.02±6.16% vs. 45.72±2.62%, p<0.001) and fractional shortening was significantly higher (15.23±2.84% vs. 20.13±1.38%, p<0.001) in group 2 than group 1. Delta (28 day minus 7 day) EF was significantly higher in group 2 than group 1 (-4.36±3.49% vs. 4.31±5.63%, p<0.001). Also, heart rate (beats/min) was significantly lower in group 2 than group 1 (251.67±25.19 vs. 199.29±31.33, p=0.025). Group 2 had a smaller infarct size (40.70±8.94% vs. 30.19±5.89%, p<0.01) than group 1 at 28-day follow-up. Oral administration of Ivabradine could improve LV systolic function and reduce infarcted tissue area in rat myocardial ischemia-reperfusion model.

Home-based telehealth exercise training program in Chinese patients with heart failure: A randomized controlled trial

BACKGROUND

Homed-based exercise training via telehealth is an effective method for cardiac rehabilitation in patients with heart failure (HF). However, little is known about the effects of telehealth exercise training among patients with HF in China.

DESIGN

A randomized controlled design with repeated measures was adopted in this study.

OBJECTIVE

To examine the effect of our telehealth exercise training program on health outcomes in patients with HF in China.

METHODS

A total of 98 participants were randomly allocated to an experimental group (n = 49) and control group (n = 49) from January 2014 to February 2015 in a teaching hospital in Chengdu, People's Republic of China. Participants in the experimental group underwent an 8-week home-based telehealth exercise training program, including 32 exercise training sessions, with regular telephone or instant messaging follow-ups and consultations. Participants in the control group received usual care. The outcome variables used in this study were the Minnesota Living with Heart Failure Questionnaire, 6-minute walking distance (6MWD), resting heart rate (HR), Hospital Anxiety and Depression Scale, left ventricular ejection fraction (LVEF), and the New York Heart Association (NYHA) classification. Data were collected at baseline, post-test (2 months after discharge), and 4 months post-test (6 months after discharge). Repeated measures ANOVA was used to examine the effects of groups, changes over time, and interaction of time and group with the above variables.

RESULTS

Statistically significant improvements were observed in the experimental group regarding quality of life (QOL) and 6MWD compared to the control group post-test. Significant improvements in QOL, 6MWD, and resting HR were sustained for 4 months post-test. However, no significant improvements were observed regarding the NYHA classification, LVEF, anxiety, and depression at either the post-test or 4-month post-test follow-ups. No patients experienced any significant complications or adverse outcomes during the program.

CONCLUSIONS

The results reveal that telehealth exercise training is an effective alternative method for cardiac rehabilitation, especially under the conditions in China.

Ivabradine Treatment Reduces Cardiomyocyte Apoptosis in a Murine Model of Chronic Viral Myocarditis

This study was designed to explore the effects of ivabradine on cardiomyocyte apoptosis in a murine model of chronic viral myocarditis (CVMC). Mice were inoculated intraperitoneally with Coxsackievirus B3 at days 1, 14, and 28, respectively. On day 42, the mice were gavaged with ivabradine for 30 days until the 72nd day. The heart of infected mice was dilated and a large number of interstitial fibroblasts infiltrated into the myocardium on day 42. Compared with the untreated CVMC mice, mice treated with ivabradine showed a significant reduction in heart rate and less impairment of left ventricular function on day 72. The positive apoptosis of myocardial cells in the untreated CVMC group was significantly higher than that of the normal group and was significantly reduced after treatment with ivabradine. The expression levels of Bax and Caspase-3 in the untreated CVMC group were significantly higher than those of the normal group and were apparently reduced in the ivabradine-treated group versus the untreated CVMC group. Bcl-2 showed a high expression in the normal group and low expression in the untreated CVMC group, but its expression level in the ivabradine-treated group were higher than that of the untreated CVMC group. These results indicate that ivabradine could attenuate the expression of Caspase-3 by downregulation of Bax and upregulation of Bcl-2 to prevent the deterioration of cardiac function resulting from ventricular myocyte loss by cardiomyocyte apoptosis.

Genome-Wide Association Approach Identified Novel Genetic Predictors of Heart Rate Response to β-Blockers

Background

For many indications, the negative chronotropic effect of β‐blockers is important to their efficacy, yet the heart rate (HR) response to β‐blockers varies. Herein, we sought to use a genome‐wide association approach to identify novel single nucleotide polymorphisms (SNPs) associated with HR response to β‐blockers.

Methods and Results

We first performed 4 genome‐wide association analyses for HR response to atenolol (a β1‐adrenergic receptor blocker) as: (1) monotherapy or (2) add‐on therapy, in 426 whites and 273 blacks separately from the PEAR (Pharmacogenomic Evaluation of Antihypertensive Responses) study. A meta‐analysis was then performed between the genome‐wide association analysis performed in PEAR atenolol monotherapy and add‐on therapy, in each race separately, using the inverse variance method assuming fixed effects. From this analysis, SNPs associated with HR response to atenolol at a P<1E‐05 were tested for replication in whites (n=200) and blacks (n=168) treated with metoprolol (a β1‐adrenergic receptor blocker). From the genome‐wide association meta‐analyses, SNP rs17117817 near olfactory receptor family10 subfamily‐p‐member1 (OR10P1), and SNP rs2364349 in sorting nexin‐9 (SNX9) replicated in blacks. The combined studies meta‐analysis P values for the rs17117817 and rs2364349 reached genome‐wide significance (rs17117817G‐allele; Meta‐β=5.53 beats per minute, Meta‐P=2E‐09 and rs2364349 A‐allele; Meta‐β=3.5 beats per minute, Meta‐P=1E‐08). Additionally, SNPs in the OR10P1 and SNX9 gene regions were also associated with HR response in whites.

Conclusions

This study highlights OR10P1 and SNX9 as novel genes associated with changes in HR in response to β‐blockers.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00246519.

Interplay Between Phosphorylation and O-GlcNAcylation of Sarcomeric Proteins in Ischemic Heart Failure

Post-translational modifications (PTMs) of sarcomeric proteins could participate to left ventricular (LV) remodeling and contractile dysfunction leading in advanced heart failure (HF) with altered ejection fraction. Using an experimental rat model of HF (ligation of left coronary artery) and phosphoproteomic analysis, we identified an increase of desmin phosphorylation and a decrease of desmin O-N-acetylglucosaminylation (O-GlcNAcylation). We aim to characterize interplay between phosphorylation and O-GlcNAcylation for desmin in primary cultures of cardiomyocyte by specific O-GlcNAcase (OGA) inhibition with thiamet G and silencing O-GlcNAc transferase (OGT) and, in perfused heart perfused with thiamet G in sham- and HF-rats. In each model, we found an efficiency of O-GlcNAcylation modulation characterized by the levels of O-GlcNAcylated proteins and OGT expression (for silencing experiments in cells). In perfused heart, we found an improvement of cardiac function under OGA inhibition. But none of the treatments either in in vitro or ex vivo cardiac models, induced a modulation of desmin, phosphorylated and O-GlcNAcylated desmin expression, despite the presence of O-GlcNAc moities in cardiac desmin. Our data suggests no interplay between phosphorylation and O-GlcNAcylation of desmin in HF post-myocardial infarction. The future requires finding the targets in heart involved in cardiac improvement under thiamet G treatment.