Use of ivabradine in catecholamine-induced tachycardia after high-risk cardiac surgery

Ivabradine in Septic Shock: A Narrative Review

In patients with septic shock, compensatory tachycardia initially serves to maintain adequate cardiac output and tissue oxygenation but may persist despite appropriate fluid and vasopressor resuscitation. This sustained elevation in heart rate and altered heart rate variability, indicative of autonomic dysfunction, is a well-established independent predictor of adverse outcomes in critical illness. Elevated heart rate exacerbates myocardial oxygen demand, reduces ventricular filling time, compromises coronary perfusion during diastole, and impairs the isovolumetric relaxation phase of the cardiac cycle, contributing to ventricular-arterial decoupling. This also leads to increased ventricular and atrial filling pressures, with a heightened risk of arrhythmias. Ivabradine, a highly selective inhibitor of the sinoatrial node's pacemaker current (If or "funny" current), mitigates heart rate by modulating diastolic depolarization slope without affecting contractility. By exerting a selective chronotropic effect devoid of negative inotropic properties, ivabradine shows potential for improving hemodynamics in septic shock patients with cardiac dysfunction. This review evaluates the plausible mechanisms and existing evidence regarding the utility of ivabradine in managing patients with septic shock.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Beyond Heart Failure and Ischemic Heart Disease: A Scoping Review of Novel Uses of Ivabradine in Adults

Ivabradine lowers heart rate by inhibiting the hyperpolarization-activated current in pacemaker cells, and its use for the treatment of heart failure (HF) and ischemic heart disease (IHD) is well described. Ivabradine may be an attractive treatment option for other conditions for which a reduction in heart rate is desirable but less is known about its role in these settings. The primary objective was to perform a scoping review summarizing the literature evaluating novel uses for ivabradine other than HF and IHD in adults. PubMed and EMBASE were searched for articles for all dates through September 2019. Search strategies combined terms generic, commercial/trade, and international names for ivabradine. Manual search of references was also performed to identify additional articles. Studies were included if they were published in English, evaluated the efficacy of ivabradine for indications other than HF or IHD in patients aged 18 years or older, and the primary outcome included clinically relevant end points. Articles were screened first by title and abstract followed by full-text screening of the remaining articles. After removal of duplicates, 1807 records were screened for inclusion and 84 studies were included in this scoping review. Novel uses of ivabradine were reported for various tachyarrhythmias, valvular heart disease, premedication for coronary computed tomography angiography, perioperative risk reduction, sepsis with and without multi-organ dysfunction syndrome, cor pulmonale, reactive airway disease, and erectile dysfunction. This scoping review identified several potential novel uses for ivabradine in adults. This review may help to identify existing gaps where further research is needed to elucidate the role of ivabradine for indications beyond HF and IHD.

Use of ivabradine and atorvastatin in emergent orthopedic lower limb surgery and computed tomography coronary plaque imaging and novel biomarkers of cardiovascular stress and lipid metabolism for the study and prevention of perioperative myocardial infarction: study protocol for a randomized controlled trial

Background

The incidence of perioperative myocardial infarction (PMI) globally is known to be around 2 to 3% and can prolong hospitalization, increased morbidity and mortality. Little is known about the pathophysiology and risk factors for PMI. We investigate the presence of elevated novel cardiac markers and preoperative coronary artery plaque through contemporary laboratory techniques to determine the correlation with PMI, as well as studying ivabradine and atorvastatin as protective pharmacotherapies against PMI in the context of orthopedic surgery.

Methods/Design

We aim to enroll 200 patients aged above 60 years who suffer from neck of femur fracture requiring surgery. Patients will be randomized to four arms (no study drugs, atorvastatin only, ivabradine only and ivabradine and atorvastatin). Our primary outcome is incidence of PMI. All patients will receive an electrocardiogram, cardiac echocardiography, measurement of novel cardiac biomarkers and computed tomography (CT) coronary angiography. A telephone interview post discharge will be conducted at 30 days, 60 days and 1 year.

Discussion

We postulate that ivabradine and atorvastatin will reduce the rate and magnitude of PMI following surgery by reducing heart rate and attenuating catecholamine-induced tachycardia postoperatively. Secondly, we postulate that postoperative reduction in heart rate and catecholamine-induced tachycardia with ivabradine will correlate with a reduction in cardiovascular novel biomarkers which will reduce atrial stretch and postoperative incidence of arrhythmia. We aim to demonstrate that treatment with ivabradine and atorvastatin will cause a reduction in the incidence and magnitude of PMI, the benefit of which is derived primarily in patients with greater atherosclerotic burden as measured by higher CT coronary calcium scores.

Trial registration

This study protocol has been listed in the Australia New Zealand Clinical Trial Registry (registration number: ACTRN12612000340831) on 23 March 2012.

Heart rate reduction with ivabradine in patients with acute decompensated systolic heart failure

INTRODUCTION

In patients with acute decompensated systolic heart failure (ADSHF) high resting heart rate (HR) could be either a compensatory mechanism or contribute to worsening heart failure. The aim of this study was to evaluate, in patients with ADSHF and resting HR >70 bpm, the early (within 24 h) and late (at discharge) effects of oral administration of ivabradine on HR reduction.

METHODS

Ten consecutive patients with ADSHF, left ventricular ejection fraction <40 % and HR >70 bpm, without other acute conditions or inotropic therapy, began open-label treatment with oral ivabradine according to a pre-established Heart Failure Unit protocol. We obtained clinical and laboratory data at four periods: admission (T0), immediately before initiation of ivabradine (T2), 24 h after initiation of ivabradine (T3), and at discharge (T4).

RESULTS

Ivabradine was administered in 60 % of the patients before the second day. HR decreased 10.7 ± 7.2 bpm at T3 (p < 0.001) and 16.3 ± 8.2 bpm at T4 (p = 0.002). The systolic blood pressure decreased at T3 (p = 0.012), returning to baseline values at T4. There was no change in diastolic and mean blood pressure. New York Heart Association (NYHA) class improvement by two levels was associated with lower HR at T4 (p = 0.033). HR and N-terminal pro-brain natriuretic peptide (Nt-ProBNP) at baseline correlated significantly [Spearman correlation coefficient (rs) = 0.789, p = 0.013]. Total Nt-ProBNP reduction correlated with the HR before (r = 0.762, p = 0.028) and after (T3: r = 0.647, p = 0.083; T4: r = 0.738, p = 0.037) ivabradine addition.

CONCLUSION

In the present cohort of patients with ADSHF and HR >70 bpm, the selective reduction of HR with oral ivabradine was safe and efficient.

Ivabradine: potential clinical applications in critically ill patients

It has been extensively demonstrated that an elevated heart rate is a modifiable, independent risk factor for cardiovascular events. A high heart rate increases myocardial oxygen consumption and reduces diastolic perfusion time. It can also increase ventricular diastolic pressures and induce ventricular arrhythmias. Critical care patients are prone to develop a stress induced cardiac impairment and consequently an increase in sympathetic tone. This in turn increases heart rate. In this setting, however, heart rate lowering might be difficult because the effects of inotropic drugs could be hindered by heart rate reducing drugs like beta-blockers. Ivabradine is a new selective antagonist of funny channels. It lowers heart rate, reducing the diastolic depolarization slope. Moreover, ivabradine is not active on sympathetic pathways, thus avoiding any interference with inotropic amines. We reviewed the literature available regarding heart rate control in critical care patients, focusing our interest on the use of ivabradine to assess the potential benefits of the drug in this particular setting.