Role of the Funny Current Inhibitor Ivabradine in Cardiac Pharmacotherapy: A Systematic Review

Personalised perioperative dosing of ivabradine in noncardiac surgery: a single-centre, randomised, placebo-controlled, double-blind feasibility pilot trial

BACKGROUND

Perioperative myocardial injury after noncardiac surgery is associated with postoperative mortality. Heart rate (HR) is an independent risk factor for perioperative myocardial injury. In this pilot trial we tested the feasibility of a randomised, placebo-controlled trial of personalised HR-targeted perioperative ivabradine.

METHODS

This was a single-centre, randomised, placebo-controlled, double-blind, parallel group, feasibility pilot trial conducted at Geneva University Hospitals. We included patients ≥75 yr old or ≥45 yr old with cardiovascular risk factors planned for intermediate- or high-risk surgery. Patients were randomised to receive ivabradine (2.5, 5.0, or 7.5 mg) or placebo according to their HR, twice daily, from the morning of surgery until postoperative day 2. Primary outcomes were appropriate dosage and blinding success rates.

RESULTS

Between October 2020 and January 2022, we randomised 78 patients (recruitment rate of 1.3 patients week-1). Some 439 of 444 study drug administrations were adequate (99% appropriate dosage rate). The blinding success rate was 100%. There were 137 (31%) administrations of Pill A (placebo in both groups for HR ≤70 beats min-1). Nine (11.5%) patients had a high-sensitive cardiac troponin T elevation ≥14 ng L-1 between any two measurements. The number of bradycardia episodes was eight in the placebo group and nine in the ivabradine group.

CONCLUSIONS

This pilot study demonstrates the feasibility of, and provides guidance for, a future trial testing the efficacy of personalised perioperative ivabradine. Future studies should include patients at higher risk of cardiac complications.

CLINICAL TRIAL REGISTRATION

NCT04436016.

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.

Perioperative Management of Novel Pharmacotherapies for Heart Failure and Pulmonary Hypertension

Heart failure (HF) and pulmonary hypertension (PH) are increasingly prevalent comorbidities in patients presenting for noncardiac surgery. The unique pathophysiology and pharmacotherapies associated with these syndromes have important perioperative implications. As new medications for HF and PH emerge, it is imperative that anesthesiologists and other perioperative providers understand their mechanisms of action, pharmacokinetics, and potential adverse effects. We present an overview of the novel HF and PH pharmacotherapies and strategies for their perioperative management.

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.

New Novel Treatment Approaches for Heart Failure With Reduced Ejection Fraction

Despite availability of standardized drug therapies with proven beneficial outcomes, heart failure is associated with poor quality of life, increased hospital readmission, and high mortality rate. In the recent years, comprehensive understanding of the pathophysiological mechanisms of heart failure has led to the development and approval of 2 new pharmacological agents, sacubitril–valsartan and ivabradine. These agents are currently approved for use in heart failure with reduced ejection fraction (HFrEF) and present as novel approaches to further improve prognosis and outcomes in patients with HF. They offer alternative treatment options for patients who are intolerant or continue to be symptomatic despite utilization of standard HF drug therapies at optimally tolerated dosages. A review of these 2 novel agents in HFrEF, including information on pivotal trials that led to its approval and its place in therapy for HFrEF, is presented.