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

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.

A randomized controlled trial of ivabradine in patients with acute myocardial infarction related cardiogenic shock

Objective

. Acute myocardial infarction-related cardiogenic shock (AMI-CS) is often accompanied by tachycardia, which, in turn, increases myocardial oxygen consumption and hinders the use of ventricular assist devices, such as intra-aortic balloon pump. Evidence suggests that ivabradine may reduce heart rate (HR) without affecting other hemodynamic parameters. The aim of the present study was to determine the effect of ivabradine on reducing HR and changes in other hemodynamic parameters such as cardiac index (CI), in patients with AMI-CS and tachycardia.

Materials and methods

. A single-center, open label, randomized clinical trial included patients diagnosed with AMI-CS and tachycardia with >100 beats per minute (BPM). Heart rate, cardiac index, and other hemodynamic parameters measured by pulmonary flotation catheter were compared at 0, 6, 12, 24, and 48 hours after randomization.

Results

. A total of 12 patients were randomized; 6 received standard therapy, and 6 received ivabradine in addition to standard therapy. Baseline clinical characteristics were similar at randomization. A statistically significant lower heart rate was found at 12 hours (p=0.003) and 48 hours (p=0.029) after randomization, with differences of -23.3 (-8.2 to -38.4) BPM and -12.6 (-0.5 to -25.9) BPM, respectively. No differences in cardiac index, or any other evaluated hemodynamic parameters, length of hospital stay, nor mortality rate were noted between both groups.

Conclusions

. The use of ivabradine in patients with AMI-CS was associated with a significant reduction in heart rate at 12 and 48 h, without affecting other hemodynamic parameters.

Evaluating the applicability of ivabradine in acute heart failure

BACKGROUND

While ivabradine has demonstrated benefits in heart rate control and prognosis for chronic heart failure patients, its application in acute decompensated heart failure remains underexplored.

HYPOTHESIS

For patients with acute decompensated heart failure with reduced ejection fraction (HFrEF) who are intolerant to β-blockers or unable to further titrate their dosage, the use of ivabradine is hypothesized to be effective and safe is improving outcomes.

METHODS

This retrospective, multicenter database analysis included patients with hospitalized decompensated heart failure with a left ventricular ejection fraction of ≤40% from June 1, 2015 to December 31, 2020. The exclusion criteria were a baseline heart rate of <70 bpm, previous use of ivabradine, mortality during admission, existing atrial fibrillation, or atrial flutter. The primary outcome was the composite of cardiovascular death and hospitalization for heart failure.

RESULTS

Of the 4163 HFrEF patients analyzed, 684 (16.4%) were administered ivabradine during their index admission. After matching, there were 617 patients in either group. The results indicated that ivabradine use was not significantly associated with the risk of the primary composite outcome (hazard ratio: 1.10; 95% confidence interval: 0.94-1.29). Similarly, the risk of secondary outcomes and adverse renal events did not significantly differ between the ivabradine and non-ivabradine cohorts (all p > .05).

CONCLUSION

For hospitalized acute decompensated heart failure patients who are intolerant to β-blockers or cannot further titrate them, ivabradine offers a consistent therapeutic effect. No significant disparities were noted between the ivabradine and non-ivabradine groups in heart failure hospitalization and cardiovascular death.

Modified reverse shock index predicts early outcomes of heart failure with reduced ejection fraction

AIMS

Increased blood pressure (BP) and decreased heart rate (HR) are signs of stabilization in patients admitted for acute HF. Changes in BP and HR during admission and their correlation with outcomes were assessed in hospitalized patients with heart failure (HF) with reduced ejection fraction (HFrEF).

METHODS

A novel modified reverse shock index (mRSI), defined as the ratio between changes in systolic BP and HR during admission, was devised, and its prognostic value in the early outcomes of acute HF was assessed using the Korean Acute HF registry.

RESULTS

Among 2697 patients with HFrEF (mean age 65.8 ± 14.9 years, 60.6% males), patients with mRSI ≥1.25 at discharge were significantly younger and were more likely to have de novo HF. An mRSI ≥1.25 was associated with a significantly lower incidence of 60-day and 180-day all-cause mortality [hazard ratio (HR) 0.49, 95% confidence interval (CI) 0.31-0.77; HR 0.62, 95% CI 0.45-0.85, respectively], compared with 1 ≤ mRSI < 1.25 (all P < 0.001). Conversely, an mRSI <0.75 was associated with a significantly higher incidence of 60-day and 180-day all-cause mortality (adjusted HR 2.08, 95% CI 1.19-3.62; HR 2.24, 95% CI 1.53-3.27; all P < 0.001). The benefit associated with mRSI ≥1.25 was consistent in sub-group analyses. The correlation of mRSI and outcomes were also consistent regardless of admission SBP, presence of atrial fibrillation, or use of beta blockers at discharge.

CONCLUSIONS

In patients hospitalized for HFrEF, the mRSI was a significant predictor of early outcomes. The mRSI could be used as a tool to assess patient status and guide physicians in treating patients with HFrEF.