Introduction: A heart rate higher than 90 beats/min indicates an unfavorable prognosis for patients with multiple organ dysfunction syndrome (MODS). We sought to investigate the effect of the pacemaker current (If) inhibitor ivabradine on heart rate, hemodynamics, and disease severity among patients with MODS.
Patients and methods: In this prospective, controlled, randomized, open-label, two-arm phase II trial, 70 patients with MODS, a sinus rhythm of at least 90 beats/min, and contraindications to β-blocker therapy were randomly assigned to receive the standard treatment ± ivabradine (5 mg twice daily) for 96 h via the enteral route. The primary outcome was the percentage of patients with a heart rate reduction of at least 10 beats/min after 96 h. Secondary outcomes included the effect of ivabradine on hemodynamics, disease severity, vasopressor use, mortality, and adverse events.
Results: There were no significant differences in the primary outcome between the ivabradine and control groups (P = 0.147). After 96 h, the daily median heart rate was reduced by 7 beats/min in the control group and by 16 beats/min in the ivabradine group (P = 0.014). No differences in secondary outcomes were observed.
Conclusions: The number of critically ill patients with MODS and a sinus rhythm of at least 90 beats/min that experienced a heart rate reduction of at least 10 beats/min after oral ivabradine treatment did not differ significantly between groups. The moderate but significant reduction of heart rate by 7 beats/min did not affect hemodynamics or disease severity.