Reducing Elevated Heart Rates in Patients with Multiple Organ Dysfunction Syndrome with the If (Funny Channel Current) Inhibitor Ivabradine.

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 (I-f) 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 beta-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.