Ivabradine reduced ventricular rate in patients with non-paroxysmal atrial fibrillation

It has been shown that I_f channels can be found in AV node, apart from the sinus node. Previous animal studies showed that I_f inhibitor resulted in the rate-dependent reduction in AV node conduction during atrial fibrillation (AF). Therefore, we aimed to examine the effect of ivabradine on ventricular rate in patients with non-paroxysmal AF.

This study was a prospective randomized, double blind, placebo-controlled study. Ivabradine, 5mg twice a day (n=21), or placebo (n=11) was administered for 1month to adult patients with non-paroxysmal AF, in addition to standard therapy. The primary end point was the change in mean ventricular rate between baseline and 1month, as assessed by 24-hour Holter.

The baseline characteristics did not differ between ivabradine and placebo groups (mean age was 59.7±13.3years, male 62.5%). Mean 24-hour ventricular rate at baseline was comparable between 2 groups. We found that ivabradine significantly decreased mean ventricular rate from 86.0±10.9beats/min to 79.2±9.6beats/min (p<0.001). In contrast, no significant change in ventricular rate was observed in placebo group (84.3±11.2 vs. 82.9±9.9beats/min, p=0.469). The effect of ivabradine on rate reduction was significantly greater than placebo (6.9±6.3 vs. 1.4±6.0beats/min, p=0.024). No drug-related adverse effects were observed in both groups.

We demonstrated that ivabradine significantly decreased ventricular rate during AF compared to placebo. Therefore, ivabradine can be a potential treatment to improve ventricular control in patients with non-paroxysmal AF. Due to the small sample size, larger studies are needed to confirm this effect of ivabradine.