Abstract 13089: Clinical Efficacy of Ivabradine in Patients with Inappropriate Sinus Tachycardia: A Prospective Randomized Placebo-Controlled Double-Blind Crossover Evaluation
Objectives. To investigate the role of ivabradine in the treatment of symptomatic inappropriate sinus tachycardia using a double-blind, placebo-controlled, crossover design.
Background. Due to its Ifblocking properties, ivabradine can selectively attenuate the high discharge rate from sinus node cells causing inappropriate sinus tachycardia.
Methods. Twenty-one subjects were randomized to receive placebo (10) or ivabradine 5 mg twice daily (11) for 6 weeks. After washout, subjects crossed over for an additional 6 weeks. Each subject underwent symptom evaluation and heart rate assessment at the start and finish of each phase.
Findings. After taking ivabradine, subjects reported elimination of > 75% of symptoms (RR, 0.25; 95% CI, 0.18-0.34, p < 0.001) with 47% of them experiencing complete elimination. These effects were associated with a significant reduction of heart rate at rest (from 88 ± 11 to 76 ± 11 bpm, p = 0.011) on standing (from 108 ± 12 to 92 ± 11 bpm, p < 0.0001), during 24-hr (from 88 ± 5 to 77 ± 9 bpm, p = 0.001) and during effort (from 176 ± 17 to 158 ± 16 bpm, p = 0.001). Ivabradine administration was also associated with a significant increase in exercise performance. No cardiovascular side-effects were observed in any patients while on ivabradine.
Conclusions. In this cohort, ivabradine significantly improved symptoms associated with inappropriate sinus tachycardia and completely eliminated them in about half of subjects. These findings suggest that ivabradine may be an important agent for improving symptoms in subjects with inappropriate sinus tachycardia.
- © 2012 by American Heart Association, Inc.