Ivabradine in the Treatment of Inappropriate Sinus Tachycardia in Patients after Successful Radiofrequency Catheter Ablation of Atrioventricular Node Slow Pathway

Background: Inappropriate sinus tachycardia (IST) occurs relatively common after catheter ablation of slow pathway in patients with atrioventricular nodal reentrant tachycardia. The treatment of IST symptoms using beta-blockers or calcium channel-blockers are often noneffective or not well tolerated. Ivabradine is a new heart rate (HR)-decreasing agent inhibiting sinus node If current. The purpose of the study was to evaluate the efficacy and safety of ivabradine in patients with persistent and beta-blocker-resistant IST after successful radiofrequency (RF) ablation of atrioventricular node slow pathway. Methods: We enrolled 14 patients (42 +/- 11 years; 10 women) affected by IST after RF ablation. Holter monitoring, treadmill stress test, and IST symptoms assessment were performed at baseline and after first, and second month of the study. Results: We observed significant reduction of mean resting HR after 30 and 60 days of ivabradine treatment compared to baseline (P < 0.001). 24-hour Holter monitoring showed a significant reduction of mean HR and mean HR during daily activity (P < 0.001). The study revealed significant improvement in exercise capacity during treadmill exercise test on ivabradine therapy (P < 0.001). Significantly lower incidence of IST-related symptoms were registered after administration of If current inhibitor. After 2 months of treatment no patients reported severe complaints assessed by means of European Heart Rhythm Association score. We did not observe severe side effects during therapy. Conclusion: Ivabradine is an effective treatment option to reduce HR and symptoms in patients with IST after RF ablation of atrioventricular node slow pathway. The therapy with ivabradine is well tolerated even with maximum daily dose. (PACE 2013; 36: 42-49)