Abstract 19221: Metoprolol vesus Ivabradine in the Treatment of Inappropriate Sinus Tachycardia
Introduction: Inappropriate sinus tachycardia (IST) is a clinical syndrome characterized by excessive resting heart rate (HR) or disproportional increasing HR during exercise. The treatment of IST symptoms using beta-blockers or calcium channel-blockers are often non-effective or not well tolerated. Ivabradine is a new agent inhibiting node IF current. The effect of this treatment is HR decreasing without influence on other cardiovascular function.
Methods: We enrolled 20 patients (36+/−10 years; 14 women) affected by IST. After 4 weeks of treatment with metoprolol we administrated ivabradine 5 mg twice a day, up to 7,5 mg twice daily. Holter monitoring was performed after first and second month of the study.
Results: We observed significant reduction of resting HR both for metoprolol and ivabradine (22,2 bpm vs 24.1 bpm, NS). During exercise or daily activity better effect occurred on ivabradine (mean HR reduction 12,3 bpm vs 20.1 bpm, p<0.001). Both drugs were well tolerated. In 3 patients on metoprolol we observed tendency to small arterial blood pressure.
Conclusions: Metoprolol and ivabradine show similar effect on resting HR in patients with IST. Ivabraine seems to be more effective to relief symptoms during exercise or daily activity. It is well tolerated even with maximum daily dose.
- © 2010 by American Heart Association, Inc.