Extended Use of Ivabradine in Heart Failure with Preserved Ejection Fraction and Inappropriate Sinus Tachycardia

Ivabradine has been used for over a decade in managing chronic coronary syndromes and heart failure (HF) with reducedejection fraction (HFrEF). HF with preserved ejection fraction (HFpEF) accounts for 50% of the total HF cases carrying equalmortality and morbidity risk as HFrEF. Increased heart rate (HR) in such cases has been shown to be associated with poorclinical outcomes. Clinical conditions like inappropriate sinus tachycardia (IST) manifest with elevated HR without anyspecific triggers. Beta-blockers have been the preferred treatment of choice for both HFpEF and IST but are often ineffective orpresent with side effects due to their negative ionotropic effects. Ivabradine, through its inhibitory action on funny current(Ifc), reduces HR without altering the inotropic mechanism. Few case reports and small case series have documented itsextended use and efficacy in reducing HR in these cardiac conditions. In this article, we present two cases who needed HRcontrol, one with HFpEF and another case of IST syndrome. Ivabradine was successfully used in both these cases to controlthe elevated HR