I think ivabradine is an excellent treatment of inappropiate sinus tachycardia, over all in some groups of patients. In my experience, in patients with low blood pressure (frequently young women), ivabradine play a good role in treatment of inappropiate sinus tachycardia. Other interesting group for this treatment are patients with an absolute contraindication to be treated with betablockers (asthma or chronic obstructive pulmonary disease) or not good tolerance (asthenia,lower exercise capacity, and so on). I recommend you this paper (J Am Coll Cardiol. 2012 Oct 9;60(15):1323-9. doi: 10.1016/j.jacc.2012.06.031. Epub 2012 Sep 12.) and encourage to get using ivabradine in this entity. I usually start with 5 mg bid, and if it is well tolerated (point out the patients about the flashing lights) during one week, I raise the dose up to 7.5 mg bid. Hope to be helful.