Inappropriate sinus tachycardia, also known as IST, is a condition of elevated sinus rate unassociated with known pathological, pharmacological, or physiological causes. Its diagnosis has been, in the past, missed or at times dismissed. It does not help that its definitions in current literature are inconsistent, and professional society consensus have had limited impact. Considering its broad setting of physiology, pathology, and uncertainties, the therapy for IST remains challenging. To date high rates of symptom recurrence, treatment failure, and complications have followed many therapies. 

Although, not well accepted by guidelines, the main hope lies in ablation procedures. Unfortunately, the results of endocardial radiofrequency ablation have not been encouraging. Today we will explore the multiple aspects of IST and the treatment techniques surrounding it.