Inappropriate Sinus Tachycardia Following Cardioneuroablation for Reflex Syncope: A Case Report and Review of the Literature Illustrating this Underappreciated Adverse Effect.

Inappropriate sinus tachycardia (IST) is a clinical syndrome that generally affects young patients and is associated with distressing symptoms. Cardioneuroablation (CNA) is a promising method for the treatment of asystolic reflex syncope, functional bradycardia or atrioventricular block. Because CNA involves parasympathetic denervation, one potential adverse effect may be IST. We present an educational case of a patient with mixed vasovagal syncope and symptomatic sinus bradycardia who underwent CNA, as a result of which bradycardia converted to IST and the patient required subsequent pacemaker implantation. We also review the incidence of IST after CNA and difficulties around the definition and treatment of post-CNA IST.