Successful ablation of Hisian ectopy identified by a reversed His bundle activation sequence.

Junctional ectopy or tachycardia have been mapped and ablated in the atrioventricular node or its posterior extensions. There is no report of Hisian ectopy convincingly demonstrated and then successfully treated by ablation. A 39-year-old man presented with a 9-year history of recurrent supraventricular ectopy refractory to medical treatment. Intracardiac mapping revealed that the ectopy originated from the His bundle, which was indicated by a reversed His bundle activation sequence during ectopy compared to that during sinus rhythm, while the right bundle branch potential was anterogradely activated. Low power RF energy delivered to the site of earliest activation completely abolished the ectopic activity without modification of Hisian or atrioventricular conduction. After a 12-month followup, the patient remains free of recurrence.