[Initial experiences with high-frequency electric ablation of the AV conduction system in the human]

For the first time, radiofrequency alternating current ablation of the AV-conduction system was performed in a 49-year-old female patient with recurrent atrial tachycardia with fast atrioventricular conduction, refractory to medical therapy, and two conventional DC-shock catheter ablation procedures. Without underlying cardiac disease, the patient had experienced almost daily episodes of tachycardia with a total of 10 syncopes. An electrophysiological study had revealed an ectopic right-atrial tachycardia and fast AV conduction up to a rate of more than 180 bpm. Soon after conventional right atrial catheter ablation, tachycardia with normal AV-conduction had recurred. Therefore, after catheter positioning (Lumelec, Cordis) at the proximal His bundle, 5 alternating current high-frequency pulses with an output energy of up to 50 W were applied under general anaesthesia. After the fourth application, the ECG revealed IIIrd degree AV-block with a His-bundle escape rhythm of 50 bpm. No complications occurred. Subsequent echocardiography did not reveal any pathological changes. The patient was put on anticoagulant therapy for the following 3 months and discharged after implantation of a permanent, activity-controlled pacemaker system (Activitrax, Medtronic). AV-block was persistent within a follow-up period of 3 months.