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His-bundle ablation followed by pacemaker implantation is today a widely accepted therapeutic choice when drug refractoriness of symptomatic AF is evident. The selection of pacing mode in patients suffering from paroxysmal AF is still controversial. Preservation of AV synchrony is an attractive option in patients with paroxysmal AF who undergo His-bundle ablation. The purpose of this study was to examine prospectively the contribution of VDDR pacing for preservation of AV synchrony. After His-bundle ablation a VDDR pacing system was implanted in 17 patients with paroxysmal AF, and all antiarrhythmic drugs were withdrawn. The endpoint of the study was defined as the onset of chronic AF. To document the onset of chronic AF 48-hour Holter recordings were made every 6-8 weeks. After a mean followup of 18.2 (range 14-21) months, VDDR pacing is still operative in 13 patients (77%). Four patients developed chronic AF after a mean follow-up of 6 months. Of several baseline characteristics, only the intraatrial P wave at implantation was significantly smaller in patients developing chronic AF than in patients in whom the VDDR mode is still operative. This pilot study suggests that VDDR pacing is an attractive pacing method for patients with paroxysmal AF after His-bundle ablation. A low intraatrial P wave electrogram at implant was associated with a higher risk for the development of chronic AF.

Objective: To evaluate exercise capacity of patients with chronic atrial fibrillation in whom His bundle ablation followed by ventricular rate response pacing (VVIR) was carried out because of drug refractoriness., Design: Prospective study., Patients: 25 consecutive patients, all with chronic symptomatic drug refractory atrial fibrillation, underwent His bundle ablation. Before this intervention all patients were on antiarrhythmic drugs to attain acceptable heart rate control and to relief symptoms., Main Outcome Measures: Exercise capacity, including measurements of VO2, was examined before and after a mean interval of seven months following His bundle ablation., Results: Exercise capacity after His bundle ablation increased from a mean of 109 (SD 49) W to 118 (46) W (P < 0.002), but VO2 at peak exercise did not change significantly. Maximum exercise capacity was achieved with a significantly lower maximum driven heart rate than the spontaneous heart rate before ablation., Conclusions: Exercise capacity of patients who underwent His bundle ablation followed by VVIR pacing remained unchanged or improved during a mean follow up of seven months. Larger patient populations with longer follow up are necessary to examine determinants of improved exercise capacity.