atrioventricular av node vagal stimulation by transvenous permanent lead implantation to modulate av node function safety and feasibility in humans background atrioventricular av node vagal stimulation avnvs has recently emerged as a novel approach to controlling av dromotropic function animal studies have demonstrated that selective epicardial avnvs is effective in controlling ventricular rate vr acutely and in the long term endocardial avnvs has been shown to significantly reduce vr acutely during atrial fibrillation af in humans however no data are available on its longterm reproducibilityobjectives the purpose of this study was to demonstrate that the posteroseptal right atrium is a suitable site for permanent pacing and allows avnvs in humans both acutely and during followupmethods in 12 candidates for implantable cardioverterdefibrillator with a history of af the atrial lead was implanted in the posteroseptal right atrium where advanced av block was achieved during temporary highfrequency stimulation hfs on implantation and 3month followup examination hfs was delivered through the permanent lead to demonstrate the possibility to gradually slow the vr until complete av blockresults on implantation vr during af was gradually slowed until complete av block which was elicited at 43 v 02 ms 50 hz after 3 months this effect remained reproducible no significant change in pacing thresholds was observed after 3 months we observed one dislodgment and one microdislodgement of atrial leadsconclusions our study demonstrates for the first time in humans that selective placement of the atrial lead yields electrical characteristics suitable for permanent pacing and enables vr to be significantly reduced under hfs these results which were reproducible during followup provide data for the development of devicebased control of vr during af