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 long-term reproducibility.


OBJECTIVE
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 follow-up.


METHODS
In 12 candidates for implantable cardioverter-defibrillator with a history of AF, the atrial lead was implanted in the posteroseptal right atrium, where advanced AV block was achieved during temporary high-frequency stimulation (HFS). On implantation and 3-month follow-up examination, HFS was delivered through the permanent lead to demonstrate the possibility to gradually slow the VR until complete AV block.


RESULTS
On implantation, VR during AF was gradually slowed until complete AV block, which was elicited at 4.3 V (0.2 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 leads.


CONCLUSIONS
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 follow-up, provide data for the development of device-based control of VR during AF.
Bianchi
Stefano
S
Cardiology Department, S. Giovanni Calibita Fatebenefratelli Hospital, Rome, Italy. stefbianchi@gmail.com
Rossi
Pietro
P
Della Scala
Alberto
A
Kornet
Lilian
L
Pulvirenti
Raffaele
R
Monari
Giancarlo
G
Di Renzi
Paolo
P
Schauerte
Patrick
P
Azzolini
Paolo
P
D015906:Angioplasty, Balloon, Coronary; D001281:Atrial Fibrillation / Q000517:prevention & control* / Q000628:therapy; D001283:Atrioventricular Node / Q000294:innervation*; D002304:Cardiac Pacing, Artificial; D017147:Defibrillators, Implantable; D004567:Electrodes, Implanted / Q000009:adverse effects; D004699:Endocardium; D004869:Equipment Safety; D005240:Feasibility Studies; D006333:Heart Failure; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D055536:Vagus Nerve Stimulation