Chronic augmentation of the parasympathetic tone to the atrioventricular node: a nonthoracotomy neurostimulation technique for ventricular rate control during atrial fibrillation.
BACKGROUND
The right inferior ganglionated plexus (RIGP) selectively innervates the atrioventricular node. Temporary electrical stimulation of this plexus reduces the ventricular rate during atrial fibrillation (AF). We sought to assess the feasibility of chronic parasympathetic stimulation for ventricular rate control during AF with a nonthoracotomy intracardiac neurostimulation approach.


RESULTS
In 9 mongrel dogs, the small endocardial area inside the right atrium, which overlies the RIGP, was identified by 20 Hz stimulation over a guiding catheter with integrated electrodes. Once identified, an active-fixation lead was implanted. The lead was connected to a subcutaneous neurostimulator. An additional dual-chamber pacemaker was implanted for AF induction by rapid atrial pacing and ventricular rate monitoring. Continuous neurostimulation was delivered for 1-2 years to decrease the ventricular rate during AF to a range of 100-140 bpm. Implantation of a neurostimulation lead was achieved within 37 +/- 12 min. The latency of the negative dromotropic response after on/offset or modulation of neurostimulation was <1 s. Continuous neurostimulation was effective and well tolerated during a 1-2 year follow-up with a stimulation voltage <5 V. The neurostimulation effect displayed a chronaxie-rheobase behavior (chronaxie time of 0.07 +/- 0.02 ms for a 50% decrease of the ventricular rate during AF).


CONCLUSIONS
Chronic parasympathetic stimulation can be achieved via a cardiac neurostimulator. The approach is safe, effective, and well tolerated in the long term. The atrioventricular nodal selectivity and the opportunity to adjust the negative dromotropic effect within seconds may represent an advantage over pharmacological rate control.
Mischke
Karl
K
Department of Cardiology, RWTH Aachen University, Aachen, Germany.
Zarse
Markus
M
Schmid
Michael
M
Gemein
Christopher
C
Hatam
Nima
N
Spillner
Jan
J
Dohmen
Guido
G
Rana
Obaida
O
Saygili
Erol
E
Knackstedt
Christian
C
Weis
Joachim
J
Pauza
Dainius
D
Bianchi
Stefano
S
Schauerte
Patrick
P
D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology* / Q000517:prevention & control*; D004285:Dogs; D004599:Electric Stimulation Therapy / Q000379:methods*; D005240:Feasibility Studies; D005726:Ganglia, Parasympathetic / Q000503:physiopathology*; D006339:Heart Rate; D006352:Heart Ventricles / Q000503:physiopathology*; D008297:Male; D013908:Thoracotomy; D016896:Treatment Outcome