Selective atrioventricular nodal vagal stimulation consistently slowed ventricular rate by an average of 45 bpm over 5 weeks in dogs with induced atrial fibrillation.
Does selective atrioventricular nodal vagal stimulation reduce ventricular rate during atrial fibrillation in chronically instrumented dogs?
Chronic selective atrioventricular nodal vagal stimulation safely and effectively reduces ventricular rate and improves cardiac indices during atrial fibrillation in a canine model.
BACKGROUND: We have previously demonstrated that selective atrioventricular nodal (AVN) vagal stimulation (AVN-VS) can be used to control ventricular rate during atrial fibrillation (AF) in acute experiments. However, it is not known whether this approach could provide a long-term treatment in conscious animals. Thus, this study reports the first observations on the long-term efficacy and safety of this novel approach to control ventricular rate during AF in chronically instrumented dogs. METHODS AND RESULTS: In 18 dogs, custom-made bipolar patch electrodes were sutured to the epicardial AVN fat pad for delivery of selective AVN-VS by a subcutaneously implanted nerve stimulator (pulse width 100 micros or 1 ms, frequency 20 or 160 Hz, amplitude 6 to 10 V). Fast-rate right atrial pacing (600 bpm) was used to induce and maintain AF. ECG, blood pressure, and body temperature were monitored telemetrically. One week after the induction of AF, AVN-VS was delivered and maintained for at least 5 weeks. It was found that AVN-VS had a consistent effect on ventricular rate slowing (on average 45+/-13 bpm) over the entire period of observation. Echocardiography showed improvement of cardiac indices with ventricular rate slowing. AVN-VS was well tolerated by the animals, causing no signs of distress or discomfort. CONCLUSIONS: Beneficial long-term ventricular rate slowing during AF can be achieved by implantation of a nerve stimulator attached to the epicardial AVN fat pad. This novel concept is an attractive alternative to other methods of rate control and may be applicable in a selected group of patients.
Zhang et al. (Tue,) conducted a other in Atrial fibrillation (n=18). Selective atrioventricular nodal vagal stimulation (AVN-VS) was evaluated on Ventricular rate slowing. Selective atrioventricular nodal vagal stimulation consistently slowed ventricular rate by an average of 45 bpm over 5 weeks in dogs with induced atrial fibrillation.
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