Abstract 12195: Right Vagus Nerve Stimulation Improves Left Ventricular Function in Heart Failure: Results of a Cross-Over Study in Dogs with Experimental Heart Failure
Background: Autonomic imbalance namely high sympathetic and low parasympathetic drive, is a feature of chronic heart failure (HF). Previous studies have shown that vagus nerve stimulation (VS) can improve autonomic balance in HF. VS can also elicit anti-inflammatory responses and normalize nitric oxide pathways both of which are beneficial in HF. This study tested the hypothesis that VS improves LV function and prevents progressive LV dilation in dogs with chronic HF.
Methods: Studies were performed in 12 dogs with moderate HF (LV ejection fraction, EF∼35%) produced by intracoronary microembolizations. All dogs underwent surgical implantation of a bipolar cuff electrode around the right vagus nerve connected to an implantable pulse generator. Dogs were then assigned to no therapy (control, n=6) or to active VS therapy (n=6) maintained for 3 months. At the end of 3 months, control dogs were crossed-over to active VS therapy and VS therapy dogs were crossed-over to no therapy (turned off) and maintained for another 3 months. Active VS was delivered for 10 sec of every minute. LV end-diastolic (EDV), end-systolic (ESV) volumes and EF were measured from ventriculograms taken just prior to initiating therapy (PRE), after the initial 3 months of treatment (POST-1) and again 3 months following the cross-over (POST-2).
Results: In dogs assigned to control, EDV was unchanged and ESV tended to increase after 3 months and EF tended to decrease. In these dogs, initiation of VS therapy had no effect on EDV but tended to reduce ESV and increase EF. In dogs assigned to VS treatment, EDV was unchanged while ESV decreased and EF increased significantly. In these dogs, withdrawal of therapy caused no change of EDV but significantly increased ESV and tended to reduce EF.
Conclusions: Long-term VS therapy improves LV function and prevents progressive LV dilation in dogs with moderate HF. The results favor continued development of VS therapy for the treatment of patients with chronic HF.
- © 2010 by American Heart Association, Inc.