Effect of vagal nerve stimulation on heart rate variability in a porcine model (1169.17)

Sympathetic and parasympathetic nervous system imbalance has been strongly associated to sudden cardiac death. Vagal nerve stimulation (VNS), although a well‐recognized clinical therapy for epilepsy and medically refractory depression, is currently under investigation as a therapy for heart failure. Our objective of this study was to determine effects of left and right VNS on heart rate variability (HRV) by using power spectral analysis, the low frequency and high frequency components of heart rate variability. Ten anesthetized pigs received an application of either right or left VNS at 15 Hz for 20 second. Right and left VNS resulted in a decrease in heart rate from 82.6±8.3 to 75.3±9.2 and 91.5±5.0 to 85.5±4.9, respectively. Right VNS significantly decreased low frequency normalized units (LF n.u.) component (60.4±4.4 vs. 38.8±6.3 baseline, p<0.05) indicating a reduced sympathetic nerve activity and increased high frequency normalized units (HF n.u.) component (23.0±4.8 vs. 46.4±6.5, p<0.05) indicating an enhanced parasympathetic nerve activity. In contrast, Left VNS did not alter either LF n.u. (37.7±12.1 vs 37.3±10.8 baseline) or HF n.u. (34.1±7.1 vs. 32.0±7.0 baseline). In conclusion, right but not left VNS modulates sympathetic and parasympathetic activity and may serve as a potential therapy to treat cardiovascular diseases.