title: Electrophysiological effects of right and left vagal nerve stimulation on the ventricular myocardium.
abstract: Vagal nerve stimulation (VNS) has been proposed as a cardioprotective intervention. However, regional ventricular electrophysiological effects of VNS are not well characterized. The purpose of this study was to evaluate effects of right and left VNS on electrophysiological properties of the ventricles and hemodynamic parameters. In Yorkshire pigs, a 56-electrode sock was used for epicardial (n = 12) activation recovery interval (ARI) recordings and a 64-electrode catheter for endocardial (n = 9) ARI recordings at baseline and during VNS. Hemodynamic recordings were obtained using a conductance catheter. Right and left VNS decreased heart rate (84 ± 5 to 71 ± 5 beats/min and 84 ± 4 to 73 ± 5 beats/min), left ventricular pressure (89 ± 9 to 77 ± 9 mmHg and 91 ± 9 to 83 ± 9 mmHg), and dP/dtmax (1,660 ± 154 to 1,490 ± 160 mmHg/s and 1,595 ± 155 to 1,416 ± 134 mmHg/s) and prolonged ARI (327 ± 18 to 350 ± 23 ms and 327 ± 16 to 347 ± 21 ms, P < 0.05 vs. baseline for all parameters and P = not significant for right VNS vs. left VNS). No anterior-posterior-lateral regional differences in the prolongation of ARI during right or left VNS were found. However, endocardial ARI prolonged more than epicardial ARI, and apical ARI prolonged more than basal ARI during both right and left VNS. Changes in dP/dtmax showed the strongest correlation with ventricular ARI effects (R(2) = 0.81, P < 0.0001) than either heart rate (R(2) = 0.58, P < 0.01) or left ventricular pressure (R(2) = 0.52, P < 0.05). Therefore, right and left VNS have similar effects on ventricular ARI, in contrast to sympathetic stimulation, which shows regional differences. The decrease in inotropy correlates best with ventricular electrophysiological effects.
authors.affiliation: Department of Anesthesiology, David Geffen School of Medicine at UCLA, Los Angeles, California.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yamakawa
authors.affiliation: University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California;
authors.forename: Eileen L
authors.initials: EL
authors.lastname: So
authors.affiliation: University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Program, David Geffen School of Medicine at UCLA, Los Angeles, California; and.
authors.forename: Pradeep S
authors.initials: PS
authors.lastname: Rajendran
authors.affiliation: Department of Anesthesiology, David Geffen School of Medicine at UCLA, Los Angeles, California.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Hoang
authors.affiliation: University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California;
authors.forename: Nupur
authors.initials: N
authors.lastname: Makkar
authors.affiliation: University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Program, David Geffen School of Medicine at UCLA, Los Angeles, California; and Department of Anesthesiology, David Geffen School of Medicine at UCLA, Los Angeles, California.
authors.forename: Aman
authors.initials: A
authors.lastname: Mahajan
authors.affiliation: University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Program, David Geffen School of Medicine at UCLA, Los Angeles, California; and.
authors.forename: Kalyanam
authors.initials: K
authors.lastname: Shivkumar
authors.affiliation: University of California, Los Angeles (UCLA) Cardiac Arrhythmia Center, David Geffen School of Medicine, Los Angeles, California; UCLA Neurocardiology Program, David Geffen School of Medicine at UCLA, Los Angeles, California; and mvaseghi@mednet.ucla.edu.
authors.forename: Marmar
authors.initials: M
authors.lastname: Vaseghi
mesh_terms: D000200:Action Potentials; D000818:Animals; D001794:Blood Pressure; D004699:Endocardium / Q000294:innervation / Q000502:physiology; D006339:Heart Rate; D010496:Pericardium / Q000294:innervation / Q000502:physiology; D013552:Swine; D014630:Vagus Nerve / Q000502:physiology*; D055536:Vagus Nerve Stimulation / Q000009:adverse effects; D016276:Ventricular Function
keywords: repolarization; vagal nerve stimulation; ventricle