Modulation of heart rate by temporally patterned vagus nerve stimulation in the anesthetized dog. Issue 2 (26th January 2016)

• Record Type: Journal Article
• Authors: Yoo, Paul B.; Liu, Haoran; Hincapie, Juan G.; Ruble, Stephen B.; Hamann, Jason J.; Grill, Warren M.
• Is Part Of: Physiological reports. Volume 4:Issue 2(2016:Jan.)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2016-01-26
• Subjects: Bradycardia -- dog -- heart failure -- neuromodulation therapy -- temporal patterned stimulation -- vagus nerve stimulation; Physiology -- Periodicals; 571
• DOI: 10.14814/phy2.12689
• Languages: English
• ISSNs: 2051-817X

Abstract

Abstract: Despite current knowledge of the myriad physiological effects of vagus nerve stimulation (VNS) in various mammalian species (including humans), the impact of varying stimulation parameters on nerve recruitment and physiological responses is not well understood. We investigated nerve recruitment, cardiovascular responses, and skeletal muscle responses to different temporal patterns of VNS across 39 combinations of stimulation amplitude, frequency, and number of pulses per burst. Anesthetized dogs were implanted with stimulating and recording cuff electrodes around the cervical vagus nerve, whereas laryngeal electromyogram (EMG) and heart rate were recorded. In seven of eight dogs, VNS‐evoked bradycardia (defined as ≥10% decrease in heart rate) was achieved by applying stimuli at amplitudes equal to or greater than the threshold for activating slow B‐fibers. Temporally patterned VNS (minimum 5 pulses per burst) was sufficient to elicit bradycardia while reducing the concomitant activation of laryngeal muscles by more than 50%. Temporal patterns of VNS can be used to modulate heart rate while minimizing laryngeal motor fiber activation, and this is a novel approach to reduce the side effects produced by VNS. Abstract : Vagus nerve stimulation‐evoked bradycardia has been identified as an important biomarker for effective treatment of heart failure. We have shown in this preclinical study that very brief bursts of electrical pulses applied at the threshold for recruiting slow B‐fibers can effectively reduce heart rate while minimizing the activation of laryngeal muscles. We predict this novel pattern of nerve stimulation will improve the therapeutic efficacy of vagus nerve stimulation in heart failure patients.