Effects of spinal cord stimulation on heart rate variability in patients with Failed Back Surgery Syndrome

Abstract

Background Building on the recent finding that chronic pain patients with impaired functioning of the descending nociceptive inhibitory system (DNIS) present lower resting heart rate variability (HRV), this study aims to investigate the impact of Spinal Cord Stimulation (SCS) on HRV in patients with Failed Back Surgery Syndrome (FBSS). More precisely, we hypothesize that SCS influences the DNIS, with increased parasympathetic tone as a consequence, as measurable by HRV analysis. Methods Twenty-two patients diagnosed with FBSS and treated with SCS participated in this study. HRV was measured with a 2-lead ECG registration tool during on and off states of SCS. HRV analysis for time, frequency, time-frequency and nonlinear domain parameters was based on a 5-minute recording segment. Results The mean heart rate and low frequency power were significantly lower when SCS was activated. HRV, absolute and normalized high frequency power significantly increased during SCS compared to without SCS. The ratio of low frequency/high frequency ratios, as parameter for global sympathetic-parasympathetic equilibrium, significantly decreased when SCS was activated. Conclusions When SCS is switched off, patients with FBSS present relatively stronger sympathetic tone and weaker parasympathetic activity. Activation of the SCS, possibly via stimulation of the DNIS, restores this disbalance of autonomic activity.

Effects of Spinal Cord Stimulation on Heart Rate Variability in Patients With Failed Back Surgery Syndrome: Comparison Between a 2-lead ECG and a Wearable Device

“…Ratios > 1 are an estimate of sympathetic dominance while ratios < 1 are in favor of parasympathetic preeminence (34, 35). The authors refer to a previous reporting for more details regarding the preprocessing and analyses of the data (18).…”

“…The authors refer to a previous reporting for more details regarding the preprocessing and analyses of the data (18).…”

“…The goal of SCS is making chronic pain tolerable, whereby benefits can be expected on functionality and health‐related quality of life (15–17). Previous studies already revealed that SCS may influence the autonomic nervous system (18, 19). More specifically, a reduced cardiac sympathetic activity during SCS can be observed (20–22).…”

Mediation of Cardiac Macrophage Activity via Auricular Vagal Nerve Stimulation Ameliorates Cardiac Ischemia/Reperfusion Injury

“…Despite not being widely recognized, the functionality of neurons in the cervical dorsal horn can also be observed in autonomic control of the cardiovascular system (Todd, 2010). In fact, spinal cord stimulation (SCS) at the lumbar region has been linked with increased vagal tone measured from HRV in patients with severe pain (Goudman et al, 2019). In addition, lumbar SCS demonstrated α7nAChR-mediated microglia inhibition in rabbits with spinal cord ischemia injury (Li H. et al, 2019).…”

Exhaled-Breath Testing Using an Electronic Nose during Spinal Cord Stimulation in Patients with Failed Back Surgery Syndrome: An Experimental Pilot Study

“…The exact mechanisms of SCS are not yet fully elucidated; however, several working mechanisms and hypotheses have been proposed on spinal, segmental and supraspinal level [6,7]. Additionally, during the latest years it is assumed that SCS induces alterations in the autonomic nervous system with an upregulation of the parasympathetic system, based on heart rate variability, respiration, and skin conductance measurements [8,9]. In the field of neuromodulation, and in chronic pain trials in general, patient-reported outcomes are still the primary choice to serve as outcome measurements [10].…”