Altered heart rate variability and pulse-wave velocity after spinal cord injury

Abstract

Background: Heart rate variability (HRV) and pulse-wave velocity (PWV), indicators of cardiac function, are altered in patients with spinal cord injury (SCI), suggesting that autonomic cardiac function and arterial stiffness may underlie the high risk of cardiovascular complications in these patients. No study has simultaneously investigated HRV and PWV in the same patients.

Aim: To evaluate cardiovascular complications in SCI patients by comparing HRV and PWV between patients with and without SCI.

Methods: In this cross-sectional pilot study, patients with (n = 60) and without SCI (n = 60) were recruited from December 7, 2019 to January 21, 2020. Each participant received a five-minute assessment of HRV and the cardiovascular system using the Medicore HRV Analyzer SA-3000P. Differences in HRV and PWV parameters between participants with and without SCI were statistically examined.

Results: We observed a significant difference between participants with and without SCI with respect to the standard deviation of all normal-to-normal intervals, square root of the mean sum of squared successive risk ratio interval differences, physical stress index, total power, very-low frequency, low frequency, high frequency, and arterial elasticity.

Conclusion: Patients with SCI have weaker sympathetic and parasympathetic activity as well as lower arterial elasticity compared to those without, suggesting that SCI may increase cardiac function loading.

Keywords: Acceleration plethysmography; Cardiac function; Heart rate variability; Pulse wave velocity; Spinal cord injury.

Figure 1

Pulse wave velocity waveform. a: Basic point to evaluate autologous platelet-rich gel wave form; b: Cardiac constriction power (cardiac output)-the deeper (-) value is better shape; c: Arterial elasticity-higher (+) value is better; d: Remaining blood volume-higher value, smaller (-) value is better.