0552 Analysis of Autonomic Activity After Continuous Positive Airway Pressure Therapy Using Heart Rate Spectral Analysis

Introduction Obstructive sleep apnea (OSA) is estimated to affect 29.5 million people living in the United States. OSA patients experience repeated airway occlusions leading to numerous episodes of apnea nightly, increasing their risk for heart disease, stroke, and diabetes. Patients benefit from CPAP because it restores processes that promote recuperation of the autonomic nervous system (ANS). Several studies have investigated the health consequences using different measurements of ANS activity like heart rate variability (HRV). HRV can be analyzed using frequency domains such as the low-frequency (LF) to high-frequency (HF) ratio, or with time domains like the exhalation to inhalation (E:I) ratio. HF and exhalation are associated with parasympathetic activity, while LF and inhalation are associated with sympathetic activity. Here, we aimed to better understand the relationship between ANS activity in OSA CPAP-compliant versus CPAP non-compliant patients using HRV analysis. We hypothesized that compliant patients will have lower LF/HF ratios and greater E:I ratios compared to noncompliant patients during various ANS test maneuvers. Methods OSA patients were divided into CPAP-compliant (n= 20) and non-compliant groups (n= 18). Patients had to have been CPAP compliant for at least 8 weeks. HRV was determined using a wireless ECG device and IntelleWave HRV Analyzer software. Data was collected while patients were supine, sitting upright, performing a Valsalva maneuver with handgrip, and deep breathing. Results Significant differences in the LF/HF ratio were found between groups when patients were supine (p< 0.001), standing (p< 0.001), and during normal breathing (p< 0.006). No significant difference was found between groups when performing the Valsalva maneuver. A significant difference in E:I ratios was observed only during deep breathing, 1.36±.15 in CPAP non-compliant patients versus 1.59±.24 in CPAP compliant patients; t (36) = -3.578, p < .001. Conclusion A greater restoration of sympathovagal activity was observed during activities with a parasympathetic predominance (lying down, standing, and normal breathing) compared to maneuvers requiring significant physiological effort (Valsalva maneuver) following CPAP therapy. This suggests a greater duration of CPAP therapy may be required to restore autonomic balance during strenuous activities. Support (if any)