The effect of COVID-19 infection on heart rate variability: A cross-sectional study

IntroductIonHeart rate variability (HRV) is a physiological phenomenon indicating the variation in the time intervals between consecutive heartbeats referred to as beat-to-beat intervals.HRV measurement is a non-invasive procedure commonly used to evaluate the effects of the autonomic nervous system (ANS) on heart rate (HR).[1] Non-invasive HRV measurement methods are divided into four main categories: time domain, spectral or Introduction and Objectives: Heart rate variability (HRV) measurement is a non-invasive procedure used to evaluate autonomic nervous system (ANS) activity.We aimed to investigate the coronavirus disease 2019 (COVID-2019) infection effects on time-domain and frequency-domain HRV parameters to determine COVID-19 effects on the ANS.Materials and Methods: From the registry of the COVID-19 outpatient clinics between July 2020 and October 2021, 6127 patients with polymerase chain reaction (PCR) results positive for COVID-19 in real-time PCR (RT-PCR) test were obtained.Eighty-seven patients with at least 24 h of Holter electrocardiogram (ECG) recording with at least 90% normal-normal interval analysis referred to as the first Holter ECG analysis.Those patients underwent follow-up for the second Holter ECG analysis within 3 months following the first positive RT-PCR tests.The HRV time and frequency domain parameters by means of six standard time domain measures: standard deviation (SD) of all normal sinus RR intervals over 24 h (SDNN), mean of the SDs of all normal sinus RR intervals for all 5-min segments (SDNN index), root-mean-square of successive normal sinus RR interval difference (rMSSD), low-frequency (LF) band, high-frequency (HF) band, and LF/HF ratios were recorded from both the first and second Holter ECG analyses.Moreover, the third Holter ECG analysis was planned for patients if any statistically significant differences were observed among the first and the second Holter ECGs.Results: After COVID-19 infection with the second Holter ECG analysis, we found a significant decrease in SDNN, SDNN index, and a significant increase in LF/HF ratio (P < 0.05).Moreover, with the third Holter ECG analysis, which was performed in 48 of the 87 patients after 3 months following the second Holter ECG analysis, we have shown that those decreases in SDNN and SDNN index were reversed, and we found a significant increase in LF band and a non-significant decrease in LF/HF ratio (P = 0.052). Conclusion:The reversal in the changes of HRV parameters that occurred within the first 3 months following COVID-19 diagnosis may be an indicator of acute autonomic dysfunction due to COVID-19 infection.