Inter- and intra-examiner reliability of short-term measurement of heart rate variability on rest in patients hospitalized with COVID-19

Abstract

Measures reflecting cardiac sympathovagal activity, particularly those associated with heart rate variability (HRV), are widely recognized and utilized in both scientific and clinical contexts. This study aimed to assess the inter- and intra-examiner reliability of short-term HRV parameters in patients hospitalized with coronavirus disease 2019 (COVID-19). A total of 103 patients (both sexes) diagnosed with COVID-19 were included in the study. HRV was analyzed using both linear and nonlinear methods. Reliability was evaluated through intraclass correlation coefficient (ICC_2.1), minimum detectable change (MDC), standard error of measurement (SEM), and coefficient of variation (CV). According to Fleiss' criteria, excellent reliability was demonstrated, with ICC values ranging from 0.970 to 0.999 for Examiner 1, and from 0.956 to 0.999, for Examiner 2. In the inter-examiner analysis, the ICCs of HRV parameters ranged from 0.972 to 0.999. SEM values for intra-examiner reliability for Examiner 1 ranged from 0.02 to 5.64, with MDC values from 0.05 to 15.64, and CV (%) from 0.28 to 8.04. For Examiner 2, SEM values ranged from 0.02 to 8.18, MDC values from 0.05 to 22.68, and CV (%) from 0.24 to 8.14. For inter-examiner reliability, SEM values ranged from 0.02 to 6.17, MDC from 0.06 to 17.11, and CV (%) from 0.34 to 9.81. Across all analyses, CVs for HRV parameters remained below 10%. Considering different time points and different examiners, short-term resting HRV measurements in patients hospitalized with COVID-19, as evaluated using a portable heart rate device, exhibit high reliability.

Keywords: COVID-19; Heart rate variability; Hospitalization; Reliability.

Fig. 1

Flowchart of patient screening and study design.

Fig. 2

Radar chart comparing intraclass correlation coefficients by assessing intra- and inter-examiner reliability.Mean RR: average R-R interval duration between heartbeats; ms: milliseconds; SDNN: Standard deviation of RR intervals; Mean HR: average heart rate; bpm: in beats per minute; RMSSD: root mean square differences of successive RR intervals; RR Tri: integral of the RR intervals histogram divided by the height of the histogram; LF: normalized unit in the low-frequency band; HF: normalized unit in the high-frequency band; SD1: standard-deviation of the instant beat-to-beat variability; SD2: long-term standard-deviation of continuous RR intervals; DFA α1: purified trend fluctuations (short-term scale); DFA α2: purified trend fluctuations (long-term scale); ApEn: approximate entropy; SampEn: sample entropy.