Table 3.
Long-term impact of COVID-19 on heart rate variability.
| Study | Time Domain | Frequency Domain | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| SDNN (ms) |
RMSSD (ms) |
pNN50 (%) |
SDANN (ms) |
SDNN Index (ms) |
Triangular Index | Mean HRV (ms) | VLF (ms2) |
LF (ms2) |
LF (nu) |
HF (ms2) |
HF (nu) |
LF/HF Ratio | Total Power (ms2) |
|
| Individuals with long COVID vs. healthy controls (vs. post-COVID-19 individuals without long COVID) | ||||||||||||||
| Acanfora 2022 [38] * | − | NS | NS | − | − | − | NS | − | + | − | ||||
| Aranyó 2022 [39] * | D: −, N: − (D: −, N: NS) | − (−) | − (NS) | − (NS) | + (NS) | |||||||||
| Marques 2022 [44] | − | + | NS | NS | NS | |||||||||
| Post-COVID-19 individuals without long COVID vs. healthy controls | ||||||||||||||
| Asarcikli 2022 [40] * | + | + | + | + | + | NS | + | − | NS | |||||
| Aranyó 2022 [39] * | D: −, N: NS | − | − | − | NS | |||||||||
| Individuals whose presence of long COVID is uncertain vs. healthy controls | ||||||||||||||
| Adler 2021 [37] | − | − | − | |||||||||||
| Freire 2022 [41] | − | − | NS | NS | NS | NS | NS | |||||||
| Kurtoğlu 2022 [42] * | − | − | − | − | − | − | − | − | NS | − | − | |||
| Liu 2021 [43] | − | − | − | − | ||||||||||
| Mekhael 2022 [45]; Dagher 2022 [48] |
− | |||||||||||||
| Shah 2022 [46] | − | |||||||||||||
| Zanoli 2022 [47] | NS | NS | ||||||||||||
Abbreviations. COVID-19, coronavirus disease 2019; D, daytime; ECG, electrocardiogram; HF, high-frequency band; HRV, heart rate variability; LF, low-frequency band; N, nighttime; NS, not significant; nu, normalized unit; pNN50, proportion of the number of pairs of successive normal-to-normal RR intervals that differ by more than 50 milliseconds divided by the total number of normal-to-normal RR intervals; RMSSD, root mean square of the successive differences; SDANN, standard deviation of the averages of normal-to-normal RR intervals; SDNN, standard deviation of normal-to-normal RR intervals; VLF, very low-frequency band. Note: ‘+’ means a statistically significant increase compared to the control, while ‘−’ means a statistically significant decrease compared to the control. ‘*’ indicates a study in which HRV was recorded using 24-h ECG monitoring.