SDNN
|
ms
|
Standard deviation of all NN intervals
|
total variability
|
RMSSD
|
ms
|
Square root of the mean of the sum of the squares of differences between adjacent NN intervals
|
short-term variability
|
NN50 count
| |
Number of pairs of adjacent NN intervals differing by more than 50 ms in the entire recording
|
spontaneous variability
|
pNN50
|
%
|
NN50 count divided by the total number of all NN intervals
|
spontaneous variability
|
LF
|
ms2
|
Power in low frequency range (≤ 0.04 Hz)
|
sympathetic and parasympathetic, but predominantly sympathetic
|
HF
|
ms2
|
Power in high frequency range (0.15–0.4 Hz)
|
parasympathetic
|
LF nu
| |
LF power in normalised units LF/(Total Power–VLF) × 100
|
sympathetic and parasympathetic, but predominantly sympathetic
|
HF nu
| |
HF power in normalised units HF/(Total Power–VLF) × 100
|
parasympathetic
|
LF/HF
| |
Ratio LF [ms2]/HF [ms2]
|
sympathetic and parasympathetic
|
TP
|
ms2
|
Total performance or total spectrum; corresponds to energy density between 0.00001 to 0.4 Hz
|
total variability
|
SD1
|
ms
|
Standard deviation of instantaneous beat-to-beat variability, extracted from Poincaré Plot
|
parasympathetic
|
SD2
|
ms
|
Standard deviation of the long-term variability, extracted from Poincaré Plot
|
sympathetic and parasympathetic
|