Table 1.
The 110 features extracted from PPG, VPG (first derivative or velocity of PPG), APG (second derivative or acceleration of PPG), and PRV (pulse rate variability).
| PPG | Interval | 1: T (time span of the pulse) | 6: PPT (interval between the systolic [S] and diastolic peaks [D]) |
| 2: T1 (rising time of the pulse) | 7: T1/T | ||
| 3: T2 (systolic time of the pulse) | 8: T2/T (the same as T3/T) | ||
| 4: T3 (diastolic time of the pulse) | 9: PW/T | ||
| 5: PW (pulse width corresponding to the midpoint of the rising phase) | 10: PPT/T | ||
| Area | 11: A1 (area of systolic phase) | 14: IPA: A2/A1 (diastolic area/systolic area) | |
| 12: A2 (area of diastolic phase) | 15: A1/A | ||
| 13: A (A1 + A2, area of the pulse) | |||
| Height | 16: H1 (height of the systolic peak) | 19: H2/H1 | |
| 17: H2 (height of the dicrotic wave) | 20: RI: H3/H1 | ||
| 18: H3 (height of the diastolic peak) | |||
| Slope | 21: RS (H1/T1) | 22: FS (H1/(T–T1)) | |
| 23–44: Std of 1–22. | 45–66: Rmssd of 1–22. | ||
| Other features | 67: TWa: area of tidal wave (TW) | 69: TWvt: product of TWv and TWt | |
| 68: TWP: power of TW | 70: TWst: stress index | ||
| 71–74: Std of 67–70. | 75–78: Rmssd of 67–70. | ||
| 79: TPcar: total power of cardiac component | 80: TPres: total power of respiratory component | ||
| VPG and APG | Height | 81: Hw (height of w point in VPG) | 85: He (height of e point in APG) |
| 82: Hz (height of z point in VPG) | 86: Hb/Ha | ||
| 83: Ha (height of a point in APG) | 87: He/Ha | ||
| 84: Hb (height of b point in APG) | 88: (Hb–He)/Ha | ||
| 89–96: Std of 81–88. | 97–104: Rmssd of 81–88. | ||
| PRV | 105: LF (low frequency power of PRV) | 108: nLF (LF/(LF+HF)) | |
| 106: HF (high frequency power of PRV) | 109: LF/HF | ||
| 107: TP (total power of PRV) | 110: SampEn: sample entropy of pulse rate |
VPG, first derivative or velocity of PPG; APG, second derivative or acceleration of PPG; PRV, pulse rate variability; Std, standard deviations; Rmssd, root mean square of the successive difference; PW, pulse width corresponding to the midpoint of the rising phase; PPT, peak to peak interval between the systolic and diastolic peaks; IPA, inflection point area ratio; TW, tidal wave; RS, rising slope of PPG; FS, falling slope of PPG.