Table 1 The ECG waveform features explored in this study
From: Lying position classification based on ECG waveform and random forest during sleep in healthy people
No. | Features | Meaning | Orientation |
|---|---|---|---|
1 | QT interval | Interval between Q peak and T end | Horizontal |
2 | RR interval | Interval between contiguous R peak | Horizontal |
3 | PR inter | Interval between P begin and QRS begin | Horizontal |
4 | PR segment | Segment between P end and QRS begin | Horizontal |
5 | ST inter | Interval between QRS end and T end | Horizontal |
6 | ST segment | Segment between QRS end and T begin | Horizontal |
7 | RT slope | Slope of the line between R peak and T peak | Double |
8 | P wide | Wide between P begin and P end | Horizontal |
9 | QS wide | Wide between Q peak and S peak | Horizontal |
10 | T wide | Wide between T begin and T end | Horizontal |
11 | TP segment | Segment between T end and next P begin | Horizontal |
12 | P peak | Amplitude of P peak | Vertical |
13 | R peak | Amplitude of R peak | Vertical |
14 | T peak | Amplitude of T peak | Vertical |
15 | T area | Area under T wave | Double |
16 | Rp-Tp x | Wide between R peak and T peak | Horizontal |
17 | Rp-Tp y | The difference of amplitude between R and T | Vertical |
18 | Tp-Te | Wide between T peak and T end | Horizontal |
19 | QR | Difference of amplitude between Q and R | Vertical |
20 | RS | The difference of amplitude between R and S | Vertical |
21 | QRS area | Area under QRS wave | Double |
22 | S peak | Amplitude of S peak | Vertical |
23 | RS slope | Slope of the line between R peak and S peak | Double |
24 | S/R | Amplitude ratio of S and R | Vertical |
25 | T/R | Amplitude ratio of T and R | Vertical |
26 | Ta/QRSa | Area ratio of T area and QRS area | Double |
27 | QRSa–Ta | Area difference of T area and QRS area | Double |
28 | ST slope | Slope of the line between J point and T begin | Double |
29 | QTc | Corrected QT interval | Horizontal |
30 | Angle qsr | Angle of ∠QSR | Double |