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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