Table 1.

The ECG waveform features explored in this study

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