Table 4.

The physiologic features of a normal ECG signal.

Phase	Description	Duration/Amplitude
P	The first upwards wave of the ECG	<80 ms
RR	The time interval between RR peaks	0.6–1.2 s
PR	The time between the P and the R wave	120–200 ms
QRS	The time between Q and S beats	80–120 ms
ST	The time between S and T beats	320 ms