Usual paper speed is 25mm/sec so 1mm (small block) = 0.04 sec, and 5mm (big block) = 0.2 sec.
Calculate atrial and ventricular rates separately if different.
Many methods to estimate the rate, for example: measure the R‐R interval in seconds and divide 60 by the R‐R interval.
Resting heart rate varies with age:
Newborn: 110 – 150 bpm
2 years: 85 – 125 bpm
4 years: 75 – 115 bpm
6 years+: 60 – 100 bpm
