It depends.
Children often have second to second variations in their heartbeats due to respiratory affects on the centers that control heart rate. Sinus arrythmia is an example of this normal physiologic "irregular heart rate".
There certainly are many much more rare and dangerous causes of an irregular heart rate but in an asymptomatic 8 year old these are extremely unlikely. I would contact your pediatrician and discuss with him/her exactly what you mean by "irregular heart rate".
The normal heart rate range for a 4-month-old kitten is typically between 160-220 beats per minute.
The normal resting heart rate for children from 1 to 2 years old is 80 to 130 beats per minute.
An average normal heart rate for a 5 month old boy is 80 beats per minute. Pulse rates for a child sleeping can be 10% lower.
about 110-120 I think. Check with a pediatrician.
the normal heart rate is 70-110 but can differ from person to person
A rest and with a normal heart the HR ( Heart rate) is between 60 - 100 BPM
normal heart rate for an 86 year old woman
30
28
30
0-3 months: Heart rate=100-150bpm Respiratory Rate=35-55 Blood Pressure=65-85/45-55
Normal conditions: 30-45bpm