Regularity: R-R intervals change, although there is usually a pattern. Typically the pattern will follow the patient's respiratory rate. R-R interval will decrease when the pt. inhales, and increase as the patient exhales.
Rate: The rate is between 60 and 100 beats/min.
P WAVE: There is one p wave in front of every QRS. The P waves appear uniform.
PRI: Measures between 0.12 and 0.20 seconds in duration. PRI is consistent.
QRS: Measures less than 0.12 seconds.