Heart Rate

Regular rhythms (constant R-R interval)

• 300, 150, 100, 75, 60, 50, 43, 37, 33...

• Atrial rate (bpm) = 300/# of large boxes between P waves

• Ventricular rate (bpm) = 300/# of large boxes between R waves

  • • If not a whole number, estimate it or calculate as: 1500/# of small boxes

Irregular or slow rhythms

• Count the number of QRS complexes that appear in 6 seconds (2 consecutive 3-second markers) X 10

• Count the number of QRS complexes that appear in 10 seconds X 6