By counting the number of QRS complexes and multiplying by six , the number per minute can be calculated — because 10 seconds times six equals 60 seconds, or 1 minute. This is a better method when the QRS complexes are irregular, as during atrial fibrillation, in which case the RR intervals may vary from beat to beat.
Read moreHow do you calculate atrial rate?
To determine atrial rate, count the number of P waves in 6 seconds and multiply by 10 . To determine the ventricular rate, count the number of QRS complexes in 6 seconds and multiply by 10. Rates greater than 100 beats per minute (bpm) are considered tachycardia. Rates slower than 60 bpm are considered bradycardia.
Read more