Question

What is the method for calculating heart rate using the small box method?

1) Counting the number of small boxes between two consecutive waveforms (R-R interval or P-P interval) and dividing it into 100
2) Counting the number of small boxes between QRS complexes and dividing it into 100
3) Counting the number of large boxes between two consecutive waveforms (R-R interval or P-P interval) and dividing it into 100
4) Counting the number of large boxes between QRS complexes and dividing it into 100

Answer 1

To calculate heart rate using the small box method on an ECG, count the number of small boxes between R waves and divide 1500 by this number to get beats per minute.

Step-by-step explanation:

The method for calculating heart rate using the small box method on an electrocardiogram (ECG) is by counting the number of small boxes between two consecutive R waves (representing a full heartbeat in the QRS complex) and dividing 1500 by this number. This approach makes use of the fact that each small box on an ECG represents 0.04 seconds. Thus, if you know the number of boxes between R waves, you can calculate the time between beats and, subsequently, the heart rate per minute. To illustrate this method, consider that there are 25 small boxes between the R peaks of two consecutive QRS complexes on an ECG printed at the standard speed of 25 mm/s. You would calculate the heart rate as follows: 1500 divided by 25 equals 60 beats per minute.