Heart Rate Calculator Methods

Question 1

6 second count method

Answer 1

Calculate HR by determining number of R-R intervals (cardiac cycles) in a 6-second interval and multiple by 10
If premature beats are present they should be included in the count.
This method is an approximation and although simplest, and fastest it is the least accurate.

Question 2

R-R Interval
Method 1
Counting seconds between peaks

Answer 2

Measure distance in seconds between the peaks of two (2) consecutive R waves and divide this number into 60 to obtain HR

60/X=HR
60/0.68=88
60/1.60=37.5 (38 rounded)
60/0.36=167

Question 3

Method 2:

Counting large squares

Answer 3

Count large squares (0.20 sec spaces) between the peaks of two (2) consecutive R waves and divide this number into 300 to obtain the HR

300/X=HR
300/3.1=97
300/8.4=36
300/1.2=250

Question 4

Method 3:

Count small squares between peaks

Answer 4

Count small squares (0.04 sec spaces) between the peaks of two (2) consecutive R waves and divide by 1500

1500/X=HR
1500/17=88
1500/9=167
1500/50=30

Question 5

Method 4:

Count small squares and use rate conversion table

Answer 5

Count the small squares (0.04 sec spaces) between two (2) consecutive R waves and, using a rate conversion table.
Convert the number of small squares into the heart rate.
Example 17 small squares = 88 bpm

Question 6

Triplicate Method:

Only useful if rhythm is regular

Answer 6

BPM is determined as follows:
1) Sélect an R wave that lines up with a dark vertical line and label it ‘A’
2) Number the next 6 dark vertical lines consecutively from left to right “300,” “150,” “100,” “75,” “60,” and “50”.
These numbers represent the BPM
3) Identify 1st R wave to the right of R wave labelled ‘A’, and label this R wave ‘B’
4) Identify the numbered dark vertical lines on either side of the wave labelled ‘B’
5) Estimate the distance of the R wave labelled ‘B’ from the nearest of the two (2) adjacent numbered dark vertical lines with respect to the total distance between them.
6) Estimate the HR by equating the estimated distance of the R wave labelled ‘B’ from the nearest adjacent numbered, dark vertical line to BPM.

Question 7

Another quick way to calculate the rate is based on the fact that the entire ECG is 10 seconds.
A) Explain how to do this

Answer 7

A) The fact that the entire ECG is 10 seconds.
So by counting the number of QRS complexes and multiplying
by 6, the number per minute can be calculated
(since 10 seconds times 6 is 60 seconds or 1 minute).

This is a better method when the QRS complexes are irregular,
since the RR intervals may vary from beat to beat in this setting.