Estimation of Heart Rate from the Electrocardiogram (ECG)
     

Overview :

The heart rate can be calculated from the ECG strip since it is printed at a constant speed.

For regular rhythm, the heart rate can be calculated by:

1) divide the number of 0.4 second time lines (1 mm) in a P-P or R-R interval into 1500.

2) divide the cycle length (time between peaks of 2 successive P or R waves) expressed in seconds into 60.

If the heart rate is irregular, measure several R-R intervals:

1) number of 0.4 second lines over the intervals

2) count the number of R-R intervals

3) divide #1 by #2 to get an average interval

4) divide #3 into 1500

  References:

Friedman HH. Diagnostic Electrocardiography and Vectorcardiography. McGraw-Hill Book Co. 1985. pages 80-81, pages 634-635