ECG Strip Heart Rate Calculator
Result:
Understanding ECG Heart Rate Calculation
Calculating heart rate from an electrocardiogram (ECG) strip is a fundamental skill in cardiac monitoring. The heart rate is determined by the time between consecutive R waves (the tallest peak in the QRS complex), which represent ventricular depolarization.
There are several methods to calculate heart rate from an ECG strip, but a common and accurate one involves measuring the R-R interval (the time between two successive R waves).
The Formula:
The most straightforward method, especially when you know the R-R interval in seconds, is:
Heart Rate (bpm) = 60 / R-R Interval (in seconds)
This formula works because there are 60 seconds in a minute. By dividing 60 by the time it takes for one heartbeat (the R-R interval in seconds), you get the number of heartbeats that would occur in one minute, which is the heart rate in beats per minute (bpm).
Alternatively, if you know the ECG paper speed (typically 25 mm/sec or 50 mm/sec), you can count the number of small or large boxes between R waves and use a corresponding formula. For a standard paper speed of 25 mm/sec:
- Using Small Boxes: Heart Rate = 1500 / Number of Small Boxes between R-R waves
- Using Large Boxes: Heart Rate = 300 / Number of Large Boxes between R-R waves
Our calculator uses the R-R interval in seconds for direct calculation, which is often the most precise method if the interval is accurately measured.
Example:
If the R-R interval measured on the ECG strip is 0.75 seconds, the heart rate would be:
Heart Rate = 60 / 0.75 = 80 bpm
If the strip speed was 25 mm/sec and there were 3 large boxes between R waves, the calculation would be:
Heart Rate = 300 / 3 = 100 bpm
Accurate measurement of the R-R interval or the number of boxes is crucial for a correct heart rate determination.