How is heart rate calculated from an ECG strip?

The correct method of calculating heart rate from an ECG strip involves counting the number of R-R intervals in a 6-second section of the strip and then multiplying that number by 10. This approach provides a quick estimation of the heart rate. Since there are 60 seconds in a minute, counting the R waves over a 6-second period gives an accurate representation that can be extrapolated to one minute by multiplying by 10.

This is particularly useful in clinical settings where time is critical, and it allows for a straightforward calculation without needing to convert between different units. The R waves are chosen because they are prominent and easily identifiable on an ECG, making them a reliable reference point for counting.

While measuring the time between R waves in milliseconds (the first choice) could theoretically provide the heart rate, it requires additional calculations and isn't as direct or practical as the second choice. Determining the frequency of P waves and evaluating the total number of beats in one minute have their uses but do not align with the most efficient or direct method for obtaining a heart rate from an ECG strip specifically.