Final answer:
To calculate the heart rate from an ECG strip with a regular rhythm, use the 300-method by counting the number of large squares between QRS complexes and dividing 300 by that number for beats per minute estimate. The 300-method is suitable when the ECG paper speed is standard (25mm/sec).
Step-by-step explanation:
To calculate the heart rate from an ECG strip when the rhythm is regular, you need to determine the number of QRS complexes that occur within a specific time frame, usually one minute. On an ECG strip, the small squares typically represent 0.04 seconds, and the larger squares represent 0.20 seconds (5 small squares). There are multiple ways to calculate the heart rate, but let's use the 300-method, which is a quick and easy way to estimate heart rate when the ECG paper speed is the standard 25mm/sec.
To use the 300-method:
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- Identify a QRS complex that lines up with a thick line on the ECG paper.
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- Count the number of large squares to the next QRS complex.
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- Divide 300 by the number of large squares between the QRS complexes.
For example, if there are 5 large squares between QRS complexes, 300 divided by 5 equals a heart rate of 60 beats per minute (bpm).
It's important to note that if the rate is extremely fast or the rhythm is irregular, other methods like the 1500-method or calculating the exact time interval between heartbeats in seconds and converting to bpm might be more accurate.