Final answer:
To calculate heart rate from an irregular rhythm ECG, count the number of QRS complexes in a 6-second interval and multiply by 10. This method provides a heart rate in bpm that accounts for the irregularity.
Step-by-step explanation:
To calculate the heart rate from an ECG strip when the rhythm is irregular, a longer strip (e.g., a 6-second interval) should be analyzed. Start by marking a starting point on a specific R wave, count the number of QRS complexes within the 6-second frame, and then multiply by 10 to get the beats per minute (bpm). This method accommodates the variability of the irregular rhythm by sampling over a more extensive period.
For example, if you count 7 QRS complexes in a 6-second strip, the heart rate would be 70 bpm (7 x 10 = 70 bpm). An irregular heart rhythm, such as arrhythmia, can produce variations in the frequency of the heartbeats, making standard calculations over shorter periods less accurate. Therefore, using a longer ECG strip for the calculation is crucial.