In the 6-second strip method, which statement is correct?

• A. Count 30 large squares and multiply by 2
• B. Count 15 large squares and multiply by 4
• C. Count 6 seconds by 10
• D. Count 30 small squares and multiply by 10

Answer: (D)

The key idea is to estimate heart rate quickly by using a 6-second ECG strip and converting the count of beats in that window to beats per minute. In a standard ECG strip, 6 seconds spans 30 large squares (0.2 seconds per large square). The practical rule is to count how many QRS complexes occur in that 6-second window and multiply by 10 to get bpm.

That makes the statement about counting 30 small squares and multiplying by 10 the best fit, because it ties the 6-second strip length to a simple multiplier to reach a per-minute rate. It reflects the same idea as counting beats in the 6-second window and scaling up to a minute.

The other options don’t align with this method, since they either imply the wrong multiplier or misstate what to count (they don’t describe counting heartbeats in the 6-second span).