I believe it is "Secondary"
Answer:
<em><u>"The number of squares between each QRS complex and multiplying by 40 milliseconds. Gives you the cycle length of a patient's heart rate. You then divide 60,000."</u></em>
Answer: I think it's D
Explanation: idk I just feel like it's right. If it's not don't come for me
The answer is in the picture
