While analyzing a patient's EKG, the nurse notes that there are four small boxes from the beginning of the P wave to the beginning of the R wave. The PR interval is:
Explanation
• On standard EKG paper, each small box represents 0.04 second on the horizontal axis (time) and 1 mm on the vertical axis (voltage)
• 0.04 second x 4 boxes = 0.16 second