Main job of upper threshold and upper threshold duration is:

Main job of upper threshold and upper threshold duration is:

• A. Cover up the T wave
• B. Detect the P wave
• C. Expand QRS
• D. Reduce baseline wander

Answer: (A)

In QRS detection, you want to avoid miscounting the T wave as a separate beat after the QRS. The upper threshold sets a high-amplitude criterion for triggering, and the upper threshold duration creates a short blanking interval after a detection. This window effectively covers up (masks) the T wave so it cannot trigger another detection, keeping the count accurate. It also helps prevent double counting from post-QRS activity. It isn’t about expanding the QRS, detecting the P wave, or reducing baseline wander—those are handled by other parts of the system.

In QRS detection, you want to avoid miscounting the T wave as a separate beat after the QRS. The upper threshold sets a high-amplitude criterion for triggering, and the upper threshold duration creates a short blanking interval after a detection. This window effectively covers up (masks) the T wave so it cannot trigger another detection, keeping the count accurate. It also helps prevent double counting from post-QRS activity. It isn’t about expanding the QRS, detecting the P wave, or reducing baseline wander—those are handled by other parts of the system.