What is the typical heart rate range for the AV node when acting as pacemaker?

What is the typical heart rate range for the AV node when acting as pacemaker?

• A. 60-100 bpm
• B. 40-60 bpm
• C. 20-40 bpm
• D. 80-120 bpm

Answer: (B)

The main concept is that the AV node can act as a backup pacemaker, and its intrinsic rhythm is slower than the SA node. When the SA node isn’t driving the heart or there’s a block preventing atrial conduction, the AV node can take over with a slower escape rhythm of about 40–60 beats per minute. This slower rate reflects its automaticity and its role as a secondary pacing focus, still maintaining enough cardiac output in many cases. The numbers in other ranges correspond to other pacing sites: the SA node normally paces about 60–100 bpm, and the ventricular escape rhythm is even slower, around 20–40 bpm. An 80–120 bpm rate would not be the typical AV nodal pacing rate.

The main concept is that the AV node can act as a backup pacemaker, and its intrinsic rhythm is slower than the SA node. When the SA node isn’t driving the heart or there’s a block preventing atrial conduction, the AV node can take over with a slower escape rhythm of about 40–60 beats per minute. This slower rate reflects its automaticity and its role as a secondary pacing focus, still maintaining enough cardiac output in many cases. The numbers in other ranges correspond to other pacing sites: the SA node normally paces about 60–100 bpm, and the ventricular escape rhythm is even slower, around 20–40 bpm. An 80–120 bpm rate would not be the typical AV nodal pacing rate.