What type of response and typical bpm does the AV node generate?

• A. Slow response, 40-60 bpm
• B. Slow response, 60-100 bpm
• C. Fast response, 30-40 bpm
• D. Fast response, 60-100 bpm

Answer: (A)

The AV node is a slow‑response pacemaker tissue, meaning its cells depolarize more slowly than the atrial/ventricular myocardium and rely on calcium for the action potential upstroke rather than sodium. This slow upstroke and automaticity give the AV node a lower intrinsic firing rate, about 40–60 beats per minute. In a healthy heart, the SA node drives at 60–100 bpm, and the AV node can take over at 40–60 bpm if the SA node fails. So the best description is a slow‑response mechanism with a rate of roughly 40–60 bpm. The other options conflict with the AV node’s slow-upstroke physiology or its typical intrinsic rate (the SA node is around 60–100 bpm, and a 30–40 bpm rate would reflect a ventricular/junctional escape rhythm rather than AV nodal pacing).