A client has a heart rate of 78 beats per minute. Which node is most likely to produce this heart rate?

Question

1. Atrioventricular (AV) node
2. Internodal pathway
3. Sinoatrial (SA) node
4. Purkinje fibers

Answer 1

Correct Answer: 3
Rationale 1: The AV node has the ability to spontaneously generate action potentials and continue the heart's contraction at a rate of 40–60 beats per minute.
Rationale 2: The internodal pathways carry action potentials from the SA node to the AV node.
Rationale 3: The SA node generates a new action potential approximately 75 times per minute.
Rationale 4: Purkinje fibers can continue to generate myocardial contractions at a rate of 30 beats per minute.
Global Rationale: The SA node generates a new action potential approximately 75 times per minute. The AV node has the ability to spontaneously generate action potentials and continue the heart's contraction at a rate of 40–60 beats per minute. The internodal pathways carry action potentials from the SA node to the AV node. Purkinje fibers can continue to generate myocardial contractions at a rate of 30 beats per minute.