In sinus rhythm, the basic rate of impulses generated by the SA node is approximately how many beats per minute?

In sinus rhythm, the basic rate of impulses generated by the SA node is approximately how many beats per minute?

• A. 50
• B. 60
• C. 70
• D. 90

Answer: (C)

The basic rate at which impulses originate from the heart’s natural pacemaker—the SA node—is about 60–100 beats per minute. In a resting, healthy adult, autonomic tone usually settles this rate toward the mid-range, around 70 beats per minute. So, using about 70 bpm to describe normal sinus rhythm best reflects the typical resting heart rate seen in most people. Values much lower or higher at rest would suggest bradycardia or tachycardia, respectively, rather than a normal resting sinus rhythm.

The basic rate at which impulses originate from the heart’s natural pacemaker—the SA node—is about 60–100 beats per minute. In a resting, healthy adult, autonomic tone usually settles this rate toward the mid-range, around 70 beats per minute. So, using about 70 bpm to describe normal sinus rhythm best reflects the typical resting heart rate seen in most people. Values much lower or higher at rest would suggest bradycardia or tachycardia, respectively, rather than a normal resting sinus rhythm.