What is the inherent pacemaking rate of atrial foci?

What is the inherent pacemaking rate of atrial foci?

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

Answer: (C)

The inherent pacemaking rate of atrial foci is typically in the range of 60 to 80 beats per minute. This is important because the atria can serve as a secondary pacemaker when the primary pacemaker (the sinoatrial node) fails to initiate an impulse. Atrial foci are capable of generating impulses, but their firing rate is generally lower than that of the sinoatrial node, which functions at a rate of 60 to 100 beats per minute. Understanding this range is crucial for interpreting EKG rhythms, especially when assessing different types of arrhythmias or looking for escape rhythms. Recognizing that atrial foci can take over pacemaking function highlights the heart's ability to adapt to various physiological conditions.