What is the firing rate of the atria?

The firing rate of the atria typically falls within the range of 60 to 100 beats per minute (bpm). This rate is associated with the activity of the atrial pacemaker cells, particularly the sinoatrial (SA) node, which is known as the natural pacemaker of the heart. The SA node initiates the electrical impulses that trigger the heartbeat, promoting coordinated contractions of the atria and ultimately leading to efficient blood flow into the ventricles.

While lower ranges such as 40-60 bpm or 20-40 bpm might represent the firing rates of other intrinsic pacemakers like the atrioventricular (AV) node or the bundle of His under certain circumstances, these would not be the normal firing rate specifically associated with the atrial pace set by the SA node. Rates above 100 bpm may be related to conditions like sinus tachycardia but are not considered the normal firing rate for the atria in steady-state physiology. Thus, the most accurate representation of the atrial firing rate is indeed 60-100 bpm.