Which heart rate range is NOT associated with junctional escape rhythm?

A junctional escape rhythm typically occurs when the SA node fails to initiate impulses, allowing the atrioventricular (AV) junction to take over as the pacemaker of the heart. This can occur at a heart rate generally within the range of 40 to 60 beats per minute (bpm), which reflects the intrinsic pacing ability of the AV junction.

As the SA node is not functioning optimally, junctional rhythms prevent the heart rate from venturing significantly higher. Although it is possible for junctional escape rhythms to be slightly higher, typically they do not exceed 60 bpm for a reliable junctional escape rhythm.

The heart rate interval of 60 to 70 bpm is sometimes observed in junctional escape rhythms, especially if the junction has more enhanced automaticity or during temporary compensatory mechanisms. However, when reaching heart rates above 70 bpm, a junctional escape rhythm becomes less likely. At rates of 80 to 90 bpm, the presence of a junctional escape rhythm is generally indicative of a shift away from junctional pacing towards other mechanisms like ectopic atrial rhythms or enhanced activity of the SA node.

Thus, the range encompassing 70 to 80 bpm is considered outside the characteristic heart rate commonly associated with junction