This rhythm is often seen as a normal variation in athletes, during sleep, or in response to a vagal maneuver. If the bradycardia becomes slower than the SA node pacemaker, a junctional rhythm may occur.
P Waves present, constant, each constant P Wave is followed by a constant QRS complex (normal width - slim), constant intervals between QRS Complexes are equal, heart rate is < 60 BPM
This rhythm is most commonly seen with breathing due to fluctuations in parasympathetic vagal tone.
The clinical significance of this dysrhythmia depends on the underlying cause. It may be normal.