Junctional rhythm

Conventionally, junctional rhythm has been divided into high junctional, mid junctional and low junctional rhythms. High junctional and low junctional rhythms have visible inverted P waves in inferior leads: preceding the QRS in the former and after the QRS in the latter. In mid junctional rhythm the P waves are not visible, being buried within the QRS due to simultaneous activation of the atria and the ventricles. QRS is narrow and the QRS morphology is normal in junctional rhythm. Junctional rhythm can be a manifestation of sick sinus syndrome. Junctional rhythm is often associated with regular cannon waves in the jugular venous pulse as the right atrium contracts against a closed AV valve.