Could any expert explain what a junctional rhythm is? Thanks!

Junctional rhythm. The "AV junction" is a connection that the electrical signal passes through from the top of the heart to the bottom. It acts as a back-up pacemaker when the hearts normal pacemaker stops working. Thus, a Junctional rhythm is a back-up rhythm that keeps your heart beating. It's typically slower than normal and less responsive to activity. Many times an artificial pacemaker is required. See PCP.
Rhythm. Sinus rhythm means activation of heart beat is activated by natural pacemaker Junctions rhythm is activated lower from the middle of heart, a-v node or lower.