Junctional rhythm

Junctional rhythm describes an abnormal heart rhythm resulting from impulses coming from a locus of tissue in the area of the atrioventricular node, the "junction" between atria and ventricles.

Under normal conditions, the heart's sinoatrial node determines the rate by which the organ beats - in other words, it is the heart's "pacemaker." The electrical activity of sinus rhythm originates in the sinoatrial node and depolarizes the atria. Current then passes from the atria through the bundle of His, from which it travels along Purkinje fibers to reach and depolarize the ventricles. This sinus rhythm is important because it ensures that the heart's atria reliably contract before the ventricles.