Junctional rhythm 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 atrioventricular node and into the bundle of His, from which it travels along Purkinje fibers to reach and depolarize the ventricles. This
Sinoatrial block lengthening of conduction time from the SA node to the atria. The p-cells in the centre of the node produce the rhythm at a regular rate, but their conduction across the node to where it meets atrial tissue is where the slowing occurs. A second degree type II, or sinus exit block, is a regular rhythm that may be normal or slow. It is followed by a pause that is a multiple of the P-P interval usually (2-4) . Conduction across the SA node is normal until the time of the pause when it is blocked. A third degree sinoatrial