How will this affect the appearance of the EKG if there is a blockage between the AV node and the AV bundle?

You should realize that when the AV nodal is blocked, this means that the ventricles and atria have been damaged. It is the AV node that is responsible for connecting the atria and the ventricles. When the AV nodes are blocked, there will be absent impulses that will be obvious through the EKG.

One thing to remember is that some people get the AV block often but this is not known to be fatal. It is important to note what degree of heart block the person is experiencing so that the proper treatments can be done. A second-degree heart block is known to be more serious than the first-degree heart block.