ECG: Junctional Rhythms

Question 1

When do junctional rhythms occur¿

Answer 1

When the electrical activation of the heart originates near or within the AV node instead of from the SA node.

Question 2

Since the normal ventricular conduction system (His-Purkinje) is used, is the QRS complex frequently broad or narrow¿

Answer 2

Narrow.

Question 3

Junctional rhythms normally slow (< 60 beats per minute)

When it’s faster than this, what is it called¿

Answer 3

An Accelerated Junctional Rhythm.

Question 4

P waves and junctional rhythms

Are they visible, and if so where p, and what is their appearance:

Answer 4

-Since the elecrical activation originates at or near the AV node, the P wave frequently is not seen.
-It
-If present, it can be
—buried within the QRS complex,
—slightly before the QRS complex or
—slightly after the QRS complex.

The morphology of the P wave will not be similar to the sinus P wave (
Frequently, the P wave is inverted in lead II if it can be seen at all.