Chapter 7-Junctional Dysrhythmias

Question 1

Define AV junction

Answer 1

AV node and surrounding tissue, including the bundle of His

Question 2

Describe Junctional Rhythms

Answer 2

Rhythms that are a result of electrical impulses coming from the AV junction rather than the SA Node

Question 3

What happens to the P wave in junctional Dysrhythmias

Answer 3

P wave is inverted and occurs before, during (hidden or buried), or after the QRS
Complex

Question 4

When the P wave occurred before the QRS complex, where did the impulse originate from

Answer 4

High in the AV junction

Question 5

When the P wave occurs during the QRS complex, where did the impulse originate from

Answer 5

Midpoint of AV junction

Question 6

When the P wave occurred after the QRS complex, where did the impulse originate from

Answer 6

Lowest aspect of AV junction

Question 7

What is the key differences for Premature Junctional Complex (PJC)

Answer 7

Rhythm- May be occasionally or frequently irregular
Rate- depends on underlying rhythm and PJCs present
P wave morphology - if seen, it is inverted, may be before, during or after QRS complex
PR interval - May be shorter than normal if P wave is before QRS complex, absent if during QRS complex or unmeasurable if after QRS complex (can only be measured if before QRS complex)

Question 8

What is this ECG strip representing

Answer 8

Premature Junctional Complex (PJC)

Question 9

How may the patient be affected by PJCs

Answer 9

Healthy heart-no signs or symptoms, if more than 4-6 PJCs in one minute, warns of serious condition, may have irregular pulse, and hypotension

Question 10

Describe Junctional Escape Rhythm

Answer 10

Originates at AV junction producing backward depolarization if of atrial tissue and at the same time stimulating depolarization of ventricles. Escape rhythms occur when SA node fails to imitate activity and rhythm is established by backup pacemaker site

Question 11

What is this ECG strip representing

Answer 11

Junctional Escape Rhythm

Question 12

How may a patient be affected by junctions escape rhythms

Answer 12

Slower heart rate than normal, loses atrial kick, may show signs and symptoms of low cardiac output including hypotension, altered mental status (confusion, disorientation)

Question 13

What is the key differences in criteria for Junctional Escape Rhythms

Answer 13

Rhythm - P-P and R-T intervals are regular and occurs at similar intervals however the P-P interval may be difficult to measure