Junctional rhythms

Question 1

Where do the P waves fall?

Answer 1

After the QRS or not at all

Question 2

What is the rate of junctional rhythms?

Answer 2

40-60bpm

Question 3

What is the rate of an accelerated junctional rhythm?

Answer 3

over 60bpm

Question 4

What is the morphology of the QRS in junctional?

Answer 4

Narrow

Question 5

What kind of rhythm is a junctional rhythm?

Answer 5

Nodal

Question 6

What kind of complex could you see in V1 for junctional?

Answer 6

rSr complex

Question 7

Do junctional rhythms affect atrial or ventricular?

Answer 7

Atrial because the AV node is above the fibrous ring

Question 8

What is the ECG appearance of a junctional premature complex?

Answer 8

-narrow QRS
-can have no preceding P wave
-can have retrograde P wave that can come before, during or after QRS
-comes early in rhythm
-compensatory pause

Question 9

Of the retrograde P wave on junctional ectopic comes before, what features does this have?

Answer 9

Shortened PR and inverted in II, III and aVF

Question 10

When do junctional rhythms arise?

Answer 10

Rate of supraventricular impulses arriving at AV node or ventricle is less than intrinsic rate of ectopic pacemaker

Question 11

What are the causes of junctional escape rhythm?

Answer 11

-severe sinus Brady
-sinus arrest
-SA exit block
-high grade second degree AV block
-3rd degree block
-hyperkalaemia
-digoxin, beta blocker or calcium channel blocker toxicity

Question 12

Rate of junctional tachycardia?

Answer 12

Above 100bpm