Chapter 10 Cardiac Pacing

Question 1

A patient has complete heart block at the level of the AV node. A narrow complex rhythm at rate of 50 bpm is produced from the bundle of His. The patient is tolerating this HR and is well perfused. Is this rhythm stable or likely to degenerate into asystole?

Answer 1

It’s generally stable and unlikely to fail suddenly

Question 2

Name 3 causes of complete heart block low in the conducting system

Answer 2

1) Degenerative conducting tissue fibrosis
2) Extensive anteroseptal myocardial infarction affecting all the bundle branches
3) Cardiomyopathy
4) Calcific valve disease

Question 3

A patient has complete heart block from low in the conducting system (purkinje fibers or myocardium). Is this rhythm stable or likely to progress to asystole?

Answer 3

Unstable
Risk of transient failure leading to syncope (Stokes-Adam attack)
Risk complete failure (complete failure, cardiac arrest)

Question 4

A patient has a broad complex complete heart block with 3 second pauses. What is the patient at risk of?

Answer 4

Asystole

Question 5

You are trying to give transcutaneous pacing and you see electrical capture. What do you check next?

Answer 5

Feel for a pulse to confirm mechanical activity that produces a pulse

Question 6

What are the four methods of providing cardiac pacing?

Answer 6

Non-invasive

1) percussion pacing (‘fist pacing’)
2) transcutaneous pacing

Invasive

1) temporary pacing wire
2) permanent pacing (implanted device)

Question 7

How do you provide percussion pacing?

Answer 7

1) Side of closed first, thump praecordium, just lateral to lower left sternal edge
2) Raise hand 20cm above chest for each thump
3) Monitor ECG for QRS complexes, have someone else feel for pulse
4) If not working, hit harder and or move site of impact
5) Quickly change to giving CPR is it’s not working

Question 8

For transcutaneous pacing, in addition to applying defibrillation pads. What other monitoring should be applied to increase accuracy and safety of pacing?

Answer 8

ECG leads.

Defibrillation pads are multi-functional but ECG monitoring may also be needed for many devices.

Question 9

You are trying to apply trancutaneous pacing but you are not getting electrical capture despite increasing the milliamps. What step can you try (that may have been ignored due to the emergent need to pace)?

Answer 9

Ensure hair is clipped
Skin is dry
Attach ECG leads
Use AP position of pads

Question 10

A defibrillation pad is placed over breast tissue but is otherwise in the correct position, is this an issue?

Answer 10

Yes, move the breast tissue out of the way and reapply

Question 11

Many pacing devices deliver in a demand mode. Movement can inhibit pacing due to artefact. If you can’t eliminate the artefact, what else can you do to make sure the patient is paced?

Answer 11

Deliver pacing in fix-rate

Question 12

What is the typical current needed to achieve electrical and mechanical capture when pacing a patient?

Answer 12

50 - 100mA

Question 13

Where should the posterior pad be placed in the AP position?

Answer 13

Between left scapula and spine

Question 14

You are trying to pace but have reached maximal milliamps, the patient is clean and shaved. What else can you try?

Answer 14

Reposition the pads

If still not getting capture, the myocardium may not be viable OR severe hyperkalaemia may prevent successful pacing

Question 15

You have found the amount of milliamps need to gain electrical capture. How much should you increase the milliamps by?

Answer 15

10% or 10mamps

Question 16

Is there any danger to staff who contact a patient who is being paced?

Answer 16

No

However it is good practice to stop pacing while giving CPR as it does not help the patient