Surgical technique & complication Flashcards
Provides an overview of how generators / leads are implanted and the respondent complications that can arise. Currently weighted 9% in the CCDS exam.
1
Q
Patients anti-coagulated with Warfarin should ideally present with an INR below what?
A
<1.5
2
Q
Restart of heparin within 24hrs post implant represents what percentage risk increase of haematoma vs unanticoagulated patients?
A
20% risk = 5x the risk of normal.
3
Q
Patients with an existing CRM device have what % prevalence of lateral subclavian vein occlusion?
A
25%.
4
Q
True / False
Pacemaker leads can be placed through mechanical valves.
A
False.
Mechanical valves are contraindicated. Bioprosthetic are not.
5
Q
List the 3 most commonly used access veins during device implantation.
A
- Cephalic
- Subclavian
- Axillary
6
Q
List two pros and two cons of the Cephalic access.
A
Pros = Direct vision & fewer potential complications.
Cons = Small & clean dissection.
7
Q
List two pros and and two cons of the Axillary access.
A
Pros = Fewer complications & large vessle can support multiple leads.
Cons = Requires Fluro & technically difficult.
8
Q
List two pros and and two cons of the Subclavian access.
A
Pros = Easy access & Large vessle can support multiple leads.
Cons = Requires Fluro & risk of Pneu/Haemothorax (also crush risk post implant).
9
Q
List two reasons why implanters prolapse the RV lead and don’t directly push the RV lead into the RV.
A
- Reduces likelihood of CS cannulation
- Reduces risk of perforation
10
Q
True / False
RA leads are normally fixated to the atrial free wall.
A
False.
RA leads are normally placed in the Appendage.
11
Q
What site in the RA may be more prone to phrenic stimulation?
A
Free wall positions.
12
Q
List 3 types of LV pacing.
A
- Transvenous via Coronary Sinus
- Epicardial
- Endocardial - best haemodynamics, however chronic antiocoagulation reqiured
13
Q
Where does the CS drain?
A
Posteroseptum of RA.
14
Q
List the CS veins in order from Proximal to Distal.
A
- Middle cardiac vein
- Posterior
- Posterolateral
- Lateral
- Anterolateral
- Anteroventricular
15
Q
60% of leads in MCV can be advanced to where?
A
Posterolateral free wall.
16
Q
Typically which two radiographic views are used to visualise the CS?
A
RAO & LAO.
17
Q
Order the target veins for CRT in terms of preference.
A
- Lateral
- Posterolateral
- Posterior
- Middle cardiac vein
- Great cardiac vein
18
Q
True / False
Greater RV to LV lead tip separation typically results in improved clinical outcome.
A
True.
19
Q
Is lead I positive or negative with RV pacing?
A
Positive.
20
Q
Is lead I positive or negative with LV pacing?
A
Negative.
21
Q
Is lead III positive or negative with LV pacing?
A
Positive.
22
Q
Is lead III positive or negative with RV pacing?
A
Negative.
23
Q
BiV pacing typically produces what axis?
A
Right Superior.
24
Q
Loss of a Q wave in I during pacing typically represents what?
A
Loss of BiV pacing.
25
When testing unipolar leads - which clips are attached where?
Anode = Red Clip = Tissue.
Cathode = Black Clip = Distal Lead electrode (Equates to lead tip electrode).
26
Phrenic Nerve Stimulation at low/normal output is a potential indicator of what?
RV perforation.
## Footnote
*Check for negative injury current.*
27
Tissue fibrosis improves lead stability however negatively influences generator current drain - explain why?
Tissue fibrosis increases effective distal electrode size = Respondent increase in current drain.
28
# Yes / No
Can you see a current of injury when implanting passive leads?
Yes.
## Footnote
*Injury current is representative of pressure on the myocardium.*
29
# True / False
'Threshold can increase immediately following deployment of passive fixation leads before lowering some minutes later'
False.
## Footnote
*This is true of active fixation leads only. Helix deployed = increased threshold for some minutes. This is not typically seen in passive fixation leads.*
30
Describe common threshold characteristics of non-steroid eluting leads from implant to 6wks follow up.
Higher thresholds for first 24hrs and rising over 7 days. Threshold stabilises 6wks post implant. Final threshold normally higher than at implant but lower than highest peak.
31
Describe common threshold characteristics of steroid eluting leads from implant to 6wks follow up.
Steroid eluting leads rarely exhibit marked changes in threshold over time.
32
What is the implant success rate for MICRA?
99.2%.
33
What are the MICRA tines made of?
Nitinol.
34
Describe satisfactory R-wave / Threshold / Impedance values of MICRA systems.
1. R-wave \> 5mV
2. Threshold \<1.0V @ 0.24ms
3. Impedance 400-1500ohms
35
# True / False
RVOT pacing leads are approximately the same level as appendage on radiograph.
True.
36
When placing a single coil RV lead, does site impact Defib Thresholds and/or sensing?
No.
## Footnote
*Typically same thresholds and sensing regardless of RV lead position.*
37
Define the difference between complete & clinical lead removal success.
Complete = All lead material removed.
Clinical = Some lead material left behind but not negatively impacting clinical outcome.
38
Success rate of lead extraction is \_\_%.
90%.
39
If the lead pin isn't fully inserted into the header, what two common outcomes can occur?
1. Sensing artefact
2. Failure to pace
## Footnote
*Lead impedance fluctuations alone aren't enough to detect this issue.*
40
List 4 contraindications to transvenous lead placement.
1. Tricuspid valve abnormalities
2. Central venous obstruction
3. Congenital heart disease
4. Technical issues
41
# True / False
Pacemaker leads can't be placed through bioprosthetic valves.
False.
## Footnote
*Pacemaker leads can be placed through bioprosthetic leads but not mechanical ones.*
42
Why is a greater RV to LV lead tip separation desirable with respect to CRT outcome?
Greater separation = greater capture field.
## Footnote
*Thus more myocardium is activated leading to improved haemodynamics.*
43
Negative injury current is an potential indicator for what?
RV perforation.
44
How is MICRA deployment defined?
When 2 of 4 tines are attached.
45
List 5 indications for lead extraction.
1. Infection
2. Malfunction
3. Thrombosis / Venous Stenosis
4. Lead Interaction
5. Requirement for MRI
46
Name two leads currently on recall.
1. Sprint Fidelis
2. Riata
47
List 6 class I removal indications for infection.
1. Endocarditis
2. Sepsis
3. Pocket abscess
4. Device erosion
5. Skin adherence
6. Occult gram-positive bacteremia
48
Device explant for chronic pain at surgical site is which indication classification?
Class IIa
49
List 3 class I removal indications for thrombosis & stenosis.
1. Thrombus on lead or fragment
2. Subclavian or SVC occlusion
3. Stent deployment to vein with lead
50
List 3 Class I removal indications for functional leads.
1. Life threatening arrhythmias caused by leads
2. Immediate threat if leads left in place (fracture and protrusion)
3. Leads interfere with other leads
51
List 3 Class I removal indications for non-functional leads.
1. Life threatening arrhythmias caused by leads
2. Immediate threat if leads left in place (fracture and protrusion)
3. Leads interfere with other leads
52
# True / False
Generator erosion is considered an indolent infection that almost always requires extraction.
True.
53
List two common predisposing factors for system infection.
1. Diabetes mellitus
2. Post operative haematoma
54
Which bacterium is most commonly causative of acute site infection?
Staphylococcus Aureus.
## Footnote
*Pussy and manifests within first few weeks.*
55
Which bacterium is most commonly causative of chronic site infection?
Staphylococcus Epidermis.
## Footnote
*Manifests months/years after implantation.*
56
What percentage of acute infections complicate new implants?
33-50%.
57
What should be assumed with bacteraemia without localising signs?
Endocarditis.
58
Does lead endocarditis typically occur before or after pocket infection?
Normally post pocket infection.
59
Is endocarditis normally introduced at implant or secondary to transient bacteraemia?
Secondary to transient bacteraemia, typically from an unidentified source.
60
How do you diagnose lead endocarditis?
Vegetation on lead via ECHO in presence of other signs of infection.
61
Occult gram positive bacteraemia is which indication class for removal?
Class I indication.
62
Occult gram negative bacteraemia is which indication class for removal?
Class IIa indication.
63
How long should one wait to confirm negative infection status following gen removal and antibiotics?
Between 3 to 10 days.
64
When should prophylactic antibiotic concentration be highest in tissue?
30-60mins prior to procedure.
65
# Yes / No
Is there data to support giving antibiotics for more than 24hrs after implantation?
No.
66
The following are all deleterious effects of which RV lead pacing site?
* LV mechanical Dyssnchrony
* Heart Failure
* LV remodelling
* AF & Increased Atrial Size
* Mitral Regurgitation
RV Apex.
67
During implant, ST segment elevation is representative of what?
Current of injury.
## Footnote
*Proportional to adhesion of lead to the myocardium. Typically the greater the injury current = more stability and less likelihood of dislodgement.*
68
How does one assess whether the lead has enough slack?
During Fluro - ask the patient to inspire deeply.
## Footnote
*This lowers the diaphragm and straightens the lead, thus allowing the assessment of slack.*
69
Why should one pace both the A and V leads at max output during implant?
To rule out diaphragmatic capture.
70
A notched P-wave is seen on ECG lead II, what does this suggest and what are its implications for lead placement?
A notched P-wave in lead II alludes to Inter-Atrial conduction delay and respondent atrial dyssynchrony.
## Footnote
*Atrial lead should be placed on the high/mid atrial septum or close to Cs Os. This will restore simultaneous contraction of the atria.*
71
How would you test for phrenic nerve stimulation during an implant?
Pace at max output possible via PSA / Device and do deep breathing manoeuvres. Look and feel for stimulation.
72
What is the incidence of pocket infection?
\<2%.
73
# Yes / No
During the implant the Dr asks if you see injury current - what do you say?
Yes.
## Footnote
*There is marked 'ST Segment' elevation post impulse on the RV channel. This is a good predictor of lead stability.*
74
# Yes / No
During the implant the Dr asks if you see injury current on both channels - what do you say?
Yes.
## Footnote
*Marked 'ST Segment' elevation is visibile on both A and V channels.*
75
Outline potential cause and cures of right-sided abdominal jumping one day post CRT implant.
Most likely atrial lead capturing phrenic nerve.
## Footnote
*Lower atrial output if possible or reposition atrial lead.*
76
Outline potential cause and cures of left-sided abdominal jumping one day post CRT implant.
Most likely LV capture of the phrenic nerve causing diaphragmatic capture.
## Footnote
*Lower LV output if possible or program different bipolar configuration.*
77
List 5 considerations that must be realised during box change procedure.
1. Check underlying rhythm
2. Turn rate response off
3. Turn ICD detection off
4. Check lead connectors - IS1, DF1, DF4, IS4 etc.
5. Check lead polarity - Unipolar pacing will cease when device leaves pocket.
78
Patient presents with the following 6hrs post PPM implant, what is the appropriate course of action?
'Clear chest sounds, No pneumothorax via X-ray, BP = 100/70mmHg, DDD 70 shows seq AVp'
1. Repeat X-ray
2. Cardiac Echo
3. Administer furosemide
4. Administer beta blocker
2 - Cardiac Echo.
## Footnote
*It sounds likely the lead has perforated which could lead to tamponade. Echo is more precise than X-ray to highlight this.*
79
Which tissue plane shows the appropriate implant level for most patients?
C - Below the fat layer yet above the muscle.
## Footnote
*D represents submuscular implants, which are rarer and predominantly for cosmetic reasons.*
80
# True / False
The following patient requires a transvenous DR PPM system.
'16yr old female, Syncope due to CHB, Fontan procedure'
False.
## Footnote
*Pacing indications are met, however fontan procedure contraindicates transvenous approach. Thus an epicardial DR PPM.*
