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.
Patients anti-coagulated with Warfarin should ideally present with an INR below what?
<1.5
Restart of heparin within 24hrs post implant represents what percentage risk increase of haematoma vs unanticoagulated patients?
20% risk = 5x the risk of normal.
Patients with an existing CRM device have what % prevalence of lateral subclavian vein occlusion?
25%.
True / False
Pacemaker leads can be placed through mechanical valves.
False.
Mechanical valves are contraindicated. Bioprosthetic are not.
List the 3 most commonly used access veins during device implantation.
- Cephalic
- Subclavian
- Axillary
List two pros and two cons of the Cephalic access.
Pros = Direct vision & fewer potential complications.
Cons = Small & clean dissection.
List two pros and and two cons of the Axillary access.
Pros = Fewer complications & large vessle can support multiple leads.
Cons = Requires Fluro & technically difficult.
List two pros and and two cons of the Subclavian access.
Pros = Easy access & Large vessle can support multiple leads.
Cons = Requires Fluro & risk of Pneu/Haemothorax (also crush risk post implant).
List two reasons why implanters prolapse the RV lead and don’t directly push the RV lead into the RV.
- Reduces likelihood of CS cannulation
- Reduces risk of perforation
True / False
RA leads are normally fixated to the atrial free wall.
False.
RA leads are normally placed in the Appendage.
What site in the RA may be more prone to phrenic stimulation?
Free wall positions.
List 3 types of LV pacing.
- Transvenous via Coronary Sinus
- Epicardial
- Endocardial - best haemodynamics, however chronic antiocoagulation reqiured
Where does the CS drain?
Posteroseptum of RA.
List the CS veins in order from Proximal to Distal.
- Middle cardiac vein
- Posterior
- Posterolateral
- Lateral
- Anterolateral
- Anteroventricular
60% of leads in MCV can be advanced to where?
Posterolateral free wall.
Typically which two radiographic views are used to visualise the CS?
RAO & LAO.
Order the target veins for CRT in terms of preference.
- Lateral
- Posterolateral
- Posterior
- Middle cardiac vein
- Great cardiac vein
True / False
Greater RV to LV lead tip separation typically results in improved clinical outcome.
True.
Is lead I positive or negative with RV pacing?
Positive.
Is lead I positive or negative with LV pacing?
Negative.
Is lead III positive or negative with LV pacing?
Positive.
Is lead III positive or negative with RV pacing?
Negative.
BiV pacing typically produces what axis?
Right Superior.
Loss of a Q wave in I during pacing typically represents what?
Loss of BiV pacing.
When testing unipolar leads - which clips are attached where?
Anode = Red Clip = Tissue.
Cathode = Black Clip = Distal Lead electrode (Equates to lead tip electrode).
Phrenic Nerve Stimulation at low/normal output is a potential indicator of what?
RV perforation.
Check for negative injury current.
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.
Yes / No
Can you see a current of injury when implanting passive leads?
Yes.
Injury current is representative of pressure on the myocardium.
True / False
‘Threshold can increase immediately following deployment of passive fixation leads before lowering some minutes later’
False.
This is true of active fixation leads only. Helix deployed = increased threshold for some minutes. This is not typically seen in passive fixation leads.
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.
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.
What is the implant success rate for MICRA?
99.2%.