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Flashcards in Lead & electrodes Deck (54):
1

Unipolar pacing which is cathode/anode

Lead tip = cathode (negative)

Can = Anode (positive)

2

Bipolar pacing, which is cathode/anode

Ring electrode = Anode (Positive)

Tip = Cathode (negative)

3

Co-axial lead - does the inner coil go to the ring or tip

Inner coil = Tip = Cathode = Negative

4

Co-axial lead - does the outer coil go to the ring or tip

Outer coil = Ring = Anode = Positive

5

Co-axial leads used a 4-layer design AKA

Quadrifilar

6

Benefit of Co-radial Vs Co-axial

Thinner diameter <6F typically

7

Is there a difference in durability and performance for Co-axial vs Co-raidal?

No - same performance

8

ICD leads are what style?

Multi-lumen

9

Passive fixation leads are difficult to remove after what time span

6m

10

Fixed helix have what dissolvable component covering the helix

Mannitol

11

Historically active fixation leads show higher chronic pacing thresholds vs. passive - TRUE/FALSE

TRUE - Although corticosteroids in modern leads have negated this

12

4 factors contraindicating transvenous lead placement

Tricuspid valve abnormalities
Central venous obstruction
Congenital heart disease
Technical issues

13

Epicardial leads are bipolar TRUE/FALSE

TRUE - bipolar or unipolar

14

What are the 2 types of conductor materials in leads

MP35N and Silver

15

What is MP35N made of

Cobalt
Nickel
Chromium
Molybdenum

16

Positives of MP35N

Biocompatible
High tensile strength
Resistance to corrosion

17

Does MP35N have a low or high resistivity

HIGH >1000ohms - therefore combined with silver

18

When combining MP35N with silver, what are the two types of design

Drawn brazen strand

Drawn filled tube

19

Drawn brazen strand positives

Increased fatigue life
High conductivity
Withstands greater mechanical stress

20

Conductors in PACING leads are generally which type

Drawn filled tube

21

Cable conductors are better than coiled conductors because....

Greater strength
Greater fracture resistance
Greater redundancy
Non-compressible

22

Coil filarity =

The number of separate wires within the coil

23

Coil pitch =

Filar diameter x number of filar in the set + space between filar sets

24

Most modern leads are tri/qaudrifilar TRUE/FALSE

True

25

Examples of Fluoropolymer insulation

PTFE - Teflon // DuPont
ETFE

26

Fluoropolymer positives

High resistance to solvents
Max biocompatibility

27

Silicone rubber positives

Most common lead material
Biostable and biocompatible

28

Silicone disadvantages

Prone to tearing and abrasion wear
High friction co-eficient

29

Define Cold Flow

Silicone deformation under constant or cyclic compression

30

Polyurethane benefits

High tear strength
High elasticity
Low friction coefficient

ALL ALLOW SMALLER LEADS

31

Polyurethane problems

Low biostability - Thus

Lead calcification is possible
Environmental stress cracking
Chain scission

32

Environmental stress cracking (ESC) occurs by which process

Macrophages induce hydrogen peroxide formation on the polymer structure. This results in oxidation-induced chain breaks and metal ion oxidation MIO

33

Two most common types of Polyurethane

Pellethane 80A = Bad

Pellethane 55D = Good

34

ST Jude OPTIM uses what

Elast-Eon

Silicone rubber + Polyurethane + Polyhexamethylene oxide

35

Stim threshold is a function of electrode radius, so a smaller size does what...

Higher current density
Lower pacing threshold
High sensing impedance

36

Benefits of textured electrode surfaces

Minimises polarisation
Improves sensing and stimulation efficiency

37

5 currently used electrode materials

Platinum-Iridium
Elgiloy (Cobalt, Chromium-nickel)
Platinum coated with platinised titanium
Platinum
Iridium-oxide
Titanium-nitride

38

Which electrode material has the lowest polarisation effect

Titanium nitride

39

4 rubbish historical electrode materials

Nickel
Copper
Silver
Nickel

40

What happens to Elgiloy when used as an anode

Starts to corrode

Stable as cathode

41

Name the corticosteroid used

Dexamethasone

42

Which lead type had sealing rings attached

5mm Uni

43

Did the 3.2mm Low Profile lead have sealing rings on the lead or in the header

In the header

44

Can and IS1 go into a 3.2mm LP header

No, the 2 sealing rings on the IS1 clash with the 3 rings of 3.2mm

UNLESS it is a modified 3.2mm header with only 2 sealing rings, not 3

45

What mm is IS-1

3.2mm (2 sealing rings)

46

What is the difference between IS4 and DF4 pins

DF4 pins step down to smaller diameter

IS4 is larger in diameter and does not step down

47

In quadripolar ICD leads is the tip the anode or cathode

Tip is always cathode

48

In quadripolar ICD leads is the ring the anode or cathode

Ring is always anode

49

True bipolar vs Integrated bipolar

True bipolar operates like a pacing lead

Integrated bipolar is tip to Defib coil

50

Benefits of true bipolar ICD sensing

Less likely to oversense

51

In integrated bipolar systems, which is the anode and which is cathode

Sensing Anode = RV defib coil = Positive

Pacing Anode = Ring electrode = Positive

Cathode = Tip electrode = Negative

52

Negatives of integrated bipolar

Larger sensing circuit = higher risk of myopotential oversnsing

53

What are anchoring sleeves made from

MDX silicone rubber

54

If the lead isn't fully inserted, what can happen

Sensing artefact

Failure to pace

LEAD IMPEDANCE ALONE ISN'T ENOUGH TO DETECT THIS PROBLEM