Devices/EP

Question 1

Class 1 Indications

Answer 1

3RD DEGREE & ADVANCED SECOND DEGREE AVB:
➢ Symptomatic bradycardia due to AV Block
➢ Documented periods of asystole >3 seconds in duration
➢ Escape rate of <40 bpm while awake; symptom free patients
➢ Post AV junction ablation
➢ Post-OP AVB not expected to resolve
➢ 2nd degree AVB regardless of type or site with associated symptomatic bradycardia

Question 2

Other indications

Answer 2

Vasovagal syncope (VVS)
Prevention and termination of tachyarrhythmias including prolonged QT syndrome (pause-dependant)
AV Block associated with MI’s
Hypertrophic & Dilated Cardiomyopathies

Question 3

Veins used for pacing

Answer 3

subclavian
cephalic
internal/external jugular

Question 4

What is Impedence?

Answer 4

Represents the opposition to current flow

Question 5

If impedene increases, current flow will…

Answer 5

decrease

Question 6

Impedence values

Answer 6

300-1000ohms

Question 7

Benefits of dual chamber pacing

Answer 7

Provides AV synchrony
Lower incidences of atrial fibrillation
Lower risk of systemic embolism and stroke
Lower incidence of congestive heart failure
Higher survival rates
Increased LV filling and resting cardiac output

Question 8

Magnet response

Answer 8

Prevents sensing, resulting in asynchronous pacemaker operation
allows assessment of pacemaker function

Question 9

What MODE(S) would you typically see once a magnet is applied over the device?

Answer 9

VOO
DOO
AOO

Question 10

Pacemaker Interogation

Answer 10

Programmed parameters
Measured data
ECG/EGM and marker channels/diagrams
Diagnostic information
Battery status
Lead status & impedance
Rate histograms

Question 11

Sensing

Answer 11

P wave amplitude at time of implant should be atleast greater than 2mV; and the R wave amplitude >5mV

Question 12

Oversensing =

Answer 12

Underpacing

Question 13

Undersensing =

Answer 13

Overpacing

Question 14

Causes of Loss of Capture

Answer 14

Lead dislodgement
Lead insulation break
Lead wire fracture
Electrical circuit failure
Battery depletion
Pacemaker or lead connector issues
Pacing/sensing parameters programmed too low or high
Electrolyte imbalance
Exit block at the lead fixation site (loss of capture)
Drug effects

Question 15

Upper Rate Behaviour

Answer 15

the pacemakers response to high atrial rates

Question 16

What mode for AFIB?

Answer 16

VVI - do not want to pace the atrium
OR
VVIR - rate responsive

Question 17

ICD’s must be able to

Answer 17

Sense small and large R waves
NOT sense T waves
Sense very small VF signals
Ignore and not sense activity in opposite chambers

Question 18

Charge time

Answer 18

The time between the detection of an arrhythmia and when the therapy is delivered.
Initiated upon the detection of an arrhythmia

Question 19

Consequences of Undersensing

Answer 19

Failure to sense VF, therefore, no appropriate therapy will be initiated
If VT goes undetected, the failure to treat it can quickly deteriorate to VF

Question 20

Consequences of Oversensing

Answer 20

Delivery of inappropriate therapies
This can lead to inducing fatal arrhythmia

Question 21

ICD Therapies include

Answer 21

Anti-tachycardia pacing
Defibrillation
Cardioversion

Question 22

Damage to insulation can cause

Answer 22

Low impedance
increase in current flow
accelerated battery depletion

Question 23

Lead conductor fracture can cause

Answer 23

High impedance
decrease in current flow
artifact/noise on EGM

Question 24

Pacemaker cells

Answer 24

SA Node
AV node
Purkinje fibres

Question 25

P-A interval indicates

Answer 25

approx time taken from the SA node-AV node

Question 26

A-H interval indicates

Answer 26

approx time it takes to travel over AVN
represents conduction time from low RA through AVN and bundle of HIS

Question 27

H-V interval indicates

Answer 27

Approx time it takes for HIS-purkinje system to ventricular myocardium

Question 28

Fast response cells

Answer 28

Cardiac myocytes
purkinje cells

Question 29

Slow response cells

Answer 29

SA node
AV node