Pacing Flashcards
PPM anatomy:
- PPM vs AICD
- 2 parts: generator and lead/s
- May be unipolar or bipolar
- Unipolar: lead in RA (SA disease), or RV (AF)
- “Dual Chamber”: leads in RA and RV
- “Biventricular”: leads in RA, RV and LV (advanced CCF)
Pacemaker (PPM) nomenclature:
-
1- Paced
–> A, V, D -
2- Sensed
–> A, V, D -
3- Response to sensing
–> None, Triggered, Inhibited, Dual (T+I) -
4- Rate modulation/ programmability
–> (ie. rate change dependent on exertion) -
5- Anti-tachy function
–> None, Pacing, Shock, Dual
Which setting should PPMs be put at for surgery:
VOO
Asynchronous, mandatory ventricular pacing. No sensing, so diathermy won’t interfere
How to determine what kind of PPM/AICD someone has:
- Ask them
- Wallet card
- Medical records
- Call each company (registries)
- CXR:
–> Radio-opaque code
–> Shape of housing
How often should PPMs be interrogated?
3 monthly.
For rhythms, but also for efficacy, battery life etc.
Indications to ‘deactivate’ a PPM/ AICD:
INDICATIONS
- Pacemaker-mediated tachycardia’
- Oversensing resulting in bradycardia/shock
- Check battery life
–> If responds appropriately to magnet (asynchronous mode), battery okay.
- EOL (AICD).
–> PPMs can be left, as they won’t keep a dying patient alive.
-
DON’T need to deactivate for:
–> Defibrillation
–> Cardioversion
–> Overdrive pacing
….Just don’t put pads directly over device (AP). Interrogate afterwards.
Most PPM should pick it up as ‘native’ and
inhibit
How to ‘deactivate’ a PPM/ AICD:
AICD
–> Magnet will deactivate
PPM
–> Magnet will default to fixed, asynchronous pacing
–> ALL modern PPMs also have the option of simply being reprogrammed at the bedside.
If no response to magnet, can add a second. (eg. obesity)
Effect of magnet is only whilst magnet is on
Complications of PPMs:
-
Failure to sense
–> Pacing spikes in inappropriate places -
Failure to pace
–> No spikes, when expected
–> Resulting bradycardia
—–> oversensing (eg. detects shiver, movement)
—–> lead fracture
—–> lead displacement
——> battery. -
Failure to capture
–> Spikes without resulting QRS
—–> Myocardial: Electrolytes, hypothermia, myocarditis, MI, new block
—–> lead displacement/ # -
Malposition
–> Twitching, hiccups
–> Perforation/ tamponade -
Pacemaker-mediated tachycardia
–> Reantrant, can’t exceed 160 or so.
–> *“Runaway” is low battery Cx of older PPMs. Massively rapid firing. -
‘Pacemaker Syndrome’
–> Iatrogenic CCF from dyssynchrony
Can a patient be touched whilst they are being externally paced?
Yes.
ECG findings in ventricular pacing:
- Spike pre-QRS
- Wide complexes
- LAD/RAD
- LBBB or RBBB morphology
-
QRS/ST discordance
–> ST/T waves should be OPPOSITE to QRS
External pacing options:
Transcutaneous
Transvenous
Trans-oesophageal
Percussion
Describe how to transcutaneously pace:
- Remove skin patches
- Sedation & analgesia
- AP pads Not directly over a PPM
- Turn to ‘demand pacing’
- Ensure lead is displaying
- Set rate at 70bpm or 30 above instrinsic rate
- Start at 70 mA
- Begin
- Increase mA until electrical capture
- Set at 10 mA above capture
-
Confirm mechanical capture on ECHO
–> May confuse jerks/pulse - Titrate PR to BP
- Ongoing analgesia
- Okay to touch patient whilst being paced
Describe how to transvenously pace:
Set up unit:
- 80 bpm
- Asynchronous
- MAXIMUM mA output
- MAXIMUM sensitivity
- Connect to a praecordial lead on monitor
- Put pacing wire into sterile sleeve
- Insert as per CVC
- Inflate balloon 15cm in (‘float’ insertion)
- Once in RV, will see deep S waves (if STE, in too far, touching wall)
- Confirm electrical/ mechanical capture
- Deflate balloon
- Change to synchronous
- Downtitrate mA
What PPM malfunction is this?
Failure to pace
What PPM malfunction is this?
Failure to sense
What PPM malfunction is this?
Runaway PPM
What PPM malfunction is this?
Failure to capture
What PPM malfunction is this?
Oversensing (failure to pace)
(interpreting artefact as native rhythm + not pacing)
What PPM malfunction is this?
Pacemaker-mediated tachycardia
