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Fellowship revision > AF blue book article > Flashcards

AF blue book article Flashcards

1
Q

What proportion of ppl age >55 are estimated to have AF?

A

5%

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2
Q

For which complications is AF a major risk factor?

A

New-onset heart failure, stroke, dementia, mortality

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2
Q

For which complications is AF a major risk factor?

A

New-onset heart failure, stroke, dementia, mortality

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3
Q

What are some modifiable lifestyle risk factors for AF?

A 
Smoking
ETOH consumption
physical inactivity
OSA
obesity; weight reduction (10%) & moderate physical activity impacts AF risk
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4
Q

Other physical examination or investigation findings which increase pts risk of AF? Targets?

A

HTN
Hyperthyroidism
Dyslipidaemia
Diabetes

Rx aims BP <130/80 & HbA1c <6.5%

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4
Q

Other physical examination or investigation findings which increase pts risk of AF? Targets?

A

HTN
Hyperthyroidism
Dyslipidaemia
Diabetes

Rx aims BP <130/80 & HbA1c <6.5%

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5
Q

What are the major goals for AF management?

A

Prevent thromboembolic events

Manage symptoms with rate & rhythm control

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6
Q

What is the threshold CHA 2DS 2-VASc score for initiation of anticoagulation in AF?

A

2

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7
Q

What is the threshold CHA 2DS 2-VASc score for initiation of anticoagulation in AF?

A

2

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8
Q

What’s the most prescribed rate control agent for AF? Other options?

A

B blockers; also useful for pts with impaired LV function

Digoxin & non-DHP CCBs are also used

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9
Q

What’s the most prescribed rate control agent for AF? Other options?

A

B blockers; also useful for pts with impaired LV function

Digoxin & non-DHP CCBs are also used

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10
Q

Does rhythm control therapy (modify cell excitability, conductivity or abnormal automaticity) have a high rate of successful conversion to sinus?

A

Yes, if administered early

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11
Q

What are some adverse effects of amiodarone?

A

Thyroid dysfunction, pulmonary toxicity, liver function derangement

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12
Q

Aside from amiodarone, what’s an alternative rhythm control agent used in AF?

A

Sotalol, particularly in pts with structurally normal hearts, HTN +/- coronary artery disease

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13
Q

For which patients is LA appendage occlusion considered in AF? How’s it done?

A

Those for whom anticoagulation is contraindicated

placed percutaneously via venous sheath + transeptal puncture

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14
Q

What did the PROTECT-AF trial show?

A

Non-inferior rate of cardiovascular death & stroke between warfarin & a LA appendage occlusion device

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15
Q

What did the PROTECT-AF trial show?

A

Non-inferior rate of cardiovascular death & stroke between warfarin & a LA appendage occlusion device

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16
Q

What are some issues with LA appendage occlusion devices?

A

Pts still require a period of anticoagulation & antiplatelet therapy to reduce risk of device-related thrombus
Occurrence & management of device-related thrombus is unknown
Pts still require rate & rhythm control for symptoms

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17
Q

What are indications for AF ablation?

A

Symptomatic persistent or paroxysmal AF, refractory to or intolerant of antiarrhythmics
tachycardia-induced cardiomyopathy secondary to AF, to reverse LV dysfunction
tachy-brady syndrome
athletes
Concomitant AF & HFrEF: ablation reduces mortality & hospitalisation for HF cf medical therapy

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18
Q

What did the CAPTAF trial & CABANA trial find?

A

AF ablation vs medical therapy significantly improved QoL @ 12 & 24/12, respectively

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19
Q

How may AF impact cognitive function? how does AF impact this risk?

A

Significant risk factor for cognitive impairment independent of it’s effect on stroke risk
AF ablation improves neurocognitive function @ 1 yr, particularly in pts with pre-ablation cognitive decline

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20
Q

What are the recommendations surrounding AF ablation & anticoagulation?

A

uninterrupted anticoagulation before & 3/12 following surgery

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21
Q

Which pts are @ more risk of progression from paroxysmal to persistent AF & new onset AF after AF ablation?

A

those with persistent AF, unmanaged risk factors for AF, structural heart disease. Increasing LA size, LA remodelling & pt frailty are additional risks.
HATCH score can help predict

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22
Q

What’s the HATCH score used for? items?

A 
Predicting progression from paroxysmal to persistent AF & new-onset AF after AF ablation
HTN
Age >=75
TIA/stroke (2)
COPD
Heart failure (2)
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23
Q

From where do most of the ectopic foci of AF originate?

A

superior pulmonary veins

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24
Q

Is AF ablation likely more successful for paroxysmal or persistent AF? Why?

A

paroxysmal
higher relative role of focal pulmonary vein triggers in paroxysmal AF while persistent AF has higher role of non-PV triggers, rotors, scar interaction, epi-endo dissociation so more complex atrial mapping is required to localise ablation targets

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25
Q

How is ablation undertaken?

A

Intravascular catheters placed
Some form of anatomic mapping & catheter guidance; for radio frequency ablation, electroanatomic mapping identifies sources of AF
navigation systems aid catheter manipulation (for radio frequency ablation, electroanatomic mapping helps guide real-time catheter manipulations. For cryoablation, electroanatomic mapping isn’t required as fluoroscopy & TOE are used to guide the catheter)
ablation with different energies- radiofrequency= thermal energy (30-50W) & cryoablation delivers cryothermal energy with liquid nitrogen -75degC

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26
Q

Is CT scanning useful for AF ablation?

A

CT imaging aims to accurately image the LA & pulmonary veins (& to Ax for pulmonary vein stenosis, a known complication of AF ablation), the images are integrated with fluoroscopy images to guide catheter ablation.

Pre-op CT when combined with electroanatomic mapping doesn’t improve safety or efficacy of AF ablation & leads to additional radiation exposure.

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27
Q

What are particular postop monitoring requirements following AF ablation?

A

ECG monitoring overnight
regular monitoring for groin complications
monitoring for cardiac tamponade

28
Q

What features of modern AF ablation have reduced the risk of post-procedural neurocognitive decline?

A

Uninterrupted perioperative anticoagulation before & for 3/12 following surgery
ACT 350-400 seconds during procedure
Reducing LA dwell time with newer technologies

29
Q

What’s the cornerstone of successful AF ablation?

A

Isolation of the pulmonary vein from LA

30
Q

How are the pulmonary veins accessed for AF ablation? Difference for RFA?

A

Via the LA
Venous sheaths are placed into the large central veins (generally femoral), catheters directed to the RA, transseptal puncture occurs, passing catheter from RA to LA
For radiofrequency ablation, 2x transseptal punctures are required as the mapping catheter isn’t integrated into the RFA catheter

31
Q

What are the 2x most used ablation energies for AF ablation?

A
  1. Radiofrequency ablation: thermal energy (30-50W), direct contact –> tissue necrosis
  2. Cryoablation (cryothermal energy–> ice & tissue necrosis)
32
Q

What are the 2x most used ablation energies for AF ablation?

A
  1. Radiofrequency ablation: thermal energy (30-50W), direct contact –> tissue necrosis
  2. Cryoablation (cryothermal energy–> ice & tissue necrosis)
33
Q

What type of AF ablation procedure takes longer & why?

A

Radiofrequency, since 3D electroanatomic mapping of the LA is required & this takes longer & requires more catheter manipulation

34
Q

What are specific risks of radiofrequency ablation & mitigating strategies?

A

Excessive pressure may lead to energy delivery to non-cardiac structures
Contact force sensors integrated in the radiofrequency catheter improve effective delivery of energy to the myocardium
Integrated cooling systems allow consistent energy delivery, reduce thrombus formation & steam pop (the audible sound from intramyocardial explosion when tissue temp reaches 100°C–> production of gas. Potentially severe complication of RFA, associated with cardiac perforation & VSD)

35
Q

Does the cryoablation catheter have an integrated circular mapping catheter?
What is placed at the pulmonary vein ostium, directly contacting the pulmonary vein ostium, creating ice & tissue necrosis leading to pulmonary vein isolation?
What guides the cryoballoon placement?
What’s more time-consuming- RFA or cryoablation?
How does it compare to RFA?

A

Yes, at the distal tip- this mapping catheter allows measurement of ectopic electrical signals
A balloon
Fluoroscopy +/- TOE guides the catheter/cryoballoon
Cryoablation generally quicker
Cryoablation has demonstrated noninferiority to RFA (FIRE and ICE trial)

36
Q

What’s TOE used for prior to commencing the procedure? And during? What views? What’s a complication which TOE & manometry (to measure chamber pressure) help mitigate/identify?

A

To exclude LA appendage thrombus

Also useful to assess chamber size & function & heart valves & pericardial space to later compare & exclude new pericardial fluid.
In repeat ablations, pulmonary vein stenosis should be excluded (a known complication of AF ablation)- pulmonary vein anatomy is usually imaged by CT scan & catheter-based mapping systems but TOE can also be useful.

During, the TOE guides interatrial septal puncture which should occur at the central thin part of the fossa ovalis. Pulmonary vein anatomy & catheter position can be confirmed.

4-chamber & bicaval views.

Aortic puncture

37
Q

Limitations of TOE?

A

General (oesophageal injury, dental damage, sore throat)
Specific: obscuring the transseptal catheter position on fluoroscopy
It must be removed during the ablation so oesophageal temperature can be monitored

38
Q

What are some of the risks of AF ablation, about which pts should be warn

A

Significant risks (incl. stroke, oesophageal injury (eg. L) atria-oesophageal fistula in 0.1%), cardiac tamponade (1%) & pulmonary vein stenosis (0.5%)) in 2%

Overall mortality 1:1000 (significant for a Rx that may be controlled with drugs & is for symptom control/QoL)

neurological complications (incl. stroke, TIA & phrenic nerve injury) in 1%- the risk of phrenic nerve injury during cryoablation is 5% & it’s 0.5% with RFA

Radiation exposure with fluoroscopy (avg fluoroscopy time 20 mins with 386mGy of radiation
exposure)

Risk of atrial stunning–> pulm oedema

Post-op expectations:
Sore throat (intubation, TOE, temp probe (oesophageal, positioned as close to ablation site as possible))
chest pain (60%): mild-moderate, usually up to 24hrs
groin pain @ cannulation site, nurse flat for several hours following groin cannulation
potential for IDC (esp w irrigated ablation techniques)

Anaesthetic risks
general
art line
positioning
suppression of the arrhythmia
TOE risks

Periprocedural thrombotic events (stroke, cognitive dysfunction)

Bleeding- groin complications such as pseudo aneurysm, AV fistula, haematoma (2%) & cardiac tamponade (1%)

39
Q

What’s the % risk of cardiac tamponade with AF ablation? times of risk? type of procedure higher risk? how treat?

A

1%
transeptal puncture, catheter manipulation, energy deployment
RF ablation higher risk (multiple transeptal punctures, greater energy deployment)
Rx with reversal of anticoagulation & perc drainage, occasionally urgent surgical drainage needed

40
Q

What’s the % risk of pulmonary vein stenosis with AF ablation? risk factors? complications?

A

0.5%

extensive ablation, multiple ablations & small pulm vv prior to ablation

may –> chronic pulmonary HTN, lung damage & RHF

41
Q

How is pulm vein stenosis treated? is there a high recurrence rate?

A

balloon angioplasty, bare or drug eluting stents- difficult to treat, high rate restenosis

42
Q

What’s the % risk of groin vascular complications with AF ablation?

A

2%

43
Q

Typical cannulation site for AF ablation?

A

femoral vein

44
Q

Why is the oesophagus so vulnerable during AF ablation? what’s the risk of L) atrio-oesophageal fistula? mortality rate if unrecognised?

A

posterior wall of LA & oesophagus are separated by only 1mm of fat, there’s a risk of thermal injury

0.1%

mortality of >90%

45
Q

Why are PPIs prescribed BD for 6/52 following AF ablation?

A

Oesophageal ulceration & erythema reasonably common

46
Q

At what oesophageal temp must the ablation be interrupted, lower power settings adopted & ablation restarted? what’s the risk of oesophageal injury with & without this strategy?

A

alert procedurals if rising
once 38.5deg C, procedure must stop, lower power settings adopted & recommence only once temp <38.5degC
This strategy reduces oesophageal injury from 36-6%

47
Q

What’s the risk of neurological injury with AF ablation & what are some types of injury?

A

1%

stroke (esp if older, persistent AF, previous stroke, DM, female), TIA, phrenic nerve injury

48
Q

mechanisms for stroke during AF ablation?

A

venous air
haemorrhage
ischaemic
thromboembolic

49
Q

What are the anticoagulation considerations for AF ablation?

A

Continue VKA or DOAC uninterrupted preop & for at least 8/52 post-procedure
VKA associated with less stroke/TIA & minor bleeding risk cf LMWH bridging, there is no change in major bleeding events with continuation of warfarin
Uninterrupted NOAC is as effective as uninterrupted VKA & may have lower risk major bleeding complications; dabigatran least bleeding complications & reversal agent available
Even if uninterrupted anticoagulation, still give heparin 100IU/kg after septal puncture, ACT kept above 300seconds
Likely reverse w protamine @ end of procedure to reduce risk groin haematoma
Resume usual anticoagulants 6hrs following surgery, PPIs BD for 6/52

50
Q

What occurs once electrical isolation of the pulm veins from LA has been confirmed by pacing within the pulmonary veins?

A

Conduction is stress tested by administration of adenosine or isoprenaline

Adenosine hyper-polarises the pulmonary veins, restoring tissue excitability & may unmask dormant pulmonary vein conduction & partially ablated pathways; typically 50% of pts have dormant PV conduction unmasked during adenosine administration which can then guide further ablation & reduce the rate of recurrence

Isoprenaline identifies non-pulmonary vein triggers for AF (eg. SVC, coronary sinus, intertribal septum)

51
Q

What proportion of pts undergoing AF ablation experience a major complication including stroke, oesophageal injury, cardiac tamponade & pulmonary vein stenosis?

A

2%

52
Q

Aside from jet ventilation, what’s another ventilation strategy that may have minimal impact on cardiac movement? Settings? Can volatiles be used? What would happen to the alveolar-arterial CO2 gradient?

A

High frequency low volume ventilation- TVs 200-250mL, RR 40-50 breaths/minute significantly reduces variation in ablation catheter contact force
Reduce insp time & exp flows must approach zero @ end-exp to avoid air stacking & hypoT
Can use volatile
Increased ET-arterial CO2 gap

53
Q

Considerations for other pharmacotherapy during jet ventilation

A

TIVA necessary

May need vasopressors due to haemodynamic changes with jet ventilation

54
Q

How could the monsoon jet ventilator be used? How monitor CO2?

A

Connect pressure hose to luer lock elbow connected to ETT, APL fully open, initial ventilation 120-130 breaths/min with driving pressure 15-20psi, 60-100% O2
Can use transcutaneous CO2 & correlate with ABG

55
Q

What’s a consideration with muscle relaxation for AF ablation?

A

Useful to ensure immobility for accuracy of endocardial mapping techniques & referenced catheters but, particularly for cryoablation, PHRENIC NERVE PACING needs to be possible- dose of NMB should therefore be restricted & recovery ensured to allow for this. Remi useful.

55
Q

What’s a consideration with muscle relaxation for AF ablation?

A

Useful to ensure immobility for accuracy of endocardial mapping techniques & referenced catheters but, particularly for cryoablation, PHRENIC NERVE PACING needs to be possible- dose of NMB should therefore be restricted & recovery ensured to allow for this. Remi useful.

56
Q

Is conscious or deep sedation for AF ablation possible?

A

Yes, but GA shows reduced recurrence rates, procedure is painful, immobility essential for accuracy of mapping & stability of ablation catheters

57
Q

What’s the current evidence & advice regarding periprocedural anticoagulation for AF ablation?

A

Continuing VKAs peri-procedurally reduces risk of periprocedural stroke & minor bleeding relative to bridging with LMWH
NOACS should also be uninterrupted
Uninterrupted NOAC is as effective as uninterrupted VKA & may have a lower risk of major bleeding complications

58
Q

Which is the NOAC with least bleeding complications for AF ablation & a reversal agent available?

A

Dabigatran

59
Q

Reversal agent for dabigatran?

A

Idarucizumab

60
Q

Does heparin still need to be administered for uninterrupted anticoagulated pts undergoing AF ablation?

A

Yes

61
Q

Dose of heparin for AF ablation?

A

Generally 100u/kg after septal puncture

62
Q

Goal ACT for AF ablation?

A

Keep >300seconds, repeat ACT every 10-15mins until achieved & then every 15-30 mins until the end of the procedure

63
Q

For how long after AF ablation should regular anticoagulation be continued?

A

At least 8/52

64
Q

What’s an important element of monitoring I should alert the proceduralist to immediately if any rapid change?

A

Temperature- and stop procedure, lower power output if oesophageal temp >38.5

65
Q

Anaesthetic considerations:

A

Anaesthetic technique influences the success of the procedure.

Remote location

  • unfamiliar staff (may not be familiar with GA pts, pressure areas etc), equipment incl for emergency
  • usually no pre-anaes room or formal recovery
  • hazards: radiation, sterile field, cramped space, noisy, may be prolonged procedure- vigilance essential
  • communication issues as staff both in control room & inside room (staff may have headsets)
  • proceduralist may want arms above head (care w brachial plexus), meticulous with pressure areas as may be narrow table, may not allow head down tip)
  • pt may require defibrillator pads
  • place all ecg leads/pads while pt awake

GA preferrable (long procedure, lower recurrence rates with GA, procedure & fluoroscopy time shorter with GA & pts prefer it generally). TIVA if using jet ventilation. ?if AVNRT, avoid volatile which suppresses the arrhythmia.

Absolute immobility for mapping & referenced catheter accuracy BUT particularly for cryoablation, phrenic nerve pacing (& observe diaphragm contraction) is necessary so need to have NMB recovery for this- remi useful.

Pressure areas important; 1-6hrs

Ventilation- movement impairs catheter stability, consider jet ventilation (eg. monsoon) or high frequency low volume ventilation (however there are systems for resp compensation within mapping software)

Oesophageal temp probe must be as close to ablation point as possible (alert proceduralist immediately if temp rise & stop if >38.5deg c)

Care with any electromagnetic interference

  • even metal objects close to the pt should be cleared prior to mapping
  • ensure warmers don’t cause electrical interference to the mapping system

Heparin 100U/kg after septal puncture, often give protamine @ conclusion to avoid groin haemostasis

smooth reversal & extubation (groin haematoma risk)

IDC- monitor urine volumes (particularly with irrigated ablation techniques)- risk fluid overload (esp with “cool flow” RFA), carefully monitor fluid balance, give fluid esp if pulm oedema is diagnosed. Useful to pass in/out catheter before wake if prolonged procedure to limit restlessness in PACU.

non-stimulating, very little postop pain (may be chest or groin or back from prol supine) but RFA more painful than cry-ablation. Generally just simple analgesia & groin LIA.

66
Q

Where’s the phrenic nerve located? incidence of phrenic nerve damage?

A

nestled btwn SVC & R) superior pulmonary vein

incidence of phrenic nerve damage varies with ablation type- highest risk with cryoablation (5%), still some risk with RFA due to heat energy but lower incidence (0.5%)

67
Q

What’s the average fluoroscopy time with AF ablation & radiation exposure in mGy? how does this compare with CT abdo & average yearly radiation exposure? lifetime risk of fatal malignancy after 1hr fluoroscopy?

A

20mins, 386mGy
CT abdo 10mGy
average yearly radiation exposure is around 5mGy
est 0.07% for males, 0.1% for females

68
Q

Success rates for AF ablation?

A

75% for pAF, 67% for persistent, success improved with continued use of antiarrhythmics
repeat procedures in 10% of pts (usually for recurrent AF)

69
Q

How is the anaesthetic technique for SVT or AVNRT ablation different from AF ablation?

A

likely LA+sedation to prevent suppression of slow pathway btwn AVN & BoH (unless pt factors make this imp0ssible eg. unable to lie flat)

Fellowship revision (78 decks)

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