Cardiology - Arrythmias: AF Flashcards
AF Risk Factors:
DEMOGRAPHICS
- western countries
- males
- Caucasians
SYSTEMIC
- Hypertension
- obesity
- OSA
- diabetes
- hyperthyroidism
STRUCTURAL HEART
- HOCM
- Valvular heart disease (esp MS)
- ACS with HF (NOT IHD itself)
OTHER
- hypomagnesaemia (50 times more likely)
- alcohol (esp binge drinking)
Demographic RF for AF
- western countries
- males
- Caucasians
Systemic RF for AF
- Hypertension
- obesity
- OSA
- diabetes
- hyperthyroidism
Structural heart disease RF for AF
- HOCM
- Valvular heart disease (esp MS)
- ACS with HF (NOT IHD itself)
Nonspecific RF for AF
- hypomagnesaemia (50 times more likely)
- alcohol (esp binge drinking)
Definition of paroxysmal AF
Self terminates within 7 days
Persistent
> 7 days
Longstanding persistent
> 12 months
Permanent
Not for rhythm strategies
AF can develop post cardiac surgery.
How often?
When is greatest risk?
When can you stop anti-arrythmics?
Develops in 25%
Greatest risk post op on Day 2 and 3
Usually self-limited
Can stop antiarrythmics by 2-3 months post op
Describe the pathology behind the three phases of AF
Phase 1: Paroxysmal AF
- stretch increases propensity for PULMONARY VEIN focuses to develop due to stretch sensitive ion channels
Phase 2: Persistent AF
- over time there is remodelling of left atrium
Phase 3: Permanent AF
- With more time it is more difficult to maintain sinus due to gross electrical and structural atrial remodelling.
What can prevent AF?
- Manage risk factors
- Mediterranean diet with extra virgin olive oil or mixed nutes
- Being fit
Once you have an episode of AF what NON-PHARMA measures can prevent RECURRENCE?
Weight loss (if >10%) causes SIX TIMES decreased recurrence rate
Increased fitness
When is urgent cardioversion indicated, and when doing it how do you sync the charge?
Indicated urgently if HD compromise
Synchronise the R wave to AVOID R-on-T event which provokes VT
? do you need anticoagulation for AF?
If AF is definitely <48 hours then you don’t need anticoagulation
BUT
If uncertain duration or >48 hours then:
- TOE to look for thrombus in LV
- post chemical cardioversion anticoagulation for 3 weeks
- post-procedure anticoagulation for 4 weeks
Agents with PROVEN EFFICACY for pharmacologic conversion
Amiodarone Flecainide Quinidine Dofetilide Ibutilide Propafenone
Agents which are LESS EFFECTIVE at pharmacological conversion
beta blockers (including sotolol) CCBs Digoxin Disopyramide Procainamide
Why is CHA2DS2-VASc better than CHADS2?
It is more SENSITIVE
On what score do you anticoagulate on CHA2DS2-VASc
If it is >=2
Components of CHA2DS2-VASc
Congestive HF (+1) Hypertension (+1) Age >=75 (+2) Diabetes mellitus (+1) Stroke or TIA (+2) Vascular disease (+1) Age 65 - 75yrs (+1) Sex female (+1)
Which components of CHA2DS2-VASc earn 2 points?
Age >= 75yrs
Stroke or TIA
What are the components of HAS-BLED?
+1 point each:
- Hypertension
- Abnormal renal Cr>200 or liver (3 x normal)
- Stroke hx
- Bleeding hx
- Labile INR (time in therapeutic range <60%)
- Elderly >65yrs
- Drug or alcohol history (>8SD per week) or drugs that cause bleeding
What HAS-BLED score is considered HIGH RISK?
> =3
In anticoagulation of non-valvular AF what NOACs are NONINFERIOR to warfarin AND have lower ICH risk?
Dabigatran 110mg BD
Rivaroxaban 20mg daily
In anticoagulation of non-valvular AF what NOACs are SUPERIOR to warfarin AND have decreased ICH risk?
Apixaban 5mg BD
OR
Apixaban 2.5mg BD if >=2 of age>80, Cr >133 or weight <60kg
In using apixaban for stroke prevention in nonvalvuar AF when must the lower dose 2.5mg BD be used?
If 2 or more of:
- age >80yrs
- Cr >133
- weight 60kg
In anticoagulation of non-valvular AF what NOACs cmopared to warfarin have a MORTALITY benefit?
Apixaban
In anticoagulation of non-valvular AF what NOACs have a HIGHER GI BLEED RISK?
Dabigatran
Rivaroxaban
(Apixaban has no difference in GI bleed rate!)
In AF management should we use rate control or rhythm control in preference?
NEITHER!
Rate control is NONINFERIOR to rhythm control for both STROKE and SURVIVAL
BUT if we definitely wanted to give RHYTHM control in management of AF who would have a HIGHER mortality with RHYTHM control?
(and therefore should definitely be rate controlled only!)
Elderly
Coronary artery disease
CCF
In tachycardia-induced cardiomyopathy what should we aim for the HR?
<80bpm
If someone has SYMPTOMS would rate or rhythm control be preferred?
If symptoms then aim for RHYTHM control
Is lenient rate control (aim <110bpm) or strict rate control (aim <80bpm) better?
If NOT with underlying cardiomyopathy then there is no significant difference EXCEPT lenient will have less clinic visits
If deciding to rate control someone in AF what medications are used first line?
And if they have pre-excitation syndrome what must you avoid?
BB and CCBs first line
BUT
If pre-excitation:
- AVOID CCB and digoxin
- GIVE beta blockers, flecainide or amiodarone
In AF when maintaining sinus rhythm, what are the issues with Class I Sodium Channel Blockers?
Class I Sodium Channel Blockers (ie flecainide and propafenon)
- negative inotrope and pro-arrhythmic effects
- Don’t use if STRUCTURAL heart disease
- AVOID in coronary heart disease and CCF
- Can result in organisation to a flutter with 1:1
In AF when maintaining sinus rhythm, what are the issues with Class III Agents?
Class III agents such as sotolol, amiodarone and dofetilide
- able to be used in coronary artery disease and structural heart disease
- Risk of QTc prolongation and torsades
What is the BEST INDICATION to use catheter ablation and pulmonary vein isolation in management of AF?
Symptomatic paroxysmal AF refractory or intolerant of AT LEAST 1 Class I or Class III antiarrythmic
In catheter ablation of AF when is it best done?
Early in AF without significant atrial enlargement
If able, why is catheter ablation better than antiarrhytmics in AF?
- better at preventing recurrent atrial tachycardias
- reduced cardiovascular hospitalisations
- better QoL
Complications with catheter ablation in AF?
- tamponade (1%)
- Stroke (0.5-1%)
- Phrenic nerve paralysis
- Pulmonary vein stenosis (presents years or months later with SOB and haemoptysis)
Complications of AF?
- increased all-cause mortality
- Stroke rate 5% per year (compared to 1% if non-AF)
- worsened HF
- Tachycardia associated cardiomyopathy
- Increased risk dementia
- increased risk nursing home placement