Atrial Fibrillation Flashcards
Major mechanisms causing AF that can be considered when choosing therapy
Assessment
Confirm rhythm diagnosis on ECG.
Perform full cardiovascular examination including BP, HR, murmurs, and signs of HF.
Assess for risk factors and co-morbidities.
- Risk factors and co-morbidities
- Obesity
- Sleep apnoea
- Hypertension
- Alcohol excess
- Thyrotoxicosis
- Valvular heart disease – aortic or mitral stenosis or regurgitation
- Cardiomyopathy, which may be rate-related
- Infection e.g., pneumonia
- Diabetes
- Heart failure
Bloods – FBC, renal function, electrolytes, TSH.
Cardiovascular morbidity and mortality associated with AF
AF is a leading cause of HF if not controlled
Cardiovascular and other conditions independently associated with AF
The Era of Wearable and Home Monitoring Devices
Believe on apple / smart watch
No need for confirmation
Allwhat you need is a trace from the pt
Confirm with ECG/monitoring
Search for underlying cause and correct it
Confirm with ECG/monitoring first
- ‒ Cardiovascular history (hypertension)
- ‒ Pulmonary disease (obstructive sleep apnoea)
- ‒Other systemic disease, infection, surgery
- ‒ Thyroid disease
- ‒Obesity
- ‒ Family history
- ‒Alcohol
Investigations
‒Walk the pt insdie the clinic /stairs for HR check
‒ ECG
‒ Bloods
– FBC, U+E, creat, TFTs, LFTs
‒ Echocardiogram;
- for pathology and evidence of HF.
- should be done in all pts
- standard in NZ
Holter monitor for heart rate control (permanent AF
Red Flags
Chest pain – manage as per Chest Pain pathway
Haemodynamic instability
Heart failure
Recent (within last 14 days) stroke or transient ischaemic attack (TIA)
Associated mitral stenosis
Syncope
Management
- Correct underlying problem
- Rate Control
- Rhythm Control (maintenance of sinus rhythm)
- Anticoagulation
If any red flags, seek general medicine advice.
If clearly < 48 hours since AF onset, seek cardiology advice for consideration of acute cardioversion.
Manage risk factors and co-morbidities.
Consider echocardiography.
Assess risk of stroke and the need for oral anticoagulation, both for pts in permanent AF and those with PAF, as both are at the same risk of stroke.
The prevalence of AF and risk of stroke in Maori and Pacific populations is approximately 10 years in advance of European groups.
- This puts these groups at increased risk at a younger age, and must be considered when discussing anticoagulation options.
Use visual aids to help the pt understand the risks and benefits of anticoagulation.
Commence rate control therapy.
Consider rhythm control including cardioversion and AF ablation, and request non acute cardiology assessment. If unsure whether rhythm control is appropriate, seek cardiology advice.
Follow up regularly and manage other cardiovascular risk factors.
Monitor heart rate. If uncontrolled rate, request non-acute cardiology assessment.
If PAF, assess for anticoagulation as for persistent AF, and seek cardiology advice or request non-acute cardiology assessment, as pts with paroxysmal AF may be better managed with rhythm control, especially if they are symptomatic.
Heart Rate Control
Aim to reduce HR to
- walking the pt up and down the surgery corridor may suffice but consider 24 hour Holter monitoring.
‒ Review rate controlling medications regularly especially when they are getting older;
- Risk of bradycardia
- PAF is a risk of sick sinus syndrome; these pts often ended on having PPM
In cardiomyopathy treat AF straight away even if they have current infection
Medications:
Beta blockers:
Consider metoprolol as initial rate control treatment.
If raised HR, start with 47.5 mg modified release (CR) metoprolol and increment every 24 to 72 hours to a max of 190 mg daily.
- Monitor BP and HR while dose is being titrated.
- If pt aged ≥ 80 years and resting HR
Calcium channel blockers
Diltiazem modified release (CD) 120 mg, 180 mg, or 240 mg to a maximum dose of 360 mg daily.
Combination of b-blockers with calcium channel blockers:
For many pts, a combination of a b-blocker and a calcium channel blocker at a medium dose e.g., metoprolol modified release (CR) 95 mg + diltiazem modified release (CD) 120 mg is a better strategy to control HR, and has fewer side effects than a maximal dose of either agent alone.
Digoxin
Third‑choice agent as it has little effect on exercise heart rate.
Use with caution and consider seeking cardiology advice before commencing.
Recent studies have shown higher mortality in pts with AF taking digoxin. 2
If pt is elderly, frail, or has renal impairment, the toxicity risks are higher and may exceed benefits.
Consider requesting non-acute cardiology assessment
- and check the serum level after 7 days, aiming for a maximum level of
Lifestyle Management
‒ BMI < 27; is a huge driven to control AF
‒ Good BP control
‒ No smoking
‒ Regular exercise
‒ Maximum 8 standard drinks/ wee
Rhythm Control
Preferred for people with:
- ‒ Paroxysmal AF
- ‒ Younger age with minimal heart disease
- ‒WPW syndrome
- ‒Unacceptable symptoms from AF
- ‒Haemodynamic compromise
- ‒ LV impairment
- Electrical Cardioversion
- Pharmacological maintenance of SR
- Amiodarone: check TFT in 3/12
- Flecainide
- Metoprolol
- Sotalol; dose 80 BD for AF (but 40 BD if used as blocker), check blood levels and ECG in 2/52
- AF ablation (PVI)
Pulmonary Vein Isolation
‒ Venous approach with trans septal puncture.
‒ Radiofrequency or cryoablation to isolate the pulmonary veins and modify structures that cause re-entry including atrial flutter
- Not for pt > 75 yrs old; tricky procedure, going form Lt to Rt atrium
- Done under GA
- Not used for prevention of thromboembolism
- Risk of oesophageal perforation; be aware of chest pain post procedure
Atrial Fibrillation Ablation
Indication
- ‒ Symptomatic AF refractory or intolerant to at least 1 Class 1 or Class 3 antiarrhythmic
- ‒ Some symptomatic pts with LVF/↓LVEF
- ‒ Young, active pt
Complications
- ‒ Thromboembolism
- – NOAC for 3 months and lifelong if CHADS2 score > 2
- ‒ Tamponade, pulmonary vein stenosis, atrio-oesophageal fistula
Results
- 5 year success 63 - 82%
- May require repeat procedure but recurrences are common in 1st 3 months and don’t predict poor outcome
- Maintenance of SR during first 3/12 is very important
- Better if young, PAF, smaller LA size, no structural heart disease
- Improved with treatment of BP, obesity, OS
Clinical risk factors of stroke , transient ischaemic attack and systemic embolisation
Anticoagulate if score is more than 2
Adjusted stroke rate according to CHA2DS2 VASc score
CHA2DS2-VASc Calculator for Atrial Fibrillation
https://clincalc.com/Cardiology/Stroke/CHADSVASC.aspx
Score Action
0 No anticoagulation required
1 (female) No anticoagulation required
1 (male) Consider anticoagulation (possibly discuss with cardiologist)
≥ 2 Anticoagulation recommended – consider individual bleeding risk and preference
The HAS BLED bleeding risk score
AF secondary to thyrotoxicosis does not need anticoagulation
Averroes Trial. Aspirin vs Apixaban in Elderly
AVERROES trial
Aspirin is not appropriate Rx for stroke prevention in the elderly with AF
Results;
compared with aspirin, apixaban was more efficacious for preventing strokes and systemic embolism in pts ≥85 years
- absolute rate [AR] 1%/year on apixaban versus 7.5%/year on aspirin
- compared with younger patients (AR 1.7%/year on apixaban versus 3.4%/year on aspirin).
Major haemorrhage was higher in pts ≥85 years compared with younger pts
- but similar with apixaban versus aspirin in both young and older individuals (4.9%/year versus 1.0%/year on aspirin and 4.7%/year versus 1.2%/year on apixaban)
- with no significant treatment-by-age interaction (P-value = 0.65).
