Atrial Fibrillation ( AF )

Disorganized electrical activity in atria- most common sustained cardiac arrhythmia.

Atrial fibrillation is a supraventricular tachyarrhythmia. It is characterized by uncoordinated atrial activity on the surface ECG , with fibrillatory waves of varying shapes , amplitudes , and timing associated with an irregular ventricular response when AV conduction is intact 
( BMJ Best Practice 2019 )

Atrial fibrillation – how common

Prevalence of AF is increasing worldwide It is the most common sustained arrhythmia AF prevalence increases with age -less than 0.1 % in > 55s 
to more than 15 % in those aged 75 yrs or over Worldwide prevalence is 1 % Men are more commonly affected than women It is thought that there are 25 to 30 % of people in the UK with AF without it being diagnosed yet It is estimated that the number of adults older than 55 with AF in the EU will double from 2010 to 2060

AF subtypes

Persistent -Episodes lasting > 7 days → spontaneous termination unlikely to occur after this time

Permanent -AF that fails to terminate using cardioversion Terminated but relapses within 24 hrs Longstanding AF→ + 1 yr, cardioversion not attempted or indicated

Paroxysmal -episodes lasting longer than 30 seconds but less than 7 days 
( often < 48 hrs ) that 
are self-terminating and recurrent process

Lone AF -Lone AF → term used to identify AF in younger patients ( < 60 ) without structural heart dis , who are at low risk of thromboembolism

Causes of Atrial Fibrillation -Coronary artery dis Hypertension Valvular heart disease LV failure ( any cause ) HOCM

Reversible -Alcohol binge Pneumonia Hyperthyroidism Acute MI Acute pericarditis Myocarditis Exacerbation of pulmonary dis PE Cardiac surgery

Why is AF important– Stroke and thromboembolism
◙ 5 times ↑ risk of stroke and thromboembolism
◙ stroke severity ↑↑ when is associated with AF
◙ peripheral thromboembolism
 Heart failure
◙ commonly associated with AF
◙ ↓ Cardiac output → pushes compromised ventricle into failure Diminished exercise capacity ↑ ed risk dementia Increased risk death ( twofold ) Tachycardia- induced cardiomyopathy and critical ischaemia Increased risk hospitalization Reduced quality of life

Any symptoms present ? enquire about Breathlessness Palpitations chest discomfort Syncope or dizziness Any signs of heart failure ↓ exercise tolerance, malaise , or polyuria Stroke , TIA or Heart failure 
( possible complications of AF )

Any identifiable cause ? Cardiac causes- as
○ hypertension
○ valvular heart disease
○ heart failure
○ IHD Respiratory causes- such as
○ chest infections
○ pulmonary embolism
○ lung cancer
○ obstructive sleep apnoea Systemic causes- as
○ excessive alcohol intake
○ thyrotoxicosis
○ electrolyte depletion
○ infections
○ diabetes H/O rheumatic fever -heart disease Obesity

Examination -Check pulse manually ~ 1 min Most patients are stable CVS and resp examination Vitals BP , Pulse , O2 , temp

What else can cause an irregular pulse -Atrial flutter Atrial extrasystoles Ventricular ectopic beats Sinus tachycardia SVTs Multifocal atrial tachycardia SR with premature atrial or ventricular palpitations

Investigations -FBC U/E LFT , GGT TFT , Bl gluocse , Hba1c Consider Calcium and magnesium CXR if suspected resp pathology CVD risk assessment

Presentation-Opportunistic finding ? in an otherwise well patient ? Symptomatic-do I need
 to admit ? for e.g for ? cardioversion or with a complication of AF is stroke , TIA or heart failure
consider admission ? AF associated with any 
of the following
 Rapid pulse > 150 bpm Low BP – systolic bp < 90 Loss of consciousness Severe dizziness Ongoing chest pain Increasing breathlessness or significantly worsened SOB Stroke , TIA or acute LVF-Admit – urgency based on
 presentation

Management -Confirmed AF and patient is stable-Use the NICE decision aid tool
( see under resources- external links provided )
to calculate the risk of stroke CHA2DS2VASc score AND consider the following

CHA2DS2VASc 
score

Score 0 – and low risk with no other risk factors – anti thrombotic therapy is not recommended
 Score 2 or greater 
○ take into account HAS-BLED score
○ Warfarin or a DOAC as per NICE Patient decision aid
○ take into account local guidance to decide which DOAC


Consider assessing risks and benefits of anti-thrombotic therapy using the sparctool 
( see under resources ) or the Keele University decision support tool and discuss with the patient – this is the same tool which is used by NICE

HAS-BLED score- Assess the bleeding risk using
 the HASBLED score
 ( therapeutic bleeding risk stratification score )
to identify modifiable risk factors

A risk of 3 or more indicates an increased 1 year risk on anti-coagulation sufficient to justify caution or more regular review

Rate limiting therapy-Recommended 1st line for most people with AF Take into account ○ symptoms ○ heart rate ○ comorbidities ○ preferences Prescribe beta blocker as 1st line e.g Bisoprolol 1.25 – 10 mg Atenolol , acetabulol , metoprolol , nadolol , oxprenolol are also licenced for AF use If beta blocker is contra-indicated and LV function normal consider a rate limiting calcium channel blocker e.g Diltiazem or Verapamil Digoxin- monotherapy only if patient is sedentary.
If beta blocker contra-indicated and there is LV dysfunction , prescribe digoxin as 1st line Amiodarone and Dronedarone for specialist initiation only Aim to keep resting HR < 80 at rest and accept 
up to 110 BPM. If resting HR > 110 / symptomatic consider
○ ↑↑ beta blocker / Ca channel blocker dose
○ add digoxin

In some patients a rate limiting strategy as first line may not be appropriate -such as-AF has a reversible cause pt has heart failure thought to be caused by AF New onset AF and electrocardioversion is planned ( in real life scenario judging if the AF has started within last 48 hrs is not always possible ) atrial flutter and ablation strategy to restore SR a rhythm control strategy is more suitable

Echocardiogram -All patients will benefit with echo following first presentation Rhythm control planned for e.g cardioversion High suspicion of structural / functional HD e.g failure , murmur Refinement of stroke / bleeding risk stratification is needed to decide upon Anticoagulation strategy

Cardiology referral -Symptomatic ( sob ,dizzy, tired , palpitations ) despite strict rate control (resting HR <80 bpm and exercise <110 ) persistent AF Vagal AF suspected ( AF in younger people with structurally normal heart ) Other arrhythmias as WPW syndrome , tachy-brady syndrome
Uncontrolled ventricular rate , arrhythmia post AF ablation Heart failure ( caused or worsened by AF ) Any stage if treatment fails to control the symptoms of AF and more specialised management is needed Paroxysmal AF and further investigations / management needed Rhythm control strategy is more suitable for e.g Electrical cardioversion / pharmacological , LA ablation , pace and ablate strategy

Links and Resources

American College of Cardiology AF Toolkit https://www.acc.org/tools-and-practice-support/clinical-toolkits/atrial-fibrillation-afib

NICE AF Decision-making toolkit https://www.anticoagulation-dst.co.uk/

SPARC– Stroke Prevention in Atrial Fibrillation Risk Tool http://www.sparctool.com/

NICE guideline atrial fibrillation https://www.nice.org.uk/guidance/cg180

HAS-BLED score via MD+CALC https://www.mdcalc.com/has-bled-score-major-bleeding-risk

European Society of Cardiology AF Management Guidelines https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Atrial-Fibrillation-Management

American College of Cardiology 2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients with Atrial Fibrillation https://ahajournals.org/doi/full/10.1161/CIR.0000000000000665

AF Association http://www.heartrhythmalliance.org/afa/uk

AF toolkit Detect protect and Perfect from London Clinical Networks – a fabulous work and must-read for GPs in London area http://www.londonscn.nhs.uk/wp-content/uploads/2017/06/detect-protect-perfect-london-af-toolkit-062017.pdf

Oxford Clinical Commissioning Group has produced useful guidance for DOACs/ NOACs initiation –Primary Care Prescriber Decision Support for Stroke Prevention in AF https://www.oxfordshireccg.nhs.uk/professional-resources/documents/clinical-guidelines/cardiovascular/prescriber-decision-support-for-DOACs-in-atrial-fibrillation.pdf

Arrhythmia Alliance is a large charity working to improve the diagnosis, treatment and quality of life for all those affected by arrhythmias https://www.heartrhythmalliance.org/aa/uk/for-clinicians

AF leaflet from Stroke Association https://www.stroke.org.uk/resources/atrial-fibrillation-af-and-stroke

Top tips for readings ECG to identify AF from Acadoodle https://www.acadoodle.com/articles/how-to-diagnose-atrial-fibrillation-top-5-tips

Canadian Cardiovascular Society AF Management guideline- covers all important aspects with easy to understand charts https://www.ccs.ca/eguidelines/Content/Topics/AtrialFib/Part%201%20Initial%20Evaluation%20of%20Atrial%20Fibrillation.htm

What is ( EPS ) electrophysiology study? PIL from University Hospital of Southampton https://www.uhs.nhs.uk/Media/Controlleddocuments/Patientinformation/Heartandlungs/Electrophysiologystudy-patientinformation.pdf

 

References

1. The management of Atrial fibrillation: summary of updated NICE guidance BMJ 2014;348:g3655
2. Atrial fibrillation: management Clinical guideline CG180 June 2014
3. NICE Pathways atrial fibrillation 2016
4. ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS European Heart Journal (2016) 37, 2893-2962
5. Medscape Atrial Fibrillation Lawrence Rosenthal et al Jan 2016
6. Oxford Handbook of Cardiology- Atrial Fibrillation
7. CKS NHS Atrial Fibrillation
8. Stroke prevention in atrial fibrillation : can we do better Br J Gen Pract 2016 ; 66 (643)
9. Kent Surrey Sussex Academic Health Science Network Primary Care Atrial Fibrillation Pathway
10. Herts Valleys Clinical Commissioning Group – Diagnosis and Primary Care Management of Atrial Fibrillation in Adults AF
11. BMJ Best Practice AF Summary via https://bestpractice.bmj.com/topics/en-gb/1
12. DePalma, Sondra M. MHS, PA-C, DFAAPA, AACC Managing atrial fibrillation in primary care, Journal of the American Academy of Physician Assistants: June 2016 – Volume 29 – Issue 6 – p 29-33 doi: 10.1097/01.JAA.0000483091.58770.f7
13. South East Clinical Network Primary care Atrial Fibrillation Pathway https://www.swahsn.com/wp-content/uploads/2017/11/Primary-Care-Atrial-Fibrillation-Pathway-KSS-AHSN.pdf
14. Atrial Fibrillation: Diagnosis and Treatment CECILIA GUTIERREZ, MD, and DANIEL G. BLANCHARD, MD, University of California, San Diego, La Jolla, California American Academy of Family Physician http://unmfm.pbworks.com/f/Atrial%20Fibrillation_Diagnosis%20and%20Treatment_AAFP.pdf
15. Atrial fibrillation 2:assessment and diagnosis Christine Cottrell Practice Nursing 2012, Vol 23, No 2 https://www.educationforhealth.org/wp-content/uploads/2015/03/PN_23_2_77_AF2_NEW.pdf
16. Managing Atrial Fibrillation in Primary Care Key issues for primary care practitioners,
    managers and commissioners of services British Heart foundation
17. Clinical pathway for people with atrial fibrillation or
    at risk of atrial fibrillation Cheshire and Merseyside Strategic Clinical Networks https://www.nwcscnsenate.nhs.uk/files/1414/4543/7970/AF_Pathway_Master_FINAL_OCTOBER_2015.pdf?PDFPATHWAY=PDF