Atrial fibrillation

3 min readJan 23, 2022

Aetiology

Unknown. Natural history likely paroxysmal and then permanent AF, since having AF at all increases chances of having it always by causing electrophysiological changes in the heart.

Why treat?

5x increase in stroke risk (double in women!)
Present in 10% >85y of age

Note one-third of all AF asymptomatic and not picked up leading to strokes but no current recommendations for screening.

Risk factors

Modifiable

HTN
Diabetes
Obesity — 10% weight loss = better AF control
Prolonged endurance training
Excess EtOH — remodels the heart and encourages AF, abstinence reduces episode frequency
CCF and CAD
OSA

Nonmodifiable

Increasing age
Male gender
Family history may play a role in some cases

Assessment

Suspect if palpitations, syncope, SOB, stroke/TIA
Check pulse (irregularly irregular, but consider differentials like 2nd degree heart block, ectopic beats, and esp sinus arrhythmia) and confirm with ECG — this can be a 12 lead, Holter, or event recorder depending on clinical findings and symptom frequency
AF confirmed? Bloods — FBC, U&E, LFTs, TFTs — needed to start DOACs — although NICE recommend not doing any!
Consider echo if suspecting underlying structural/functional heart disease or planning cardioversion.

Management — The ABCs per ESC

A = Anticoagulation to avoid strokes

1. Calculate CHA2DS2VASc score for thromboembolic risk

≥2: offer anticoagulation if bleeding risk allows
1: consider anticoagulation in men, do not offer anticoagulation in women
0 in men or ≤1 in women: do not offer anticoagulation; review this once >65y age, or CVD comorbids develop

2. Calculate ORBIT score for bleeding risk

≤2 = low risk
3 = medium risk
≥4 = high risk
If high bleeding risk, modify risk factors

3. Offer DOACs first-line for anticoagulation if low ORBIT score and high CHADSVASc.

Use warfarin if valvular AF, ie mechanical heart valves or moderate-severe mitral stenosis.

4. Review annually with INR if on warfarin and U&Es if on DOACs to ensure correct doses. If not on anticoagulation, recheck CHADSVasc at age 65 or if they develop diabetes/CAD/CCF/PAD/stroke/TIA/emboli

NOTE: age and falls risk are NOT contraindications to anticoagulation by themselves! See studies below:
One 1999 study calculated that a person with an approximate CHADSVASc of 4 had to fall 295 times for the risk of falls to outweigh the benefits of warfarin!
https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/484991
Low-Dose Edoxaban in Very Elderly Patients with Atrial Fibrillation | NEJM
(took peeps half >80 and half >85y in a Japanese population and randomised them to either low dose edoxaban or placebo. Similar all-cause mortality and better QOL in the edoxaban with lower strokes/emboli but 3.3% risk major bleed vs 1.8% in placebo)

B = Better symptom control

Rate control

Default option for the majority. Aim HR ≤110bpm in most, if still symptomatic or LV function worsening aim HR ≤80bpm

First line: one of either beta blocker (not sotalol) or rate-limiting CCB (avoid CCB in heart failure)
Second-line: dual therapy with 2 of BB/CCB/digoxin
Digoxin monotherapy if sedentary or not tolerating above

Rhythm control

Only use over rate control if aiming to reduce symptoms, however EAST-AFNET4 trial suggest might be role for these in those with new-onset atrial fibrillation. May be more favourable if

young
first AF or short history
no/few comorbids or heart issues
rate control difficult to achieve
AF precipitated by temporary event like acute illness
Note: If same-day onset, discuss with cardiology urgently. If >48h since onset, they will instead need 3w anticoagulation at least.

First-line: electrical cardioversion
After cardioversion: beta blockers (not sotalol), dronedarone if certain criteria met, amiodarone if CCF (up to a year).
If cardioversion fails: left atrial ablation plus minus pacemaker insertion.

C = CVD risk factor/comorbid optimisation

Address all CVD risk factors together to reduce AF burden; controlling just HTN alone for example isn’t going to work. Target all the following

Aim BP ≤130/80 in hypertension
Optimal glycaemic control if diabetic
Lose weight if obese
Regular physical activity
Reduce alcohol intake
Caffeine — no evidence causes or contributes to AF
Sleep apnoea — treat with CPAP