6.0 Atrial fibrillation + anticoagulation

atrial fibrillation is the most common sustained cardiac arrhythmia

with increasing prevalence

left untreated atrial fibrillation is a significant risk factor

for stroke + other morbidities

men are more commonly affected than women

prevalence increases with age

therapeutics aims of drug therapy

reduce symptoms, palpitations

prevent complications, stroke

onset within 48 hours treatment plan

• Electrical cardiovert those with life-threatening haemodynamic instability (i.e. perfusion failure) that is thought due to AF. Do not delay to achieve anticoagulation.

• In those with no life-threatening haemodynamic instability, offer RATE or RHYTHMcontrol if <48 hours

• RATE control is preferred except for those in whom:

  • AF has a reversible cause

  • Have heart failure thought to be primarily caused by AF

  • Have new-onset atrial fibrillation

  • Have an atrial flutter which is considered suitable for ablation strategy (not covered in this lecture)

  • Rhythm control would be more suitable based on clinical judgement

• ONLY offer anticoagulation if

  • Sinus rhythm is not restored within 48-hours

  • At high risk of AF recurrence

  • High risk of stroke (separate guidance available)

if established AF after 48 hours since onset

• Start RATE control (preferred for most patients except for those listed on previous slide)

• If AF persists after heart rate has been controlled or unsuccessful, we can use electrical (not pharmacological) RHYTHM control (cardioversion), if the intention is to go onto long-term pharmacological rhythm control.

• Although electrical cardioversion should be used, we may augment this with with a drug called amiodarone (see later slides)

• In those where long-term rhythm control is intended, we delay cardioversion until they have been anticoagulated for at least 3 weeks. During that period offer rate control. Please see the BNF treatment summary (given later) for further information about this.

• If not already receiving anticoagulation therapy, offer heparin for immediate anticoagulation. This is while a full assessment of clot risk has been made and a suitable long term anticoagulant started.

rate control drugs

• standard beta blockers, carvedilol/bisoprolol

• rate limiting calcium channel blockers, verapamil/ diltiazem

calcium channel blockers

alternatives to beta blockers if contraindicated (patient has asthma)

rhythm control drugs

• flecainide acetate

• amiodarone hydrochloride

• sotalol

flecainide acetate

blocks Na⁺ channel → slows conduction via heart

most common choice as its better tolerated than many other anti-arrythmicmedicines

only used for those with a normal functioning heart, no cardiac defects

flecainide acetate dose

50 mg BD - 300mg OD

flecainide acetate monitoring

regular ECGs, once a week after starting dose + after dose change

flecainide acetate side effects

visual disturbance

GI symptoms

Amiodarone hydrochloride

blocks K⁺ channels → slowing cardiac conduction

go to treatment for those with structural heart disease/other AF medicines don’t work

Amiodarone hydrochloride dose

200mg TDS (3 daily) for 1 week

→ 200mg BD for another week

→ 200 mg OD continuously/ the lowest dose required to control the arrythmia

Amiodarone hydrochloride monitoring

thyroid function test every 6 months

LFT before then every 6 months

serum potassium before chest x ray

Amiodarone hydrochloride side effects

• corneal microdeposits

• thyroid function derangements

• hepatotoxicity

• pulmonary toxicity (pneumonitis)

Sotalol

slows heart rate + type II/III anti-arrhythmic at higher dose

blocks K⁺ channels to slow cardiac conduction

Sotalol monitoring

regular ECGS

can cause arrhythmias so monitoring is crucial

Sotalol side effects

bradycardia

fatigue

cold extremities

light headedness

paroxysmal AF

where a sudden episode occurs

to manage paroxysmal AF

large dose of antiarrhythmics to stabilise cardiac rhythm long term