Atrial Fibrillation (AF)

Algorithm

Management

Factors

Duration of symptoms
Clinical presentation of the patient
Potential complications of medication and anticoagulation

Duration symptoms

Paroxysmal = episode of AF that terminates spontaneously

Persistent = episode of AF that requires cardioversion

Permanent = AF is resistant to multiple cardioversions

Clinical presentation

May be unstable. If stable and the AF is rate controlled (i.e. ventricular rate <100 bpm), there is no overt need for hospital admission.

Trigger

AF may be generated by pericarditis, sepsis, PE, or other organic cause. In these cases, it is management of the underlying disorder that leads to cessation of the AF.

In general, if possible, rhythm control is preferred to rate control. For those with recent (convincing Hx onset <48 hrs ago) AF, opt for cardioversion.

Investigations

FBC, Coag., U&E, LFT, Inflam. markers
Chest X ray
ECG
ECHO - LA diameter, LV systolic function, valvular abnormality etc. - can be done in OPD if patient is clinically well

Medication

Rate control strategy

Rate control - 1st line = β-blockers (i.e. metoprolol, bisoprolol) or nondihydropyridone Ca⁺⁺ channel blockers (Diltiazem)
Sotalol is reserved for recurrent AF. Sotalol, a nonselective beta blocker with class III anti-arrhythmic activity, provides excellent rate control, but due to difficulties in initiation. It is associated with ↑QT interval so patients started on Sotalol need 48 hours monitoring on telemetry. There is an increased risk of sudden death in patients with a decreased ejection fraction, it is reserved for recurrent AF
Digoxin is a useful additional therapy in patients poorly controlled on B-blocker/ CCB or in patients with underlying heart failure
Amiodarone is indicated for rate control in patients who do not achieve adequate rate control on beta-blocker/ CCB / Digoxin or any combination of the above

Rhythm control strategy

Ibutilide infusion

1g MgSO₄ diluted in 50ml saline given over 15 mins, then,
1mg Ibutilide diluted in 50ml saline given over 15 mins
10mL of Corvert® injection 87mcg/mL = 1mg Ibutilide fumarate
Repeat Ibutilide infusion in 20 mins if still in AF
Ibutilide can be given as an IV infusion in patients who have paroxysmal atrial fibrillation but are symptomatic during their episodes. Give after Mg⁺⁺ loading to prevent VT

Flecainide

Flecainide In patients with lone AF, flecainide or propafenone can be beneficial in maintaining sinus if treatment is initiated whilst the patient is in sinus rhythm
Flecainide and propafenone are contraindicated in coronary artery disease

Sotalol

Sotalol can be an effective agent in a rhythm control strategy if the QT interval is less than 460 milliseconds, renal function is normal, and there is no LV dysfunction.

Amiodarone

Amiodarone is recommended if LV dysfunction and renal impairment

β blockers

B blockers are first line agents in patients with coronary artery disease
In CUH, Vernakalant (Brinavess) injection is kept in the Drugs Press in Resusc
Consider catheter ablation if symptomatic AF with left atrial enlargement on echocardiography

Cautions restricting medical therapy

Beta blockers - care in asthmatics and LV failure

Diltiazem - raise LFTs and worsen LV function

Digoxin - visual disturbance, heart block (beware overdose)

Amiodarone -NB interaction with Warfarin, rhabdomyolysis, photosensitivity, liver dyscrasias, thyroid dyscrasias

Anticoagulation

Assess CHADS-vasc and HAS-bled before deciding on anticoaulation.

CHADS-Vasc
	Criteria	Score
C	CCF	1
H	Hypertension	1
A	Age (≥75)	2
D	Diabetes	1
S	stroke or TIA	2
V	Vascular event (MI, PVD)	1
A	Age (65-74yrs)	1
S	Sex (female)	1

NICE 2014 recommendations:

CHADS-Vasc	Recommendations
0	No anticoagulation
1	Consider anticoagulation
2	Recommend anticoagulation

HAS-bled

1-year risk of major bleeding in patients with AF.

Risk of major bleeding in AF
	Condition	Score
H	Hypertension systolic >160mmHg	1
A	Abnormal Renal fxn	1
A	Abnormal liver fxn	1
S	Stroke (prior history of)	1
B	Bleeding (Hx prior or predisposition)	1
L	Labile INR	1
E	Elderly (age >65)	1
D	Drink (>16 units/week)	1
D	Drugs (that predispose to bleeding e.g. NSAIDs)	1

HAS-bled score ≥3 = "high risk".

Stroke prevention

Do not offer stroke prevention therapy to people aged <65 years with AF and no risk factors other than their sex (that is, very low risk of stroke equating to a CHA2DS2-VASc score of 0 for men or 1 for women).

Anticoagulation is indicated in all patients with atrial fibrillation, except the 10-15% of cases where there is no structural heart disease and no underlying cause found (‘Lone A fib’ which should nevre be Dx in ED - cardiology / AF clinioc after Ix)
Rivaroxaban 20 mg OD [15mg OD if ↓ Creat.Cl] - more on NCHD.ie or Warfarin is indicated if one or more risk factors:
- age >75 years, hypertension, diabetes mellitus
- congestive heart failure, previous diagnosis of TIA or CVA
- LV systolic dysfunction (LV ejection fraction 35% or less)
In general, Warfarin is preferred (over a DOAC) in AF patients with:
- HOCM
- "Valvular" (usually ≥moderate M. stenosis) AF
- Low eGFR
In patients who require urgent cardioversion, patients should be anti coagulated Rivaroxaban (for 6 weeks) or therapeutic dose LMWH for 48 hours and commenced on Warfarin therapy for six weeks thereafter. Urgent cardioversions should be TOE-guided to minimize the risk of embolic stroke
In situations where a patient requiring Rivaroxaban or Warfarin for AF undergoes a PCI, the Warfarin should be restarted as soon as practicable post-procedure. The drug regimen the patient will be on will therefore include ±aspirin 75mg, ±Clopidogrel 75mg and Warfarin at a therapeutic dose

Follow up

All patients (still in AF or cardioverted) require OPD follow up for Ix (e.g. ECHO to check for structure, LV fxn & chamber size) and consideration of delayed rhythm control (even if asymptomatic)
In CUH, please refer, via ICM to the "Atrial Fibrillation Clinic"

Special Considerations

Post Operative AF

AF (no prior Hx) Dx within 5 days of a surgical procedure requiring GA
β-blockers to control rate are first line
Amiodarone second line
Ibutilide or DC cardioversion as per non-post-op situations

AMI

DC cardioversion if evidence of ongoing ischaemia or haemodynamic compromise
IV Amiodarone infusion indicated to slow a rapid ventricular response to AF and improve LV function in acute MI
IV Β blockers and the non-dihydropyridine class of Ca⁺⁺ channel blockers should be used to effect rate control in acute MI patients who do not show evidence of LV failure, heart block or bronchospasm
Anticoagulation should be given via unfractionated heparin to a target APTT of 1.5 -2.0 normal, or therapeutic low molecular weight heparin dosage (LMWH, 1mg/ kg body weight twice a day)

Pregnancy

In pregnancy, the rate control medications of choice include Digoxin or Diltiazem
AF developing during pregnancy, Procainamide or Quinidine pharmacologically cardiovert
DC cardioversion if unstable
Anticoagulation (LMWH) in recommended throughout pregnancy for patients with AF

WPW

Catheter ablation is treatment of choice
Immediate cardioversion if very rapid AF (risk VF)
Ibutilide is recommended to restore sinus rhythm in patients with AF and WPW who are not haemodynamically compromised

mEHRA

modified European Heart Rhythm Association classif.
Score	Symptoms	Description
1	None	AF does not cause any symptoms
2a	Mild	Normal daily activity not affected by symptoms related to AF
2b	Moderate	Moderate Normal daily activity not affected by symptoms related to AF, but patient troubled by symptoms
3	Severe	Normal daily activity affected by symptoms related to AF
4	Disabling	Normal daily activity discontinued

Atrial Fibrillation