Atrial Fibrillation



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 less than 80 beats per minute), 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.

Investigations

  • FBC, Coag., U&E, LFT, Inflam. markers
  • Chest X ray
  • ECG
  • ECHO - LA diameter, LV systolic function, valvular abnormality etc.

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 (because it is associated with prolongation of the QT interval, patients started on Sotalol need 48 hours monitoring on telemetry) and 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.
  • 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. This should be given after Mg++ loading to prevent VT.

Flecainide

  • Flecainide.In patients with lone AF, Flecainide or propafenone can be beneficial in maintaining sinus rhythm if treatment is initiated whilst the patient is in sinus.
  • 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

Assessing risk of stroke in AF.

  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.

Condition Score
H Hypertension
systolic >160mmHg
1
A Abnormal Renal fxn 1
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
Drugs (that predispose to bleeding e.g. NSAIDs) 1

HAS-bled score ≥3 = "high risk".


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’)
  • Rivaroxaban 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 patients who require urgent cardioversion, patients should be anti coagulated Rivaroxaban (for 6 weeks) or with therapeutic dose low molecular weight heparin 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. Clopidogrel should be given for at least 1 month after implantation of a bare metal stent, and at least six months after implantation of a drug eluting stent. Decisions with regard to discontinuing any of this regimen should be done in consultation with the Consultant Cardiologist attending the patient.

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 beta blockers and the non-dihydropyridine class of calcium 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.

Wolff-Parkinson-White syndrome

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


Content by Dr Ronan Curtin Dr Íomhar O' Sullivan 12/04/2011. Reviewed by Dr ÍOS 09/03/2005, 24/04/2007, 09/02/2008. Last review Dr C Luke, Dr ÍOS 19/02/19