ATRIAL FIBRILLATION

Acute onset (<48 hours)

Assess clinically, e.g. heart failure, mitral stenosis, thyrotoxicosis, hypertension, age and other medical conditions. Consider anticoagulation with heparin or warfarin.

Synchronized direct current (DC) cardioversion is occasionally necessary in emergency. Consider if first episode.

Non-acute/chronic (> 48 hours)

As above, but not immediate DC cardioversion, unless emergency.

MEDICINE TREATMENT

Patients with rheumatic heart disease require anticoagulation with warfarin. Patients under the age of 65 with no heart diseases or other risk factors may be managed with aspirin alone.

Risk factors of stroke in atrial fibrillation are:

»     cardiac failure,

»     hypertension, »     age > 65,

»     diabetes, and »     stroke.

If patient has one of those risk factors use either aspirin or warfarin. Where more than one risk factor is present, use warfarin

Initial therapy

Anticoagulant with warfarin:

• Warfarin, oral, 5 mg daily adjusted according to INR.
  

• Atenolol, oral, 50–100 mg daily.
  
  • Contraindicated in asthmatics, heart failure.
    

OR

In CCF:

• Carvedilol, oral. failure.
  

PLUS

If control not adequate add:

• Digoxin, oral 0.25 mg daily according to response.
  
  • Higher doses require digoxin trough level monitoring.
    

If -blockers are contra-indicated, e.g. asthma or severe peripheral vascular disease:

• Verapamil, oral, 80 mg 12 hourly.
  

If not controlled on those agents, refer to specialist for consideration of alternative therapy, e.g. amiodarone.

DC cardioversion in selected cases, after 4 weeks warfarin anticoagulation.

Long-term therapy

Continue warfarin anticoagulation long-term, unless contra-indicated:

•     Warfarin, oral, 5 mg daily.

Control with INR to therapeutic range:

o INR between 2–3 patient is stable; do 3 monthly monitoring

o INR < 1.5 or > 3.5 do monthly monitoring

Caution

Use warfarin only if INR can be monitored regularly.

For rate ontrol:

• Atenolol, oral, 50–100 mg daily.
  
  • Contraindicated in asthmatics, heart failure.
    

In CF:

• Carvedilol, oral.
  

See section 3.4: Congestive cardiac failure.

PLUS

If control not aequate add:

• Digoxin, oral 0.25 mg daily according to response.
  
  • In patients with impaired renal function (eGFR<60 mL/minute), consider 0.125 mg daily and adjust according to trough level monitoring.
    
  • o In all patients, digoxin trough level monitoring is required at all doses.
    

If -blockers are contra-indicated, e.g. asthma or severe peripheral vascular disease:

• Verapamil, oral, 80 mg 12 hourly.
  

If not controlled on these agents, refer to specialist for consideration of alternative.

Prevention of recurrent paroxysmal atrial fibrillation

Only in patients with severe symptoms despite the above measures:

• Amiodarone, oral, 200 mg 8 hourly for 1 week. Specialist initiated.
  
  • Followed by 200 mg 12 hourly for one week o Thereafter 200 mg daily.
    

Precautions:

• Halve dosage of warfarin and monitor INR closely, until stable.
  
• Avoid concomitant digoxin.
  
• Monitor thyroid function every 6 months as thyroid abnormalities may develop.
  
• Ophthalmological examination every 6 months.