How to Treat Atrial Fibrillation?

Medical Treatment::

• Patients with rheumatic heart disease need warfarin anticoagulation.
• Patients under the age of 65 may be managed with aspirin alone without heart disease or other risk factors.

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. If there is more than one risk factor, use warfarin
Initial therapy
Anticoagulate 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.
• The use of ACE inhibitors, beta-blockers and spironolactone in heart failure significantly reduces mortality.
• Digoxin has only been shown to reduce hospitalisation.

Diuretic
Mild volume overload (mild CCF) and normal renal function, thiazide diuretic:

• Hydrochlorothiazide, oral, 25-50 mg daily.
• Caution in patients with gout.
• Contraindicated in impaired renal function.

Significant volume overload or abnormal renal or hepatic function, loop diuretic:

• Furosemide, oral, daily.
• Initial dose: 40 mg/day.
• Higher dosages may be required, particularly if also renal failure.

Note:

• Reduce the dose of diuretics before adding an ACE inhibitor unless the patient is clinically fluid overloaded.
• After the introduction of an ACE inhibitor, try to reduce the diuretic dose and consider a change to hydrochlorothiazide.
• There is no recommended routine use of potassium supplements with diuretics.
• They should only be used in the short term to correct documented low serum potassium level.

ACE inhibitor, e.g:

• Enalapril, oral, 2.5 mg 12 hourly up to 10 mg 12 hourly.

If ACE inhibitor intolerant, i.e. intractable cough:
Angiotensin Receptor Blocker (ARB), e.g:

• Losartan, oral, 50-100 mg daily. (Specialist initiated)

Spironolactone

• Use with an ACE inhibitor in patients presenting with Class III or IV heart failure.
• Do not use if GFR <30 mL / minute.
• Monitoring of potassium levels is essential if spironolactone is used with an ACE inhibitor or other potassium sparing agent or in the elderly.
• Spironolactone, oral, 25 mg once daily.

Beta-blockers
For all stable patients with heart failure who tolerate it.
Patients should not be fluid overloaded or have low blood pressure before initiation of therapy.

• Carvedilol, oral.
• Initial dose: 3.125 mg daily.
• Increase after two weeks to 3.125 g 12 hourly, if tolerated.
• Increase at two-weekly intervals by doubling the daily dose until a maximum of 25 mg 12 hourly, if tolerated.
• If not tolerated, i.e. worsening of cardiac failure symptoms, reduce the dose to the previously tolerated dose.
• Up-titration can take several months.

Digoxin
Symptomatic CCF owing to systolic dysfunction.

• Digoxin, oral, 0.125 mg daily. Specialist initiated.
• Digoxin trough blood levels (before the morning dose) should be maintained between 0.65 and 1.5 nmol / L
• Patients at high risk of digoxin toxicity are:
• the elderly,
• patients with poor renal function,
• hypokalaemia, and
• patients with low body weight.

Anticoagulants
Heparin for DVT prophylaxis.
For patients admitted to hospital, unless contraindicated:

• Unfractionated heparin, SC, 5 000 units 8 hourly.

Warfarin:
Narrow QRS complex (supraventricular) tachydysrhythmias

• Poor rate control.
• Severe symptoms.
• Warfarin, oral, 5 mg daily.
• Control with INR to therapeutic range, i.e. between 2.0 and 2.5.

Anti-dysrhythmic drugs

• Cardiac Dysrhythmias.
• Exclude the underlying structural heart disease in all patients with cardiac dysrhythmias.
• Only for potentially life-threatening ventricular dysrhythmias.
• Always exclude electrolyte abnormalities and drug toxicity first.

Thiamine
Consider in all unexplained heart failure.

• Thiamine, oral/IM, 100 mg daily.

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:
• INR between 2-3 patient is stable; do 3 monthly monitoring
• INR < 1.5 or > 3.5 do monthly monitoring

For rate control:

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

In CCF:

• Carvedilol, oral
• Immediate precipitating factor(s) of the CCF must be identified and treated to prevent further damage to the heart.
• Potentially reversible causes include:
• Anaemia,
• Thiamine deficiency,
• Thyroid disease,
• Ischaemic heart disease,
• Valvular heart disease,
• Haemochromatosis, and
• Constrictive pericarditis.

PLUS
If control not adequate 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.
• 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
• 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.