AF Amiodarone Or Digoxin
Atrial Fibrillation (AF) is by far the most commonly encountered in the Emergency Department and is associated with the potential for serious consequences including stroke, deterioration of underlying cardiac disease, prolonged hospital stay, and increased mortality.
AF is an irregular, disorganized, electrical activity of the atria characterized by absent P waves and an irregular baseline on ECG.
The objectives of Acute Atrial Fibrillation Management :
- Rate control
- Prevention of Thromboembolism
- Correction of the rhythm disturbance
Rate control ? Rhythm control ?
RHYTHM CONTROL
- Conversion to NSR either by electrical (DCC) or pharmacological (AAD) cardioversion.
- Haemodynamically unstable: Electrical
- Haemodynamically stable: Either pharmacological or electrical conversion
- Preferred: greater efficacy (85% vs 45%) and low proarrhythmic risk but required generalized anaethesia
RATE CONTROL
- Slowing AV conduction
- Slow ventricular response rate → better ventricular filling with blood.
- If intolerable to S/E of rate-control agent
→ Combining lower-dose digoxin + B-blockers/CCBs - Amiodarone effective for patient who are not cardioverted to NSR
AMIODARONE OR DIGOXIN ?
AMIODARONE : Benzofuran derivative , Class III AAD
MOA :
Potassium channel inhibition.Prolongation of the myocardial cell-action potential duration and refractory period
Noncompetitive α- and β-adrenergic inhibition
DIGOXIN : Digitalis glycosides
MOA :
Na-K ATPase inhibitor
Vagomimetic effect – HR & AV conduction
Sympathetic activity – baroreceptor sensitization
Potassium channel inhibition.Prolongation of the myocardial cell-action potential duration and refractory period
Noncompetitive α- and β-adrenergic inhibition
DIGOXIN : Digitalis glycosides
MOA :
Na-K ATPase inhibitor
Vagomimetic effect – HR & AV conduction
Sympathetic activity – baroreceptor sensitization
Research :
Hou et al 1995
Digoxin, while not as effective as amiodarone in the treatment of recent-onset atrial fibrillation and flutter, appears to be safer.
Joseph et al 2000
The active treatment group was significantly more likely to have reverted to sinus rhythm than the rate control group ( Digoxin ).
Thomas et al 2004
The overall rates of cardioversion after trial drug infusion and defibrillation were high for all groups (amiodarone, 94%; sotalol, 95%,; digoxin, 98%; P = not significant), but there was a trend toward a higher incidence of serious adverse reactions in the amiodarone group.
Hofmann et al 2006
Amiodarone, given as an intravenous bolus is relatively safe and more effective than digoxin for heart rate control and conversion to sinus rhythm in patients with atrial fibrillation and a rapid ventricular rate.
Digoxin, while not as effective as amiodarone in the treatment of recent-onset atrial fibrillation and flutter, appears to be safer.
Joseph et al 2000
The active treatment group was significantly more likely to have reverted to sinus rhythm than the rate control group ( Digoxin ).
Thomas et al 2004
The overall rates of cardioversion after trial drug infusion and defibrillation were high for all groups (amiodarone, 94%; sotalol, 95%,; digoxin, 98%; P = not significant), but there was a trend toward a higher incidence of serious adverse reactions in the amiodarone group.
Hofmann et al 2006
Amiodarone, given as an intravenous bolus is relatively safe and more effective than digoxin for heart rate control and conversion to sinus rhythm in patients with atrial fibrillation and a rapid ventricular rate.
CONCLUSION :
Based on current evidence , Amiodarone also effective in rate control when other agent fails or contraindicated. However, Amiodarone associated with various adverse effect. Close monitoring and precaution is needed.
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