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Three Part Question

In [patients going into AF, 3 days post CABG who have good LV function and are haemodynamically stable] is [Amiodarone compared to Digoxin] the best treatment in [causing return to sinus rhythm]?

Clinical Scenario

You are a busy consultant doing a ward round before the first case gets into theatre. You come to a 75 year old lady 3 days post CABG who has gone into AF overnight with a rhythm of 160. Her BP is 100/60 and she has a good LV and was in sinus rhythm preoperatively. You congratulate the SHO for starting amiodarone at 2am but she then asks you why three of your consultant colleagues insist on digoxin whereas 2 of your colleagues always use amiodarone. As you have just set up a critical appraisal journal club, instead of answering her, you suggest that you both go away and attempt to retrieve the evidence by the end of the week.

Search Strategy

Medline 1966-07/02 using the OVID interface.
[(exp cardiac surgical procedures/ or cardiac surgical procedure$.mp) OR (exp coronary artery bypass/ or coronary artery bypass.mp)] AND amiodarone.mp AND (exp digoxin/ or digoxin.mp)

Search Outcome

Only 10 papers were found of which 9 were irrelevant or reviews. The remaining paper is shown in the table.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Cochrane AD et al, 1994, Australia	30 previously stable patients who developed sustained AF >20 mins. following Myocardial revascularisation, valve surgery or combined procedures. 15 patients received a loading dose of 5mg/kg iv over 30 mins then an infusion of 25mg/hr. Rate increased to 40mg/hr if rate >120 in 6 hours. Treatment continued for 24 hours after reversion to SR 15 patients received Digoxin, 500mcg iv over 30 mins. Then 250mcg iv after 2 hours, then 125 mcg iv after 5hrs and 9hrs. Then oral Digoxin started on a per kg basis (formula not given)	PRCT	Reduction in heart rate in the first 6 hours	Amiodarone group146 to 89 bpm Digoxin group144 to 95 bpm P=0.33	Randomisation was on the basis of their hospital number – flawed method Not blinded study Small numbers no power study done No control group
			Conversion to SR after 24 hours	Amiodarone group14 out of 15Digoxin group12 out of 15 p=0.87
			Length of hospital stay	Rate control 13.2+/-2 days Antiarrhythmia strategy 9.0+/- 0.7 days P=0.05

Comment(s)

Despite a large number of papers that look at either amiodarone or Digoxin in isolation or in comparison with other agents, this is the only study that directly compares these two treatments. It is a small study without a control group and it not surprisingly shows little difference between the two drugs. The treatment of AF after cardiac surgery is however an important topic and therefore further BETs should look at Sotalol, Propafenone, and quinidine and even no treatment.

Clinical Bottom Line

There is no evidence that either Amiodarone or Digoxin is the best treatment for AF after cardiac surgery.

References

1. Cochrane AD, Siddins M, Rosenfeldt FL, et al. A comparison of amiodarone and digoxin for treatment of supraventricular arrhythmias after cardiac surgery. Eur J Cardiothorac Surg 1994;8:194-8.