Interactive Cardiovascular and Thoracic Surgery 3:510-515(2004)
© 2004 European Association of Cardio-Thoracic Surgery
Best evidence topic - Arrhythmia |
Prophylactic Amiodarone effectively prevents post-operative atrial fibrillation
Joel Dunning*,
Phil Botha and
Muneer Amanullah
Department of Cardiothoracic Surgery, Freeman Hospital, Freeman Road, Newcastle upon Tyne NE7 7DN, UK
* Corresponding author
joeldunning{at}doctors.org.uk
Received May 6, 2004;
accepted May 10, 2004
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Abstract
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A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether prophylactic Amiodarone can safely reduce the incidence of atrial fibrillation (AF) post-cardiac surgery. Altogether 90 papers were found using the reported search, of which 12 presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses of these papers are tabulated. We conclude that there is strong evidence that both oral and intravenous Amiodarone given prophylactically reduces the incidence of post-operative AF, with a number needed to treat of only seven to prevent an episode of AF.
Key Words: Evidence-based medicine; Thoracic surgery; Atrial fibrillation; Amiodarone; Review
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1. Introduction
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A best evidence topic was constructed according to a structured protocol. This protocol is fully described in the ICVTS [1].
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2. Clinical scenario
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You are in the bar with an American colleague while attending the European cardiothoracic conference in Monaco, and he is shocked that you do not give all your patients prophylactic Amiodarone to reduce the incidence of atrial fibrillation (AF). You find yourself unable to counter his arguments although you suspect that there must be a higher incidence of bradycardia and hypotension in his patients. Thus, as you are due to meet him on the conference golf course tomorrow; you therefore resolve to look up the evidence before teeing off!
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3. Three part question
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In [patients undergoing Cardiac Surgery] is [prophylactic Amiodarone] effective in [reducing the post-operative incidence of Atrial Fibrillation]
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4. Search strategy
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Medline 1966–July 2003 using the OVID interface.
[exp thoracic surgery/ OR cardiac surgery.mp. OR exp cardiac surgical procedures/ OR cardiac surgical procedures.mp. OR exp cardiopulmonary bypass/ OR exp coronary artery bypass/ OR CABG.mp] AND [exp amiodarone/ OR amiodarone.mp] AND [exp atrial fibrillation/ OR atrial fibrillation.mp]
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5. Search outcome
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90 abstracts were found, of which 78 were irrelevant. 11 RCTs and a meta-analysis were found [2–13] and these are shown in Table 1.
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6. Comment(s)
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Nine of the 11 papers show a significant reduction in the incidence of atrial fibrillation with prophylactic Amiodarone. The remaining two showed a non-significant trend to lower AF. Included in these papers are two very well-conducted studies reported in the NEJM and the Lancet journals, respectively. Giri et al. reported a ‘number needed to treat’ of only 6.5 to prevent an occurrence of AF.
Complications were low in all studies except in that of Butler et al., who found a significantly higher rate of bradycardia and pauses in the Amiodarone group, and Hohnloser who had to stop Amiodarone in 18% of his patients due to QT prolongation. Significant bradycardia was investigated in all other studies, but found to be non-significant.
The results of most of these studies have been summarized by meta-analysis by Crystal et al. [13]. He combined the data from nine of these studies and found a rate of AF of 37% in all control groups but 22.5% in the amiodarone groups. This gives a number needed to treat of 6.9. He did not however summarise the data on the rates of complications.
Thus although it is clear that Amiodarone significantly reduces the incidence of AF, the optimal Amiodarone regime that should be employed remains unclear, as these ranged from oral Amiodarone being started up to 7 days preoperatively to I.V. Amiodarone 2 h after return to ICU.
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7. Clinical bottom line
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There is strong evidence that both oral and intravenous Amiodarone given prophylactically reduces the incidence of post-operative AF, with a number needed to treat of only seven to prevent an episode of AF.
doi:10.1016/j.icvts.2004.05.003
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References
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Abstract
1. Introduction