TEE-guided cardioversion with short-term anticoagulation may be effective for people with atrial fibrillation undergoing electrical cardioversion

TEE-guided cardioversion with short-term anticoagulation may be effective for people with atrial fibrillation undergoing electrical cardioversion

ARTICLE IN PRESS Evidence-based Cardiovascular Medicine (2006) 10, 110–112 Evidence-based CARDIOVASCULAR MEDICINE www.elsevier.com/locate/ebcm ATRI...

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ARTICLE IN PRESS Evidence-based Cardiovascular Medicine (2006) 10, 110–112

Evidence-based

CARDIOVASCULAR MEDICINE www.elsevier.com/locate/ebcm

ATRIAL FIBRILLATION

TEE-guided cardioversion with short-term anticoagulation may be effective for people with atrial fibrillation undergoing electrical cardioversion$ Marcia Maiumi Fukujima, Debbie Singh

Background

Participants

People with atrial fibrillation are conventionally treated with therapeutic anticoagulation for three weeks before and four weeks after cardioversion to reduce the risk of thromboembolism. Using transesophageal echocardiography to guide short-term anticoagulation has been proposed as an alternative.

Participants were 1222 adults with atrial fibrillation of more than two days duration. Six month followup was available for 1034 people (85%). Mean age 66 years; 32% were women.

Intervention Objective Klein and colleagues assessed the effects of a transoesophageal echocardiography-guided strategy in people with atrial fibrilliation of more than two days duration undergoing electrical cardioversion. The primary endpoint was a composite of cerebrovascular accident, transient ischaemic attack, and peripheral embolism at six months. Secondary endpoints were haemorrhage, mortality, and sinus rhythm.

Participants assigned to transesophageal echocardiography were stratified according to the presence of thrombus and given anticoagulant therapy at their initial visit, at the time of cardioversion and for four weeks thereafter. People in the conventional arm received three weeks of warfarin therapy before cardioversion, followed by four weeks of postcardioversion warfarin. Decisions about ongoing anticoagulant therapy between eight weeks and six months were made by individual clinicians.

Method This randomised controlled trial took place in 70 clinical sites between August 1994 and August 1999. Follow up occurred after six months. $ Abstracted from Klein AL, Grimm RA, Jasper SE et al. Efficacy of transesophageal echocardiography-guided cardioversion of patients with atrial fibrillation at 6 months: a randomized controlled trial. Am Heart J 2006;151:380–9.

Main results At six months, there was no significant difference between groups in composite embolic events (risk ratio 2.47, 95% CI 0.78 to 7.88), all-cause mortality (risk ratio 1.48, 95% CI 0.76 to 2.92), or the occurrence of normal sinus rhythm (62.2% vs

1361-2611/$ - see front matter & 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.ebcm.2006.04.029

ARTICLE IN PRESS Atrial fibrillation

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58.1%, p ¼ 0:51). The rate of haemorrhages was lower in the transoesophageal echocardiographyguided group (risk ratio 0.58, 96% CI 0.35 to 0.97, p ¼ 0:04).

Caveats

Authors’ conclusions The authors concluded that, after six-month follow up, a transoesophageal echocardiography-guided strategy is similarly effective to conventional anticoagulation in people with atrial fibrillation of more than two days duration undergoing electrical cardioversion.

Overall quality topic importance method quality practical use Poor

Fair

cardioversion, there was greater incidence of sinus rhythm at six months in the TEE guided group. This appears to be the first clinical trial comparing such treatments at longer term follow up.

Good

Excellent

Commentary Atrial fibrillation is a significant cause of cardioembolic stroke, which is one of the most mentally and physically incapacitating conditions.1,2 Klein and colleagues previously suggested that at eight weeks follow up, TEE-guided cardioversion was associated with fewer haemorrhagic events compared to traditional treatment. There was no difference between groups regarding embolic events or death.3 The authors also found that a TEE-guided strategy was economically feasible compared to a conventional approach.

This study’s contribution This paper suggests that, at six months, TEE-guided cardioversion with short-term anticoagulation allowed safe and early electrical cardioversion and remains better than traditional therapy concerning bleeding complications. There was no difference in embolic events, mortality, or maintenance of sinus rhythm. The other important finding was that in people who actually had a

This large randomised trial recruited participants from many countries. However, the study could not be blinded. The authors acknowledged that the time for recruitment and randomisation was too long and the study stopped early, which meant the study was underpowered for the endpoint of stroke. Fifteen percent of participants were lost to follow up, which is a high rate. People with terminal conditions such cancer were not excluded, and congestive heart failure was not stratified by functional levels. This may have lead to bias in the mortality analysis. Unfractionated heparin (inpatients) or warfarin (outpatients) or combined therapy was given to both TEE-guided and the conventional treatment groups. Although target anticoagulation was well established for both subgroups, this was not rigorously controlled and could have affected the bleeding rate. People in the TEE-guided group who had embolic events and were not in atrial fibrillation had subtherapeutic INR/PTT. The mean age of participants who died in the TEE-guided group tended to be higher, and participants had many comorbid conditions. Older people have more abnormal findings in cardiac evaluation, thus they are also more likely to have cardioembolic stroke, even in the presence of atherosclerotic risk factors.4 TEE itself might help to diagnose other conditions such as aortic plaques, valve dysfunction, spontaneous echo contrast, and others that could be specifically treated, reducing the risk of vascular events, especially in older people who are more likely to have atrial fibrillation associated with other risk factors for stroke. It is not clear whether other risk factors were specifically treated (hypertension, hypercholesterolemia, etc). When a thrombus was found in the TEE group, the patient was not submitted to cardioversion. This group should have been stratified by stroke risk and analysed separately.

Implications The most recent ACC/AHA and ACCP guidelines for atrial fibrillation suggest that TEE-guided

ARTICLE IN PRESS 112 cardioversion for screening for thrombus is an alternative to conventional therapy.5 Recent trials suggest a tendency towards long-term anticoagulation therapy rather than cardioversion or use of antiarrhythmic drugs, restricting the indications of TEE-guided strategies. However, a TEE-guided strategy could be considered for specific purposes, such as symptomatic people with recent onset atrial fibrillation, those at high risk of stroke or bleeding and those with subtherapeutic or unknown anticoagulation.

M. Maiumi Fukujima, D. Singh 3. Klein AL, Grimm RA, Murray RD et al. Use of transesophageal echocardigraphy to guide cardioversion in patients with atrial fibrillation. N Engl Med J 2001;344:1411–20. 4. Fukujima MM, Tatani SB, Aguiar AS et al. Transesoph ageal echocardiography discloses unexpected cardiac sources of embolus in stroke patients aged more than 45 years. Arq Neuropsiquiatr 2005;63:941–5. 5. Fuster V, Ryde ´n LE, Asinger RW et al. ACC/AHA/ESC Guidelines for the management of patients with atrial fibrillation. Circulation 2001;104:2118–50. The authors did not report study sponsorship. Study enquiries to [email protected] Results abstracted by Debbie Singh.

References 1. Cerebral Embolism Task Force. Cardiogenic brain embolism. Arch Neurol 1986;43:71–84. 2. Cerebral Embolism Task Force. Cardiogenic brain embolism: the second report of the Cerebral Embolism Task Force. Arch Neurol 1989;46:727–43.

Commentary provided by Marcia Maiumi Fukujima PhD, Neurologist, Emergency Medicine and Evidence Based Medicine, Department of Medicine, Federal University of Sa ˜o Paulo, Brazil.