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Three Part Question

Can [patients with recent onset atrial fibrillation (less than 48 hours)] after successful [cardioversion] be [discharged safely from the emergency department]

Clinical Scenario

A 47-year-old man attends the emergency department with a 12-h history of palpitations and slight chest tightness. On examination he is found to be in atrial fibrillation with fast ventricular response. He is haemodynamically stable. You decide to cardiovert the patient as he is symptomatic. After successful cardioversion he is feeling well and remains stable. His cardiac markers and electrolytes are also normal. You wonder whether he can go home immediately or if he needs to stay in hospital for a further period of observation.

Search Strategy

Medline 1970–May 2012 via NHS Evidence web interface. [atrial AND fibrillation.ti,ab OR exp ATRIAL FIBRILLATION] AND [cardioversion.ti,ab OR *ELECTRIC COUNTERSHOCK OR electroversion.ti,ab OR countershock.ti,ab OR electrical AND cardioversion] AND [Emergency AND Department, ti,ab] [Limit to: Publication Year 1970–Current and Humans and English Language].

Embase 1980–18 April 2012 via the NHS Evidence web interface [atrial AND fibrillation.ti,ab OR exp ATRIAL FIBRILLATION] AND [cardioversion.ti,ab OR *ELECTRIC COUNTERSHOCK/ OR electroversion.ti,ab OR countershock.ti,ab] AND exp Emergency Room/81 records
The Cochrane Library date of searching 18 April 2012: MeSH descriptor Electric Countershock explode all trees AND MeSH descriptor Atrial Fibrillation explode all trees AND MeSH descriptor Emergency Medical Services explode all trees.

The NICE guideline published in 2006 on the management of atrial fibrillation was also reviewed.

Search Outcome

Ninety-six papers were found out of which seven were relevant to the search question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Michael et al, 1999, Canada	289 Consecutive ED patients with a primary diagnosis of recent-onset AF	Retrospective cohort study	Discharge from ED. ED return rate after chemical cardioversion. ED return rate after electrical cardioversion. Thromboembolic event	99% (160/161) of successfully cardioverted patients were discharged home from the ED. 12% ED return rate (11/89), 10 for relapse of AF and 1 for a new problem. 10% ED return rate (7/71): 6 for relapse of AF. None	Complication rate may be underestimated because the follow-up period was 7 days and limited to return visits to the study site
Burton et al, 2004, USA	388 Patients (mean age 61 years; range 20–93 years) who underwent ED electrical cardioversion in 4 institutions. Duration was less than 48 h in 99% of the cohort	Retrospective health records survey	Discharge from ED. Return to ED. Thromboembolic event	333 (86%) Patients were discharged to home from the ED: 301 after electrical cardioversion success and 32 with electrical cardioversion failure. 39 Patients (10%) returned to the ED within 7 days, 25 of these patients (6% of successful electrical cardioversion patients) returned because of relapse of AF. None	Record survey only. Follow-up only done for 7 days
Jacoby et al, 2005, USA	Patients were eligible for study inclusion, they presented to the ED with recent-onset AF/flutter or if they presented with AF/flutter of an unknown duration but received therapeutic anticoagulation. 24 Patients were included in the study and 30 ED cardioversions were performed on 24 enrolled patients (average age 63 years; 63% men; 37% receiving warfarin). The presenting rhythm was AF in 87% of patients and atrial flutter in 13%	Prospective cohort study with a retrospective control group conducted at a community teaching hospital in the USA. Outcomes of ED electrocardioversion of patients with recent-onset AF/flutter were compared with those of a control group, obtained by chart review of patients admitted with the same inclusion criteria during the 1-year study period	Discharge from ED. Adverse event including thromboembolic event. Relapse rate	18 Of the 24 patients were discharged home from the ED after cardioversion. None. Five patients reported a relapse of their dysrhythmia	Small sample size, which is based on convenience sampling. Discharge rate not very high
Lo et al, 2006, Australia	All patients with acute AF who received biphasic cardioversion were enrolled. Acute AF was defined as AF in which symptoms had been present for less than 48 h	A prospective, descriptive study at a tertiary hospital ED over a 6-month period. Data collected included: patient demographics, past medical history, details of biphasic cardioversion, outcome, complications, disposition, and length of stay	Discharge from ED after cardioversion. Relapse rate at 3 months follow-up. Thromboembolic event	26 Out of 31(83.8%) were discharged after successful cardioversion. Seven patients out of 32 (22%) had recurrence. None	Sample size was small. No formal protocol describing the decision-making process, hence there may be a selection bias. Risk of interviewer bias at follow-up
Scheuermeyer et al, 2010, UK	400 Patients who underwent direct-current cardioversion	Retrospective cohort study	Discharge home from ED. Return visits. Adverse events (death or thromboembolic) over 30 days follow-up	Of the 141 patients included in the chart review, 96.5% (136/141) were discharged after cardioversion. A total of 22 return visits occurred, of which 12 (3%; 12/400) were related to AF/flutter. None (95% CI 0.0 to 0.8% for all outcomes)	Results of this two-centre study may not be generalisable to diverse settings. Retrospective studies are subject to missing or improperly coded data. The duration of AF or flutter is based on self-reported patient histories and may not be accurate
Stiell et al, 2010, Canada	660 Patients (average age 65 years) with recent-onset AF (628) or flutter (32) presenting to an adult university hospital ED	Retrospective cohort study	Discharge from ED. Relapse rate. Adverse events rate. Thromboembolic event or death	97% (639/660) Patients were discharged home of whom 90% (595/660) were in sinus rhythm. 8.6% (57/660) Over 7 days. 7.6% (50/660) Of which transient hypotension (6.7%; 44/660) was the commonest. None	The follow-up period was limited to 7 days, so adverse events occurring beyond this period would have been missed
Vinson et al, 2012, USA	206 Patients (aged 64.0 ± 14.4 years) presenting to three community-based hospitals with presumed recent-onset AF (92.7%) or flutter	Prospective cohort study among three neighbouring suburban	Overall discharge rate. Discharge rate in those cardioverted. ED adverse events due to attempted cardioversion. Thromboembolic events within 30 days	88.8% (183/206). 91% (105/115). 2.6% (4/115). 1% (2/206) (95% CI 0.1 to 3.5%). Both cases involved cerebrovascular accidents. Both patients had a previous history of AF and were not receiving anticoagulation at the time of the thromboembolic event, one due to previous haemorrhagic complications and the other due to persistent refusal	Patient enrolment employed convenience sampling which may lead to potential selection bias. The number of patients with recent-onset AF or flutter who were not included in the study is not known. Data about practice patterns may not be generalisable to other settings and patient populations

Comment(s)

Atrial fibrillation is the most common dysrhythmia encountered by emergency physicians. According to the available evidence, cardioversion followed by discharge home from the emergency department is an appropriate strategy to consider in patients with recent-onset atrial fibrillation of less than 48 h duration and stable vital signs, without another diagnosis necessitating admission. The rate of thromboembolic events in patients who were cardioverted to sinus rhythm was very low and overall adverse event rates were also exceptionally low. It is also mandatory to stroke risk stratify any patient who presents with atrial fibrillation for appropriate thromboprophylaxis using a validated scoring system even if they have been cardioverted to sinus rhythm in the emergency department. Although this strategy is safe and effective, the return visit rate for relapsed atrial fibrillation is between 3% and 22%. Patients should be made aware of this possibility.

Editor Comment

AF, atrial fibrillation; ED, emergency department.

Clinical Bottom Line

Stable patients with recent onset of atrial fibrillation after cardioversion and stroke risk stratification can be discharged home with adequate follow-up after a period of observation. Level 2 evidence, grade B recommendation.

References

1. Michael JA, Stiell IG, Agarwal S, et al. Cardioversion of paroxysmal atrial fibrillation in the emergency department. Ann Emerg Med 1999;39:379–87.
2. Burton JH, Vinson DR, Drummond K, et al. Electrical cardioversion of emergency department patients with atrial fibrillation. Ann Emerg Med 2004;44:20–30.
3. Jacoby JL, Cesta M, Heller MB, et al. Synchronized emergency department cardioversion of atrial fibrillation saves time, money and resources. J Emerg Med 2005;28:27–30. J Emerg Med 2005;28:27–30.
4. Lo GK, Fatovich DM, Haig AD. Biphasic cardioversion of acute atrial fibrillation in the emergency department. Emerg Med J 2006;23:51–53.
5. Scheuermeyer FX, Grafstein E, Stenstrom R, et al. Thirty-day outcome of emergence department patients undergoing electrical cardioversion for atrial fibrillation or flutter. Acad Emerg Med 2010;17:408–15.
6. Stiell IG, Clement CM, Perry JJ, et al. Association of the Ottawa Aggressive Protocol with rapid discharge of emergency department patients with recent-onset atrial fibrillation or flutter. Can J Emerg Med Care 2010;12:181–91.
7. Vinson DR, Hoehn T, Graber DJ, et al. Managing emergency department patients with recent-onset atrial fibrillation. J Emerg Med 2012;42:139–48.