Management and Disposition of Atrial Fibrillation in the Emergency Department: A Systematic Review

Management of atrial fibrillation (AF) and atrial flutter (AFL) in the emergency department (ED) varies greatly, and there are currently no United States guidelines to guide management with regard to patient disposition after ED treatment. The aim of this systematic review was to evaluate the literature for decision aids to guide disposition of patients with AF/AFLin the ED, and assess potential outcomes associated with different management strategies in the ED.

Methods and Results

A systematic review was done using PubMed (MEDLINE), Cochrane Central Register of Controlled Trials (CENTRAL), and EMBASE, combining the search terms “Atrial Fibrillation”, “Atrial Flutter”, “Emergency Medicine”, “Emergency Service”, and “Emergency Treatment”. After removal of duplicates, 754 articles were identified. After initial screening of titles and abstracts, 69full text articles were carefully reviewed and 34 articles were ultimately included in the study based on inclusion and exclusion criteria. The articles were grouped into four main categories: decision aids and outcome predictors, electrical cardioversion-based protocols, antiarrhythmic-based protocols, and general management protocols.

Conclusion

This systematic review is the first study to our knowledge to evaluate the optimal management of symptomatic AF/AFLin the ED with a direct impact on ED disposition. There are several viable management strategies that can result in safe discharge from the ED in the right patient population, and decision aids can be utilized to guide selection of appropriate patients for discharge.

Keywords: Atrial Fibrillation, Atrial Flutter, Emergency Medicine, Emergency Service, Emergency Treatment

Introduction

Atrial fibrillation (AF) is the most common dysrhythmia worldwide, with an estimated prevalence of 2.7 to 6.1 million in the United States (US) alone[1]. The risk for developing AF increases with advancing age, and the US prevalence is predicted to increase to as high as 12.1 million by the year 2030 as the elderly population continues to grow [2]. Along with the increased burden of disease, emergency department (ED) visits for symptomatic AF have continued to rise over the last 25 years, almost doubling from 1993 to 2004 [3]. Despite a fairly stable relative rate of hospitalizations, the absolute number of hospitalizations for AF continues to climb as ED visits become more frequent [3]. National incremental healthcare costs of AF in the US are estimated to range from $6 to $26 billion, and a large portion of these expenses are related to inpatient hospitalization [4]. By preventing unnecessary hospital admissions for AF, it could be surmised that both healthcare costs and unwanted complications associated with hospitalization could be significantly reduced. The most recent American Heart Association/American College of Cardiology/Heart and Rhythm Society guidelines for management of AF do not specifically address management in the ED [5]. However, recent guidelines from the Canadian Cardiovascular Society do provide recommendations for ED management of AF, noting that there is increasing evidence that many patients with AF can be safely managed in the ED and discharged to home, without necessitating hospitalization [6]. The aim of our study was to search the existing literature for management strategies and decision aids for triaging ED patients with AF, specifically with a plan for selecting patients appropriate for outpatient management.

Methods

Study Population

We performed a literature search on October 12, 2016 using PubMed (MEDLINE), Cochrane Central Register of Controlled Trials (CENTRAL), and EMBASE. The searches combined the terms “Atrial Fibrillation”, “Atrial Flutter”, “Emergency Medicine”, “Emergency Service”, and “Emergency Treatment”. Additional relevant articles that were identified as references for the articles found during the primary search were also included in the review process. Articles published in English were accepted for this review, and non-English language articles were excluded at the title/abstract screening stage. Randomized controlled trials, non-randomized controlled trials, prospective and retrospective cohort studies, case-control studies, and case series were included. Cross-sectional studies, case reports, editorials, letters, comments, abstracts and poster presentations, guidelines, meta-analyses, and review articles were excluded.

After the initial database search and removal of duplicates, articles were screened and included or excluded based on title and abstract information. The articles that were included after this initial screening stage were then analyzed using full-text review, and included or excluded based on the previously mentioned inclusion/exclusion criteria. The entire screening process was performed by two independent reviewers (JV, MS)utilizing the Covidence web-based software platform, and conflicts were resolved by consensus with the assistance of a third independent reviewer (AG). The methodology for this systematic review is summarized in [ Figure 1 ].

Data extraction was performed individually by the two primary independent reviewers for the studies that were included after full text analysis. Relevant factors from each study were assessed for the final qualitative analysis, including study design, patient population, follow-up period, and interventions and outcomes.

Results

We identified a total of 939 articles (416 from PubMed, 81 from Cochrane Library, and 442 from EMBASE). Duplicates were excluded, resulting in 754 remaining articles. These articles were carefully screened based on information gathered from the titles and abstracts, leaving 69 articles to be analyzed by full text review. Twenty articles were excluded because although they discussed the management of AF/AFLin the ED, they did not specifically address patient disposition from the ED. Nine articles used one of the study designsthat we chose to exclude and 4 had irrelevant patient outcomes for our topic of interest. Finally, 2 articles were excluded because their primary focus was on long-term patient outcomes. This left 34 remaining studies to be included in our review. There were 4 randomized controlled trials, 10 prospective cohort studies, 12 retrospective cohort studies, 6 prospective case series, and 2 retrospective case series. Because our inclusion criteria allowed for some variety in the content of our articles, we grouped the articles into 4 separate categories: decision aids and outcome predictors, electrical cardioversion-based protocols, antiarrhythmic-based protocols, and general management protocols.

Decision Aids and Outcome Predictors

Seven of the articles focused specifically on how to determine which patients with AF/AFLcan be safely discharged from the ED by analyzing short term outcomes and creating novel prediction models and decision aids [ Table 1 ] [7-13]. The retrospective analysis done by Mulcahy et al reviewed the charts of all patients who presented to the ED with new-onset AF from 1987 to 1992, all of whom were subsequently admitted to the inpatient ward per hospital policy at that time[7]. Based on the overall hospital courses and interventions required while inpatient, they found that about one-third of these patients did not merit inpatient hospitalization, and 98% of those that did require inpatient care were easily identified while in the ED. RED-AF, a prediction model created by Barrett et al, assigned points for 12 clinical variables in ED patients with AF/AFL and predicted the risk of an adverse event at 30 days based on total points[8]. The initial model had modest predictive discrimination and was later prospectively validated with similar performance as the original cohort[11]. The biggest predictors of increased risk for short-term adverse events were increased age, inadequate ED rate control, dyspnea, smoking, and home beta-blocker use [8]. The AFFORD prediction model for 30-day adverse events was also created by Barrett et al, a few years after RED-AF, and assigned points to 17 different variables for risk stratification [12]. Atzema et al created both a complex as well as a pragmatic clinical decision instrument for risk-stratification, both of which performed well for predicting 30-day all cause mortality [13]. Compared with the complexity of the previous models, the pragmatic model (TrOPs-BAC) includes only 6 variables (positive troponin, other acute ED diagnosis, pulmonary disease, bleeding risk, age 75 years or older, and congestive heart failure) and can easily be memorized for quick reference. Atzema et al performed a large retrospective cohort study to look for factors associated with death within 90 days of an ED discharge after a visit for AF/AFL, and found that having no follow-up care was associated with the highest risk for short-term death (hazard ratio [HR] 2.27) [9]. This group also explored predictors for repeat ED visits for AF/AFL within 2 weeks of an ED discharge, and found that follow-up with a cardiologist or internist was associated with the lowest hazard for repeat visits (HR 0.61) [10].

Table 1

AF = atrial fibrillation, AFL = atrial flutter, CHF = congestive heart failure, ED = emergency department, NPV = negative predictive value, PPV = positive predictive value

Electrical Cardioversion-Based Protocols

Seven of the articles primarily analyzed the safety and efficiency of direct-current cardioversion (DCCV) as a means to successfully discharge patients home from the ED [ Table 2 ] [14-20]. Conversion rates for DCCV were as high as 97% in the prospective cohort study by Jacoby et al, and no lower than 78%, which was the rate observed by Dankner et al [15,17]. In each of these studies, almost all of the patients who converted to normal sinus rhythm (NSR) were discharged home from the ED. Several of the studies noted a small number of minor ED complications with DCCV, primarily related to procedural sedation[14,16,18,19,20]. No major adverse events were observed within 3 months of discharge after ED DCCV in any of the included studies. Notably, hemodynamic instability was an exclusion criterion for all of these studies, so DCCV was done purely on an elective basis. Additionally, 3 of the 7 studies required the onset of AF/AFL to be less than 48 hours prior to ED presentation for study inclusion[14,16,20]. The other 4 studies permitted an earlier onset of symptoms, but the large majority of patients still only had symptoms for 48 hours or less, no fewer than 68% of the cohort in the AFL study done by Scheuermeyer et al [14,16,18,19].

Table 2

AF = atrial fibrillation, AFL = atrial flutter, CC = chemical cardioversion, DCCV = direct current cardioversion, ED = emergency department, INR = international normalized ratio, NSR = normal sinus rhythm, SOU = short observation unit

Antiarrhythmic-Based Protocols

Ten of the articles dealt with medical management of AF in the ED, either with chemical cardioversion or rate control alone [ Table 3 ] [21-30]. Chemical cardioversion had varying success rates depending on the pharmacologic agent that was chosen. The combinations of verapamil-quinidine and digoxin-quinidine used by Innes et al resulted in 84% and 45% conversion rates to NSR, respectively[21]. Intravenous (IV) and oral (PO) propafenone had 70% and 78% successful conversion rates, respectively [22,23].The use of IV ibutilide resulted in conversion rates ranging from 64% to 76% [24,25,26,28]. IV procainamide was used by Stiell et al and White et al with a 50% and 67% success rate, respectively [27,30]. Hirschl et al compared a variety of different medications, and found that flecainide (95%) and ibutilide (76%) had the highest rates of conversion to NSR [28]. Similar to the DCCV studies, all of these studies required a recent onset of AF/AFL for study inclusion.Only one of the articles in our study evaluated rate control alone with regard to ED discharge, comparing outcomes of those who received beta-blockers vs. calcium channel blockers, finding no significant differences in discharge rates or short-term adverse events [29].

Table 3

AF = atrial fibrillation, AFL = atrial flutter, BB = beta blocker, CCB = calcium channel blocker, DCCV = direct current cardioversion, DIG-Q = digoxin plus quinidine, ED= emergency department, IV = intravenous, LOS = length of stay, NSR=normal sinus rhythm, PO = by mouth, VER-Q= verapamil plus quinidine

General Management Protocols

The final category included ten articles, which either explored the efficacies of several different AF/AFL management strategies with the goal of ED discharge, or used specific protocols designed to appropriately triage and disposition ED patients with AF/AFL [ Table 4 ] [31-40].Michael et al and Vinson et al compared several different ED management strategies, with DCCV being the most successful with regard to conversion to NSR [31,38]. However, 97% and 89% of all patients were discharged to home in Michael and Vinson’s groups, respectively, including those who only underwent rate control or observation. Vinson et al observed a 29% rate of spontaneous cardioversion in the ED without any intervention; this rate improved to 69% within 48 hours of discharge to home[ 38]. Scheuermeyer et al looked at outcomes of ED patients with symptomatic AF and no other underlying medical cause who received a similar variety of interventions, with 85% of patients discharged home from the ED and a 0.8% rate of stroke or death at 30 days [ 37]. Koenig et al observed an 81% discharge rate with no major adverse events after utilization of an ED observation unit for those who did not respond initially to ED management [ 32]. Stiell et al used a case series to evaluate the Ottawa Aggressive Protocol, which consisted of administration of IV procainamide followed by DCCV for those who did not convert to NSR initially, and showed that 97% of patients were discharged home from the ED without any major adverse events [ 36]. Kim et al and Decker et al both randomized patients to undergo protocols geared toward ED discharge vs. hospital admission, and found no significant difference in short-term adverse events [33,35]. Zimetbaum et al and Ptaszek et al compared their AF protocols to standard ED care, and found a 49% and 80% decreased probability of hospital admission, respectively, with no significant differences in short-term adverse events or hospitalizations [34,40]. Elmouchi et al created the Spectrum Health ED AF protocol, which had different treatment algorithms based on time of AF onset, and required close follow-up in an AF-specific clinic [39]. Out of 100 included patients, there were only 10 repeat ED visits and 3 hospitalizations for AF within 90 days, with no deaths or thromboembolic events.

Table 4

AF = atrial fibrillation, AFL = atrial flutter,CC = chemical cardioversion, DCCV = direct current cardioversion, ED= emergency department, EDOU = emergency department observation unit, IV = intravenous, LOS = length of stay, NSR = normal sinus rhythm, SC = spontaneous cardioversion, TE = thromboembolic

Discussion

To our knowledge, this is the first systematic review to evaluate the optimal management of AF/AFL in the ED, specifically with regard to appropriate triaging and disposition. Based on the results of the included articles, there are multiple, varying strategies to approach management as well as risk stratification. Moreover, our review suggests that by using these strategies, most patients can be safely discharged from the ED and managed successfully in the outpatient setting. Based on our review, we concluded three major findings: 1) decision aids and prediction models can be useful for determining ED disposition, 2) electrical cardioversion is more successful than medical management in converting to NSR, and 3) conversion to NSR is not required to allow for safe ED discharge.

Deciding which patients are safe to discharge from the ED and which require inpatient admission is not always straightforward, but one of our primary findings was that using prediction models can be helpful for stratifying patients. The RED-AF and AFFORD clinical tools both had modest predictive discrimination for their outcomes of interest, and the decision instruments created by Atzema et al were highly predictive of 30-day all cause mortality [8,11,12,13].Unlike many of the articles in this review, these decision aids did not exclude patients with other underlying acute medical conditions requiring hospitalization,which could broaden their applicability.Each of these studies was done at a single academic institution, and further validation in a variety of ED settings would strengthen the case for widespread use of these decision instruments. Regardless of risk stratification, transitions of care are an important aspect of acute AF/AFL management. Atzema et al demonstrated in 2 different articles that patients without adequate short-term follow-up had worse outcomes, reinforcing that close outpatient follow-up is important to ensure a safe ED discharge [9,10].

Electrical cardioversion was largely very successful in the articles we reviewed and helped with discharge from the ED. Several of the studies in the DCCV group directly compared electrical and chemical cardioversion, and found DCCV to have significantly higher successful conversion rates [14,17,19,20]. Although none of the studies in the antiarrhythmic group directly compared chemical cardioversion to DCCV, all of the pharmacologic agents had lower conversion rates than the results seen in the DCCV studies. A few of the chemical cardioversion studies used DCCV as an adjunct therapy for those who did not initially respond to the pharmacologic agents, with subsequent improvement of successful cardioversion [24,27,30]. In each study in the DCCV and antiarrhythmic groups, almost all patients who converted to NSR were discharged home from the ED. Importantly, with either DCCV or chemical cardioversion, it was critical to know the exact onset of the AF/AFL episode to ensure that the onset was less than 48 hours duration. In many cases this cannot be reliably determined and would thus warrant a transesophageal echocardiogram. This limits the utility of this strategy in many patients. In addition, in these patients with new onset AF/AFL, it is possible that many will spontaneously convert without an intervention in the ED, as a large proportion will likely have paroxysmal AF/AFL.

The final group of articles employed a combination of rate control, DCCV, chemical cardioversion, and observation alone, most by using implemented pathways and protocols with the aim of ED discharge when possible. These studies demonstrated a high success rate of ED discharge, regardless of the type of acute management that was chosen or rhythm status at time of discharge. It is interesting to note that the articles in the general management group demonstrated a similar rate of short-term adverse events to the articles in the DCCV and chemical cardioversion groups, many of which required patients to convert to NSR in order to be discharged [15,17-18,20,25-30]. While conversion to NSR seems desirable, particularly in patients with acute onset of AF/AFL, there is no particular reason that persistence of AF/AFL should preclude ED discharge, provided that rate control is adequate and the patient is otherwise stable and not severely symptomatic. This is supported by the articles that observed reasonably high rates of spontaneous conversion to NSR, as well as the studies mentioned that observed high rates of safe discharges, regardless of ED intervention[31,37,38]. Future studies exploring optimal ED management for symptomatic AF/AFL with rate control or observation alone could help elucidate if and when aggressive rhythm control is actually merited.

Limitations

There are several limitations to consider in this review. We performed a qualitative assessment of a somewhat heterogeneous group of articles based on our study design, and thus did not perform any summative statistical calculations for either population baseline characteristics or outcomes. We did not restrict study inclusion based on individual study quality, which may inherently allow for bias in our overall assessment based on the individual study results. Although many of the studies had relatively large sample sizes, some of the studies involved small patient populations, which could limit the external validity of their results [16,21,25,26,33]. Finally, we excluded non-English language studies, and it is possible that in doing so excluded some studies that may have been pertinent to our review.

Disclosures

Dr. Gehi reports grant support from Bristol-Myers-Squib Foundation and speaker’s honoraria from Zoll, Biotronik, and Abbott.

Conclusion

This systematic review is the first study to our knowledge to evaluate the optimal management of symptomatic AF/AFL in the ED with a direct impact on ED disposition. Based on our findings, there are several viable strategies to employ, all of which may result in a safe ED discharge to home in the right patient population. A suggested general protocol is included in [ Figure 2 ]. The decision aids included in our study can be helpful for determining which patients can be safely managed in the outpatient setting and which require inpatient evaluation. The use of cardioversion in the ED can help expedite discharge, and DCCV has a higher success rate than chemical cardioversion, but conversion to NSR is not a requisite for a safe ED discharge.Early outpatient follow-up is crucial to prevent repeat ED visits and ensure long-term care.However, future studies of acute AF/AFL care are needed to develop management strategies that are comprehensive, in order to determine best practices and demonstrate scalability of systems of care to a variety of settings.