We have proven ourselves highly capable of managing atrial fibrillation in the Emergency Department. In recent years, a number of prospective cohorts have demonstrated that with the use of IV anti-arrhythmic medication and electrical cardioversion, patients presenting to the Emergency Department with new onset atrial fibrillation can be successfully discharged in sinus rhythm consistently and with minimal adverse events. In 2010, Steill et al published a case series of 660 patients who were cardioverted in the Emergency Department (1). What they coined the “Ottawa Aggressive Protocol” consisted of chemically managed rate control followed by a trial of procainamide loaded over an hour and, if this failed to convert the patient, DC electrical cardioversion. Using this protocol, Steill et al cite the number of patients who were discharged home in normal sinus rhythm to be 595 (90.2%). In a recent systematic review published in the European Journal of Emergency Medicine, Coll-Vinent et al found that in patients who underwent Emergency Department cardioversion, 78.2%-100% were discharged home in a normal sinus rhythm (2).
But competency is not directly translatable into efficacy. Despite this proof of concept, there is limited data examining the patient-oriented benefits these aggressive rhythm control strategies produce. In fact, the majority of such studies employ the “rhythm at Emergency Department discharge” as their measure of success. And though being discharged from the Emergency Department in a sinus rhythm seems preferential over atrial fibrillation, little is known regarding the extent of this benefit, as very few trials rigorously monitored patients following discharge from the Emergency Department. How many of these patients remained in a sinus rhythm and for how long? Steill et al found that only 8.6% of their cohort returned to the Emergency Department within one week of cardioversion with any reoccurrence of atrial fibrillation. Unfortunately these numbers were calculated from a chart extraction of the Ottawa Hospital health records database and do not directly reflect the number of patients who experienced atrial fibrillation over the 7 days following Emergency Department discharge (1). Decker et al, in a small cohort of 150 patients, cite a recurrence rate of 10% at 6 months (3). What is the true recurrence rate? Even more importantly, does reestablishing sinus conduction lead to improved patient health and wellbeing?
The question at hand remains, what exactly are we achieving by performing cardioversions in the Emergency Department? We have known for some time that despite being capable of maintaining patients in a sinus rhythm with moderate success, an aggressive rhythm control strategy does not prevent the long term sequelae associated with atrial fibrillation. The AFFIRM trial published in the NEJM in 2002, demonstrated that in a cohort of 4060 patients with atrial fibrillation, although the use of a rhythm control strategy reduced the time patients spent in atrial fibrillation, it did not reduce the rate of death, MI or ischemic stroke (4). When the 1391 patients experiencing their first episode of atrial fibrillation or the 1252 patients presenting within 48 hours of symptom onset were examined separately, no additional benefit was discovered (4). Since the AFFIRM trial’s publication a number of studies, performed in various subsets of atrial fibrillation patients, have validated that rhythm control strategies do not prevent the long-term sequelae associated with this chronic disease (5,6)
Since rate control is the preferred long-term treatment strategy of atrial fibrillation, what exactly are our goals for cardioversion in the Emergency Department? Is there a long-term health benefit to aggressive rhythm control in the Emergency Department? Does this lead to noticeable improvements in patient outcomes? Unfortunately conclusive data on these questions has yet to be published. The few RCTs examining the benefits of aggressive management of atrial fibrillation in the Emergency Department are small and inconclusive. Despite this paucity of convincing evidence, I would argue that the mathematical likelihood of benefit is incredibly low. Atrial fibrillation is a chronic disease, with sequelae measured in events per patient year. The rate of short-term adverse events is exceedingly low, with some cohorts citing a 30-day event rate of less than 1% (7). To design a study powered to identify a statistically meaningful difference, the sample size required would be unrealistically high. Especially given that the long-term utilization of such rhythm control strategies have not yielded clinically important improvement in patient outcomes. Furthermore the act of emergent cardioversion, does not avert the need for anticoagulation, as this decision should be based off the patient’s risk of thromboembolic event independent of their rhythm at discharge (8).
If we can agree that the clinical benefits of aggressive cardioversion in the Emergency Department are minimal, then the only remaining justification for Emergency Department cardioversion are the positive effects on patient wellbeing and comfort. The current argument in support of Emergency Department cardioversion hinges on the supposition that a state of sinus regularity is preferred when compared to the electrical chaos induced by atrial fibrillation (9). Until recently this claim has been exclusively supported by anecdotal descriptions of patient experience, its validity had never been examined in a prospective fashion.
Published online June 2015 in the Annals of Emergency Medicine, Ballard et al sought to objectively assess the effects of Emergency Department cardioversion on patients’ wellbeing and comfort (10). The authors surveyed 730 patients who were treated for new onset atrial fibrillation and discharged from one of 21 medical centers in Northern California. Of this cohort, 652(89%) responded to a structured phone survey. Though the data was prospectively gathered, these patients were not randomized to either a rate or rhythm control strategy, but rather the manner of treatment was left entirely to the judgment of the treating physician. Of the 652 respondents the majority, 432 (67.3%) were managed with rate control therapy alone. Regardless of management strategy, 410 (62.9%) of the patients were discharged from the Emergency Department in a sinus rhythm. Among those patients who underwent electrical cardioversion, 92.2% were in sinus rhythm upon discharge. If you consider discharge rhythm as a metric of success than electrical cardioversion was a far more accomplished strategy than either pharmacological cardioversion or rate control therapy alone, which accounted for 81.6% and 49.7% of patients in a sinus rhythm respectively at discharge (10). Despite its obvious superiority in rhythmic control, what benefits does cardioversion provide for patients’ symptom burden at 30-days?
The authors measured 30-day wellbeing using the Atrial Fibrillation Effect on Quality-of-life (AFEQT) score. This 18-question tool was intended to assess the patients’ perception of the burden of disease. The surveys were administered via telephone performed by trained research assistants at least 28-days following Emergency Department visit. Overall 539 patients (82.7%) reported some degree of symptom burden related to their atrial fibrillation upon discharge. The use of cardioversion did not decrease the rate or degree of symptom burden at 30-days. When the authors analyzed the AFEQT scores in quartiles of severity rather than the dichotomous symptom/no symptom outcome, they found no additional benefit to Emergency Department cardioversion. Certainly this data is far from perfect. This was a non-randomized cohort and it is unclear how well the AFEQT score captures symptom burden (10). Despite these shortcomings, findings are consistent with the body of literature examining whether an aggressive rhythm control strategy approves patient wellbeing. A number of trials have examined the long-term benefits rhythm control has on reducing symptom burden. These trials have consistently demonstrated that when compared to rate control alone, an aggressive rhythm control strategy provided no additional perceivable benefit to patients’ wellbeing and comfort (11).
The act of electrical cardioversion within 48 hours of symptom onset is commonly perceived as a safe practice. In a recent review of the existing literature, Cohen et al found that out of 1593 patients, only one (0.06%) stroke was reported. Despite this cursory endorsement, I would caution that safety is measured in the thousands and the current data is far too limited and ripe with publication bias to truly assess safety. Additionally a recent research letter published in JAMA called into question the safety of the 48-hour window we have traditionally used to determine suitability for Emergency Department cardioversion. Nuotio et al published a secondary analysis of the FinV trial registry which examined 2481 patients in atrial fibrillation who underwent electrical cardioversion within 48-hours of symptom onset. In this cohort the risk of ischemic event increased significantly (0.03% to 1.1%) when time to symptom onset was greater than 12 hours. And although 1.1% is still a relatively low event rate, given the absence of any clear clinical benefit, the benefit-harm ratio does not favor an aggressive rhythm control strategy (12).
Modern medicine far too often values competency over efficacy. Whether it is door to balloon time, or the 6-hour sepsis bundle, we are constantly measured in surrogates thought to be associated with improvements in patient outcomes. The quality of our care has been distilled down to what can be marked as complete on a checklist. Although the evidence clearly demonstrates Emergency Physicians are capable of effectively cardioverting new onset atrial fibrillation in the Emergency Department, one cannot help but asking, to what end?
- Stiell, I.G., Clement, C.M., Perry, J.J. et al. Association of the Ottawa Aggressive Protocol with rapid discharge of emergency department patients with recent-onset atrial fibrillation or flutter. CJEM. 2010; 12: 181–191
- Coll-Vinent, B., Fuenzalida, C., Garcia, A. et al. Management of acute atrial fibrillation in the emergency department: a systematic review of recent studies. Eur J Emerg Med. 2013; 20: 151–159
- Decker, et al. A Prospective, Randomized Trial of an Emergency Department Observation Unit for Acute Onset Atrial Fibrillation. Annals of Emergency Medicine, 2007.
- Wyse DG, Waldo AL, Dimarco JP, et al. A comparison of rate control and rhythm control in patients with atrial fibrillation. N Engl J Med. 2002;347(23):1825-33.
- Van gelder IC, Hagens VE, Bosker HA, et al. A comparison of rate control and rhythm control in patients with recurrent persistent atrial fibrillation. N Engl J Med. 2002;347(23):1834-40.
- Roy D, Talajic M, Nattel S, et al. Rhythm control versus rate control for atrial fibrillation and heart failure. N Engl J Med. 2008;358(25):2667-77.
- Scheuermeyer FX, Grafstein E, Stenstrom R, et al. Thirty-day and 1-year outcomes of emergency department patients with atrial fibrillation and no acute underlying medical cause. Ann Emerg Med. 2012;60(6):755-765.e2.
- Wang TJ, Massaro JM, Levy D, et al. A risk score for pre- dicting stroke or death in individuals with new-onset atrial fibrillation in the community — the Framingham Heart Study. JAMA 2003;290:1049-56
- Stiell IG, Birnie D. Management of recent-onset atrial fibrillation in the emergency department. Ann Emerg Med. 2011; 57:31–2.
- Ballard, DW. et al. Emergency Department Management of Atrial Fibrillation and Flutter and Patient Quality of Life at One Month Postvisit. Annals of Emergency Medicine
- Thrall G, Lane D, Carroll D, Lip GY. Quality of life in patients with atrial fibrillation: a systematic review. Am J Med. 2006;119(5):448.e1-19.
- Nuotio I, Hartikainen JE, Grönberg T, Biancari F, Airaksinen KE. Time to cardioversion for acute atrial fibrillation and thromboembolic complications. JAMA. 2014;312(6):647-9.