Patients with Atrial Fibrillation in the Emergency Department: Strategies to Achieve Best Outcomes

Case Description

A female with a history of diabetes and hypertension presented to the emergency department (ED) with new-onset palpitations. She first noticed the palpitations four hours earlier while at her desk, and had never previously experienced these symptoms. She denied associated syncope, chest pain, shortness of breath, leg pain, or leg swelling. Vital signs were: T=37.5^oC, HR=142, BP=145/56, and O₂Sat=99% on room air. On exam, she had no evidence of acute decompensated heart failure. The initial ECG revealed atrial fibrillation with rapid ventricular response (Figure 1); therefore, the emergency physician recommended a synchronized electrical cardioversion at 200 joules with deep sedation. The patient successfully converted to normal sinus rhythm (NSR) on the initial attempt without complications. Based on a CHA₂DS₂-VASc score of 2, she was prescribed apixaban and scheduled for a follow-up cardiology clinic visit in 48 hours.

Atrial Fibrillation in the ED

Atrial fibrillation (AF) and atrial flutter are two of the most common narrow complex tachyarrhythmias diagnosed in the ED. AF affects between 1-2% of the adult population in the United States and becomes increasingly common as patients age, with 9% of those >65 years impacted.¹ Due to expected longer life expectancy and lingering comorbidities such as hypertension and coronary artery disease, the incidence of AF in the U.S. is predicted to more than double from 1.2 million in 2010 to 2.6 million in 2030.¹ From 2007-2014, AF contributed to approximately four million ED visits, with a rising cost from $7 to $10 billion over the same time period.² Although hospitalizations for patients with AF decreased from 70% to 62% in 2007-2014, the cost continued to increase due to a rise in ED visits and resource consumption (Figures 2 and 3).² Historically, AF in U.S. emergency departments has typically been managed with rate control; this has left rhythm control strategies in the hands of cardiologists or hospitalists, due to the perceived risks and resource requirements of ED cardioversion as well as hesitation on the part of the emergency physician to initiate anticoagulation at discharge. However, the future of AF management rests on emergency physicians’ decisions regarding early versus late rhythm strategies with electrical or chemical cardioversion. Emergency physicians are in a unique position to play a key role in enabling an outpatient plan for eligible patients presenting with AF. The ED serves as a key access point to reshape the care of patients with AF by offering early interventions that would ultimately help reduce avoidable hospitalizations and alleviate the tremendous burden that AF places on the U.S. healthcare system.

Evaluation and Treatment of AF    

From the perspective of the emergency physician, the initial evaluation of a patient presenting with AF should determine whether the patient is stable or unstable, whether it is persistent versus paroxysmal AF, the time of symptom onset, associated comorbidities, current anticoagulation, and chronic rhythm and rate control medications. After the initial evaluation, the proper management strategies can be instituted to ensure safe patient outcomes and efficient care. When a patient presents with an AF exacerbation, the critical decision after the patient has been stabilized in the ED is to admit or send home. Patients who meet criteria for admission for AF have an associated diagnosis that requires admission, such as acute coronary syndrome or congestive heart failure exacerbation.³ Patients can be safely discharged if they have a proper anticoagulation plan, no underlying heart disease or alternative diagnoses, rate control, and cardiology follow-up.³

Rate Versus Rhythm Control

Nearly two decades ago, the AFFIRM trial led to a culture among many U.S. emergency physicians that favors rate control over an early rhythm control strategy due to the lack of survival benefit and associated reduction in medication side effects.⁴ The heart rate goal in patients with AF is <110 beats per minute (bpm) based on the RACE II trial demonstrating no difference in negative composite outcomes, such as arrhythmia and cardiovascular death, compared to strict rate control at 80 bpm.⁵ Rate control has also been favored due to the risk of thromboembolic events, such as stroke, associated with cardioversion in the ED. Rate control is achieved by using medications such as metoprolol, diltiazem, and digoxin, while monitoring blood pressure and symptom improvement. Furthermore, recent evidence suggests that the addition of intravenous magnesium can facilitate both earlier rate and rhythm control in the ED.⁶

Although rate control has been the standard of care in acute AF exacerbation in the ED, early rhythm control strategies using synchronized electrical cardioversion at 200 joules has been shown to be effective in controlling AF symptoms and decreasing hospital admission rates without causing increased harm from thromboembolic events.^7,8 However, real-world evidence suggests the risk of thromboembolism associated with ED cardioversion ranges from 0.3-0.8%.⁹ The risk of thromboembolism further increases with prolonged delay since onset of AF >12 hours, lack of anticoagulation, advanced age, and comorbidities such as diabetes and heart failure associated with higher risk.⁹ Over a third of patients seen in the ED with a primary diagnosis of AF are eligible for ED cardioversion.¹⁰

Synchronized electrical cardioversion also requires more ED staff resources and comes with a risk of complications from sedation; therefore, chemical cardioversion may be a preferred option in some patients. For example, chemical cardioversion with procainamide is a common first-line approach in Canada for eligible patients presenting with recent-onset AF; accordingly, admission rates are significantly lower than in the U.S. (27% vs 67%, respectively).¹¹ Other agents used for chemical cardioversion include ibutilide and flecainide, among others. Chemical cardioversion has shown to be 50%,  while synchronized electrical cardioversion has been 80-90% effective in the ED setting.^12,13 Additionally, discharge home within four hours was achieved in 67% of electrical cardioversion cases versus only 32% of chemical cardioversion cases.¹⁴ Chemical cardioversion is associated with side effects such as hypotension, prolongation of the QT interval, and arrhythmias; therefore, patients must be continuously monitored on telemetry for specific intervals according to each agent. While some health outcomes may not be affected by rate versus rhythm control, many patients may prefer to be in NSR.¹³

Risk Reduction for Thromboembolism After Discharge

AF is a major risk factor for embolic stroke. Overall, asymptomatic AF is responsible for up to one-quarter of all embolic strokes.¹⁵ As more patients are diagnosed with AF, their risk for stroke accumulates every year. One main approach to reduce this risk is anticoagulation. The CHA₂DS₂-VASc score is the best risk stratification tool currently available to determine which patients with AF should be considered for anticoagulation. However, some gaps exist. Several studies have shown that while most eligible patients with AF do not receive appropriate anticoagulation in the ED, the ED offers a new role in bridging that gap. Another study found that 83.5% of patients with a history of AF who suffered an embolic stroke were not appropriately anticoagulated despite an indication.¹⁶ The 2019 AHA/ACC/HRS AF management guidelines recommend direct oral anticoagulants (DOACs) such as apixaban and rivaroxaban for adequate anticoagulation in those with a CHA₂DS₂-VASc score of ≥2.¹⁷ Guidelines also recommend warfarin for patients with moderate to severe mitral valve disease and those with a mechanical heart valve.¹⁷Alternatively, for patients with an increased risk of bleeding or unstable INRs on warfarin, a left atrial appendage closure device (ie, WATCHMAN device, Boston Scientific) is another category of intervention associated with decreased stroke and bleeding risk.¹⁸ Recommending this device in the ED is outside the scope of practice for emergency physicians, but subsequent evaluation by a cardiologist or electrophysiologist can determine if this option is best.

Creation and Implementation of AF Pathways

Due to the burden of AF on the healthcare system, the ED plays an integral role in determining novel strategies that decrease hospital admission rates, maintain NSR, and decrease repeat ED visits. A multidisciplinary approach involving input from nursing/nurse practitioners (NP), physician assistants (PAs), emergency physicians, cardiologists, and electrophysiologists that creates a collaborative pathway to reduce barriers to outpatient AF management enables early discharge and guideline-concordant care. The involvement of cardiologists and electrophysiologists is paramount to providing patients with timely and adequate follow-up care. Figure 2 shows a sample AF outpatient pathway.

The increasing prevalence of ED observation units also allows for decreasing hospitalization rates by allowing additional time for rate control of AF to occur, while also providing overnight telemetry, pharmacological cardioversion, and coordination of outpatient AF management.¹ This was most evident in studies that demonstrated patients with proper rate control and a plan for delayed cardioversion, as well as in patients who did not receive cardioversion that spontaneously converted to NSR at a high rate.¹⁹ Bellew et al demonstrated the use of ED observation units has decreased AF admissions by 20% with a 40% cost reduction.²⁰ Typical inpatient length of stay for patients with a primary diagnosis of AF is 2-3 days, while ED observation units have decreased length of stay to <1 day.²⁰ Furthermore, Pluymaekers et al recently demonstrated that delayed cardioversion did not differ from early cardioversion in the maintenance of NSR.¹⁹ Among the delayed cardioversion group, conversion to NSR within 48 hours occurred spontaneously in 69% patients, without any difference in thromboembolic events.¹⁹ Given the various treatment options and their associated risks, emergency physicians should engage their patients with shared decision making before settling on a final plan.

Summary

Emergency physicians play a unique role in creating innovative strategies and driving future AF management. These strategies can lead to decreased hospitalizations, reduced cost, and fewer thromboembolic events in AF patients. Closing the gap between usual care and best practices for AF patients in the ED requires collaboration between emergency physicians and NPs, PAs, cardiologists, and electrophysiologists. A renewed focus to implement changing practice patterns is needed to achieve the best evidence-based outcomes for patients with AF. 

Disclosures: Dr. Baymon has no conflicts of interest to report regarding the content herein. Dr. Baugh reports he is a consultant and advisory board member for Janssen Pharmaceuticals, and a coinvestigator for Boehringer Ingelheim.

For more information on this topic, see our podcast interview with Dr. Baymon and Dr. Baugh:

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