Atrial fibrillation (AF) is the most common sustained cardiac rhythm disturbance. AF is a risk factor for ischemic stroke and heart failure, both of which represent significant public health problems. With an increasing prevalence among an aging population, symptomatic AF-related ED visits have been rising and will likely continue to rise.
Traditionally, ED patients thought to have recent-onset AF have been hospitalized for monitoring and evaluation of more serious conditions. More recently, clinicians have been utilizing a more aggressive approach in which stable ED patients with presumed recent-onset AF are treated with elective cardioversion without anticoagulation. While previous reports suggest that this approach is associated with a high rate of cardioversion to sinus rhythm and a low rate of hospitalization and complications, there is no consensus on whether it is better than traditional approaches.
Seeking Confirmation on Recent-Onset AF Treatment
In the February 2012 Journal of Emergency Medicine, David R. Vinson, MD, and colleagues published a prospective multicenter study that describes the management of ED patients with presumed recent-onset AF. “It had been our anecdotal experience at three affiliated community EDs that taking an aggressive cardioversion approach to managing patients with recent-onset AF was effective and associated with few complications,” says Dr. Vinson. “In this study, we put our practice patterns under critical scrutiny to confirm the safety and effectiveness of ED cardioversion and to accurately measure the incidence of thromboembolism 30 days after discharge.”
“Clinicians who are already practicing a more aggressive approach to restoring sinus rhythm can be reassured by the safety and efficacy that was observed in our study.”
Dr. Vinson and colleagues analyzed 206 patients with recent-onset AF. A majority of these (115) were deemed eligible for cardioversion, via parenteral medications or the application of direct current. While the electrical route was more effective at restoring sinus rhythm (96% vs 60%), it required procedural sedation. As a result, the pharmacologic approach was a little safer, according to Dr. Vinson. When one method was found to be unsuccessful in a patient, the other was often utilized in a two-step approach.
Important Results on Cardioversion
Overall, 88.8% of patients in the investigation were discharged home. Adverse events that required ED intervention occurred in only 2.9% of patients, all of whom recovered. Spontaneous conversion to normal sinus rhythm in the ED was observed in 28.6% of the 206-patient cohort. Attempted cardioversion was carried out in 56.3% of patients (Figure). “In this population, more than 95% of patients achieved conversion, most of whom went home from the ED,” notes Dr. Vinson. “The restoration of sinus rhythm has many advantages. It alleviates their symptoms, reduces their stroke risk, and decreases the need for hospitalization.”
Among those in whom cardioversion was contraindicated, most received intravenous rate reduction medications and were discharged home on rate-control drugs and anticoagulation with arranged timely follow-up. Short-term home observation with urgent follow-up was used in 7.8% of patients, all of whom presented early in their symptom course. “A sizeable proportion of patients with recent-onset AF will spontaneously cardiovert within 48 hours,” Dr. Vinson explains. “Among those who were prescribed short-term home observation, 68.8% spontaneously converted. If they remained in AF, we were still within the 48-hour window and could consider pursuing cardioversion if indicated.”
The most important safety outcome from the study, according to Dr. Vinson, came from 100% patient follow-up of the entire cohort. “At 30 days after discharge, just two of the 206 patients were found to have developed a thromboembolic event,” he notes. “Only one of these had undergone ED cardioversion. This shows that ED cardioversion does not appear to increase patients’ risk for post-cardioversion strokes.” Although the results are promising, Dr. Vinson warns that not all patients with recent-onset AF in the ED are good candidates for cardioversion. “Physicians should assess a patient’s underlying cardiac function, particularly structural abnormalities, and their overall risk for stroke,” he says (Table). “Younger, healthier patients with anatomically normal hearts are the best candidates for this approach.”
Investigating Broader Population of AF Patients
Dr. Vinson and colleagues are currently undertaking a 2,000-patient, prospective study at nine Kaiser Permanente EDs in three states in an effort to investigate a broader population of patients with AF. “We want to study variations in AF management,” he says. “EDs take different approaches to patient management, so it’s important to see how these variations affect outcomes. In the meantime, clinicians who are already practicing a more aggressive approach to restoring sinus rhythm can be reassured by the safety and efficacy that was observed in our study. Those who practice conventional treatment approaches may want to consider elective cardioversion for select patients with recent-onset AF.”
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