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Study Overview
Objective. To assess whether immediate restoration of sinus rhythm is necessary in hemodynamically stable, recent onset (< 36 hr), symptomatic atrial fibrillation in the emergency department.
Design. Multicenter, randomized, open-label, noninferiority trial, RACE 7 ACWAS (Rate Control versus Electrical Cardioversion Trial 7--Acute Cardioversion versus Wait and See).
Setting and participants. 15 hospitals in the Netherlands, including 3 academic hospitals, 8 nonacademic teaching hospitals, and 4 nonteaching hospitals. Patients 18 years of age or older with recent-onset (< 36 hr), symptomatic atrial fibrillation without signs of myocardial ischemia or a history of persistent atrial fibrillation who presented to the emergency department were randomized in a 1:1 ratio to either a wait-and-see approach or early cardioversion. The wait-and-see approach consisted of the administration of rate-control medication, including intravenous or oral beta-adrenergic-receptor blocking agents, nondihydropyridine calcium-channel blockers, or digoxin to achieve a heart rate of 110 beats per minute or less and symptomatic relief. Patients were then discharged with an outpatient visit scheduled for the next day and a referral for cardioversion as close as possible to 48 hours after the onset of symptoms. The cardioconversion group received pharmacologic cardioversion with flecainide unless contraindicated, then electrical cardioversion was performed.
Main outcome measures. Primary outcome was the presence of sinus rhythm on electrocardiogram (ECG) recorded at the 4-week trial visit. Secondary endpoints included the duration of the index visit at the emergency department, emergency department visits related to atrial fibrillation, cardiovascular complications, and time until recurrence of atrial fibrillation.
Main results. From October 2014 through September 2018, 437 patients underwent randomization, with 218 patients assigned to the delayed cardioversion group and 219 to the early cardioversion group. Mean age was 65 years, and a majority of the patients (60%) were men (n = 261). The primary end point of the presence of sinus rhythm on the ECG recorded at the 4-week visit was present in 193 of 212 patients (91%) in the delayed cardioversion group and in 202 of 215 patients (94%) in the early cardioversion group. The –2.9 percentage points with confidence interval [CI] –8.2 to 2.2 (P = 0.005) met the criteria for the noninferiority of the wait-and-see approach.
For secondary outcomes, the median duration of the index visit was 120 minutes (range, 60 to 253) in the delayed cardioversion group and 158 minutes (range, 110 to 228) in the early cardioversion group. The median difference between the 2 groups was 30 minutes (95% CI, 6 to 51 minutes). There was no significant difference in cardiovascular complications between the 2 groups. Fourteen of 212 patients (7%) in the delayed cardioversion group and 14 of 215 patients (7%) in the early cardioversion group had subsequent visits to the emergency department because of a recurrence of atrial fibrillation. Telemetric ECG recordings were available for 335 of the 437 patients. Recurrence of atrial fibrillation occurred in 49 of the 164 (30%) patients in the delayed cardioversion group and 50 of the 171 (29%) patients in the early cardioversion group.
In terms of treatment, conversion to sinus rhythm within 48 hours occurred spontaneously in 150 of 218 patients (69%) in the delayed cardioversion group after receiving rate-control medications only. Of the 218 patients, 61 (28%) had delayed cardioversion (9 by pharmacologic and 52 by electrical cardioversion) as per protocol and achieved sinus rhythm within 48 hours. In the early cardioversion group, conversion to sinus rhythm occurred spontaneously in 36 of 219 patients (16%) before the initiation of the cardioversion and in 171 of 219 (78%) after cardioversion (83 by pharmacologic and 88 by electrical).
Conclusion. For patients with recent-onset, symptomatic atrial fibrillation, allowing a short time for spontaneous conversion to sinus rhythm is reasonable as demonstrated by this noninferiority study.
Commentary
Atrial fibrillation accounts for nearly 0.5% of all emergency department visits, and this number is increasing.1,2 Patients commonly undergo immediate restoration of sinus rhythm by means of pharmacologic or electrical cardioversion. However, it is questionable whether immediate restoration of sinus rhythm is necessary, as spontaneous conversion to sinus rhythm occurs frequently. In addition, the safety of cardioversion between 12 and 48 hours after the onset of atrial fibrillation is questionable.3,4
In this pragmatic trial, the findings suggest that rate-control therapy alone can achieve prompt symptom relief in almost all eligible patients, had a low risk of complications, and reduced the median length of stay in the emergency department to 2 hours. Independent of cardioversion strategy, the authors stressed the importance of management of stroke risk when patients present with atrial fibrillation to the emergency department. In this trial, 2 patients had cerebral embolism even though both were started on anticoagulation in the index visit. One patient from the delayed cardioversion group was on dabigatran after spontaneous conversion to sinus rhythm and had an event 5 days after the index visit. The other patient, from the early cardioversion group, was on rivaroxaban and had an event 10 days after electrical cardiology. In order for the results of this trial to be broadly applicable, exclusion of intraatrial thrombus on transesophageal echocardiography may be necessary when the onset of atrial fibrillation is not as clear.
There are several limitations of this study. First, this study included only 171 of the 3706 patients (4.6%) screened systematically at the 2 academic centers, but included 266 from 13 centers without systematic screening. The large amount of patients excluded from the controlled environment made the results less generalizable in the broader scope. Second, the reported incidence of recurrent atrial fibrillation within 4 weeks after randomization was an underestimation of the true recurrence rate since the trial used intermittent monitoring. Although the incidence of about 30% was similar between the 2 groups, the authors suggested that the probability of recurrence of atrial fibrillation was not affected by management approach during the acute event. Finally, for these results to be applicable in the general population, defined treatment algorithms and access to prompt follow-up are needed, and these may not be practical in other clinical settings.2,5
Applications for Clinical Practice
The current study demonstrated immediate cardioversion is not necessary for patients with recent-onset, symptomatic atrial fibrillation in the emergency department. Allowing a short time for spontaneous conversion to sinus rhythm is reasonable as long as the total time in atrial fibrillation is less than 48 hours. Special consideration for anticoagulation is critical because stroke has been associated with atrial fibrillation duration between 24 and 48 hours.
—Ka Ming Gordon Ngai, MD, MPH
1. Rozen G, Hosseini SM, Kaadan MI, et al. Emergency department visits for atrial fibrillation in the United States: trends in admission rates and economic burden from 2007 to 2014. J Am Heart Assoc. 2018;7(15):e009024.
2. Healey JS, McIntyre WF. The RACE to treat atrial fibrillation in the emergency department. N Engl J Med. 2019 Mar 18.
3. Andrade JM, Verma A, Mitchell LB, et al. 2018 Focused update of the Canadian Cardiovascular Society guidelines for the management of atrial fibrillation. Can J Cardiol. 2018;34:1371-1392.
4. Nuotio I, Hartikainen JE, Grönberg T, et al. Time to cardioversion for acute atrial fibrillation and thromboembolic complications. JAMA. 2014;312:647-649
5. Baugh CW, Clark CL, Wilson JW, et al. Creation and implementation of an outpatient pathway for atrial fibrillation in the emergency department setting: results of an expert panel. Acad Emerg Med. 2018;25:1065-1075.
Study Overview
Objective. To assess whether immediate restoration of sinus rhythm is necessary in hemodynamically stable, recent onset (< 36 hr), symptomatic atrial fibrillation in the emergency department.
Design. Multicenter, randomized, open-label, noninferiority trial, RACE 7 ACWAS (Rate Control versus Electrical Cardioversion Trial 7--Acute Cardioversion versus Wait and See).
Setting and participants. 15 hospitals in the Netherlands, including 3 academic hospitals, 8 nonacademic teaching hospitals, and 4 nonteaching hospitals. Patients 18 years of age or older with recent-onset (< 36 hr), symptomatic atrial fibrillation without signs of myocardial ischemia or a history of persistent atrial fibrillation who presented to the emergency department were randomized in a 1:1 ratio to either a wait-and-see approach or early cardioversion. The wait-and-see approach consisted of the administration of rate-control medication, including intravenous or oral beta-adrenergic-receptor blocking agents, nondihydropyridine calcium-channel blockers, or digoxin to achieve a heart rate of 110 beats per minute or less and symptomatic relief. Patients were then discharged with an outpatient visit scheduled for the next day and a referral for cardioversion as close as possible to 48 hours after the onset of symptoms. The cardioconversion group received pharmacologic cardioversion with flecainide unless contraindicated, then electrical cardioversion was performed.
Main outcome measures. Primary outcome was the presence of sinus rhythm on electrocardiogram (ECG) recorded at the 4-week trial visit. Secondary endpoints included the duration of the index visit at the emergency department, emergency department visits related to atrial fibrillation, cardiovascular complications, and time until recurrence of atrial fibrillation.
Main results. From October 2014 through September 2018, 437 patients underwent randomization, with 218 patients assigned to the delayed cardioversion group and 219 to the early cardioversion group. Mean age was 65 years, and a majority of the patients (60%) were men (n = 261). The primary end point of the presence of sinus rhythm on the ECG recorded at the 4-week visit was present in 193 of 212 patients (91%) in the delayed cardioversion group and in 202 of 215 patients (94%) in the early cardioversion group. The –2.9 percentage points with confidence interval [CI] –8.2 to 2.2 (P = 0.005) met the criteria for the noninferiority of the wait-and-see approach.
For secondary outcomes, the median duration of the index visit was 120 minutes (range, 60 to 253) in the delayed cardioversion group and 158 minutes (range, 110 to 228) in the early cardioversion group. The median difference between the 2 groups was 30 minutes (95% CI, 6 to 51 minutes). There was no significant difference in cardiovascular complications between the 2 groups. Fourteen of 212 patients (7%) in the delayed cardioversion group and 14 of 215 patients (7%) in the early cardioversion group had subsequent visits to the emergency department because of a recurrence of atrial fibrillation. Telemetric ECG recordings were available for 335 of the 437 patients. Recurrence of atrial fibrillation occurred in 49 of the 164 (30%) patients in the delayed cardioversion group and 50 of the 171 (29%) patients in the early cardioversion group.
In terms of treatment, conversion to sinus rhythm within 48 hours occurred spontaneously in 150 of 218 patients (69%) in the delayed cardioversion group after receiving rate-control medications only. Of the 218 patients, 61 (28%) had delayed cardioversion (9 by pharmacologic and 52 by electrical cardioversion) as per protocol and achieved sinus rhythm within 48 hours. In the early cardioversion group, conversion to sinus rhythm occurred spontaneously in 36 of 219 patients (16%) before the initiation of the cardioversion and in 171 of 219 (78%) after cardioversion (83 by pharmacologic and 88 by electrical).
Conclusion. For patients with recent-onset, symptomatic atrial fibrillation, allowing a short time for spontaneous conversion to sinus rhythm is reasonable as demonstrated by this noninferiority study.
Commentary
Atrial fibrillation accounts for nearly 0.5% of all emergency department visits, and this number is increasing.1,2 Patients commonly undergo immediate restoration of sinus rhythm by means of pharmacologic or electrical cardioversion. However, it is questionable whether immediate restoration of sinus rhythm is necessary, as spontaneous conversion to sinus rhythm occurs frequently. In addition, the safety of cardioversion between 12 and 48 hours after the onset of atrial fibrillation is questionable.3,4
In this pragmatic trial, the findings suggest that rate-control therapy alone can achieve prompt symptom relief in almost all eligible patients, had a low risk of complications, and reduced the median length of stay in the emergency department to 2 hours. Independent of cardioversion strategy, the authors stressed the importance of management of stroke risk when patients present with atrial fibrillation to the emergency department. In this trial, 2 patients had cerebral embolism even though both were started on anticoagulation in the index visit. One patient from the delayed cardioversion group was on dabigatran after spontaneous conversion to sinus rhythm and had an event 5 days after the index visit. The other patient, from the early cardioversion group, was on rivaroxaban and had an event 10 days after electrical cardiology. In order for the results of this trial to be broadly applicable, exclusion of intraatrial thrombus on transesophageal echocardiography may be necessary when the onset of atrial fibrillation is not as clear.
There are several limitations of this study. First, this study included only 171 of the 3706 patients (4.6%) screened systematically at the 2 academic centers, but included 266 from 13 centers without systematic screening. The large amount of patients excluded from the controlled environment made the results less generalizable in the broader scope. Second, the reported incidence of recurrent atrial fibrillation within 4 weeks after randomization was an underestimation of the true recurrence rate since the trial used intermittent monitoring. Although the incidence of about 30% was similar between the 2 groups, the authors suggested that the probability of recurrence of atrial fibrillation was not affected by management approach during the acute event. Finally, for these results to be applicable in the general population, defined treatment algorithms and access to prompt follow-up are needed, and these may not be practical in other clinical settings.2,5
Applications for Clinical Practice
The current study demonstrated immediate cardioversion is not necessary for patients with recent-onset, symptomatic atrial fibrillation in the emergency department. Allowing a short time for spontaneous conversion to sinus rhythm is reasonable as long as the total time in atrial fibrillation is less than 48 hours. Special consideration for anticoagulation is critical because stroke has been associated with atrial fibrillation duration between 24 and 48 hours.
—Ka Ming Gordon Ngai, MD, MPH
Study Overview
Objective. To assess whether immediate restoration of sinus rhythm is necessary in hemodynamically stable, recent onset (< 36 hr), symptomatic atrial fibrillation in the emergency department.
Design. Multicenter, randomized, open-label, noninferiority trial, RACE 7 ACWAS (Rate Control versus Electrical Cardioversion Trial 7--Acute Cardioversion versus Wait and See).
Setting and participants. 15 hospitals in the Netherlands, including 3 academic hospitals, 8 nonacademic teaching hospitals, and 4 nonteaching hospitals. Patients 18 years of age or older with recent-onset (< 36 hr), symptomatic atrial fibrillation without signs of myocardial ischemia or a history of persistent atrial fibrillation who presented to the emergency department were randomized in a 1:1 ratio to either a wait-and-see approach or early cardioversion. The wait-and-see approach consisted of the administration of rate-control medication, including intravenous or oral beta-adrenergic-receptor blocking agents, nondihydropyridine calcium-channel blockers, or digoxin to achieve a heart rate of 110 beats per minute or less and symptomatic relief. Patients were then discharged with an outpatient visit scheduled for the next day and a referral for cardioversion as close as possible to 48 hours after the onset of symptoms. The cardioconversion group received pharmacologic cardioversion with flecainide unless contraindicated, then electrical cardioversion was performed.
Main outcome measures. Primary outcome was the presence of sinus rhythm on electrocardiogram (ECG) recorded at the 4-week trial visit. Secondary endpoints included the duration of the index visit at the emergency department, emergency department visits related to atrial fibrillation, cardiovascular complications, and time until recurrence of atrial fibrillation.
Main results. From October 2014 through September 2018, 437 patients underwent randomization, with 218 patients assigned to the delayed cardioversion group and 219 to the early cardioversion group. Mean age was 65 years, and a majority of the patients (60%) were men (n = 261). The primary end point of the presence of sinus rhythm on the ECG recorded at the 4-week visit was present in 193 of 212 patients (91%) in the delayed cardioversion group and in 202 of 215 patients (94%) in the early cardioversion group. The –2.9 percentage points with confidence interval [CI] –8.2 to 2.2 (P = 0.005) met the criteria for the noninferiority of the wait-and-see approach.
For secondary outcomes, the median duration of the index visit was 120 minutes (range, 60 to 253) in the delayed cardioversion group and 158 minutes (range, 110 to 228) in the early cardioversion group. The median difference between the 2 groups was 30 minutes (95% CI, 6 to 51 minutes). There was no significant difference in cardiovascular complications between the 2 groups. Fourteen of 212 patients (7%) in the delayed cardioversion group and 14 of 215 patients (7%) in the early cardioversion group had subsequent visits to the emergency department because of a recurrence of atrial fibrillation. Telemetric ECG recordings were available for 335 of the 437 patients. Recurrence of atrial fibrillation occurred in 49 of the 164 (30%) patients in the delayed cardioversion group and 50 of the 171 (29%) patients in the early cardioversion group.
In terms of treatment, conversion to sinus rhythm within 48 hours occurred spontaneously in 150 of 218 patients (69%) in the delayed cardioversion group after receiving rate-control medications only. Of the 218 patients, 61 (28%) had delayed cardioversion (9 by pharmacologic and 52 by electrical cardioversion) as per protocol and achieved sinus rhythm within 48 hours. In the early cardioversion group, conversion to sinus rhythm occurred spontaneously in 36 of 219 patients (16%) before the initiation of the cardioversion and in 171 of 219 (78%) after cardioversion (83 by pharmacologic and 88 by electrical).
Conclusion. For patients with recent-onset, symptomatic atrial fibrillation, allowing a short time for spontaneous conversion to sinus rhythm is reasonable as demonstrated by this noninferiority study.
Commentary
Atrial fibrillation accounts for nearly 0.5% of all emergency department visits, and this number is increasing.1,2 Patients commonly undergo immediate restoration of sinus rhythm by means of pharmacologic or electrical cardioversion. However, it is questionable whether immediate restoration of sinus rhythm is necessary, as spontaneous conversion to sinus rhythm occurs frequently. In addition, the safety of cardioversion between 12 and 48 hours after the onset of atrial fibrillation is questionable.3,4
In this pragmatic trial, the findings suggest that rate-control therapy alone can achieve prompt symptom relief in almost all eligible patients, had a low risk of complications, and reduced the median length of stay in the emergency department to 2 hours. Independent of cardioversion strategy, the authors stressed the importance of management of stroke risk when patients present with atrial fibrillation to the emergency department. In this trial, 2 patients had cerebral embolism even though both were started on anticoagulation in the index visit. One patient from the delayed cardioversion group was on dabigatran after spontaneous conversion to sinus rhythm and had an event 5 days after the index visit. The other patient, from the early cardioversion group, was on rivaroxaban and had an event 10 days after electrical cardiology. In order for the results of this trial to be broadly applicable, exclusion of intraatrial thrombus on transesophageal echocardiography may be necessary when the onset of atrial fibrillation is not as clear.
There are several limitations of this study. First, this study included only 171 of the 3706 patients (4.6%) screened systematically at the 2 academic centers, but included 266 from 13 centers without systematic screening. The large amount of patients excluded from the controlled environment made the results less generalizable in the broader scope. Second, the reported incidence of recurrent atrial fibrillation within 4 weeks after randomization was an underestimation of the true recurrence rate since the trial used intermittent monitoring. Although the incidence of about 30% was similar between the 2 groups, the authors suggested that the probability of recurrence of atrial fibrillation was not affected by management approach during the acute event. Finally, for these results to be applicable in the general population, defined treatment algorithms and access to prompt follow-up are needed, and these may not be practical in other clinical settings.2,5
Applications for Clinical Practice
The current study demonstrated immediate cardioversion is not necessary for patients with recent-onset, symptomatic atrial fibrillation in the emergency department. Allowing a short time for spontaneous conversion to sinus rhythm is reasonable as long as the total time in atrial fibrillation is less than 48 hours. Special consideration for anticoagulation is critical because stroke has been associated with atrial fibrillation duration between 24 and 48 hours.
—Ka Ming Gordon Ngai, MD, MPH
1. Rozen G, Hosseini SM, Kaadan MI, et al. Emergency department visits for atrial fibrillation in the United States: trends in admission rates and economic burden from 2007 to 2014. J Am Heart Assoc. 2018;7(15):e009024.
2. Healey JS, McIntyre WF. The RACE to treat atrial fibrillation in the emergency department. N Engl J Med. 2019 Mar 18.
3. Andrade JM, Verma A, Mitchell LB, et al. 2018 Focused update of the Canadian Cardiovascular Society guidelines for the management of atrial fibrillation. Can J Cardiol. 2018;34:1371-1392.
4. Nuotio I, Hartikainen JE, Grönberg T, et al. Time to cardioversion for acute atrial fibrillation and thromboembolic complications. JAMA. 2014;312:647-649
5. Baugh CW, Clark CL, Wilson JW, et al. Creation and implementation of an outpatient pathway for atrial fibrillation in the emergency department setting: results of an expert panel. Acad Emerg Med. 2018;25:1065-1075.
1. Rozen G, Hosseini SM, Kaadan MI, et al. Emergency department visits for atrial fibrillation in the United States: trends in admission rates and economic burden from 2007 to 2014. J Am Heart Assoc. 2018;7(15):e009024.
2. Healey JS, McIntyre WF. The RACE to treat atrial fibrillation in the emergency department. N Engl J Med. 2019 Mar 18.
3. Andrade JM, Verma A, Mitchell LB, et al. 2018 Focused update of the Canadian Cardiovascular Society guidelines for the management of atrial fibrillation. Can J Cardiol. 2018;34:1371-1392.
4. Nuotio I, Hartikainen JE, Grönberg T, et al. Time to cardioversion for acute atrial fibrillation and thromboembolic complications. JAMA. 2014;312:647-649
5. Baugh CW, Clark CL, Wilson JW, et al. Creation and implementation of an outpatient pathway for atrial fibrillation in the emergency department setting: results of an expert panel. Acad Emerg Med. 2018;25:1065-1075.