Discussion
This is a unique study that compared ED patients with AF for more than
48 hours’ duration who subsequently underwent TEE and then electrical
cardioversion by emergency physicians back in the ED versus in the
cardiology department. Successful cardioversion, defined at discharge,
showed that over 90% of cardioversions were successful in both groups.
Time to TEE was approximately one day for both groups. However, time to
cardioversion, time kept in the hospital post-procedure, and LOS in the
hospital were significantly shorter in the ED group versus the
cardiology department group. This was thought to be due to several
factors. All patients who were cardioverted underwent procedural
sedation. Those who had the procedure performed in the ED had the
sedation performed by a second ED physician which could be arranged
relatively quickly. However, at the time of the study, the patients who
underwent cardioversion in the cardiology department needed to wait for
an anesthesiologist to perform the sedation. As there was no dedicated
anesthesiologist, this could result in a significant waiting period.
Also, there was a logistical need to arrange for a monitored observation
area in the cardiology department. Some of the patients in the
cardiology department underwent additional workups and treatment for a
secondary issue such as anemia. Also, there may have been a trend to
quickly discharge post-procedure patients from a busy urban ED.
Interestingly there was no significant difference in the readmission
rate to the hospital one-month post-hospital discharge and no known
significant negative outcomes in the ED cardioversion group.
This study is the first to be done to examine ED cardioversion post-TEE
performance in patients whose atrial fibrillation was more than 48
hours’ duration. Previous studies have described ED electrical
cardioversions of less than 48 hours’ duration with success rates
ranging from 85.5 to 97%.9 Burton et al. described a
7-day 10% return of patients, of whom 78% (25/32) returned due to a
recurrence of AF.1 A recent multicenter randomized
control trial assigned ED patients with recent-onset AF (<36
hours) who were symptomatic yet hemodynamically stable to be treated
either with early cardioversion or with a “wait-and-see” approach. At
4-week follow-up, AF recurred in 49/164 (30%) in the delayed
cardioversion group versus in 50/171 (29%) of the earlier cardioversion
group.10 Scheuermeyer et al. performed a random 30-day
follow-up chart review of 400/1233 AF patients who had undergone ED
electrical cardioversion. Only 22 patients (5.5%) returned to the ED
within one month for symptoms that were deemed potentially related to
the index visit, with six patients (1.5%) requiring repeat
cardioversion.8 The current study described an overall
94% success rate of rhythm control at discharge (141/151), with an
overall 30-day return rate of 22% (32/151), of whom only 44% (14/32)
returned due to recurrent AF, constituting 9.3% of the total study
population. It is interesting to note that in the current study, the ED
patients fared as well as those in the cardiology cohort. Clinical
backgrounds and reasons for ED return also did not differ between the
groups. Further investigation into the short-term and longer-term
success of ED electrical cardioversion of AF of >48 hours’
duration after TEE performance is necessary. It seems, based on the
results of the current study, that this approach may be at least as
successful as some reports of ED cardioversion of AF of <48
hours’ duration.
It has been noted that patients with AF >48 hours’ duration
who were treated with standard practice, i.e. weeks of anticoagulation
before cardioversion, were not always adequately
anticoagulated.11,12 TEE studies performed on patients
with AF <48 hours have shown left atrial thrombi in 1.4% of
patients, of whom 63% were receiving prior anticoagulation therapy,
whereas patients not on prior anticoagulation medication had a 4%
prevalence of left atrial thrombi.13 The data from
these studies seem to point to the conclusion that timing of onset of AF
should not be the only factor in determining a therapeutic approach to
AF, and that performance of a TEE to rule out atrial thrombi may be
warranted despite prior anticoagulation for even a short duration of AF.
In a recent analysis of anticoagulation management with warfarin
involving more than 120,000 patients in the Veterans Affairs health care
system, the mean proportion of time in the therapeutic range was 58%,
with significant variation across sites.14 With the
new oral anticoagulants, this becomes less of an
issue.15
The most prominent results of the current study were the differences in
length of stay of patients based on where their cardioversion was
performed. Time to TEE performance was not significantly different, but
once it was performed, time to cardioversion, time to discharge, and
inevitably length of hospital stay were all significantly shorter
(p<0.001 for the latter three variables) for patients who were
cardioverted in the ED versus those cardioverted in the cardiology ward.
Differences in in-patient versus ED lengths of stay in AF patients have
previously been shown. Ptaszek et al. demonstrated a marked difference
in in-patient LOS after the creation of an AF pathway (64 hours
post-intervention versus 104 hours pre-intervention) with no significant
corresponding reduction in ED stay.16 Other ED studies
have cited shorter lengths of stay and higher patient satisfaction with
ED AF cardioversion.7,9 As the frequency of AF related
hospital visits is predicted to rise,2 it is necessary
to create strategies to reduce the length of stay, thereby reducing
hospital costs. The current study suggests that the performance of TEE
in patients with AF of > 48 hours’ duration to rule out
thrombi, and subsequent performance of electrical cardioversion in the
ED reduces the length of hospital stay and is at least as safe as when
performed on the cardiology ward.
Some EDs with fast turn-around time may choose to put such patients into
an observation ward. While there is much literature on the use of an ED
observation ward to manage patients with atrial fibrillation, none
specifically look at the subcategory of those arriving more than 48
hours after onset.17–21 For those EDs that do have an
observation unit, this treatment strategy may be appropriate.
On the other hand, many EDs have problems with crowding resulting in the
boarding of patients.22-24 This strategy may also be
advantageous in this setting, potentially resulting in earlier discharge
from the hospital than having the patient wait to be treated on the
cardiology ward.