Müllerleile, Cathrin Theis, Karsten Bock, Helge Servatius, Arian

Prognostic Role of Subsequent Atrial Tachycardias Occurring During Ablation of
Persistent Atrial Fibrillation: A Prospective Randomized Trial
Thomas Rostock, Tushar V. Salukhe, Boris A. Hoffmann, Daniel Steven, Imke Berner, Kai
Müllerleile, Cathrin Theis, Karsten Bock, Helge Servatius, Arian Sultan and Stephan Willems
Circ Arrhythm Electrophysiol. 2013;6:1059-1065; originally published online October 25, 2013;
doi: 10.1161/CIRCEP.113.001019
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Original Article
Prognostic Role of Subsequent Atrial Tachycardias
Occurring During Ablation of Persistent Atrial Fibrillation
A Prospective Randomized Trial
Thomas Rostock, MD; Tushar V. Salukhe, MRCP, MD; Boris A. Hoffmann, MD;
Daniel Steven, MD; Imke Berner, MD; Kai Müllerleile, MD; Cathrin Theis, MD;
Karsten Bock, MD; Helge Servatius, MD; Arian Sultan, MD; Stephan Willems, MD
Background—The role of subsequent atrial tachycardias (AT) in the context of persistent atrial fibrillation (AF) remains
undetermined. This study evaluated the prognostic role of subsequent ATs for arrhythmia recurrences after catheter
ablation of persistent AF.
Methods and Results—A total of 110 patients with persistent AF (63±9 years; 22 women; 61 long-lasting persistent AF)
underwent pulmonary vein isolation followed by electrogram-guided ablation. After AF terminated to AT, patients were
separated by the randomization protocol to receive either direct cardioversion (group A) or further ablation of subsequent
ATs to sinus rhythm (group B). After a mean follow-up of 20.1±13.3 months after the first procedure, significantly more
group B patients were in sinus rhythm as compared with patients in group A (30 [57%] versus 18 [34%]; P=0.02). Moreover,
recurrences of AF were significantly less frequent of group B than in group A patients (10 [19%] versus 26 [49%]; P=0.001).
After the last procedure (follow-up, 34.0±6.4 months), significantly more group B patients were free of AF as compared
with patients of group A (49 [92%] versus 39 [74%]; P=0.01). The proportion of AT recurrences did not differ between the
2 groups after the first and final procedures. The strongest predictor for an arrhythmia-free survival after a single procedure
was randomization to the procedural end point of termination to sinus rhythm by elimination of subsequent ATs (P=0.004).
Conclusions—Catheter ablation of subsequent ATs increases freedom from AF but not AT, suggesting a contributing role of
subsequent ATs in the mechanisms of persistent AF.
Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT01896570. (Circ Arrhythm Electrophysiol. 2013;6:1059-1065.)
Key Words: arrhythmias, cardiac ◼ atrial fibrillation ◼ catheter ablation ◼ tachycardia, ectopic atrial
W
ith an increasing complexity of catheter ablation techniques for the treatment of persistent atrial fibrillation
(AF), subsequent atrial tachycardias (AT) have evolved as an
important arrhythmia in terms of mechanistic cause, prognostic relevance, and treatment strategies.1–6 Although arrhythmia
recurrences after pulmonary vein (PV) isolation as the sole
procedural strategy predominantly consist of AF, subsequent
ATs represent approximately half of all recurrences after
extensive biatrial substrate ablation.1–4,7–9 Therefore, a proarrhythmogenic consequence of the ablation procedure itself by
creating the basis for zones of slow conduction or enhanced
electric automaticity has been proposed to cause these ATs.10
However, a cumulating body of evidence emerges, demonstrating that subsequent ATs appear as a result of a substrate
transformation to the incapability to maintain fibrillatory
activity and a hierarchical organization of the arrhythmia.11–13
Nevertheless, the prognostic role of subsequent ATs occurring
after termination of persistent AF for the long-term outcome
has not been determined thus far.
Editorial see p 1047
Clinical Perspective on p 1065
The aim of this study was to evaluate the impact of sequential ablation of subsequent ATs occurring after termination of
persistent AF on the outcome and potential consequences on
the type of arrhythmia recurrences during follow-up.
Methods
Study Population
The patients were selected using the following inclusion criteria:
persistent AF lasting for a minimum duration of 1 month before
the procedure, a history of ≥1 attempt at electric cardioversion, AF
Received July 23, 2013; accepted October 7, 2013.
From the II. Medical Clinic, Department of Electrophysiology, University Medical Center, Johannes Gutenberg-University, Mainz, Germany (T.R.,
C.T., K.B.); Department of Electrophysiology, University Hospital Eppendorf, University Heart Center, Hamburg, Germany (T.R., T.V.S., B.A.H., D.S.,
I.B., K.M., C.T., K.B., H.S., A.S., S.W.); and Royal Brompton Hospital, Royal Brompton and Harefield NHS Foundation Trust and National Heart Lung
Institute, Imperial College London, London, United Kingdom (T.V.S.).
Correspondence to Thomas Rostock, MD, II. Medical Clinic, Department of Electrophysiology, University Medical Center, Johannes GutenbergUniversity Mainz, Langenbeckstr 1, D-55131 Mainz, Germany. E-mail [email protected]
© 2013 American Heart Association, Inc.
Circ Arrhythm Electrophysiol is available at http://circep.ahajournals.org
DOI: 10.1161/CIRCEP.113.001019
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by guest on December 22, 2013
1059
1060 Circ Arrhythm Electrophysiol December 2013
refractory to antiarrhythmic drug therapy, and no previous ablation
procedure. Long-standing persistent AF was defined as arrhythmia
duration of ≥12 months. The study was approved by the institutional
review board and ethics committee. All patients provided written informed consent. Patients were enrolled at the University Heart Center
Hamburg between June 25, 2009, and October 13, 2010.
PVI
SR (n = 8)
(n = 110)
AF (n = 22)
Electrogram-guided
Ablation
SR (n = 11)
(n = 102)
DC
Conversion
to AT
Study Design
The patients were randomized before the procedure into one of the
study arms. In all patients, a stepwise ablation procedure was performed consisting of PV isolation as the first step followed by electrogram-based ablation of the left atrium (LA), coronary sinus (CS),
and the right atrium (RA) as required. The end point of electrogrambased ablation was termination of AF either with conversion to an
AT or directly to sinus rhythm (SR). AT was defined as an organized
atrial activity with a consistent endocardial activation sequence and
monomorphic P-waves. If the patient terminated directly into SR during electrogram-based ablation, the procedure was completed without
ablation of ATs. The randomization protocol was started after AF termination with conversion to AT. In group A patients, AT was electrically cardioverted without specific mapping, and ablation of AT and
PV isolation were confirmed or completed if necessary during SR. No
further ablation was performed. In group B patients, all subsequent
ATs were targeted for ablation until SR was achieved.
Ablation Procedures
The following catheters were introduced via a femoral vein access:
(1) A steerable decapolar catheter (Inquiry; IBI, Irvine Biomedical,
Inc, Irvine, CA) was positioned within the CS; (2) a circumferential
decapolar diagnostic catheter (Lasso; Biosense-Webster, Diamond
Bar, CA) for mapping of the PVs; (3) a nonsteerable quadripolar diagnostic catheter (Inquiry; IBI, Irvine Biomedical, Inc) was placed
in the right atrial appendage; and (4) a 3.5-mm externally irrigated
tip ablation catheter (Thermocool; Biosense-Webster). Access to LA
was achieved by a single transseptal puncture with the 2 catheters
placed into the LA via the same puncture. A single bolus of 50 IU/kg
body weight heparin was administered after transseptal puncture. The
activated clotting time was assessed every 30 minutes and maintained
within a range of 250 to 350 seconds. In all study patients, the stepwise ablation approach with the desired procedural end point of AF
termination was used. The ablation protocol performed as standard at
our institution has been described previously in detail.2,9 Electric isolation of the PVs was the first step in all procedures. PV isolation was
defined by elimination or dissociation of PV potentials recorded on
the Lasso catheter. After complete electric PV isolation, mapping and
ablation were routinely continued in the LA. For the purpose of AF
cycle length (AFCL) measurement, the Lasso catheter was placed in
the LA appendage. After an initial assessment of AF behavior (local
AFCL within the LA, CS, and RA and AFCL gradient between chambers), electrogram-guided ablation targeting specific electrogram
Table 1. Patient Baseline Characteristics
Age, y
Group A
Group B
P Value
63±10
64±9
0.454
(n = 69)
Group A
Group B
(n = 35)
(n = 34)
DC
AT ablation
SR
Figure 1. Study flowchart with numbers of patients. AF indicates
atrial fibrillation; AT, atrial tachycardia; DC, direct cardioversion;
PVI, pulmonary vein isolation; and SR, sinus rhythm.
patterns and electrogram behaviors was performed, consisting of
continuous electric activity, high-frequency complex fractionated activity, locally short AFCL or intermittent local burst activity, temporal activation gradient between the distal and proximal bipoles of the
roving ablation catheter, and local spreading of centrifugal activation.
Ablation of the CS was performed when the LA AFCL became longer than the local AFCL in the CS. Mapping and ablation using the
same criteria were continued in the RA if AF did not terminate during
LA and CS ablation.
Mapping of ATs was performed using conventional techniques.6,14
In case of macroreentrant ATs, linear ablation was performed, and
the end point of bidirectional block was assessed and confirmed by
differential pacing maneuvers after restoration of SR. Focal ATs were
mapped by assessing the earliest endocardial activation in relation to
P-wave onset or, if P-wave onset could not be clearly identified, to a
fixed intracardiac electrogram. After AT termination, no attempt at
arrhythmia reinduction was performed.
Ablation was performed with a maximum power output of 30 W using an irrigation rate of 10 to 30 mL/min (0.9% saline infused with the
CoolFlow Pump, Biosense-Webster) for the PVs, 35 W and an irrigation rate between 30 and 60 mL/min in the LA, and ≤30 W in the RA.
RF current was applied within the CS with a maximum of 25 W and
a manually adjusted irrigation rate to keep the tip-temperature <42°C.
Follow-Up
All patients were seen regularly every 3 months in our outpatient
clinic. Before visits, the patients received ≥2 separate 24-hour HolterECGs. A detailed history of the patients’ symptoms suggestive for
potential arrhythmia recurrences was taken. In case of undocumented
Table 2. Comparison of Procedural Data
Female (n, %)
12 (22)
20 (36)
0.095
Hypertension (n, %)
38 (69)
35 (64)
0.549
Baseline AFCL, ms
Diabetes mellitus (n, %)
5 (9)
5 (9)
1.000
Congestive heart failure (n, %)
6 (11)
6 (11)
1.000
Coronary artery disease (n, %)
13 (24)
14 (25)
Amiodarone treatment (n, %)
20 (36)
18 (33)
Group A
Group B
P Value
LAA
172±27
169±28
0.715
RAA
175±30
175±28
0.979
0.829
CS
170±24
168±27
0.662
0.692
Procedure duration, min
195±68
242±65
< 0.001
Left atrial size, mm
45±7
46±6
0.675
Fluoroscopy time, min
53±21
66±21
0.001
LVEF, %
58±10
60±9
0.296
RF time, min
93±37
109±33
0.015
12 (1–120)
13 (1–120)
0.220
AFCL indicates atrial fibrillation cycle length; CS, coronary sinus; LAA, left
atrial appendage; and RAA, right atrial appendage.
Duration of continuous AF, mo
AF indicates atrial fibrillation; and LVEF, left ventricular ejection fraction.
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Rostock et al Role of ATs in AF Mechanisms 1061
%
Group A (DC for AT)
80
p = 0.02
Group B (AT ablation)
70
p = 0.001
60
57
50
49
40
30
p = ns
34
24
20
10
0
19
17
SR
AT
AF
Figure 2. Rhythm outcome after first ablation at a mean followup of 20.1±13.3 months. AF indicates atrial fibrillation; AT, atrial
tachycardia; DC, direct cardioversion; and SR, sinus rhythm.
symptoms suspicious for arrhythmia recurrences, documentation
by additional Tele-ECG recordings was performed. A documented
symptomatic or asymptomatic arrhythmia episode lasting >30 seconds was defined as recurrence.
An initial blanking period of 3 months was accepted. During the
blanking period, antiarrhythmic drug treatment was continued at
the discretion of the operator. All antiarrhythmic drugs (excluding
β-blocker for the treatment of hypertension) were ceased after the
blanking period. Patients with an arrhythmia recurrence after the
blanking period were offered and scheduled for a redo procedure.
Ablation Approach of Repeat Procedures
As the first step, electric conduction of the PVs were assessed using
a circumferential mapping catheter, and reisolation was performed.
If AF persisted, electrogram-guided ablation was performed with the
same techniques as described for the index procedure. Mapping and
ablation of AT were also performed using the techniques described
above. The end point was termination of all occurring arrhythmias
with procedural achievement of SR in all patients regardless of the
initial randomization protocol.
Statistical Analysis
All continuous variables are reported as mean±SD and medians
with ranges, whereas categorical variables were summarized as
proportions. Categorical variables were compared using the χ2 test.
Comparison between groups was performed with either Student
t test or the χ2 test. For non-normally distributed variables, the
Mann–Whitney U test was used. A P value of <0.05 was considered
to indicate a statistically significant difference. On the basis of our
clinical experience, we assumed a P value of 0.05 for α error and
a P value of 0.15 for β error (β−1=0.85). With an expected rate of
the arrhythmia-free survival of 0.6 (group B) and 0.3 (group A), we
calculated a sample size of 100 patients. On the assumption of an
overall rate of loss to follow-up of 10%, we included a total number of 110 patients in both groups. Time to arrhythmia recurrence
was estimated using the Kaplan–Meier method and compared by
the log-rank test. Multivariate analysis by means of a logistic regression model and stepwise backward selection was performed to
identify significant and independent predictors of arrhythmia recurrence. Independent variables were chosen when a P<0.10 emerged
on univariate analysis. Variables in the initial model for arrhythmia
recurrence included the procedural end point (randomization group),
age, male sex, history of hypertension, diabetes mellitus, congestive
heart failure, coronary artery disease, amiodarone treatment, LA diameter, and left ventricular ejection fraction, time of continuous AF
and baseline AFCL in left atrial appendage, right atrial appendage
and CS, respectively. The 95% confidence limits of correlation coefficients were determined by Fisher r-to-z transformation. Statistical
analysis was performed with a statistical software package (version
21; SPSS, IBM, Armonk, NY).
Results
Patient Characteristics
A total number of 110 patients with persistent (N=49;
45%) and long-standing persistent (N=61; 55%) AF were
included. The mean age was 63±9 years, and 22 patients
were female. The patients were in continuous persistent
AF for 25±30 months (median, 12; range, 1–120). Fiftyfive patients were randomized to a procedural end point
of cardioversion after AF termination with conversion to
AT (group A), and 55 patients were randomly assigned to
group B where the targeted end point was achievement of
SR by ablation of all subsequent ATs. The baseline characteristics of patients in both groups are demonstrated in
Table 1. One third of patients were on amiodarone (N=38;
35%), 8 (7%) on flecainide or propafenone, and 2 patients
Figure 3. Rhythm outcome after each ablation
procedure. The cumulative outcome after all procedures is demonstrated in the gray bar at the
bottom. AF indicates atrial fibrillation; AT, atrial
tachycardia; DC, direct cardioversion; and SR, sinus
rhythm.
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1062 Circ Arrhythm Electrophysiol December 2013
(2%) on dronedarone. Overall, 36 (33%) patients received
β-blocker for either ventricular rate control or treatment of
hypertension.
Procedural Results
In all patients, the procedure was started in spontaneous AF.
The first step of ablation, PV isolation, resulted in AF termination in 8 (7%) patients (3 in group A and 5 in group
B). Termination of AF occurred with a mean of 3.4±0.7
PVs isolated and with conversion directly into SR in all
of these patients. The remaining 102 patients underwent
electrogram-based ablation of the atrial substrate. In 11
(10%) patients, AF terminated during ablation directly into
SR (7 during LA ablation and 4 during RA ablation). Sites
of AF termination were located in the LA, CS, and RA in
72%, 8%, and 19%, respectively. Termination of AF was not
achieved by PVI and biatrial defragmentation in 22 (20%)
A
patients, and electric cardioversion was required to restore
SR (Figure 1).
In group A patients, SR was achieved in all patients by
electric cardioversion. In patients of group B, a total number of 83 AT occurred after AF termination (2.3±0.8 ATs
per patient). Seventy-four (89%) ATs were successfully
terminated to SR by ablation. In 2 patients, the mechanism
of the first AT occurring after AF termination could not be
identified, and the patients were cardioverted. In another
5 patients, the procedure was not continued after elimination of ≥2 subsequent ATs because of prolonged procedure
durations, and the final AT was terminated by cardioversion.
Procedural data of patients in both groups are demonstrated
in Table 2.
Clinical Outcome After Ablation
A total of 106 patients were eligible for outcome analysis. Three
patients were lost to follow-up, and 1 patient died 16 months
after ablation because of malignancy. All remaining patients
completed a follow-up of ≥24 months after study inclusion.
Rhythm Outcome After First Ablation
After a mean follow-up of 20.1±13.3 months after the first
ablation procedure, significantly more group B patients were
in SR as compared with patients in group A (30 [57%] versus
18 [34%]; P=0.02). Moreover, recurrences of AF were significantly less frequent in group B patients than those in group
A patients (10 [19%] versus 26 [49%]; P=0.001). The exact
numbers of rhythm outcomes after a single procedure are
demonstrated in Figures 2 and 3. The Kaplan–Meier arrhythmia-free survival estimation showed a trend toward a better
outcome in group B patients as compared with patients of
group A without reaching statistical significance (Figure 4A).
However, freedom from AF survival estimation revealed a significantly better outcome in patients of group B than in group
A patients (P=0.005; Figure 4B).
B
Rhythm Outcome After Last Ablation
The mean follow-up time for patients with multiple procedures was 34.0±6.4 months. The mean number of procedures
was similar in group A and B patients (1.7±0.7 versus 1.8±0.7;
%
p = ns
100
Group A (DC for AT)
90
80
70
Group B (AT ablation)
85
72
60
p = 0.018
50
40
p = ns
30
20
2
10
0
Figure 4. Kaplan–Meier survival curve after first ablation ([A]
patients in sinus rhythm [SR] vs no SR and [B] patients in atrial
fibrillation [AF] vs no AF). AT indicates atrial tachycardia; and DC,
direct cardioversion.
SR
26
7.5
7.5
AT
AF
Figure 5. Rhythm outcome after last ablation at a mean followup of 34.0±6.4 months. AF indicates atrial fibrillation; AT, atrial
tachycardia; DC, direct cardioversion; and SR, sinus rhythm.
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Rostock et al Role of ATs in AF Mechanisms 1063
P=0.857; Figure 3). Ultimately, significantly more group B
patients were free of AF after the last procedure as compared
with patients of group A (49 [92%] versus 39 [74%]; P=0.01;
Figure 5). The arrhythmia-free survival estimation after the
last procedure again revealed a more favorable outcome in
group B patients, however failing to achieve statistical significance (Figure 6A). Nevertheless, freedom from AF was significantly higher in group B as compared with that in group A
patients (P=0.016; Figure 6B).
Predictors for Procedural Success
Patient characteristics as presented in Table 1, and baseline
AFCL were evaluated in univariate and multivariate regression analyses. Even after adjustment for higher left ventricular
ejection fraction and a longer baseline AFCL in the RA, randomization to group B remained a strong predictor of arrhythmia-free survival (Table 3).
A
Adverse Events
In the study patients, no major complications occurred including cardiac tamponade, phrenic nerve injury, stroke, or atriaesophageal fistula. In 3 patients, groin hematoma occurred after
the ablation procedure, 1 of them requiring blood transfusion.
Discussion
Main Findings
This prospective randomized study revealed the following data
on the prognostic role of subsequent ATs occurring after AF
termination: First, the elimination of subsequent ATs is associated with a significant decrease in recurrences of AF but not
ATs. Second, subsequent ATs can be successfully ablated in the
majority of patients with an acceptable procedural investment.
Third, the strongest predictor for an arrhythmia-free survival
after a single stepwise ablation procedure was the targeted procedural end point of termination to SR by ablation of subsequent
ATs. Thus, these data support the hypothesis of the contributing
role of subsequent ATs in the mechanisms of persistent AF.
AT Substrates in AF
Procedural AF termination is most commonly associated with
conversion to AT with the majority of them underlying a macroreentrant mechanism.3,4,9,15,16 Conversion of AF to AT characteristically occurs after an arrhythmia organization, which is
represented by a continuous increase of the AFCL up to a critical level ≈200 ms.3,4,13,16,17 The mechanisms and antiarrhythmic
processes by which electrogram-guided ablation of AF results
in arrhythmia organization yet are still not completely clear and
are a critical matters of discussion. Recently, 2 different new
computational mapping techniques have been introduced to
map and ablate more specifically the arrhythmia-perpetuating
atrial substrate of persistent AF. The focal impulse and rotor
modulation approach is based on multispline contact mapping
of rate-dependent repolarization to assess the shortest successive activation times and rate-dependent conduction slowing to
identify propagation paths that are depicted in a computational
color-coded map.18 In contrast, panoramic mapping is based on
noninvasively acquired cardiac surface potentials and unipolar
electrograms using a 252-electrode vest placed on the patients’
torso.19 Although these 2 different mapping techniques revealed
divergent data in terms of spatiotemporal stability of AF sources,
both studies demonstrated multiple (≥2) rotors or focal activity
B
Table 3. Univariate and Multivariate Regression Analyses for
Predictors of Arrhythmia-Free Survival After First Ablation
Baseline Variable
P Value
Odds Ratio
95% Confidence
Interval
Univariate predictor of arrhythmia-free survival
Randomization to group B
0.033
0.426
0.194–0.933
Multivariate predictors of arrhythmia-free survival
Figure 6. Kaplan–Meier survival curve after last ablation ([A]
patients in sinus rhythm [SR] vs no SR and [B] patients in atrial
fibrillation [AF] vs no AF).
LVEF
0.029
0.933
0.878–0.993
Baseline RAA AFCL
0.049
0.969
0.939–1.000
Randomization to group B
0.004
0.191
0.063–0.581
AFCL indicates atrial fibrillation cycle length; LVEF, left ventricular ejection
fraction; and RAA, right atrial appendage.
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1064 Circ Arrhythm Electrophysiol December 2013
maintaining the atria in AF.20,21 Interestingly, a hierarchical order
of simultaneously existing sources seems to define the dynamics and dominance of each element in the perpetuation of AF.20
Considering that an arrhythmia organizing effect has also been
described for left atrial linear ablation,12 the following mechanisms may explain the antifibrillatory effect of subsequent AT
ablation: (1) the focal, rotor, or macroreentrant activity of a subsequent AT may have had an arrhythmogenic role in the persistent AF processes, and its elimination potentially decreases
the number of residual AF sources. (2) Linear lesions for the
treatment of macroreentrant ATs may constrain dominant or preferred wavefront propagation paths of meandering sources of AF
with the potential to restrict their spatiotemporal propagation.
(3) Contiguous lesions for the treatment of multiple subsequent
ATs in addition to linear lesions create electric boundaries in the
atria (eg, inferior LA-CS, left atrial appendage-anterior wall,
interatrial septum) with the result of a substrate compartmentalization that prevents AF sources to sustain.
Improving Outcomes of Persistent AF Ablation
The best end point for persistent AF ablation critical to arrhythmia-free survival remains contested. Broadly, the spectrum of
instruments consist of PV isolation alone,7,8 electrogram-guided
ablation,2 and linear ablation.22 The stepwise ablation approach
combines these techniques, importantly however, with the end
point of procedural AF termination.16 The predictive value of AF
termination seems to depend on the rate AF termination. Although
studies with a low or moderate AF termination rate (<35%) did
not show a correlation to long-term success,23,24 AF termination
rates >50% revealed a significant association to a favorable outcome when the procedural end point was achieved.9,15,16,25 We
think our study is the first to demonstrate a significant reduction
in AF recurrence after a single procedure when the end point of
ablation of all subsequent ATs to SR is sought from the outset of
persistent AF ablation. With the focal impulse and rotor modulation ablation approach, AF terminated by a limited amount of
RF (mean, ≈15 minutes) with conversion to AT in one third of
the patients.21 Certainly, these more individualized and patienttailored approaches will enhance our understanding of the mechanisms of persistent AF. However, the impact of subsequent ATs
on AF recurrences after such a specified computational-guided
mapping approach needs clarity. A similar result as shown in this
trial will further substantiate the theory of an important contributory role of subsequent ATs in AF mechanisms.
Limitations
In the present study, no significant difference between both
groups was observed in terms of recurrences of any atrial
tachyarrhythmia after both the first and last ablation procedures.
The study may have been underpowered to detect a statistically
significant difference in outcomes between the 2 groups.
Conclusions
Subsequent ATs are the predominant arrhythmia remnants
after AF termination. Further ablation aiming at elimination of
all subsequent ATs significantly reduces recurrences of AF but
not AT. Thus, the results of this study corroborate the hypothesis that subsequent ATs have the potential to contribute to the
multifaceted mechanisms of persistent AF.
Sources of Funding
Dr Salukhe was supported by the British Heart Foundation
FS/09/018/26963.
Disclosures
None.
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CLINICAL PERSPECTIVE
Procedural atrial fibrillation (AF) termination is predominantly associated with the occurrence of regularized atrial tachycardias (AT) requiring further mapping and ablation to achieve conversion into sinus rhythm. However, the prognostic role
of subsequent ATs occurring after AF termination for the long-term outcome remains undetermined. In this prospective
randomized trial, we compared the single procedure and overall outcome of patients undergoing ablation of subsequent ATs
versus those who did receive electric cardioversion once AF has terminated into regularized AT. After the first procedure,
significantly more patients with ablation of subsequent ATs were in sinus rhythm as compared with those without. Moreover,
both after the first and the last ablation procedures, the proportion of patients free of AF recurrences was significantly greater
in the group of patients who underwent ablation of subsequent ATs. Recurrences of ATs were equally prevalent in both
groups. The strongest predictor for a successful single-procedure outcome was the ablation of subsequent ATs. The data of
the present study demonstrate that ablation of subsequent regularized ATs increases freedom from AF. Thus, termination to
sinus rhythm by elimination of subsequent ATs should be considered a prognostic importantly and therefore integral part of
persistent AF ablation. Ablation of subsequent ATs decreased recurrence rates of AF but not AT. Therefore, these data further
corroborate a potentially contributing role of subsequent ATs in the mechanisms perpetuating persistent AF.
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