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Sarawuth Limprasert, M.D., oranis Chantrarat, M.D., Preecha Uerojanaungkul, M.D.
Department of Medicine, Phramongkutklao Hospital, Bangkok 10400, ailand.
12-Month Single-Procedure Outcomes after Atrial
Fibrillation Catheter Ablation in Phramongkutklao
Hospital: A Single Center 10-Year Experience
ABSTRACT
Objective: is study aimed to report the ecacy and safety of 1-year outcome for single-procedure radiofrequency
catheter ablation (RFCA) at Phramongkutklao Hospital.
Methods: Review of medical records was carried out on consecutive patients with symptomatic atrial brillation (AF)
who had undergone rst-time RFCA in Phramongkutklao Hospital between January 2009 and December 2018. e
ecacy and safety of outcomes aer 1 year of RFCA were collected, analyzed, and validated using descriptive data.
Results: 61 patients underwent RFCA for the rst time. 77.05% were male, with a mean age of 58.31 ± 10.83 years.
Paroxysmal AF presented in 65.57%. 49.18% had hypertension, 9.84% had a history of ischemic stroke or transient
ischemic attack, 6.56% had diabetes, 6.56% had coronary artery disease, and 4.92% had heart failure. 96.72% of
RFCA procedures were performed under local anesthesia and conscious sedation. Pulmonary vein isolation was
performed in all patients. Rooine, mitral isthmus line, and posterior wall isolation were created in 27.87%, 13.11%,
and 3.28%, respectively. Additional complex fractionated atrial electrograms (CFAEs) were targeted in 19.67%. Aer
12 months, 45.45% remained in sinus rhythm, with only one patient experiencing a procedure-related complication
with cardiac tamponade.
Conclusion: e 1-year results of single-procedure RFCA for treating AF at our center, while not highly successful
in our rst decade, were comparable to other series. Notably, there was a relatively low rate of complications.
Keywords: Atrial brillation; radiofrequency ablation (Siriraj Med J 2021; 73: 114-120)
Corresponding author: Sarawuth Limprasert
E-mail: sarawuthlim@pcm.ac.th
Received 29 April Revised 16 November 2020 Accepted 17 November 2020
ORCID ID: https://orcid.org/0000-0002-9506-6525
http://dx.doi.org/10.33192/Smj.2021.16
INTRODUCTION
Atrial brillation (AF) is a signicant health problem
and the most common form of arrhythmia. e prevalence
tends to uctuate between 1-4% in European countries, but
0.49-1.9% in Asian countries.
1
In ailand, the prevalence
is 1.88% in the elderly population.
2
is prevalence tends
to be higher in patients with comorbidity, such as 3.46%
in patients with hypertension and 22.55% in patients
with ischemic stroke.
3,4
Moreover, AF is one of the severe
independent risk factors of mortality. It is associated with
an increased risk of death, at 2.15 times in female patients
and 1.72 in male patients.
5
It is also associated with an
increased risk of stroke, at 3.2 times in females and 3.4
times in males. Furthermore, it causes increased risk of
heart failure at 3.4 times in both females and males.
6
In
addition to the treatment of specic comorbidity and
anticoagulant therapy for stroke prevention in patients
with AF, rhythm control is an advertent practice. is
approach can help relieve patient’s symptoms and improve
quality of life, which demonstrates its higher eectiveness
Limprasert et al.
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and safety compared to antiarrhythmic drug therapy.
7
Besides symptoms improvement, it can also enhance
the le ventricular ejection fraction (LVEF) by up to
9%.
8
ere are numerous trends showing the additional
benets of catheter ablation in patients with AF, though
data is sparse concerning aspects such as reduced stroke
rate, mortality rate, and the risk of dementia.
9,10
Treating AF patients with catheter ablation was
developed and has increased in popularity over the
last decades. In 2019, data from the Asia-Pacic region
showed this procedure was performed in 446.1 patients
per 1 million in the Japanese population, but in only 1.9
patients per 1 million in the ai population.
11
Even though
this treatment method has been used for many years, the
success rate is a point of concern. Although the success
rate of catheter ablation is higher than antiarrhythmic
therapy, the success rate for these treatments is only 64%
and 58%, respectively.
12
e strategy used in catheter ablation, learning
curve, and experience of the operator are all critical
success factors. Phramongkutklao Hospital, the largest
hospital serving the Royal Thai Army, has played a
signicant role in caring for soldiers and civilians with
AF for decades. Information for patients with AF and
treatment outcomes aer catheter ablation would be
benecial for the development of patient care. e aim
of this single-center, retrospective, observational study
was to analyze the safety and ecacy of single-procedure
catheter ablation for AF.
MATERIALS AND METHODS
Population and data collection
Consecutive patients with symptomatic AF who had
undergone rst-time radiofrequency catheter ablation
(RFCA) at Phramongkutklao Hospital between January
2009 and December 2018 were enrolled in this research.
e study protocol was approved by the institutional review
board of the Royal ai Army Medical Department (Issued
No. S069h/2019_Exp). AF diagnosis was conrmed by
documentation of 12-leads electrocardiography (ECG)
or ambulatory ECG monitoring. AF was classied into
two groups as paroxysmal and persistent type according
to all standard international guidelines. We collected
the essential baseline characteristics of the patients,
which included age, gender, weight, height, comorbid
diseases, antiarrhythmic drug use, and history of electrical
cardioversion. Echocardiographic data before the procedure,
which could aect the outcomes, were also recorded.
Pre-procedural care
Pre-procedural care was performed in the usual
manner, with adequate anticoagulant administered for
at least three weeks or until there was no thrombus in the
le atrium detected by transesophageal echocardiography,
before performing the procedure.
Ablation strategies
e RFCA was performed in the fasting state under
conscious sedation with local anesthesia or general
anesthesia according to the patient’s and operator’s
preference. e ablation technique and strategy were
designed by the operator, but pulmonary vein isolation
(PVI) was targeted in all patients with point-by-point RF
ablation widely encircling the antrum of the pulmonary
veins. PVI strategy alone were performed in patients
with paroxysmal AF. Additional ablation such as the
rooine, mitral isthmus line, posterior wall isolation,
cavotricuspid isthmus, and complex fractionated atrial
electrograms (CFAEs) ablation were performed according
to the operator’s consideration in patients with persistent
AF. Ablation catheters with contact force sensing were
used in all patients. e radiofrequency energy was
delivered with the power of 30-35 watts at anterior wall
and 25-30 watts at posterior wall. e endpoint of the
procedure was PVI, which conrmed by entrance block
into pulmonary vein. Anticoagulant management with
activated clotting time was performed under standard
guidelines. e uoroscopic time was also collected. If
any complications occurred, the details were prescribed.
Post-procedural care
All patients were monitored for 24 hours as inpatient
before discharge. Unless there were complications, the
anticoagulant was routinely restarted in the evening on
a procedural day. We also monitored all the possible
complications throughout the period of admission.
Follow-up and outcome measures
All patients received initial follow-up at
Phramongkutklao Hospital in an outpatient clinic not
more than two weeks post-procedure, followed by every
one to three months according to the doctor and patient’s
preference. To provide adequate time concerning the
evaluation of the ecacy and safety of the procedure,
patients’ data with at least twelve months of follow-up
period were included in the analysis of outcomes. At
follow-up, each patient’s heart rhythm was clinically
evaluated and subjected to 12-lead electrocardiogram
(ECG). Selected patients had 24 or 48 hours of ambulatory
ECG monitoring if the doctor requested, depending
on each patient’s symptoms. Aer three months of the
blanking period, each patient’s rhythm was recorded at
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116
every outpatient visit for 12 months aer the procedure.
e antiarrhythmic drugs utilized aer the procedure
were also recorded.
e recurrence of arrhythmia was dened as any
episode of atrial tachyarrhythmia, including atrial
brillation, atrial utter, or atrial tachycardia, lasting
more than 30 seconds recorded beyond the rst three
months aer the procedure.
Clinically-relevant complications associated with
the procedure were monitored throughout the follow-up
period.
Statistical analysis
e data are presented using descriptive statistics.
Continuous variables are expressed as mean ± standard
deviations and categorical variables as percentages. To
determine the success rate of the procedure, we assessed
arrhythmia-free survival using the Kaplan-Meier method.
RESULTS
Patient characteristics
From January 2009 to December 2018, a total of 72
RFCA procedures were performed. Sixty-one patients
underwent RFCA for the rst time, while 11 had a previous
AF ablation. e baseline characteristics of the patients
who underwent RFCA for the rst time are shown in
Table 1. Overall, 77.05% of patients were male, with
a mean age of 58.31 ± 10.83 years. Mean body mass
index (BMI) was 26.11 ± 6.53 kg/m
2
. Paroxysmal AF
presented in 65.57% of the patients, while 34.43% had
persistent AF. According to the comorbidity of the
patients, 49.18% had hypertension, 9.84% had a history
of ischemic stroke or transient ischemic attack, 6.56%
had diabetes, 6.56% had coronary artery disease, and
4.92% had heart failure. e mean CHA
2
DS
2
VASc was
1.46. e mean time between initial diagnosis and the
procedure was 2.33 ± 2.95 years.
In terms of pre-procedural management, 11.48%
underwent electrical cardioversion prior to RFCA.
Antiarrhythmic drugs were prescribed in 60.66% of
patients. Amiodarone, propafenone, and ecainide were
prescribed in 34.43%, 24.59%, and 1.64% of patients,
respectively.
Echocardiographic ndings
e mean LVEF was 64.10 ± 11.12 %. e mean
LA size was 42.15 ± 5.31 mm in diameter and 63.23 ±
27.01 ml in volume. e mean tissue Doppler E/E’ ratio
was 9.18 ± 4.09.
Procedural details
In 61 patients who underwent RFCA for the rst
time, 96.72% of procedures were performed under local
anesthesia and conscious sedation. Pulmonary vein
isolation was performed in all patients. Rooine, mitral
isthmus line, and posterior wall isolation were created
in 27.87%, 13.11%, and 3.28% of patients, respectively.
Additional CFAEs were targeted in 19.67%. e mean
uoroscopic time was 109.03 ± 32.12 minutes. Table 2
provides the details of the procedure.
Procedural outcome
Aer 12 months of follow-up, there was complete
data in 44 patients. Twenty patients (45.45%) remained
in sinus rhythm aer a single RFCA. Among the patients
for whom sinus rhythm could not be maintained, eighteen
patients (40.91%) had atrial brillation, and six patients
(13.64%) had atrial utter recurrence within one year.
Table 3 shows the overall outcomes. Arrhythmia-free
survival curve aer a single RFCA attempt is shown in
Fig 1.
Complications
From a total of 61 patients, only one patient (1.64%)
had cardiac tamponade, while one patient (1.64%) had
non-clinically signicant pericardial eusion. In the latter
case, the operator detected minimal pericardial eusion
during RFCA and decided to stop the procedure. ere
was no esophageal injury, phrenic nerve injury, vascular
complication at the puncture site, deep vein thrombosis,
or stroke/transient ischemic attack found.
DISCUSSION
AF is the most common type of arrhythmia and is
increasing in terms of its prevalence. Hence, there are
numerous patients who require treatment. Apart from
treating patients’ comorbidity, lifestyle modication, and
anticoagulant therapy to prevent stroke, rhythm control
by RFCA is one of the procedures gaining interest due
to its promising outcomes. Due to the complexity of this
procedure, which may result in some complications,
however infrequently, it can be life-threatening. e single-
procedure success rates demonstrated in several studies
vary depending on not only the patients’ characteristics
such as type of AF and comorbidity, but also the center’s
experience. According to a recent meta-analysis, the
pooled overall single-procedure success rate, dened
as the percentage of patients free of atrial arrhythmia
or not requiring a second procedure at 12 months, was
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TABLE 1. Baseline characteristics of the patients.
Characteristics
Patients
(n=61)
Age (years) mean ± SD 58.3 ± 10.8
Male n (%) 47 (77)
BMI (kg/m
2
) mean ± SD 26.4 ± 7.6
Type of atrial brillation n (%)
Paroxysmal 40 (65.6)
Persistent 21 (34.4)
Comorbidity n (%)
CAD 4 (6.6)
Previous stroke/TIA 6 (9.8)
Heart failure 3 (4.9)
Hypertension 30 (49.2)
Diabetes 4 (6.6)
CHA
2
DS
2
VASc score mean ± SD 1.5 ± 1.4
Previous cardioversion n (%) 7 (11.5)
Time between initial diagnosis and procedure (years) mean ± SD 2.3 ± 2.9
AAD before procedure n (%)
Amiodarone 21 (34.4)
Flecainide 1 (1.6)
Propafenone 15 (24.6)
AAD after procedure n (%)
Amiodarone 26 (42.6)
Flecainide 0 (0)
Propafenone 14 (23)
Echocardiographic features mean ± SD
LVEF (%) 64.1 ± 11.1
LA diameter (mm) 42.2 ± 5.3
LA volume (ml) 63.2 ± 27
E/e’ 9.2 ± 4.1
Abbreviations: AAD, antiarrhythmic drug; BMI, body mass index; CAD, coronary artery disease; LA, le atrium; LVEF, le ventricular
ejection fraction; TIA, transient ischemic attack
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TABLE 2. Details of the procedure.
Characteristics
Patients
(n=61)
RFCA strategy n (%)
PVI 61 (100)
Rooine 17 (27.9)
MI line 8 (13.1)
CFAEs 12 (19.7)
PWI 2 (3.3)
CTI 11 (18)
Fluoroscopic time (minutes) mean ± SD 109 ± 32.1
Abbreviations: CFAEs, complex fractionated atrial electrograms; CTI, cavotricuspid isthmus; MI, mitral isthmus; PVI, pulmonary vein
isolation; PWI, posterior wall isolation; RFCA, radiofrequency catheter ablation
TABLE 3. Ecacy and safety outcome aer 12 months of follow-up.
Outcome
Patients
(n=44)
Overall free from atrial arrhythmia n (%) 20 (45.4)
Complication n (%)
Pericardial effusion 1 (1.6)
Cardiac tamponade 1 (1.6)
Esophageal injury -
Phrenic nerve injury -
DVT -
Vascular complication at puncture site -
Stroke/TIA -
Death -
Abbreviations: DVT, deep vein thrombosis; TIA, transient ischemic attack
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64.2%.
13
Although a pioneering group demonstrated a
very high success rate of 86% in treating paroxysmal
AF with RFCA
14
, the rate decreased to less than 70%
in more recent studies. A study comparing the success
rate based on the results of 7-day Holter monitoring at
six months follow-up in two dierent RFCA strategies
showed 42% aer circumferential, and 66% aer segmental
pulmonary vein ablation in sinus rhythm.
15
Another
study revealed the arrhythmia-free survival rate aer
single RFCA was 40% at one year.
16
ese dierences
in outcomes can be attributed to the learning curve
and supplementing technological development. In our
studies, the overall success rate aer a single RFCA was
45.45%, which is somewhat lower than some published
data. e higher recurrence may have been due to the
operator’s experience; it should be presumed there are
many things to deal with in the learning curve for this new
procedure. Moreover, certain sophisticated technologies
which could improve the success rate were not available
at our center in the early part of the past decade. An
individual patient’s characteristics also might inuence
the outcome aer RFCA. In our series, there were a
number of non-paroxysmal AF patients and also a long
duration between the time of rst diagnosis and RFCA,
which could have caused higher recurrence rates. e
latter factor is one of the variables in a simple score
model for predicting AF recurrence aer RFCA.
17
Even
with the lack of operator’s learning curves and advanced
technologies, the complication rate related to RFCA
in our series was relatively low. Only one patient had
a signicant procedure-related complication, cardiac
tamponade, which was promptly treated and resulted
in a good outcome. Cardiac tamponade remains the
most common potentially life-threatening complication
associated with RFCA. e overall incidence of pericardial
complication is 1.5%, which corresponds to our series.
Importantly, the infrequency of complications at our
center can ensure patients’ safety with our safety protocols.
e data from this study demonstrate the safety and
ecacy of RFCA for AF patients in our center. However,
there were some limitations, which are commonly seen
in retrospective studies. First, there was missing follow-
up data in a number of patients. Second, symptom
improvement and quality of life were the main treatment
targets, but data was not systematically recorded. Hence,
data collection was not possible for analysis. Finally, an
important limitation was the lack of several lifestyles
and risk factor modication data, which evidently may
reduce the AF burden.
18
While we applied this treatment
strategy to all AF patients, there were many missing
Fig 1. Atrial arrhythmia free survival aer 12 months of follow-up.
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120
records. If individual risk factors are not be modied,
it could cause the recurrence of atrial arrhythmia, even
aer successful RFCA.
CONCLUSION
e 1-year results of single-procedure RFCA for
treating AF at Phramongkutklao Hospital, while not
highly successful in our rst decade, were comparable
to other series. Notably, there was a relatively low rate of
procedure-related complications. Other factors, which
were not measured in this study, such as the operator’s
experience and ongoing advanced technologies as well
as the enthusiastic treatment of associated risk factors,
may contribute to improved outcomes in AF patients.
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