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ECG & EP CASES
Successful Radiofrequency Catheter
Ablation of Scar-related Atypical Right
Atrial Tachycardia with Paroxysmal Atrial
Fibrillation by Using a Three-Dimensional
Mapping System
Yae-Min Park
Young-Hoon Kim
Yae-Min Park, MD., Jong-Il Choi, MD, Hong-Euy Lim, MD, Sang-Weon Park, MD, Young-Hoon Kim, MD, PhD
Division of Cardiology, Department of Internal Medicine, Korea University Medical Center, Seoul, Korea
Successful radiofrequency catheter ablation of scar-related atypical
right atrial tachycardia with paroxysmal atrial fibrillation by using a
three-dimensional mapping system
ABSTRACT
A 61-year-old woman was admitted to our institution with frequent episodes of palpitations and dyspnea
caused by paroxysmal atrial tachycardia. She had a history of paroxysmal atrial fibrillation and atrial
tachycardia and had previously undergone radiofrequency catheter ablation. An extensive area encompassing
the crista terminalis and high septum in the right atrium was identified as the scar zone by voltage mapping.
The activation map of the right atrium revealed slow activation at the crista terminalis surrounded by a lowvoltage scar zone that spread centrifugally throughout the right atrium. Focal ablation at the site of earliest
low amplitude and discrete signals at the crista terminalis immediately terminated tachycardia, which was no
longer inducible thereafter. This case illustrates that 3-dimensional mapping may be helpful for identifying
the mechanism of arrhythmia and unusual isthmus, and thereby facilitates successful ablation.
Key words:
■
atrial tachycardia
■
catheter ablation
Introduction
■
3-dimensional mapping
mapping offer advantages over conventional
mapping by reconstructing a 3-dimensional image
Conventional techniques for radiofrequency
of the cardiac chamber.
catheter ablation provide less data regarding
In this report, we describe a case of paroxysmal
accurate spatial location and preclude accurate
atrial tachycardia (AT) in which a 3-dimensional
electroanatomical mapping of complex cardiac
mapping system facilitated successful ablation.
arrhythmia. Recent advances in electroanatomical
Case
Received: January 4, 2013
Accepted: March 30, 2013
Correspondence: Young-Hoon Kim, MD, PhD, Division of Cardiology,
Korea University Medical Center, 126-1 Anam-Dong 5Ga, Seongbuk-Gu,
Seoul, 136-705
Tel: 82-2-920-6394, Fax: 82-2-927-1478, E-mail: [email protected]
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The Official Journal of Korean Heart Rhythm Society
A 61-year-old woman presented with recurrent
palpitations. Electrocardiography during the
palpitations showed wide QRS tachycardia (Figure 1),
ECG & EP CASES
Figure 1. Baseline electrocardiography during palpitations showed wide QRS tachycardia. The mechanism was
determined to be atrial tachycardia with 1:1 ventricular conduction during a previous electrophysiologic study.
and 24-h Holter monitoring revealed frequent
sinus, a decapolar catheter in the high right atrium,
unsustained episodes of paroxysmal AT and atrial
and a quadripolar catheter in the bundle of His.
fibrillation (AF). She was previously diagnosed with
First, the geometry of the left and right atrium
paroxysmal AF 4 years ago, and it had been well-
were obtained using the NavX system (St Jude
controlled with antiarrhythmic medication.
Medical Inc., St Paul, MN, USA). We eliminated 4
However, paroxysmal AT with 1:1 ventricular
pulmonary vein potentials by circumferential antral
conduction frequently occurred and the patient was
ablation. Voltage mapping was performed in both
highly symptomatic. Therefore, she underwent
atria; the area characterized by voltages of ＜0.1
radiofrequency catheter ablation for paroxysmal AT
mV was defined as a scar. An extensive area in
2 years ago. Focal ablation at the high right atrial
right atrium, specifically the high and low crista
septum eliminated AT during the previous ablation
terminalis, and the high right atrial septum were
session and she had been stable for 2 years prior to
identified as scar zones (Figure 2). We then
this event. Echocardiography revealed a mildly
attempted to induce tachycardia by rapid atrial
reduced left ventricular ejection fraction (40.5%)
pacing. Sustained AT was induced with a cycle
and slightly enlarged cardiac chambers. The
length of 367 ms. The earliest activation was
anteroposterior diameter of left atrium was 48.5
observed at the mid-crista terminalis area (CS 19,
mm. Antiarrhythmic drugs were ineffective and
20), and the relative conduction of the right atrium
sinus node dysfunction developed. She therefore
to the left atrium was 2:1 (Figure 3A). The
decided to undergo catheter ablation for
tachycardia cycle length shortened (328 ms) and
paroxysmal AT and AF.
the relative conduction of the right atrium to the
An electrophysiologic investigation was performed
left atrium became 1:1 (Figure 3B). In an electro-
by placing a duodecapolar catheter in the coronary
physiologic investigation, entrainment mapping
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ECG & EP CASES
Figure 2. An extensive area in the right atrium encompassing the high and low crista terminalis and high right atrial
septum is identified as the scar zone.
excluded the cavotricuspid isthmus and left atrium
without procedure-related complications and she
as part of the tachycardia circuit. Additionally, an
has remained free of symptomatic recurrence of
activation map in the right atrium was created. It
arrhythmia for 2 months.
revealed slow conduction at the crista terminalis
surrounded by a low-voltage scar zone that spread
Discussion
centrifugally throughout the right atrium. The area
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was consistent with the site of earliest activation
The present case shows that a single area of slow
visualized in electrograms at 24 ms prior to P-wave
conduction at the crista terminalis may act as the
onset (Figure 3B). Low-amplitude, discrete
critical tachycardia isthmus for atypical AT. This
potentials were recorded at that site. Entrainment
case further emphasizes the advantages of a 3-
pacing showed perfectly concealed entrainment
dimensional voltage and activation map to identify
(post-pacing interval minus tachycardia cycle
the mechanism of the tachycardia and slow-
length of ＜10 ms). Therefore, this area was revealed
conducting isthmuses at uncommon sites. The
as the critical tachycardia focus. Focal ablation at
slow-conduction area on the activation map was
the site of earliest signal with an open irrigated tip
proved to be the critical isthmus by arrhythmia
catheter immediately terminated the tachycardia,
termination during ablation.
which was thereafter non-inducible. Fluoroscopic
Radiofrequency catheter ablation is the treatment
and 3-dimensional images of the ablation sites are
of choice for several cardiac arrhythmias. The
shown in Figures 4 and 5, respectively. The
conventional approach using intracardiac electro-
induction test was repeated and no AT or AF was
grams during sinus rhythm or tachycardia has
inducible. The patient was successfully discharged
inherent limitations. Localization and demonstration
The Official Journal of Korean Heart Rhythm Society
ECG & EP CASES
A
B
Figure 3. (A) Sustained atrial tachycardia was induced with a cycle length of 367 ms and the earliest activation at the
mid-crista terminalis (CS 19, 20). (B) The tachycardia cycle length shortened (328 ms) and the relative conduction of the
right atrium to left atrium was 1:1. The earliest activation with low amplitude and discrete potentials were recorded at
the ablation catheter 24 ms prior to P-wave onset.
Abl: ablation, CS: coronary sinus, HRA: high right atrium.
of the focus or entire reentrant circuit with
several potential sites for ablation and to go
conventional mapping catheters remains difficult.
precisely to the most suitable site. Recently, 3-
Furthermore, conventional mapping techniques
dimensional mapping became popular during
(i.e., pacing maneuvers) are limited by the risk of
electrophysiologic investigations and catheter
tachycardia termination or conversion to a
ablation. The mechanism of tachycardia can be
1
nonclinical arrhythmia. Moreover, 2-dimensional
easily determined, and the wave front propagation
fluoroscopic imaging limits the ability to evaluate
and the scar zone that contributes to the
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ECG & EP CASES
A
B
Figure 4. Fluoroscopic images of ablation sites (white arrow indicates an A LAO 35˚, and B RAO 35˚, respectively).
LAO: left anterior oblique; RAO: right anterior oblique.
propagation map and then minimizing the ablation
lesion may also avoid late recurrence of scarrelated atypical flutter or AT.
In conclusion, 3D mapping may be particularly
helpful in patients who have recurrent atrial flutter
or AT following a previous ablation because it can
identify the slow-conduction zone or breakthrough
site and the scar zone easily-which can then be
precisely targeted.
References
Figure 5. Three-dimensional image of ablation sites.
Yellow point indicates the site of arrhythmia termination.
tachycardia can be documented. Therefore, the use
of a 3-dimensional mapping system may improve
procedural outcomes and clinical success.2 In
particular, the efficacies of 3-dimensional mapping
of atypical atrial flutter or AT following cardiac
surgery were reported.3,4 The accurate identification
of tachycardia isthmus by creating a voltage and
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The Official Journal of Korean Heart Rhythm Society
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