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\begin{document}

\title{First successful ablation of atrial tachycardia from right atrial
appendage using circular pulse field ablation catheter}



\author[1]{Qinmei Xiong}%
\author[1]{Jinzhu Hu}%
\author[1]{Quanbin Dong}%
\author[1]{Liang Xiong}%
\author[1]{Qianghui Huang}%
\author[1]{Ju-xiang LI}%
\author[1]{Qi Chen}%
\author[1]{Kui Hong}%
\affil[1]{Nanchang University Second Affiliated Hospital}%


\vspace{-1em}



  
  \date{June 17, 2024}


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\selectlanguage{english}
\begin{abstract}
\textbf{Introduction:} Atrial tachycardia(AT) occurring from the right
atrial appendage(RAA) is relatively uncommon, while the catheter
ablation is complicated by the anatomic characteristics.
\textbf{Methods:} We reported a case of 60-year-old male patient who was
admitted with incessant AT. \textbf{Results:} The tachycardia activation
mapping demonstrated that the AT originated from the tip of RAA. Pulsed
field ablation(PFA) using the circular mapping\&PFA catheter terminated
AT without any complication. \textbf{Conclusions:} This case
corroborates that PFA might be an alternative strategy for ablation of
atrial arrhythmia originating from the atrial appendage.%
\end{abstract}%



\sloppy


\textbf{First successful ablation of atrial tachycardia from right
atrial appendage using circular pulse field ablation catheter}

Short-title: Fulse field ablation of focal AT from RAA

Qinmei Xiong\textsuperscript{1} PhD, Jinzhu Hu\textsuperscript{1} PhD,
Quanbin Dong\textsuperscript{1} PhD, Liang Xiong\textsuperscript{1} PhD,
Qianghui Huang\textsuperscript{1} MD, Juxiang Li\textsuperscript{1} PhD,
Qi Chen\textsuperscript{1} PhD, Kui Hong\textsuperscript{1} PhD

\textsuperscript{1}Cardiovascular Department, the
2\textsuperscript{nd}affiliated hospital of Nanchang University, China

Correspondence

Qi Chen, Cardiovascular Department, the 2\textsuperscript{nd} affiliated
hospital of Nanchang University, China.

Email: efycq@189.cn

Conflict of interest:

The authors declare no conflict of interest.

\textbf{Abstract}

\textbf{Introduction:} Atrial tachycardia(AT) occurring from the right
atrial appendage(RAA) is relatively uncommon, while the catheter
ablation is complicated by the anatomic characteristics.

\textbf{Methods:} We reported a case of 60-year-old male patient who was
admitted with incessant AT.

\textbf{Results:} The tachycardia activation mapping demonstrated that
the AT originated from the tip of RAA. Pulsed field ablation(PFA) using
the circular mapping\&PFA catheter terminated AT without any
complication.

\textbf{Conclusions:} This case corroborates that PFA might be an
alternative strategy for ablation of atrial arrhythmia originating from
the atrial appendage.

Keywords: atrial tachycardia; right atrial appendage; pulse field
ablation

\textbf{Introduction}

Atrial tachycardia(AT) occurring from the right atrial appendage(RAA) is
relatively uncommon, with a proportion of approximately 8\% among all
focal AT patients\textsuperscript{1}. Nevertheless, right atrial
appendage tachycardia(RAAT) is not easily terminated and is commonly
associated with tachycardiomyopathy, whihe the catheter ablation of RAAT
is complicated by its anatomic characteristics. Hereby, we presented a
case of incessant AT which was termintaed by pulse field ablation(PFA)
using circular PFA catheter.

\textbf{Case presentation}

A 60-year-old male patient complained with persistent palpitations and
chest tightness for two months. He was prescribed with metoprolol after
being diagnosed with ``inappropriate sinus tachycardia'' in other
hospitals. However, it did not work and he was admitted to our
department for further treatment. The 24-hour Holter
electrocardiogram(ECG) showed incessant AT, presenting with mean heart
rate of 124bpm. As shown in the baseline 12-lead ECG(Figure1A),
low-amplitude positive P-wave can be observed in leads I, II, and avF,
while negative P wave in avR and V1 leads. Accordingly, it indicated
that AT originating from RAA should be taken into consideration. After
informed consent was obtained, the tachycardia activation mapping using
three-dimensional electroanatomic reconstruction system(CARTO, Biosense
Webster) and a conventional 3.5 mm tip steerable catheter (NaviStar,
Biosense Webster, CA, USA) confirmed that the AT originated from the tip
of RAA. A conventional radio frequency ablation attempt (power: 30 W,
target temperature: 43*C, irrigationflow rate: 17 mL/min) was performed
but failed to eliminate AT. Given that the potential risk such as
cardiac tamponade and invalid conventional ablation of RAA, we decided
to use PFA catheter for second ablation after thorough communication
with the patient.

After signing the informed consent form, the second ablation procedure
was performed using the circular mapping\&PFA catheter(Jinjiang
Electronic Medical Equipment Co., Ltd. PRC). Both the right atrium and
the RAA were reconstructed. The AT activation mapping was in agreement
with RAA origin(Figure 2). During the mapping process in the RAA, the AT
could terminate spontaneously and sinus rhythm was restored transiently.
Moreover, the earliest activation point of the focal RAA-originated AT
was away from sinus node mapped during sinus rhythm. Four electrodes of
the circular mapping\&PFA catheter, which located at the earliest
activation site, were selected for PFA using 1800Volts, 480\selectlanguage{greek}μ\selectlanguage{english}s. The AT
was terminated at the first attempts(Figure 3). A total of three
overlapping applications were delivered. No AT can be induced by burst
atrial pacing or isoproterenol administration. The substrate remapping
after ablation showed that only a small area of low voltage at the tip
of RAA was observed. No complications occurred. Acute procedural success
was achieved as shown in the post-ablation 12-lead ECG(Figure 1B). At
one-month follow-up, the patient was free of ATs and atrial premature
beats.

\textbf{Discussion}

The focal AT occurring from the RAA is relatively uncommon, while the
catheter ablation is complicated by the anatomic characteristics. The
thin nature of RAA raises the risk of cardiac perforation during
catheter ablation, especially in the apex of RAA. Traditional catheter
ablation using radiofrequecy energy is always difficult to achieve a
target temperature due to the fact that the pectinate component of the
RAA does not allow energy infiltration into the AT focus. Thus,
therapeutic options for ablation within RAA has been extensively
investigated. Previous study suggested that irridated-tip catheter might
be helpful for these patients\textsuperscript{2}. The combination of
catheter ablation and video-assisted thoracoscopic atrial appendectomy
has also be considered effective to manage focal AT from
RAA\textsuperscript{3}. Compared to this more invasive approach,
cryoballoon ablation has been found to be an alternative therapeutic
strategy that might obviate unnecessary and harmful radiofrequency
ablative attempts\textsuperscript{4, 5}. However, it should be noted
that the tip pf the cryoballoon is rigid and can lead to more
extensively inaccurate lesion. Recently, Lukas Urbanek et al reported a
case of an incessant AT arising from RAA that successfully treated with
pulsed field ablation using four electrodes of 31-mm FARAWAVE
catheter\textsuperscript{6}.

In this case, circular PFA catheter was firstly used for mapping and
ablation of focal AT from RAA. It has been shown to be safe and
successfully eliminate AT at the first attempts within 3s. PFA has been
recently introduced for PV isolation in atrial fibrillation
patients\textsuperscript{7}. It is a nonthermal ablative modality which
can destabilize cell membranes and preserve extracelluar matrix by
forming irreversible nanoscale pores and leakage of cell contents,
culminating in cell death. Notably, specific characteristic threshold
field strengths could be observed in various tissues, with the lowest
threshold values in cardiomyocytes. This myocardial specificity could
potentially limit collateral damage of adjacent tissue and avoid
post-ablation complications. PFA within RAA can reduce the risk of
pericardial tamponade caused by atrial appendage rupture due to RFA or
cryoballoon ablation. In addition, a deeper ablation lesion can be
achieved by PFA than traditional energy, which can lead to effective
elimination of deep lesions in the pectinate muscle of RAA. The ablation
procedure of PFA is often accomplished within milliseconds or even
shorter, which greatly shortens the operation time and further reduces
the risk of complications. Thus, for ablation of special structures such
as the atrial appendage, PFA seems safer and more effective than RFA or
cryoablation. It can be concluded that PFA might be an alternative
strategy for ablation of atrial arrhythmia originating from the atrial
appendage. Further research is needed to confirm our findings.

\textbf{References}

1. Freixa X, Berruezo A, Mont L, Magnani S, Benito B, Tolosana JM,
Perafan P, Tamborero D, Brugada J. Characterization of focal right
atrial appendage tachycardia. Europace : European pacing, arrhythmias,
and cardiac electrophysiology : journal of the working groups on cardiac
pacing, arrhythmias, and cardiac cellular electrophysiology of the
European Society of Cardiology 2008;\textbf{10} (1):105-9.

2. Zhang T, Li XB, Wang YL, et al. Focal atrial tachycardia arising from
the right atrial appendage: electrophysiologic and electrocardiographic
characteristics and catheter ablation. Int J Clin Pract. 2009. 63(3):
417-424.

3. Guo XG, Zhang JL, Ma J, et al. Management of focal atrial
tachycardias originating from the atrial appendage with the combination
of radiofrequency catheter ablation and minimally invasive atrial
appendectomy. Heart Rhythm. 2014. 11(1): 17-25.

4. Chun KJ, Ouyang F, Schmidt B, Kuck KH. Focal atrial tachycardia
originating from the right atrial appendage: first successful
cryoballoon isolation. J Cardiovasc Electrophysiol. 2009. 20(3):
338-341.

5. Yorgun H, Sunman H, Canpolat U, Aytemir K. Cryoballoon ablation of
focal atrial tachycardia originating from right atrial appendage: Case
report and review of the literature. Indian Pacing Electrophysiol J.
2019. 19(4): 164-166.

6. Urbanek L, Chen S, Bordignon S, et al. First pulse field ablation of
an incessant atrial tachycardia from the right atrial appendage. J
Interv Card Electrophysiol. 2022. 65(3): 577-578.

7. Reddy VY, Neuzil P, Koruth JS, et al. Pulsed Field Ablation for
Pulmonary Vein Isolation in Atrial Fibrillation. J Am Coll Cardiol.
2019. 74(3): 315-326.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image1/image1}

\end{center}
\end{figure}

Figure 1. (A) Baseline 12-lead ECG shows AT from the RAA(135bpm); (B)
Post-ablation 12-lead ECG shows sinus rhythm(86bpm). AT:atrial
tachycardia; RAA: right atrial appendage.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image2/image2}

\end{center}
\end{figure}

Figure 2. (A) PFA catheter positioned in the RAA and fluoroscopic right
anterior oblique image of RAA angiography; (B) PFA catheter positioned
in the RAA and fluoroscopic left anterior oblique image of RAA
angiography; (C) Electroanatomic reconstruction of the RA/RAA and
electrograms recorded by the PFA catheter located at the earliest
activation site. PFA: pulse field ablation; RA: right atrium; RAA:right
atrial appendage.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image3/image3}

\end{center}
\end{figure}

Figure 3. Subsequent AT termination to SR at the first application of
PFA. AT:atrial tachycardia; SR: sinus rhythm; PFA: pulse field
ablation.

\selectlanguage{english}
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