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\begin{document}

\title{High-power, short-duration ablation of the atrioventricular node}



\author[1]{Mahmoud Alsaiqli}%
\author[1]{Rafsan Ahmed}%
\author[2]{Leonell Freytes}%
\author[3]{Ola Rehaw}%
\author[1]{Harshith Chandrakumar}%
\author[2]{Adam Budzikowski}%
\author[2]{Ahmed Jallad}%
\affil[1]{Department of Medicine SUNY Downstate Medical Center Brooklyn NY 11226}%
\affil[2]{Department of Cardiology SUNY Downstate Medical Center Brooklyn NY 11226}%
\affil[3]{Internal Medicine Department University of Alabama at Birmingham Birmingham Alabama 35233}%


\vspace{-1em}



  
  \date{May 22, 2024}


\begingroup
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\selectlanguage{english}
\begin{abstract}
\textbf{Introduction} Atrioventricular node (AVN) radiofrequency
ablation is a highly effective treatment of atrial tachycardias
resistant to other management modalities. There are limited studies that
compare different radiofrequency ablation catheters. Our study aimed to
compare the effectiveness of several types of ablation catheters in AVN
ablation. \textbf{Methods} We identified patients who underwent AVN
ablation for different indications at our institution. Data related to
patients and procedures were collected through retrospective chart
review. The radiofrequency catheters used were: plain non irrigated,
externally irrigated (EI), and contact force sensing with 10-20 gm of
force in two different settings: low power long duration (LPLD) (30W,
45\selectlanguage{ngerman}°C, and 60 sec) and high-power short duration (HPSD) (50W, 43°C, and
12 sec). We compared the different catheters in terms of success rate
using logistic regression and lesion time using linear regression.
\textbf{Results} We identified 66 patients who underwent AVN ablation,
out of which 31 were female (47\%). The patients were elderly, with a
mean age of 73.27 years. The indications were resistant atrial
fibrillation in 74\%, atrial flutter in 18\%, and other atrial
tachycardias in 8\% of patients. Types of catheters used were plain non
irrigated in 48\%, EI in 2\%, LPLD in 16\%, and HPSD in 34\% of
patients. All ablation procedures were successful with no immediate
post-procedure complications. Regarding lesion time, HPSD was
significantly shorter compared to plain catheters by 403.42s{[}-631.67,
-175.17{]}. \textbf{Conclusions} Radiofrequency ablation of AVN is a
highly effective treatment modality for atrial tachyarrhythmias that
failed other management methods. While plain catheter, LPLD, and HPSD
were equally safe and effective, HPSD catheter had significantly shorter
lesion time and thus procedure time.%
\end{abstract}\selectlanguage{ngerman}%



\sloppy


Mahmoud Alsaiqli\textsuperscript{1}, Rafsan Ahmed\textsuperscript{1},
Leonell Freytes\textsuperscript{2}, Ola Rehaw\textsuperscript{3},
Harshith Chandrakumar\textsuperscript{1}, Adam S
Budzikowski\textsuperscript{2}, Ahmed Jallad\textsuperscript{2}.

\textsuperscript{1}Department of Medicine, SUNY Downstate Medical
Center, Brooklyn, NY 11226

\textsuperscript{2}Department of Cardiology, SUNY Downstate Medical
Center, Brooklyn, NY 11226

\textsuperscript{3}Internal Medicine Department, University of Alabama
at Birmingham, Birmingham, Alabama 35233

Corresponding author:

Name: Mahmoud Alsaiqali

Address: 186 Lenox Rd, apt 1H, Brooklyn, NY

Email: Mah.saikaly@gmail.com

Phone: 6195171587

\textbf{Declarations:}

\textbf{Ethics approval and consent to participate}

Study have been performed in accordance with the Declaration of
Helsinki. Informed consent was waived as the study is a retrospective
chart review with minimal risk to the patients. A copy of the ethical
approval is available upon request.

\textbf{Consent for publication}

Not applicable

\textbf{Availability of data and materials}

The datasets used and/or analyzed during the current study are available
from the corresponding author on reasonable request.

\textbf{Competing interests}

The authors declare no conflict of interest.

\textbf{Funding}

This research received no external funding.

\textbf{Authors' contributions}

Conceptualization: AB and AJ. Data Collection: MA, RA, and HC. Writing -
Original Draft: MA, OR, and LF. Figure creation: OR. Writing - Review \&
Editing: LF, AB, and AJ. Supervision: AB and AJ.

\textbf{Introduction}

Atrioventricular node (AVN) radiofrequency ablation is a highly
effective treatment of atrial tachycardias resistant to other management
modalities. There are limited studies that compare different
radiofrequency ablation catheters. Our study aimed to compare the
effectiveness of several types of ablation catheters in AVN ablation.

\section*{Methods}

{\label{methods}}

We identified patients who underwent AVN ablation for different
indications at our institution. Data related to patients and procedures
were collected through retrospective chart review. The radiofrequency
catheters used were: plain non irrigated, externally irrigated (EI), and
contact force sensing with 10-20 gm of force in two different settings:
low power long duration (LPLD) (30W, 45\selectlanguage{ngerman}°C, and 60 sec) and high-power
short duration (HPSD) (50W, 43°C, and 12 sec). We compared the different
catheters in terms of success rate using logistic regression and lesion
time using linear regression.

\section*{Results}

{\label{results}}

We identified 66 patients who underwent AVN ablation, out of which 31
were female (47\%). The patients were elderly, with a mean age of 73.27
years. The indications were resistant atrial fibrillation in 74\%,
atrial flutter in 18\%, and other atrial tachycardias in 8\% of
patients. Types of catheters used were plain non irrigated in 48\%, EI
in 2\%, LPLD in 16\%, and HPSD in 34\% of patients. All ablation
procedures were successful with no immediate post-procedure
complications. Regarding lesion time, HPSD was significantly shorter
compared to plain catheters by 403.42s{[}-631.67, -175.17{]}.

\section*{Conclusions}

{\label{conclusions}}

Radiofrequency ablation of AVN is a highly effective treatment modality
for atrial tachyarrhythmias that failed other management methods. While
plain catheter, LPLD, and HPSD were equally safe and effective, HPSD
catheter had significantly shorter lesion time and thus procedure time.

\textbf{Keywords:} Atrial Fibrillation, Radiofrequency Ablation, AVN
Ablation, High Power Short Duration

\section*{Introduction}

{\label{introduction}}

In 1987, transcatheter ablation of cardiac arrhythmias~via
radiofrequency (RF) current was introduced to avoid the complications
associated with direct current fulguration(1). In RF ablation, low
voltage high-frequency electrical energy (30KHz -- 1.5MHz) is~delivered
to the endocardial surface producing well-circumscribed lesions
resulting in more accurate and focal tissue ablation(1). In 1995, RF
ablation was further refined using saline irrigation to cool the
catheter tip, making larger RF lesions possible and thus increasing its
efficacy(2, 3).

Although AF ablation is relatively safe, the procedure still carries a
risk of complications (4, 5). Several factors are taken into
consideration to ensure the safety and efficacy of PVI, such
as~transmurality~of lesions, necrosis of tissue and scar formation, and
absence of excessive cardiac injury. These factors can be controlled by
adjusting RF parameters such as power, duration, electrode, and lesion
size(6-9). Currently, two broad ablation strategies are used: low-power,
long-duration (LPLD) and high-power short-duration (HPSD)(10, 11). ~HPSD
has been shown to lower time spent per lesion and reduce deep tissue
heating and collateral injury(9-12).

While several studies compared different radiofrequency ablation
catheters in AF ablation(13), few studies are available for
atrioventricular node (AVN) ablation. This study aims to compare the
effectiveness of various types of RF ablation catheters in AVN ablation.

\section*{Methods}

{\label{methods-1}}

Study Design

Our study assessed the effect of catheter type on the success rate and
lesion time in patients who underwent AVN ablation. We used a
retrospective cohort design for data collection.

Settings and Population

We included all patients who underwent AVN ablation at our institution,
SUNY Downstate Medical Center, between 2007-and 2022. Procedures were
performed by different operators at our institution.

Data Collection

We have classified the ablation catheters into the following categories:
Unirrigated 8 and 10 mm, internally irrigated (Chilli II, Boston
Scientific, Marlborough, MA), externally irrigated (Cool Path, Abbott,
Minneapolis, MN), externally irrigated force sensing (TactiCath, Abbott,
Minneapolis, MN). With force-sensing catheters, lesions were applied
with force ranging from 10-20 grams. LPLD settings were power 30W,
temperature 45°F, and 60 sec in duration, whereas HPSD settings were
power 50W, temperature upper limit 43°C, and 12 sec in duration.

The exact details of the procedure are explained elsewhere(14). Besides
procedure-related variables, we collected baseline demographic and
patient-related data, including ethnicity, age, sex, and past medical
history. Lesion time was defined as the duration of radiofrequency
ablation. Successful ablation was defined by documenting the complete AV
block.

Data Analysis

Our study compared different catheters in terms of success rate and
lesion time. Continuous variables were reported as mean ± standard
deviation(SD) in case of a normal distribution or median and
interquartile range(IQR) in case of skewed distribution. We used
logistic regression to compare the success rate between different
catheters and linear logistic regression to compare lesion time. The
plain catheter was the reference point. Results were reported as mean
along with 95\% CI. All statistical analyses were performed using
statistical software R version 3.5.0 (R Foundation for Statistical
Computing, Vienna, Austria)(15).

\section*{Results}

{\label{results-1}}

We identified 66 patients who underwent AVN ablation, out of which 31
were female. The patient was elderly with an average age of 73 years.
Each patient had several comorbidities with a median of 5 per patient
IQR(4, 5). The general characteristics of patients are summarized in
table 1.

The indications were resistant atrial fibrillation in 74\%, atrial
flutter in 18\%, and other atrial tachycardias in 8\% of patients.
Figure 1 shows the types of catheters used. The main catheters used were
plain and CF catheters.

All ablation procedures were successful with no immediate post-procedure
complications. Regarding lesion time, HPSD was significantly shorter
compared to plain catheters by 403.42s{[}-631.67, -175.17{]}. Table 2
shows the exact difference in lesion time between catheters used.

\section*{Discussion}

{\label{discussion}}

To our knowledge, this is the first study to compare the different
radiofrequency ablation catheters in AVN ablation. Patients were elderly
with multiple comorbidities. The procedure was highly successful with no
immediate complications. HPSD catheter was significantly shorter
compared with the plain catheter.

The main current indication for AVN ablation is atrial tachyarrhythmias
that are resistant to other treatment modalities, especially in the
elderly population(16, 17). Two large trials assess the role of AVN
ablation in resistant atrial tachycardia. In the ablate and pace trial,
156 with resistant atrial fibrillation had AVN ablation with permanent
pacemaker placement. After the procedure, patients had improved quality
of life and improved left ventricular function (18). In patients with
heart failure and symptomatic AF, AVN ablation with cardiac
resynchronization (CRT) reduced HF-related hospitalization and improved
quality of life(19). As in previous research, our population was elderly
with several comorbidities. The indication was atrial tachyarrhythmia
resistant to medical therapy, mainly atrial fibrillation(74\%). We
assessed the short-term effectiveness of the procedure with no data on
long-term effects.

The procedure is typically highly successful with a low complication
rate. The overall success rate is above 97\%(16). In our study, all
procedures were successful with no immediate complications. We could not
assess for factors associated with procedure success/failure as we had
no failed ablation.

Ablation catheters have advanced in the design to improve safety and
effectiveness. Several new catheters were introduced, including
irrigated and contact force catheters. Several studies and systemic
reviews compared the safety/effectiveness of different catheters in
atrial fibrillation ablation(20-22). Studies in atrial fibrillation
favored HFSD in success rate and procedure time(23-25). Direct current
energy was used in the early stages but was soon replaced by
radiofrequency due to better safety and effectiveness (16). Few/no
studies compared different radiofrequency ablation catheters in AVN
ablation. In our study, a contact force catheter with HPSD settings was
significantly associated with lower lesion time by 403.42s{[}-631.67,
-175.17{]}. The success rate was similar to other catheters(all
successful) with no immediate complications.

Current medical practice has increasing complexity with introducing new
management modalities. Comparative effectiveness research is essential
to improve the quality of care and guide policymakers, clinicians, and
patients in deciding on their care(26). Our study has several
limitations. First, procedures were done by different operators, which
could confound our results. Differences in lesion time could be related
to different expertise levels between different operators. Another
limitation was the short follow-up time. There were no immediate
post-procedure complications. However, no data regarding long-term
safety and efficacy were available. We had no data regarding long-term
patient outcomes such as morbidity, mortality, and quality of life.
Complications are likely to occur in the immediate post-procedure time;
as a result, we likely to document the severe complications that would
happen. The main aim of the study was to compare different
radiofrequency ablation catheters. Data regarding the long-term effect
of AVN ablation is needed; however, that was not the focus of our
research. It is unlikely that the long-term effects would be related to
the type of catheter used.

\section*{Conclusion}

{\label{conclusion}}

Radiofrequency ablation of AVN is a highly effective method for
resistant atrial tachycardias that failed other management methods.
While plain catheters, EI, LPLD, and HPSD were equally safe and
effective, HPSD catheters had significantly shorter lesion time.

References

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chest catheter desiccation of the atrioventricular junction using
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2. Ruffy R, Imran MA, Santel DJ, Wharton JM. Radiofrequency Delivery
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3. Jaïs P, Shah DC, Haïssaguerre M, Hocini M, Garrigue S, Le Metayer P,
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\section*{}

{\label{section}}

Table 1. General patient characteristics\selectlanguage{english}
\begin{longtable}[]{@{}ll@{}}
\toprule
& Total (N=66)\tabularnewline
\midrule
\endhead
Age &\tabularnewline
Mean (SD) & 73 (\selectlanguage{ngerman}± 10)\tabularnewline
Sex &\tabularnewline
Female & 31 (47 \%)\tabularnewline
Male & 35 (53 \%)\tabularnewline
Ethnicity &\tabularnewline
Black & 44 (67 \%)\tabularnewline
White & 13 (20 \%)\tabularnewline
Hispanic & 1 (2 \%)\tabularnewline
Unknown & 8 (11 \%)\tabularnewline
DM & 28 (42 \%)\tabularnewline
HTN & 58 (88 \%)\tabularnewline
HLD & 24 (36 \%)\tabularnewline
CAD & 28 (42 \%)\tabularnewline
CKD & 11 (17 \%)\tabularnewline
CHF & 54 (82 \%)\tabularnewline
Afib & 58 (88 \%)\tabularnewline
Aflutter & 16 (24 \%)\tabularnewline
Stroke & 9 (14 \%)\tabularnewline
COPD & 4 (6 \%)\tabularnewline
OSA & 2 (3 \%)\tabularnewline
\bottomrule
\end{longtable}

DM: diabetes mellitus, HTN: hypertension, CAD: coronary artery disease,
CKD: chronic kidney disease, CHF: congestive heart failure, Afib: atrial
fibrillation, Aflutter: atrial flutter, COPD: chronic obstructive
pulmonary disease, OSA: obstructive sleep apnea.

Table 2. Lesion time difference\selectlanguage{english}
\begin{longtable}[]{@{}llll@{}}
\toprule
Catheter & Lesion time* & P-value & P-value\tabularnewline
\midrule
\endhead
(Intercept) & 556.32{[} 404.15, 708.49{]} & 0.00 & 0.00\tabularnewline
EI & -436.32{[}-1212.23, 339.59{]} & 0.26 & 0.26\tabularnewline
LPLD & -293.75{[} -619.10, 31.60{]} & 0.08 &\tabularnewline
HPSD & -403.42{[} -631.67,-175.17{]} & 0.00 & 0.00\tabularnewline
\bottomrule
\end{longtable}

*Plain catheter as the reference point. EI: external irrigation, LPLD:
low power long duration, HPSD: high power short duration

Figure 1. Types of catheters used\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image1/image1}

\end{center}
\end{figure}

Plain: plain non irrigated catheter, EI: external irrigation, LPLD: low
power long duration, HPSD: high power short duration

\selectlanguage{english}
\FloatBarrier
\end{document}

