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\begin{document}

\title{Three-Dimensional Visualization of Bidirectional Preferential Pathway
Conduction of Premature Ventricular Contractions Originating from the
Outflow Tract}



\author[1]{Seina Yagyu}%
\author[1]{Koichi Nagashima}%
\author[1]{Sayaka Kurokawa}%
\author[2]{Yuji Wakamatsu}%
\author[1]{Naoto Otsuka}%
\author[2]{Satoshi Hayashida}%
\author[1]{Shu Hirata}%
\author[1]{Yasuo Okumura}%
\affil[1]{Nihon University School of Medicine}%
\affil[2]{Nihon University School of Medicine Graduate School of Medicine}%


\vspace{-1em}



  
  \date{June 17, 2024}


\begingroup
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\selectlanguage{english}
\begin{abstract}
Introduction: Presence of preferential pathway conduction is mostly
detected as fractionated presystolic potentials preceding the QRS onset
during premature ventricular contractions (PVCs) and late potentials
during sinus rhythm (SR), but the electrophysiologic mechanisms and
significance of these potentials have not been fully clarified. We
describe a PVC case series in which the preferential pathway conduction
was 3-dimensionaly visualized by coherent mapping with the conduction
velocity vector. Methods: Five PVCs (2 from the left coronary cusp, 2
from the commissure of the left and right coronary cusps, and 1 from the
pulmonary artery) in 4 patients for which a fractionated presystolic
potential during the PVCs and late potential during SR were recorded at
the successful ablation site were reviewed, and 3-dimensional coherent
activation maps with the conduction velocity vector during the PVCs and
SR were reconstructed. Results: At the successful ablation site, an
``M''-shaped discrete presystolic-potential and ``W''-shaped discrete
late-potential were recorded in all patients. The configuration of the
flipped electrogram of the presystolic-potential nearly matched that of
the electrogram exhibiting the late-potential. We created coherent
activation maps annotating the onset of the presystolic potentials
during the PVCs, and the offset of the late potentials during SR, which
suggested bidirectional conduction of the preferential pathway
connecting the PVC origin to the myocardium. Conclusion: In this case
series, the M-shaped presystolic potential and W-shaped late potential
were reversely matched. These reverse potentials, and the coherent
activation vector maps during PVCs and SR suggested bidirectional
conduction of the preferential pathway in opposite directions.%
\end{abstract}%



\sloppy


\textbf{Introduction}

Premature ventricular contractions originating from the outflow tract
(OT), in particular left ventricular OT (LVOT), often conduct through a
preferential pathway to breakout into the global ventricular
myocardium.\textsuperscript{1, 2}The presence of preferential pathway
conduction is mostly detected as fractionated presystolic potentials
preceding the QRS onset during PVCs and late potentials during sinus
rhythm (SR), and the site with those observations is considered to be an
optimal site for a successful ablation.\textsuperscript{3-5} Based on
these findings, a radiofrequency (RF) application to the preferential
conduction is a well-developed strategy of PVC ablation, but the
electrophysiologic mechanisms and significance of presystolic and late
potentials during PVCs and SR at the successful ablation site have not
been fully clarified. We describe a PVC case series in which the
preferential pathway conduction was 3-dimensionaly visualized by
coherent mapping with the conduction velocity vector. This case series
might add new insight into the mechanisms of preferential pathways and
PVCs.

\textbf{Methods}

\textbf{Patient characteristics}

Of 51 patients (27 male, 52.4\selectlanguage{ngerman}±17.1 years) without structural heart
disease who underwent catheter ablation of focal PVCs originating from
the OT in 2018-2020, 15 cases had LVOT origins and 4 of those patients
had PVCs with a fractionated presystolic potentials during the PVCs and
late potentials during SR recorded at the successful ablation site. We
reviewed these 4 cases using coherent activation maps.

Mapping and ablation were performed using a 3.5-mm-tip catheter
(ThermoCool SF; Biosense Webster, Diamond Bar, CA, USA). Coherent
activation mapping with the conduction velocity vector during the PVCs
was created with the use of an electroanatomic mapping system (CARTO3
system V7, Biosense Webster) with bipolar electrograms, high pass
filtered at 20 to 30 Hz and low pass filtered at 400 Hz. If the
presystolic potential was seen, the presystolic potential was manually
annotated to its onset. With the use of the mapping points for the PVC,
the coherent SR activation map was also created by manual annotation to
the offset of the electrograms during the SR beat preceding the PVCs.
The late potential was also annotated to its offset. The twelve-lead
electrocardiograms and bipolar intracardiac electrograms were recorded
with a band pass filter of 30 to 500 Hz at paper speeds of 100 to 200
mm/s and stored on a digital recording system (LabSystem PRO, Bard
Electrophysiology, Lowell, MA).

\textbf{Results}

\textbf{Case 1}

A 71-year-old man underwent an ablation procedure for PVCs at 35,000
beats/day. The PVCs had a right bundle branch block/inferior axis
configuration (Figure 1A). An ``M''-shaped discrete
presystolic-potential preceding the QRS onset of the PVC by 32 ms was
seen at the right coronary cusp-left coronary cusp commissure, where a
``W''-shaped discrete late-potential was recorded during SR (Figure 1B).
The configuration of the flipped electrogram of the
presystolic-potential nearly matched that of the electrogram exhibiting
the late-potential during SR. We created coherent activation maps
annotating the onset of the presystolic potentials during the PVC (PVC
map, Figure 1C) and offset of the late potentials during SR (SR map,
Figure 1D). Those potentials and vector map revealed the bidirectional
conduction of the preferential pathway connecting the PVC origin in the
right coronary cusp-left coronary cusp (LCC) commissure to the LVOT
myocardium. An RF application (30 W) at that site eliminated both the
PVCs and late potential during SR within 4.5 seconds.

\textbf{Case 2-4}

Similarly, the PVC characteristics in cases 2-4 are shown in the Table
and the electrophysiological features in Figures 2-4 including the PVC
morphologies (Figures 2A-4A), presystolic potential during the PVC, and
late potentials during SR at the successful ablation sites (Figures
2B-4B), and coherent vector activation maps annotating the presystolic
potential during the PVC (Figures 2C-4C) and late potentials during SR
(Figures 2D-4D). Bidirectional conduction of the preferential pathways
was seen in all cases.

In case 4, 2 different PVCs were targeted: 1 from the PA and the other
from the LCC. Bidirectional conduction of the preferential pathway was
suggested in both PVCs.

\textbf{Discussion}

Several previous reports have suggested that these potentials indicate
the preferential pathway conduction connecting the origin of an
arrhythmia and the myocardial breakout site, and a preferential pathway
potential guided ablation can be an effective strategy for PVC
ablation.\textsuperscript{1, 3, 7} We reported that presystolic
potentials during PVCs and late potentials during SR were seen at the
successful ablation site, and the configuration of the vertically and
horizontally-flipped presystolic potentials during PVCs nearly matched
that of the late potentials during SR.\textsuperscript{8} In this case
series, we also found that the M-shaped presystolic potentials during
PVCs and the W-shaped late potentials during SR were reversely matched.
These reversed potentials might indicate bidirectional conduction of the
preferential pathway in opposite directions.\textsuperscript{8} To
demonstrate the hypothesis, we created an activation vector mapping with
the annotation of the onset of the presystolic potentials and offset of
the late potentials. At several points around the successful ablation
site, both the presystolic potentials during PVCs and late potentials
during SR were observed. At the PVC origin, the presystolic potentials
during PVCs were earliest and the offset of the ventricular electrogram
during SR was latest. Coherent maps visualizing the vector of this
preferential conduction indicated that the propagation direction of the
presystolic potentials was opposite to that of the late potentials,
which was supportive of our hypothesis.

These potentials are commonly seen in the periaortic area, but rare in
the RVOT³. In our case series, however, those potentials were also seen
in the peri-pulmonary-artery (PA) area. Based on our findings, those
M-shaped and W-shaped potentials may reflect the slow conduction due to
the smaller amount of myocardium adjacent to the valve annulus such as
the aortic valve and pulmonary valve.

The flipped M-shaped presystolic potentials matched the W-shaped late
potentials in the majority of our cases, but not in some cases. Those
observations might be explained by the difference in the direction
between the propagation of the preferential pathway to the ventricular
myocardium during the PVC and the propagation of the ventricular
myocardium to the preferential pathway during SR. Regarding the
association of the catheter position with the direction of the
preferential pathway conduction, if the catheter position is not
parallel to the direction of the preferential pathway conduction, those
potentials might not be reversely matched. To assess the configuration
of those potentials, we should consider the catheter position.

\textbf{Conclusion}

In this case series, the M-shaped presystolic potentials during PVCs and
the W-shaped late potentials during SR were reversely matched. Those
reversed potentials and the coherent activation vector maps during PVCs
and SR suggested bidirectional conduction of the preferential pathway in
opposite directions.

\textbf{References}

1. Yamada T, Murakami Y, Yoshida N, Okada T, Shimizu T, Toyama J,
Yoshida Y, Tsuboi N, Muto M, Inden Y, Hirai M, Murohara T, McElderry HT,
Epstein AE, Plumb VJ and Kay GN. Preferential conduction across the
ventricular outflow septum in ventricular arrhythmias originating from
the aortic sinus cusp. \emph{J Am Coll Cardiol} . 2007;50:884-91.

2. Yamada T, Platonov M, McElderry HT and Kay GN. Left ventricular
outflow tract tachycardia with preferential conduction and multiple
exits. \emph{Circ Arrhythm Electrophysiol} . 2008;1:140-2.

3. Hachiya H, Yamauchi Y, Iesaka Y, Yagishita A, Sasaki T, Higuchi K,
Kawabata M, Sugiyama K, Tanaka Y, Kusa S, Nakamura H, Miyazaki S,
Taniguchi H, Isobe M and Hirao K. Discrete prepotential as an indicator
of successful ablation in patients with coronary cusp ventricular
arrhythmia. \emph{Circ Arrhythm Electrophysiol} . 2013;6:898-904.

4. Morita N, Iida T, Akira U and Kobayashi Y. Extensive preferential
pathway ablation for the elimination of premature ventricular
contractions arising from the right ventricular outflow tract.
\emph{Indian Pacing Electrophysiol J} . 2013;13:88-93.

5. Shirai Y, Goya M, Isobe M and Hirao K. Preferential Pathway Pacing
within the Aortic Sinus of Valsalva: Strong Evidence for the Existence
of Preferential Conduction with Different Exit Sites Traversing the
Ventricular Septum. \emph{J Cardiovasc Electrophysiol} . 2015;26:805-8.

6. Soejima K, Stevenson WG, Maisel WH, Sapp JL and Epstein LM.
Electrically unexcitable scar mapping based on pacing threshold for
identification of the reentry circuit isthmus: feasibility for guiding
ventricular tachycardia ablation. \emph{Circulation} . 2002;106:1678-83.

7. Tada H, Naito S, Ito S, Kurosaki K, Ueda M, Shinbo G, Hoshizaki H,
Oshima S, Taniguchi K and Nogami A. Significance of two potentials for
predicting successful catheter ablation from the left sinus of Valsalva
for left ventricular epicardial tachycardia. \emph{Pacing Clin
Electrophysiol} . 2004;27:1053-9.

8. Yagyu S, Nagashima K, Watanabe R, Arai M, Wakamatsu Y, Otsuka N and
Okumura Y. Anterograde and retrograde insulated pathway conduction
evidenced by intracardiac electrogram morphologies during premature
ventricular contractions and sinus rhythm.\emph{HeartRhythm Case Rep} .
2019;5:155-158.

\textbf{Table}\selectlanguage{english}
\begin{longtable}[]{@{}llllll@{}}
\toprule
\begin{minipage}[b]{0.14\columnwidth}\raggedright\strut
Case\strut
\end{minipage} & \begin{minipage}[b]{0.14\columnwidth}\raggedright\strut
1\strut
\end{minipage} & \begin{minipage}[b]{0.14\columnwidth}\raggedright\strut
2\strut
\end{minipage} & \begin{minipage}[b]{0.14\columnwidth}\raggedright\strut
3\strut
\end{minipage} & \begin{minipage}[b]{0.14\columnwidth}\raggedright\strut
4-1\strut
\end{minipage} & \begin{minipage}[b]{0.14\columnwidth}\raggedright\strut
4-2\strut
\end{minipage}\tabularnewline
\midrule
\endhead
\begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
Age\strut
\end{minipage} & \begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
71\strut
\end{minipage} & \begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
58\strut
\end{minipage} & \begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
69\strut
\end{minipage} & \begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
13 Male 64 \%\strut
\end{minipage} & \begin{minipage}[t]{0.16\columnwidth}\raggedright\strut
13 Male 64 \%\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
Sex\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
Male\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
Male\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
Female\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
LVEF (\%)\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
69 \%\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
57 \%\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
64 \%\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
PVC number (/day)\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
35,000\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
90,000\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
15,000\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
74,000\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
74,000\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
PVC origin\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
LCC-RCC comissure\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
LCC-RCC comissure\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
LCC\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
PA\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
LCC\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
PVC morphology\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
RBBB\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
RBBB\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
RBBB\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
RBBB\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
RBBB\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
PVC axis\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
Inferior\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
Inferior\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
Inferior\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
Inferior\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
Inferior\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
Transitional zone\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\textless{} V1\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\textless{} V1\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\textless{} V1\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
V1\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
V1\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
EGM-QRS interval (ms)\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
32\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
20\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
40\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
28\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
24\strut
\end{minipage}\tabularnewline
\bottomrule
\end{longtable}

EGM, electrogram; LBBB, left bundle branch block; LCC, left coronary
cusp; LVEF, left ventricular ejection fraction; PA, pulmonary artery;
PVC, premature ventricular contraction; RBBB, right bundle branch block;
RCC, right coronary cusp; SHD, structural heart disease.



\textbf{Figure legends}

\textbf{Figure 1.} Twelve-lead electrocardiogram of a PVC recorded
during the procedure \textbf{(A)} . Intracardiac electrograms at the
successful ablation site. A presystolic potential during the PVC and
late potential during SR are recorded by the ablation catheter. The late
potential during SR was eliminated after the successful
ablation\textbf{(B)} . Coherent vector activation maps annotating the
presystolic potentials during the PVC \textbf{(C)} and late potentials
during SR\textbf{(D)} . The ablation catheter at the successful ablation
site is shown in the figure.

SR, sinus rhythm; PVC, premature ventricular contraction; LCC, left
coronary cusp; RCC, right coronary cusp; ABL, ablation.

\textbf{Figure 2-4.}

Similarly, a twelve-lead electrocardiogram of a PVC obtained during the
procedure \textbf{(2A-4A)} , intracardiac electrograms recorded at the
successful ablation site \textbf{(2B-4B)} , and Coherent vector
activation maps \textbf{(2C-4C, 2D-4D).}

\textbf{Hosted file}

\verb`Figure 9.12.14.pptx`  available at \url{https://authorea.com/users/361261/articles/482721-three-dimensional-visualization-of-bidirectional-preferential-pathway-conduction-of-premature-ventricular-contractions-originating-from-the-outflow-tract}

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

