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\begin{document}

\title{How to visualize and reconstruct the pulmonary valve and contiguous
structures with intracardiac echocardiography: a simplified multi-step
approach.}



\author[1]{Francesco De Sensi}%
\author[2]{Luigi Addonisio}%
\author[2]{Gennaro Miracapillo}%
\author[2]{Marco Breschi}%
\author[2]{Paolo Orselli}%
\author[1]{Alberto Cresti}%
\author[2]{Ugo Limbruno}%
\affil[1]{usl 9 }%
\affil[2]{Misericordia Hospital}%


\vspace{-1em}



  
  \date{May 08, 2024}


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\selectlanguage{english}
\begin{abstract}
Ventricular tachycardia and premature ventricular complexes (PVCs)
arising from right ventricular outflow tract (RVOT) are the most common
type of ventricular arrhythmias (VAs) in patients without structural
heart disease. Radiofrequency ablation is now the gold standard of
treatment in this setting due to high efficacy rates and optimal safety
profile {[}2{]} During the last few years, the pulmonary valve (PV) and
the pulmonary artery (PA) have attracted much attention as reliable
sites of origin of RVOT-type arrhythmias. In the mean while intracardiac
echocardiogram (ICE) has undoubtedly improved our understanding and
approach to manage these arrhythmias accurately characterizing the PV
and its contiguous structures. Aim of this paper is to provide an
illustrated step-by-step guide on how to use ICE with the CARTOSOUND?
module to visualize and reconstruct 3D shell of the RV, the PV, as well
of other anatomical structures (i.e., the aortic valve and coronary
arteries) to perform aware and safe ablation in this region. A new
reconsideration of the existent classification of these VAs is also
provided.%
\end{abstract}%



\sloppy


\textbf{Keywords}

Intracardiac echocardiography, pulmonary valve PVCs, outflow tract
ventricular arrhythmias

\textbf{Main text (words count: 2935)}

Ventricular tachycardia and premature ventricular complexes (PVCs)
arising from right ventricular outflow tract (RVOT) are the most common
type of ventricular arrhythmias (VAs) in patients without structural
heart disease {[}1{]}. Radiofrequency ablation is now the gold standard
of treatment in this setting due to high efficacy rates and optimal
safety profile {[}2{]}. Using fluoroscopy and then electro-anatomical
mapping, in order to standardize mapping and ablation procedures, RVOT
was conventionally divided into a ``septal'' wall, postero-medially
oriented and facing the aortic root and the proximal part of aorta, and
the antero-laterally directed free wall. Each one was therefore divided
in three equal areas, named 1 posterior, 2 median and 3 anterior
{[}3{]}. RVOT arrhythmias more commonly originate and could be ablated
from the septal areas than from free wall {[}4{]}. During the last few
years, the pulmonary valve (PV) and the pulmonary artery (PA) have
attracted much attention as reliable sites of origin of RVOT-type
arrhythmias. Since seminal reports by Timmermans et al, several series
of left bundle branch block (LBBB) type VAs were described originating
from or above the pulmonary valve {[}5,6{]}. Distinct EKG features may
rise suspicion of PVCs originating from PV or PA, larger R/S ratio in
V2, late ([?] V4) precordial transition, tall R waves in the inferior
leads, predominantly negative forces in I, aVL/aVR ratio of Q wave
amplitude \textgreater{}1 {[}7-9{]}. In order to acquire better contact
with the cusps above the PV and on the PA wall the ablator catheter can
be advanced and deflected in a ``candy cane'' shape (reversed U-curve
technique) {[}10-12{]}. Interestingly, mapping in these regions reveals
a late sharp potential in the sinus beats which inverses becoming
pre-potential during PVCs. In a recent experience, Zhang and colleagues
performed radiofrequency ablation of RVOT-type VAs based on the mapping
and ablation of pulmonary sinus cusps (PSCs) as the first-line strategy,
eliminating 90\% (81/90) of arrhythmias {[}13{]}. According to this
observation it could be speculated that PV represents the ``real''
source of the ectopy, historically considered to originate from regions
below the valve, and ablation in ROVT is efficacy ``simply'' when
disconnects the focus from the rest of myocardium. Interesting
histopathological observations support this theory by showing that
ventricular myocardium may extend into the PA beyond the semilunar
valve. These myocardial sleeves, which are as long as those located in
the pulmonary veins and enhancing atrial fibrillation, are characterized
by abnormal automaticity and/or triggered activity, thus capable of
firing the ventricular ectopy {[}14,15{]}. Myocardial voltage extension
into the pulmonary artery in humans has been also demonstrated in vivo
using a three-dimensional (3D) mapping system (CARTO?, Johnson \&
Johnson, Biosense Webster) integrated with intracardiac echocardiography
(ICE) scans (CARTOSOUND? module) to accurately localize the PV plane.
Near field, high voltage electrograms were recorded in 11 out of 24
patients (46\%) with an ablation catheter above the, ICE localized, PV.
In all patients, arrhythmic foci were localized in the PA (median 8.2 mm
above the PV) and reclassified as pulmonary arterial arrhythmias
{[}16{]}. This example shows how ICE has undoubtedly improved our
understanding and approach to manage these arrhythmias and how accurate
and detailed characterization of the PV and its contiguous structures is
crucial for mapping, ablating, and better reclassifying the origin of
these types of VAs. Aim of this paper is to provide an illustrated
step-by-step guide on how to use ICE with the CARTOSOUND? module to
visualize and reconstruct 3D shell of the RV, the PV, as well of other
anatomical structures (i.e., the aortic valve and coronary arteries) to
perform aware and safe ablation in this region.

\textbf{Anatomical considerations}

Anatomically, the PV is formed by three semilunar cusps attached to
connective tissue of the annulus, a ring-shaped structure, with a mean
diameter of 20 mm, that delimits the right ventricle chamber at the
junction with the pulmonary arterial trunk. PV consists of three cusps:
anterior, left, and right, separated by a commissure with an overlap
area between cusps called the lunula. On the superior border of the PV,
there is a pocket formed by the valve cusp and adjacent arterial wall,
called the sinus of Valsalva {[}17{]}. The left cusp is the closest to
the aortic root, the aortic valve, and the epicardial aspect of basal
left ventricle, being these structures located posteriorly to it (Fig.
1). Normally, left cusp is close to the left main coronary artery and to
the proximal part of anterior interventricular descending branch, before
it approaches the commissure between the left and anterior cusp and the
medial side of it {[}18{]}. This close proximity has been exploited to
ablate, from the left pulmonic cusp, arrhythmias originating from the
left ventricular summit {[}19{]}. The remaining part of the anterior
cusp and the right cusp are considered non-septal ones because they lie
above anterolateral free wall, in contact with the right atrial
appendage. In normal hearts, the right coronary artery originates from
the right sinus of Valsalva beside the right ventricle at a level that
is far below the valve, and separates from RVOT as it then goes down
through the atrioventricular groove. An important aspect to keep in mind
when dealing with PV reconstruction is that the valve lies on an oblique
transverse plan, with the left cusp tilted more downward compared to the
other cusps {[}20{]}. Furthermore, although the semilunar valves are
approximately on the same level, the pulmonary valve is oriented on a
perpendicular plane with respect to the aortic valve. This explains why
the aortic valve is displayed on face during intracardiac echo
visualization (2D), while the pulmonary valve is seen on edge, and
vice-versa {[}21{]}. Both short- and long-axis views need to be
visualized for an optimal SOUND reconstruction of the annular plane, the
cusps, and the sinus of Valsalva.

\textbf{SOUNDSTAR reconstruction of pulmonary valve and contiguous
structures}

The Soundstar catheter is advanced in the right atrium and positioned
in ``home view'' through a femoral vein {[}22{]}. After choosing a
stable reference (i.e. surface ECG), with the ICE catheter in contact
with the cardiac tissue, respiration gating (RG) is acquired. Thus,
contour acquisition can start. In order to increase the accuracy of the
reconstruction and procedural safety, it is highly recommended that
contours be acquired in the same cardiac (i.e. end of QRS) and
respiratory phase. The steps for an optimal anatomical reconstruction
workflow are listed below:

\begin{enumerate}
\tightlist
\item
  With the ICE beam in ``home view'' position, the contours of the right
  ventricle inflow and outflow tracts (with tags on tricuspid annulus),
  right coronary cusp (RCC), non-coronary cusp (NCC), and AORTA can be
  acquired (Fig. 2, Panel A). ICE images are displayed in two
  dimensions. Thus, in order to fill all the volume of the cardiac
  chambers and main vessels, multiple scans must be acquired, possibly
  on several planes. The more scans are acquired, the more the volume is
  filled in. By performing counterclockwise and clockwise rotations of
  the handpiece, it is possible to acquire more lateral (Fig. 2, Panel
  B) and septal (Fig. 2, Panel C) portions of RV and tricuspid valve,
  respectively. In each scan it is also recommended to acquire tags of
  the tricuspid annulus in order to anatomically open the tricuspid
  orifice. Overcoming the more septal projection of the tricuspid valve,
  a further clockwise rotation of the handpiece allows visualization of
  the most septal portion of the right ventricle outflow tract (RVOT)
  together with the AORTA {[}RCC, NCC, and left ventricle (LV){]} (Fig.
  2, Panel D). At this level one can appreciate the semilunar aspect of
  the aortic valve. Often it is possible to discern between the valvular
  annulus, the sinus of Valsalva and the sinus-tubular junction.
\item
  By taking advantage of the markers related to the tricuspid valve,
  which have been acquired on various projections, it is possible to
  highlight the valve on the SOUND MAP of the RV and open it as an
  ``anatomical structure.'' This allows the operator to safely advance
  the ICE catheter into the right ventricle with an anterior deflection
  of the probe. (We suggest setting the CARTO ``main window'' and the
  ``additional window'' to have a RAO projection and a posterior view to
  help navigate the tricuspid ring). Once inside the RV, keeping the ICE
  beam pointing downwards, it is possible to acquire the RV apex in
  different positions by means of slight clockwise or counterclockwise
  rotations (Fig. 3, Panel A). During these acquisitions it is possible
  to visualize intracavitary structures, such as the moderator band and
  papillary muscles, reconstructing their thickness into the sound map,
  if necessary, for ablation purposes (not the subject of this paper).
  By advancing the ICE catheter to the base of the RVOT and rotating
  clockwise, it is possible to acquire the classic LV projections up to
  the mitral valve (Fig. 3, Panel B).
\item
  A further clockwise rotation allows the aortic valve to be visualized
  in short-axis view. In this projection it is possible to acquire the
  aortic cusps (left, right, and non-coronary). Note: the aortic valve
  has a semilunar shape; thus, the three cusps are also well visualized
  in the same scan when the left main (LM) of the left coronary arteries
  appears (Fig. 4, Panel A). In general, the LM arises 1 cm above the
  valvular plane and the contours of the three cusps should not be taken
  at this level in order to avoid designing the valvular plane at too
  high a level. At this stage, if the clinical practice of the imaging
  center allows integration with CT images, it is highly recommended to
  acquire FLOATING OS contours on cusp junctions and on the insertion of
  the LM. Once the LM has been identified, with a slight clockwise
  rotation it should be possible to follow and acquire the bifurcation
  in the anterior descending artery and circumflex artery (Fig. 4, Panel
  B). At this level, multiple scans can be performed to acquire each
  tract of these arteries in short-axis view. Sometimes it is possible
  to follow (and reconstruct) the anterior descending artery to the
  medial tract (Fig. 5, Panel A and B).
\item
  For both the aortic and pulmonary cusps, slight rotations are
  recommended in order to acquire more projections to improve the
  definition and correct proportions. Proceeding with clockwise
  rotation, passing the short axis of the aortic valve, the ICE beam
  cuts the most septal portion of the pulmonary artery in long-axis
  view. Here, it is possible to acquire the LCC, RCC, RVOT, LPC, and PA
  (Fig. 6, Panel A). With a slight clockwise rotation, the anterior cusp
  of the pulmonary valve is also displayed. This will allow
  reconstruction of the APC, LPC, PA, and RVOT (Fig. 6, Panel B).
  Depending on the anatomy of the patient, it may be necessary to
  slightly advance or withdraw the probe. Rotating further clockwise
  will give access to viewing the right cusp of the pulmonary valve
  (RCP) on the long axis; hence, it will be possible to acquire the
  RVOT, AORTA, RPC, and PA (Fig. 6, Panel C). All through the described
  acquisitions, it is also crucial to tag valvular points at the level
  of the leaflet attachments on the annulus, in order to open the valve
  as an ``anatomical structure.'' During each phase of point 4, the
  operator must be careful to fill in as much as possible of the right
  ventricle volume under the valve, spanning the diameter from the
  septal to lateral wall: this will help to provide a more accurate,
  extended navigation of the electro-catheters (Video S1). The valvular
  annulus points (acquired in ``floating'' modality, always at the end
  of QRS, with the valve closed) will be kept as reference for the valve
  plane in the other projections (see step 6 below).
\item
  Once the ICE beam is directed towards the most lateral aspect of the
  RV wall, a gentle withdrawal of the probe to the RV inflow region
  (under the HIS location) sometimes allows the aorta to be displayed
  from below. Refining the projections with probe rotations makes it
  possible to recognize the origin of the right coronary artery 1 cm
  above the valve plane, at the bottom of the right sinus of Valsalva
  (Fig. 7, Panel A). From this point, further counterclockwise rotations
  make it possible to reconstruct the entire medial tract of the artery
  while it crosses the atrioventricular groove between the right
  ventricle and the right atrial appendage (Fig. 7, Panel B). These
  projections allow further RV volume to be filled in.
\item
  The final part of the workflow acquires images of the pulmonary cusps
  and vessel in short-axis view. The general maneuvers to perform are as
  follows: withdrawing the probe in the ``home view,'' advancing the ICE
  catheter upwards 1-3 cm above into the atrium or towards the superior
  vena cava (SVC), making a slight tilt of the handpiece to the right
  (for a posterior deflection of the beam), and applying a clockwise
  rotation. The beam should cut the pulmonary artery at the valve level.
  The already reconstructed SOUND map can guide the operator accurately
  during the slight rotation and tilting movements (Video S2). This
  projection can display the APC, LPC, RPC, AORTA {[}the LPC can be
  found closer to the RCC; the cusp oriented to the right side (away
  from LV) is the RPC, while the one farthest from the aorta is the
  APC{]} (Fig. 8, Panel A). The reconstruction of the valve cusps in
  short-axis view may be misleading if the contours are not traced in
  the same ECG trace (at the end of the QRS); hence, one must keep in
  mind that the valve is semilunar, and, therefore, the commissures
  lines may also be seen 1 cm above the ventricular arterial junction.
  This is why the previous acquired valvular annulus tags (during
  long-axis visualization) must be used as references for the valvular
  plane. If the image cannot be set on the exact plane, contours of the
  intersections between the cusps (commissures) can be acquired as
  ``floating'' instead of as ``map.'' It will give an idea where each
  cusp lies on the cranial view (Fig. 8, Panel B). At this point, slight
  clockwise and counterclockwise rotations can be performed in order to
  cross the AP and RVOT in short-axis view, filling the volume of these
  structures into the SOUND map (Fig. 8, Panel C).
\end{enumerate}

\textbf{Final considerations: a tentative re-classification of
ventricular arrhythmias originating from the right ventricle outflow
tract.}

Once the described workflow has been completed, an accurate
reconstruction of the PV plane, the PA, and the RV underneath the valve
is obtained, and this allows to easily navigate the catheters in the map
using multiplanar orientations {[}22{]}. Usually, we display two
contemporary zoomed projections of the pulmonary valve: one on the
sagittal plane (from right or left view) or on the coronal plane (from
anterior or posterior view); and one on the transverse plane, from the
superior (cranial) or inferior (caudal) view. In this way, using the
sagittal or coronal projections, we identify if the catheter is above or
below the valve. Conversely, using transverse projections, we can know
with certainty which wall the catheter is in perfect contact with (the
lateral, septal, anterior, medial, or posterior wall). Navigating the
regions underneath or above the valve, we can be assisted by a cranial
or caudal view respectively. Moving the region of interest from a
lateral to a septal aspect, we can change between a right or left view.

Since we use ICE systematically, we realized the former classification
of the anatomical location of RVOT-type VAs {[}3{]} can be overcome. In
fact, the old historical division into three sites (site 1, site 2, and
site 3) identifying the posterior, medial, and anterior aspects of the
septum of the lateral wall was simply based on radioscopic views (RAO
and LAO). In our opinion, a new classification, similar to that used for
aortic cusp VAs, should be used. Independently if the origin of the VAs
is above or below the pulmonary valve, the regions to be described
should be the RPC area, the LPC area, and the APC area. According to
this new concept, with rare exceptions, the RPC should comprise the old
sites 1-2 of the lateral free wall, the APC should encompass the old
site 3 of both the free and septal walls, and the LPC should correspond
to the old sites 1-2 of the septal wall. If more accuracy is desired,
one could specify if the point of interest is in a junction area
(LPC-APC junction, RPC-LPC junction, or RPC-APC junction). This
classification is not only more anatomically appropriate, it also brings
the advantage of improving etiological knowledge of these forms of
arrhythmias. Indeed, proving that pulmonary cusps may be the real site
of origin of all RVOT-type VAs is a fascinating and elegant hypothesis
to be demonstrated through high definition. For this reason, the work by
Zhang et al is pioneering, but it is limited by the use of pulmonary
angiography as the method for visualizing the pulmonary cusps {[}13{]}.
In our experience, ICE with CARTOSOUND? map reconstruction allows a 3D
reconstruction in great detail, avoiding fluoroscopy and iodine contrast
use with a pigtail catheter {[}23{]}. Beside this, CARTOSOUND? module
allows ``in vivo'' reconstruction of the course of coronary arteries,
easily of the left one, whit more complexity for the right one. As
mentioned above, this is relevant in term of safety of ablation, because
of close proximity of left main, its bifurcation and the proximal part
of left anterior descending with the left pulmonary sinus of Valsalva.
Finally, SOUND maps could be merged with TAC or MRI 3D shell
reconstruction of the heart (CARTOMERGE? and CARTOSEG? module) thus
providing a definitely ``image-guided'' procedural workflow with
maximized ratio between efficacy and safety {[}24{]}.

\textbf{Acknowledgements}

The authors want to sincerely thank Nicola Zaurino and Giuliano Cerruti,
competent and dedicated engineers from Biosense and Webster, who hardly
worked in the images and videos reconstructions.

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\textbf{Figure Legends}

\textbf{Figure 1}

\textbf{Computed tomography images of the heart} .

\emph{Panel A} . axial scan: from a caudal view the reader can recognize
the PV as the most anterior (in the superior aspect of the image)
structure of the heart in close contact with the basal septum and aortic
root. The space between LPC, LCC and LVOT is the LV summit. While the PV
is cut ``on face'', the AV is cut ``on edge''. \emph{Panel B} : sagittal
scan: from a left side view is clearly appreciable the closeness between
LPC and Left Main coronary artery. In this projection the PV is cut ``on
edge'', while the AV is cut ``on face''. The PV lies at a level just
superior to the AV and runs on an oblique plan (from antero-superior
towards postero-inferior position). LV: left ventricle, RV: right
ventricle, AV: aortic valve, PV: pulmonary valve, APC: anterior
pulmonary cusp, RPC: right pulmonary cusp, LPC: left pulmonary cusp,
LCC: left coronary cusp, RCC: right coronary cusp, NCC: non coronary
cusp, LVOT: left ventricle outflow tract, RVOT: right ventricle outflow
tract, RA: right atrium, RAA: right atrial appendage, LA: left atrium,
LAA: left atrial appendage, LM: left main

\textbf{Figure 2}

\selectlanguage{english}\textbf{Step 1: initial reconstruction of the right ventricle and aortic
root. (2D intracardiac echo frames with the ICE beam visualized are
fused with CARTOSOUND? reconstruction of some structures for the reader
to better understand the 3D anatomy and the relationship between right
and left structures).}

\emph{Panel A} : ICE catheter in ``home view'' neutral position.
Acquisition of TV tags, RV volume, AV in long axis view with
visualization of RCC and NCC. \emph{Panel B:} ICE catheter rotated
counterclockwise (anterior) to acquire a more lateral portion of the
right ventricle (RV). Acquisition of other TV tags and other RV
contours. \emph{Panel C:} ICE catheter rotated clockwise (posterior) to
acquire a more septal portion of the right ventricle (RV). Acquisition
of other TV tags and other RV contours. Delineation of aortic valvular
plane. \emph{Panel D:} ICE catheter rotated more clockwise to acquire
the most septal portion of the right ventricle outflow tract (RVOT). The
aorta with aortic cusps (NCC and RCC) and left ventricle (LV) (at the
level of the outflow tract) are also visible on the same projection.
ICE: Intracardiac echocardiography, TV: tricuspid valve, RV: right
ventricle, AV: aortic valve, RCC: right coronary cusp, NCC: non coronary
cusp, LCC: left coronary cusp, PA: pulmonary artery.

\textbf{Figure 3}

\textbf{Step 2: detailed reconstruction of right ventricle and septum.}

\emph{Panel A:} Exploiting the TV tags, with anterior flection the ICE
catheter is advanced into the RV at basal level with the beam facing
downward. With gentle movements of the probe other RV contours are
acquired to fill the RV volume. It is possible at this level to
distinguish intracavitary structures (i.e. papillary muscles, moderator
band). \emph{Panel B:} With serial clockwise rotations LV is displayed
and reconstructed with the possibility to reconstruct also the papillary
anatomy (not the aim of this paper). TV: tricuspid valve, RV: right
ventricle, LV: left ventricle, PA: pulmonary artery.

\textbf{Figure 4}

\textbf{Step 3: reconstruction of aortic valve and left coronary
artery.}

\emph{Panel A:} With the ICE catheter positioned at the base of the RVOT
with the beam facing upwards the AV is displayed in short-axis view.
Aortic cusps (LCC, RCC, NCC) can be reconstructed. When the LM is
visualized aortic cusps contours should not be traced (the beam is
already cutting at the level of the sinus of Valsalva). \emph{Panel
B:}From the same position of Panel A, a slight counterclockwise rotation
allows the operator to follow the LM until the bifurcation in LAD and
LCX. Multiple contours of these vessels traced in short axis view (with
gentle clockwise and counterclockwise torsions) permit the SOUND
reconstruction of the coronaries. ICE: intracardiac echocardiography,
RVOT: right ventricle outflow tract, AV: aortic valve, LCC: left
coronary cusp, RCC: right coronary cusp, NCC: noncoronary cusp, LM: left
main, LAD: left anterior descendent (artery), LCX: circumflex (artery).

\textbf{Figure 5}

\textbf{Step 3: delineation of the left anterior descendent artery
course.}

\emph{Panel A} : The ICE probe is positioned at the base of the RVOT
with the beam directed upwards visualizing the space between the two
semilunar valves and arterial roots. This is the tract where the LAD is
closest to the PA. Only LPC is displayed. \emph{Panel B} : with slight
counterclockwise rotations it is possible to follow the entire course of
the LAD until its medial (exceptionally the distal) tract evaluating its
proximity with the LPC. ICE: intracardiac echocardiography, RVOT: right
ventricle outflow tract, LAD: left anterior descendent (artery), PA:
pulmonary artery, LPC: left pulmonary cusp.

\textbf{Figure 6}

\textbf{Step 4: visualization and reconstruction of the pulmonary valve
in long-axis view.}

\emph{Panel A:} ICE catheter at the base of the right ventricle outflow
tract (RVOT) with the beam oriented upwards. The most septal portion of
PV in long axis view is visualized. At this level part of the RVOT, LPC,
PA, RCC and LCC are displayed. \emph{Panel B:} a gentle clockwise
rotation allows to visualize both LPC and APC. \emph{Panel C} : with
further clockwise torsion the beam cuts the right pulmonary cusp ``on
edge, the visualization of the aorta indicates a posterior direction of
the beam. During each phase of this step annular tags must be acquired.

\textbf{Figure 7}

\textbf{Step 5: visualization and reconstruction of the right coronary
artery.}

\emph{Panel A:} ICE catheter is withdrawal under the HIS location with
the US beam directed upwards. Aorta and PA are both visualized in the
long axis view; sometimes, at this, level the origin of right coronary
artery can be traced. \emph{Panel B:} slight clockwise rotations allow
to follow and reconstruct the proximal course of the R\_CORO in the AV
groove. Further RV volume can be filled in. ICE: intracardiac
echocardiography, US: ultrasound, PA: pulmonary artery, AV:
atrioventricular, RV: right ventricle.

\textbf{Figure 8}

\textbf{Step 6: visualization and reconstruction of the pulmonary valve
in short-axis view.}

\emph{Panel A:} from the ``home view,'' gently advancing the probe
towards the SVC, while slightly tilting posteriorly and towards right
and by making a clockwise or counterclockwise rotation (depending on the
anatomy), the operator should be able to orient the beam on the
pulmonary artery. The aortic valve is displayed in long-axis
view.\emph{Panel B} : intracardiac echocardiography (ICE) catheter in
the right atrium with the beam oriented on the short axis of the
pulmonary artery.

\textbf{Supplemental material}

\textbf{Video S1}

Visualization of the pulmonary valve in the long axis view from the base
of the RVOT. Contours tracings and reconstruction in the CARTOSOUND\selectlanguage{english}?
map.

\textbf{Video S2}

Visualization of the pulmonary valve in the short axis view from the
right atrium /SVC.\selectlanguage{english}
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