Representative Intraprocedural Images
Figure 2A shows a fluoroscopic image of the ICE catheter in the RA while
a pulmonary venogram is performed. The ICE catheter was subsequently
advanced and positioned in the LA and the left superior PV (Figure 2B).
The appendage was also visualized from lower in the LA (Figure 2C), from
the right ventricular outflow tract and pulmonary artery, and from the
coronary sinus (Figure 2D).
As with 2D ICE, imaging was initially performed of the tricuspid valve,
RA, and right ventricle from the “home view” (Figure 3A). Clockwise
rotation of the catheter brought into view the aorta, the left
ventricle, mitral valve, and the interatrial septum (Figure 3 – online
video). The interatrial septum was clearly visualized in both 2D and 3D
(Figure 3B). In Figure 3C, images from the home view in a patient with a
prominent moderator band in the right ventricle are shown in 2D and 3D.
As with 3D TEE, volumetric imaging with the novel ICE catheter requires
an optimized 2D image. An example of a transseptal catheterization is
shown in Figure 4. In panel A, a standard 2D ICE view of the interatrial
septum is shown with the needle tenting alongside the 3D reconstruction
of the same view. In Figure 4B, a sheath can be seen after it was
advanced across the septum. One patient undergoing cryoballoon ablation
had a 18 mm atrial septal occluder in place (Amplatzer, Abbott,
Plymouth, MN) that had been implanted almost two decades earlier. A 2D
ICE image of the interatrial septum demonstrates the sheath inferior to
the closure device (Figure 4C). In panel D, a 3D image of the
cryoballoon sheath crossing the septum beneath the closure device is
shown.
In one patient who underwent radiofrequency ablation, the catheter tip
electrode was visualized on the posterior wall. Figure 5 shows the 2D
cross sections of the image, where the hyperechoic tissue from ablation
is noted as well as the 3D reconstruction. On video recording (Figure 5
online), the saline bubbles from irrigation can be visualized.
Cryoballoon ablation was performed in seven of the patients. In Figure
6A, the cryoballoon is visualized in the left superior PV in 2D. Another
unique feature of the 4D ICE system is the ability to digitally steer
the volumetric images from the console. In doing so, images such as
those shown in Figure 6B can be obtained, showing an en-face view of the
cryoballoon in the left superior PV. Color Doppler was added to this
image as shown in panel C, demonstrating a leak around the balloon. The
ICE catheter was also advanced into the LA and Figure 6D shows the
balloon after warming and deflating (online video Figure 6D). The
cryoballoon itself could be seen well with 2D and 4D imaging, but it was
difficult to image past or through the cryoballoon due to reflections
from the balloon.
Pulsed field ablation was performed in one patient using the PulseSelect
system (Medtronic), which involves a circular shaped ablation catheter
with multiple gold ablation electrodes. Images of this investigational
catheter in the left superior PV and LA are shown in Figure 7 (panels A
and B, respectively). Irrigation from the catheter in the left superior
PV can be seen in the online video.
Because of the ability to place the ICE catheter in various locations
closer to the left atrial appendage, visualization during LAAC
procedures has improved. Figure 8A demonstrates a 3D image of an
implanted LAAC device, obtained from the LA. From the LA, views can be
obtained to measure the mitral shoulder after device deployment. This is
shown in Figure 8B using the glass view feature. Lastly, the ICE
catheter can be withdrawn from the LA and advanced into the coronary
sinus to visualize the closure device in the left atrial appendage
(Figure 8C).