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Page 8 of 12 Bui et al. Vessel Plus 2021;6:31 https://dx.doi.org/10.20517/2574-1209.2021.97

Despite data showing the utility of augmented reality in cardiac procedures, its use in congenital heart
[46]
defects is still limited. Preliminary attempts have been discussed by Opolski et al. in a 30-year-old patient
with congenitally corrected transposition of the great arteries and dextrocardia who required transcatheter
pacemaker implantation. His congenital heart disease and dextrocardia resulted in altered fluoroscopic
orientation, making it technically difficult to identify the optimal location of the pacemaker. However, with
the aid of augmented reality, surgeons were able to identify an appropriate location and use it to guide the
pacemaker .
[46]

Limitations of augmented reality
The challenge with implementing AR in surgeries for congenital heart diseases is related to the wide variety
of anatomy that patients can present with. Like VR, manipulating simulations to display different intricacies
of each patient’s cardiac anatomy can present as a difficult technical task . Additionally, it is also
[47]
technically difficult to accurately register the heart in congenital heart diseases due to extensive elastic
deformation that occurs with respiration and cardiac rhythm. Hence, procedures with few movement and
deformation are usually preferred for AR use as it requires less tracking and processing power for the best
image resolution [31,48] .

As with the other 3D imaging modalities, the use of AR technology is limited due to its high initial set-up
[26]
cost of up to ten thousand dollars . Furthermore, there is the issue of discomfort due to the size and weight
of the head-mounted display after long periods of use. Surgeons should also be aware of a phenomenon
called inattentional blindness while using AR, where the ability to identify sudden unexpected objects
within the visual field can be affected. They will need to learn how to reduce visual clutter to avoid
inattentional blindness and minimize surgical complications .
[48]

Another issue that resulted in the limited use of AR in surgery is its inability to portray depth
perception [31,49] . Several solutions have been devised to address this issue, like light and shade control with
rendering techniques, the use of color-coded pictorial depth cues, or the use of stereoscopy. Choi et al.
[49]
suggested a new system using a combination of AR with VR that will allow manipulation of the images from
different angles. This system integrates both imaging modalities in a single window with an aligned view
axis to allow seamless switching between imaging modalities. It also allows the input of distance
information between the surgical tool and target organ, which further enhances its ability to overcome the
depth perception issue during AR use .
[49]

FUTURE CONSIDERATIONS
The limited use of advanced visualization technologies is likely due to the lack of formal education . Both
[47]
VR and AR come with a learning curve that can be addressed if there is a proper training program for its
use. This program will need to have a standardized evaluation, ways to assess skills retention, and also
include fail-safe methods to convert back to the use of traditional imaging modalities if technical issues
arise [5,47] . Table 1 compares some of the characteristics to consider for each visualization imaging modality.

Perhaps there is more potential for mixed reality holograms, an evolution of AR, in the field of congenital
heart disease. A recent article discussing a 9-year-old boy with DORV, and transposition of the great
arteries utilized mixed reality holographic visualization of his cardiac CT angiography images for analysis of
his complex anatomy and presurgical planning. Thirty-six congenital heart disease professionals underwent
the holographic experience and were asked to identify the anatomical structures, diagnose the disease, come
up with a surgical plan, and rate their overall experience. The participants commented that this holographic
visualization made comprehending the pathology easier. Furthermore, they were able to come up with a