Medical Design Briefs - March 2024 - 14

Pulsed Field Ablation
PFA Threshold
(V/cm)
3800 V/cm
4000
3000
1750 V/cm
2000
1000
400 V/cm
Myocardium
Fig. 3 - Differing susceptibilities to pulsed field ablation
Practically, this means that a PFA system
for cardiac electrophysiology can
be designed to supply double the needed
electric field strength, while still
having a 100 percent safety margin to collateral
tissue damage. The clinical benefits
of this inherent safety mechanism
(and its enormous magnitude) cannot
be overstated.
Finally, the patient-to-patient variability
encountered by electric field-mediated
ablation is small (smaller than in thermalbased
ablation), making the procedure
more predicable and consistent. In summary:
The benefits of PFA in electrophysiology
include easy, fast, highly effective
procedures, significantly reduced risk of
complications due to thermal injury, and
consistency and predictability.
The Future of PFA in
Electrophysiology
PFA in electrophysiology is still an
emerging technology. First-generation
products have just recently been introduced
to the European market, and one
commercial system has recently been
14
FDA approved via the Breakthrough designation
pathway. However, results from
clinical trials have been incredibly promising,
to the point that some commentators
expect PFA to almost completely
usurp the use of thermal ablation modalities
in the electrophysiology market
within the next few years.
More likely, many clinicians who are
presently
trained
in
(and
proficient
with) radiofrequency or cryogenic ablation
will continue use of these technologies
until compelled to switch. Radiofrequency
and cryogenic ablations are
still highly effective therapies with low
incidences of side effects. Experienced
clinicians can perform these procedures
quickly, effectively, and quite safely.
Much of the excitement around PFA
in electrophysiology seems to be a blue
sky effect. Specifically, relatively inexperienced
users of PFA are demonstrating
procedural speeds, efficacies, and rates
of complications that are equivalent to
extant thermal modalities. Equivalence
is not a compelling rationale for a wholesale
technological shift in a multi- billionwww.medicaldesignbriefs.com
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4x
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dollar market; there is clearly some anticipation
that clinical experience and
further innovation will deliver even
greater positive outcomes.
Technologically, there is still significant
basic science work remaining to understand
and optimize the numerous parameters
which affect performance. This
lack of understanding has given rise to a
" proprietariness " problem: every system
must be regarded as completely proprietary,
with every attribute of its performance
(from catheter geometry to field
strength intensity, to pulse timing and
duration) completely unique to that specific
device for that unique clinical application,
which limits opportunities to
generalize performance across systems
or implementations.
Other Clinical Applications of PFA
Given the robust excitement for PFA
in electrophysiology, there has also been
emerging interest in applications of PFA
in other clinical areas. These are even
newer, and not as well understood, but
could presumably include any application
which can also demonstrate a similar
clinical benefit in terms of tissue
selectivity, safety, procedural speed, or
ease-of-use. Examples of applications
where known clinical work is ongoing
include:
* Prostate cancer and prosthetic
hyperplasia.
* Pancreatic cancer.
* Mucosal remodeling.
* Lung cancer.
* Diabetic foot ulcers (DFUs).
* Skin cancer.
* Gastrointestinal cancer.
Many of these applications may theoretically
benefit from the advantages of PFA,
but the basic science identifying the particular
value (e.g., cell-type specific ablation
thresholds to avoid collateral tissue
damage) are less well-known than in the
electrophysiology market. These indications
will require significant clinical
work to advance PFA technology.
Challenges in PFA System
Development
PFA systems are unlike most any other
energy-based medical device. They require
very fast electrical pulses, delivered
at very high voltages and high currents,
which strain the capabilities of electronics,
control systems, and sensors. Electrical
hazards take different forms than
Medical Design Briefs, March 2024
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Medical Design Briefs - March 2024

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