Vision-MR Ablation Catheter 2.0 for Treatment of Type I Atrial Flutter

Typical or type I atrial flutter (AFL) is a macroreentrant atrial tachycardia
that propagates at the tricuspid annulus in the right atrium, runs up the
atrial septum, counter-clockwise or clockwise around the atrium and through the
cavotricuspid isthmus (CTI). It usually presents as mainly negative atrial
deflections in the inferior leads with a 'saw-tooth pattern' at rates of
240-350 bpm per minute.
The incidence of atrial flutter in the US is 88/100,000 and increases
exponentially with age (Granada, 2000). Ablation of recurrent symptomatic type
I AFL is a class I indication and a relatively straightforward procedure with a
low complication and high success rate (Brugada; 2020, Natale, 2000). The
procedures are anatomically guided with therapy delivery targeted along the
cavotricuspid isthmus (CTI) in the right atrium.

Currently in the US, ablation procedures are performed within the cardiac
catheterization (cath) lab under x-ray and fluoroscopy to guide catheter
navigation within the anatomy. While mapping and navigation software is
available to create renderings of the cardiac anatomy, and intracardiac echo
(ICE) may provide 2D views, 3D visualization of anatomic features is limited in
this environment. In addition, the use of x-ray exposes the patient and the
clinician to potential risks of ionizing radiation.

Performing the procedure in the magnetic resonance imaging (MRI) environment
can provide the patient and clinician safety benefits by limiting exposure to
ionizing radiation, and potential procedural benefits by leveraging real-time
MRI of anatomical features (Barkhausen, 2017). Specifically, anatomical
features such as deep *pouches* on concave morphology of the CTI may require
accurate manipulation and navigation of the catheter to complete the ablation
procedure. These abnormalities (found in 11% of AFL patients (Baccillieri,
2019)) are not visible with x-ray and are associated with increased procedure
times and complications in the traditional cath lab (Baccilleri, 2019;
Heidbüchel, 2000; Da Costa, 2004; Regoli, 2018). Although ICE is exceedingly
helpful for such cases, it adds additional costs, requires prior expertise, and
is not used in the majority of AFL cases. Real-time MRI provides clinicians
visualization of these anatomical structures to guide therapy delivery and may
reduce procedure time.

Devices to perform real-time MR-guided cardiac electrophysiology studies and
ablation procedures have been in development over the past 10+ years (Nazarian,
2008; Hoffmann, 2010; Sommer, 2013; Grothoff, 2014; Hilbert, 2016; Chubb, 2017;
Paetsch, 2019). Recently Imricor Medical Systems (Imricor, Burnsville, MN)
launched the first CE marked MR-guided ablation catheter (Vision-MR Ablation
Catheter) and Electrophysiology (EP) system in Europe for treatment of type I
atrial flutter.

The Vision-MR Ablation Catheter is designed to function and handle similar to
traditional marketed radiofrequency (RF) ablation catheters used in the cath
lab under x-ray and fluoroscopy. This design, along with starting with a
straight-forward, anatomically guided ablation procedure (type I atrial flutter
ablations), allows physicians to optimize the MR-specific workflows and
imagining techniques for potentially more complex MR-guided procedures in the
future.

The purpose of the VISABL-AFL study is to demonstrate safety and efficacy of RF
ablation of type I atrial flutter (AFL) with the Vision-MR Ablation Catheter
2.0 in conjunction with the Osypka HAT 500 RF generator and irrigation pump.

Data collected from this trial will be used to support US pre-market
application of the Vision-MR Ablation Catheter 2.0 and Osypka HAT 500
generator/irrigation pump with the proposed indication for use in treatment of
type I atrial flutter in patients 18 years or older.

Data on the performance and safety of supportive investigational products
(including the Vision-MR Diagnostic Catheter, Vision-MR Dispersive Electrode,
Advantage-MR EP recorder and stimulator, the NorthStar Mapping System) will
also be collected prospectively during this investigation.

The follow-up period is 3 months.

Generally the tests performed within the study are standard of care, limiting
the risk of participating in the study for the patients. At some sites it can
be that the follow-up visits are not standard of care. In that case the extra
visits and data collection compared to standard of care will allow for closer
monitoring of the patient, which is important for identifying and management
potential adverse events as well as facilitation of the collection of more
comprehensive data of the investigational device(s).

Imricor is sponsoring the VISABL-AFL clinical investigation. The study is a
prospective, single-arm, multi-center, global investigational study of the
safety and efficacy of type I atrial flutter ablation procedures performed with
the Vision-MR Ablation Catheter 2.0 and Osypka HAT 500 RF generator and
irrigation pump.

Site selection will include sites in the US and Europe, with an enrollment cap
of 50% of the total enrollment population coming from outside the US.

The VISABL-AFL clinical investigation is expected to run for approximately 12
months (9months for subject enrollment and 3-month follow-up of the final
subject).

Phase 1: Set-Up and Vascular Access
Following sedation, place the appropriate ECG electrodes and MRI body coil on
the chest and place the Vision-MR Dispersive Electrode on the leg. The subject
will be connected to the Invivo Expression patient monitoring system that will
allow wireless monitoring. Vascular access will be obtained for both the
diagnostic and ablation catheters in the femoral vein(s).

Phase 2: Ablation under MR Guidance
Position subject in MRI, perform standard safety checks. Perform pre-procedure
scans to obtain cardiac shells for mapping and guidance software (NorthStar).
Visualize catheter access in real-time MRI, the physician will then Insert and
advance the Imricor Vision-MR Diagnostic Catheter into the lower inferior vena
cava from the femoral vein access point. Image the catheter tip using active
catheter imaging (or optionally, the NorthStar Mapping System) to advance the
catheter into the coronary sinus (CS). Following the above the physician will
advance the Imricor Vision-MR Ablation Catheter 2.0 to the right atrium in the
same manner as in the previous step with the diagnostic catheter. The subject's
fluid balance will be monitored during the procedure to avoid fluid volume
overload per standard of care.
After navigating the ablation catheter to the desired ablation target
location(s) identified via the imaging software. Ablation will be performed
using individual lesions in a single site for up to 60 seconds in duration
before discontinuing energy delivery. Proper position will be confirmed by MR
imaging and/or EP signals before delivery of each lesion. The procedural
endpoint will be demonstration of bidirectional block at the CTI via
differential pacing maneuvers.

The VISABL-AFL investigation studies the use of a next generation ablation and
diagnostic catheters, EP system, and a novel mapping system to perform RF
ablation treatment for type-1 atrial flutter in the MRI. The data is essential
for understanding how the investigational device(s) perform under the clinical
trial condition in this patient population, ultimately supporting market
approval submissions in the EU and US.

The additional burden to the patients would be a follow up visit at 1 week and
3 months to determine adverse event and arrhythmia recurrences. Depending on
the site, these visits or phone calls may be standard of care. All other
pre-screening procedures would be considered standard of care for patients
receiving an RF ablation procedure for their type-1 atrial flutter. The extra
visits and data collection compared to standard of care will allow for closer
monitoring of the patient, which is important for identifying and management
potential adverse events as well as facilitation of the collection of more
comprehensive data of the investigational device(s).

Non-participation in this study does not preclude patients from receiving RF
ablation for their type-1 atrial flutter in the MRI as they can receive this
therapy with the 1st generation catheters and EP system currently CE marked.
The benefit for the patient is expected to be the same as when receiving the
treatment with the currently marked released device version. The benefit of
this new version relates to a behavior of the shaft to improve handling (IB
3.1.1).