Summary of Safety and Effectiveness (Draft)
1. General Information
Trade Name REVELATION® Tx Microcatheter with NavAblator™ Ablation System
Generic Name: Cardiovascular Ablation Catheter
Description REVELATION® Tx Microcatheter / NavAblator™ Catheter Ablation system consists of:
·
REVELATION TxREVELATION®Tx
Ablation Microcatheter
· NavAblator™ Ablation Catheter
· Naviport™ Guiding Catheter
·
REVELATION® Tx SELECT™elect
Switch Box
· REVELATION® Tx Cables
Applicant: Cardima®, Inc.
47266 Benicia
Street
Fremont, CA 94538 USA
Toll Free 888-354-0300
Phone: 510-354-0300
Fax 510-657-4476
Modular
PMA #M010005P020039
Date of Panel Recommendation:
Date of notice of approval to the applicant:
2. Indications for Use
The Cardima Inc., REVELATION® Tx
Microcatheter with NavAblator™
RF Ablation System is indicated for the treatment of Atrial
Fibrillation in patients with drug refractory paroxysmal atrial fibrillation by
mapping, pacing and ablating with a compatible
radiofrequency generator, creating a set of continuous linear
lesions along the lateral and septal walls and along the isthmus in the right
atrium.
The REVLATION® Tx is intended for the creation of continuous linear lesions for the purpose of interrupting arrhythmia pathways.
The
NavAblator™
is intended for the creation of linear lesions
at the isthmus for the purpose of interrupting arrhythmia pathways when the
REVELATION Tx is not used to complete the isthmus region.
The REVELATION Tx
and the NavAblator connect to standard mapping/recording
equipment and to compatible RF generators with accessory cables and a passive
switchbox interface.
The Naviport guiding catheter (an approved device) is intended for access and delivery of the REVELATION Tx to the desired atrial site.
3. Device Description
The
Cardima REVELATION® Tx Microcatheter System consists of a
single use, steerable, multi-electrode ablation microcatheter (3.7F) with an
atraumatic, flexible, non-electrically active tip, and a single use,
deflectable NavAblator™ "hot tip" ablation catheter (8F)
with an electrically active tip.
Accessories to the system include the Cardima Naviport® (a
cleared device under K974683), the Tx Select SELECT™ Switchbox
and the associated connecting cables.
The connecting cables and the passive switchbox (Tx SELECT™ Switchbox) are the interface between both ablation catheters and any commercially available electrocardiograph, pacing stimulator and any commercially available endocardial radio frequency generator that is thermocouple compatible.
The REVELATION® Tx catheter has eight flexible electrodes and eight thermocouple temperature sensors in a linear array on the distal end of the catheter. The most distal tip of the catheter is a highly flexible (floppy) non-electrically active platinum coil for fluoroscopic visualization and atraumatic placement. The REVELATION® Tx is designed for the creation of thin linear lesions in the atrium for the treatment of atrial fibrillation by placing the linear array of electrodes along a desired trajectory in the atrium, conforming to the curvature of the wall.
The companion endocardial ablation catheter, the NavAblator™, has four electrodes, one of which is the "hot tip" RF ablation electrode with a thermocouple embedded in its tip. The NavAblator™ is intended for the creation of lesions (either linear or focal) from its tip when diverse myocardial anatomy requires the features of a "hot tip" ablation catheter to achieve effective lesions.
Both ablation catheters in this system are designed for mapping intracardiac potentials, pacing and ablating cardiac tissue with RF energy.
4. Contraindications, Warnings, and Precautions
Contraindications
· This procedure is contraindicated in patients with active systemic infection.
· The catheters in this system should not be used to create lesions in conditions where the catheter would be unsafe (e.g., intracardiac thrombus).
Warnings
· This device is not intended for ablation from within the coronary vasculature.
· Use of RF energy may interfere with proper function of pacemakers and implantable cardioverter/defibrillators. Refer to PPM/ICD manufacturer’s instruction on use of RF energy with these devices mentioned.
· Never advance or retract device against unknown resistance or damage to device or its components may occur.
· Improper handling or use including reuse of this device may result in device failure and/or possible complications.
Precautions
· Catheter placement should be accomplished under fluoroscopic imaging.
· The long-term risks of fluoroscopic exposure have not been established.
· The long-term risks of radiofrequency ablation have not been established.
· Use in conjunction with the Tx SELECT™ switchbox and Tx Catheter Cable. (See technical specification and requirements)
· Excessive bending or kinking of the device may cause damage to the device or its components.
· Always consult the RF-Generator Operating Manual and follow precautions prior to delivery of RF-Energy.
· The safety and effectiveness of the use of this system in treating children or pregnant women have not been established.
· This device should only be used by physicians thoroughly trained in the techniques of transvenous intracardiac studies and/or electrophysiology studies.
5. Alternative Practices and Procedures
According to recent ACC/AHA/ESC guidelines, the recommended clinical course for the treatment of Atrial Fibrillation is medical therapy (drugs) intended to first minimize risk of stroke with anticoagulants and second, in more advanced arrhythmias, control heart rhythm by cardioverting (mechanically or pharmaceutically) followed by maintenance of normal sinus rhythm (NSR).
Stroke risk management involves antiplatelet/anticoagulant medication. Heart rhythm management progresses from the use of beta blockers to antiarrhythmic drugs (AADs) that range from Class 1C AADs including propafenone and flecainide, to Class III AADs, including sotalol and Amiodarone that can sometimes precipitate significant side effects, including arrhythmias.
Anticoagulation therapy for stroke risk management requires long-term commitment from the patient for recurring clotting time evaluations and has its own risks associated with increased bleeding.
The antiarrhythmic drugs (AADs) tend to become less effective over time and AF can return in spite of all medications, continuing the risk of stroke and decreasing the quality of life for the patient with AF. In addition, in the presence of heart disease, hypertension or coronary artery disease, AAD therapy faces still further challenges.
Thus, AAD therapy for the management of AF is, at best, palliative. Their ability to maintain sinus rhythm ranges from 39% to 79%. It has been reported for a particular Canadian patient population that 65% of the patients maintained NSR on Class III agent (Amiodarone) after a mean follow up of 16 months. However, these drugs can be proarrhythmic and organ toxic, precipitating such conditions as Torsade de pointes, ventricular tachycardia, thyrotoxicosis, prostatism and pulmonary and renal toxicity and photosensitivity.
6. Marketing History
The REVELATION® Tx
Microcatheter has been approved for commercial distribution in the European
Union since November, 1998 and has been distributed in EU countries since that
date. This device is also registered
for commercial distribution in those other countries that accept EU
certification (CE Mark).
7. Potential Adverse Effects
Risks to patients include all those risks currently associated with electrophysiology diagnostic procedures and radiofrequency catheter ablation procedures, such as:
• Bleeding
• Cardiac or vessel wall injury or perforation
• Cerebrovascular accident
• Conduction system abnormalities
• Death
• Hematoma at entry site
• Local or systemic infection
• Pericardial effusion
• Permanent atrioventricular block
• Phrenic nerve damage
• Pneumothorax
• Thromboembolic events
7. Summary of Preclinical Studies
Biocompatibility
The devices were evaluated consistent with the requirements of ISO 10993. The testing demonstrated that the devices that are subject of this submission are biocompatible based upon testing at the Level 1 classification of blood-contacting medical devices.
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TEST |
SUMMARY OF RESULTS |
CONCLUSION |
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In-Vitro
Cytotoxicity |
No evidence of causing cell
lysis or toxicity greater than mild reactivity |
Acceptable |
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In-Vitro
Hemolysis |
Mean hemolysis = 0%, 1%, 2% |
Acceptable |
USP
Acute Systemic Toxicity in Mice
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No evidence of systemic
toxic reaction |
Acceptable |
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USP
Intracutaneous Toxicity in Rabbits (Acute) |
No evidence of significant
irritation or reactivity |
Acceptable |
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Delayed
Contact Sensitization in the Guinea Pig (Maximization Method) |
No evidence of causing
delayed dermal contact sensitization |
Acceptable |
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Thromboresistance
in Dog |
Minimal thrombus formation,
no different than control. |
Acceptable |
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Rabbit
Pyrogen Study |
No evidence of pyrogenicity |
Acceptable |
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C3a
Complement Activation |
Lower than “Low biomaterial
reference control” |
Acceptable |
Animal
Studies
Cardima conducted four animal
studies in support of the safety and performance of the REVELATION® Tx and the NavAblator™. These studies provided evidence of
preclinical safety and evidence of the most appropriate system settings to
achieve optimal ablation lesions in the right atrium to create a “non-surgical
MAZE” approach to treating atrial fibrillation.
Three animal studies of the
REVELATION®
Tx indicated that the REVELATION® Tx was capable of creating
continuous, linear transmural lesions, that a continuous lesion can be formed
from sequential electrode ablations; that a set temperature of 50°C-55°C at
35W maximum power output were the best procedural parameters for minimal
coagulum formation and optimal lesion formation. These studies also demonstrated that a low pre-ablation pacing
threshold was an indicator of good tissue contact and that a large increase in
the pacing threshold was a good indicator that lesions had been formed. There were no device-related complications in
any of these studies. Further, no correlation between RF energy delivery
parameters and lesion size and location could be clearly identified.
In support of the NavAblator™ a study with six dogs was conducted to evaluate the safety and performance of the device when used to create linear lesions in the isthmus of the right atrium, where anatomical challenges may require a "hot tip" device to reach certain areas of the isthmus. The procedural parameter settings used primarily in this study temperature was 60°C for 60 seconds with power output between 25W and 50W.
|
Device |
Study+Objectives |
N |
Outcome |
|
REVELATION® Tx |
Performance of |
7 |
·
No
catheter-related complications occurred. ·
Contiguous, transmural lesions were obtained. ·
Thrombus was generally absent on electrodes at 45°
and 50°C. · An upper power limit of 25W in this study showed good control of thrombus formation. |
|
Performance of REVELATION®
Tx |
6 |
·
No significant catheter placement difficulties in the IVC, SVC, or
sub-Eustacian isthmus ·
Contiguous, transmural lesions were obtained in the isthmus with a
superior approach. ·
Bipolar and unipolar electrograms were typically of good quality
without significant noise. ·
Pacing data confirmed. ·
Small thrombus observed on some electrodes ·
Recommended temp set range (based on this study) is 50°-55°C |
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REVELATION®
Tx |
RF Lesion Formation in
Canine Thigh Muscle. Assessment of lesion size and thrombus
formation in 28 lesions created in 2 dogs |
2 |
·
Continuous lesion was formed from sequential electrode
ablations. ·
Thrombus was not observed when 45°C was used, occasionally
at50° and 55°C |
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Radio
Frequency Ablation Using the NavAblater™ for In Vivo Lesion Formation. Assess ability of |
6 |
·
No coagulum was observed on the catheter tip following ablation. ·
Pathology reports no pericardial effusion, perforation, thrombus or
valvular damage in any of the 6 animals. ·
Pathology confirmed transmural lesions were formed. ·
Unipolar and bipolar electrograms were of good quality, free of
noise, and equivalent to those obtained with Cordis-Webster catheter. ·
Pacing threshold was low (<1mA @ 2.0 msec) and was comparable to
the Cordis-Webster catheter. |
Electro-mechanical
Studies
Consistent with the 1995 draft guidance from CDRH, FDA for Cardiac Ablation catheters (Mark Massi, Barbara Zimmerman) performance testing was conducted to demonstrate the reliability and material properties of the REVELATION® Tx and the NavAblator™.
The REVELATION® Tx is not a deflectable catheter nor does it have an open lumen, so joint seal and deflection fatigue testing was not performed. The NavAblator™ does not have a lumen, so joint seal testing was not performed. However, it is a deflectable catheter, so deflection fatigue testing was conducted. The results demonstrate the design of both catheters is robust and consistent with similar devices for similar indications, where comparison can be made. Unlike "conventional" endocardial RF ablation catheters, the REVELATION® Tx has been designed to provide a more flexible and less traumatic interface with endocardial tissue at its distal tip.
The electrical characteristics of the devices were evaluated consistent with IEC 60601-1 and 601-2-2 and found to be compliant with the relevant standards.
The accessory cables and the passive switchbox interface for this system were also tested for reliability and compliance with relevant international standards and found to be compliant. In the case of the switchbox, a third-party evaluation was performed by TÜV Product Services and a certification of compliance was issued.
8. Summary of Clinical Studies
Study Design
The study design is a multi-center, prospective, non-randomized, single-arm, controlled study in which the patients serve as their own control. The “control” is the establishment of a baseline for each patient during a monitoring period in which patients record symptomatic episodes of atrial fibrillation (AF) with portable event monitor cards and transmit these recordings once per week during a 30-day period prior to final determination of eligibility and subsequent treatment. This study design is consistent with the recommendation for ablation catheter study designs reported by the Circulatory Support Advisory Panel in its meeting of June/July, 1995.
The purpose of the study is to assess the safety and effectiveness of the REVELATION® Tx Ablation System in the treatment of patients with drug refractory paroxysmal AF by creating linear lesions with RF energy in the right atrium.
Patient Assessment
Drug refractory patients with diagnosed paroxysmal atrial fibrillation were assessed prior to treatment to establish a baseline episode frequency of symptomatic atrial fibrillation. Follow up assessments were conducted at one month, three months and six months post ablation for changes in episode frequency, changes in antiarrhythmic medication requirements, general cardiac status and adverse events.
Demographics
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Gender |
Age in years Mean ± SD |
Age Range in Years |
Frequency |
% |
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Female |
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27.9-77.1 |
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Male |
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Total |
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100.0 |
Data Aanalysis
and Result
The dataresults
indicate significant reduction in the frequency of spontaneous symptomatic AF
episodes experienced by the patients in this study, with an average reduction
of 73.6% ±
5.2%82.9 + 3.0
and a median reduction of 93.8__%
with a 4.01% 3.38% complication
rate.
In addition, these patients reported a
significant improvement in quality of life, based upon improvements in the
scores of the SF-36 and AFSS questionnaires, demonstrating improvement in all
eight SF-36 quality of life scales at both the three and six month follow up
assessments. There were quite
substantial and clinically significant and highly statistically significant
improvements for four of the eight domains (Role Physical, Role Emotional,
Vitality, and Social Functioning) at both of these follow up assessments,
clearly indicating overall substantial patient benefit.
|
Criteria |
3 Month (n=93) freq/n (%) |
6 Month (n=81) freq/n (%) |
|
# of subjects with
Episode Reduction compared to Baseline |
76/93 (83.9) |
79/81 (97.5) |
|
³50% Reduction a, c |
58/93 (64.5) |
69/81 (85.2) |
|
100% Reduction |
33/93 (35.5) |
44/81 (54.3) |
|
<50% Reduction c |
33/93 (35.5)c |
12/81 (14.8)c |
|
No
Reduction |
15/93 (16.1) |
2/81 (2.5) |
|
Withdrew |
4/93 (4.3) |
8/81 (9.9) |
|
Non-Compliant
(event monitor) |
4 |
22 |
|
Patient not yet at
3, 6 months |
12 |
19 |
|
Mean % reduction ±
SE |
53.1 b ± 6.6 |
82.9 b ± 3.0 |
a ³75% for 3-4 baseline
episodes b p<0.0001
b Statistics
do not include five subjects with disputed numbers of baseline episodes.
c Includes those with
“no reduction” as a subset of the <50% reduction group. In the >50% reduction group, those with
100% reduction are included.
Device Failures and
Replacements
There were no device failures or replacements in this study.
9. Conclusions
Drawn from the Studies
Risk/Benefit
Risks to include all those risks associated with all electrophysiology diagnostic procedures and radiofrequency catheter ablation procedures. The risks of the procedure are related primarily to mechanical injury to the heart and vessels from catheter manipulation and thermal injury due to RF current delivery, including the risk of thromboembolism and myocardial infarction. The standard risks of anesthesia also exist and include allergic reactions, medical complications and death.
Benefits for drug refractory patients is
are
the potential for reduced symptoms of AF without the adverse effects of
the drugs or with a reduced dependency on the medication, for an improved
quality of life.
Safety
The
Major
complication rate associated with this study waswere 4.013.4%. A small number (53) of minor complications
associated with this study occurred in 26% of the subjects (31/115) and were largely
mild and transient in nature, related to the cardiac catheterization procedure
and not the devices. There
were and no deaths associated with
this study.
Effectiveness
The study demonstrated that the majority of the patients treated in this study reported a statistically and clinically significant reduction in the frequency of AF episodes and similar improvements in quality of life.
The results of these
studies have demonstrated the safety and effectiveness of the Cardima
REVELATION®
Tx Ablation System.
10. Panel
Recommendations
11.
CDRH Decision
10.Approval
Specifications
Table 2, Clinical Success
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Patients were
evaluated for Quality of Life on two established scales: SF-36 and AFSS. The results for the SF-36 are illustrated in
Figure 4, below.
Figure 4, SF-36 Results Over Six Months
The
Atrial Fibrillation Severity Scale results are illustrated in Figure 5, below.
Figure
5, AFSS Mean Scores Over Six Months
Device Labeling (Draft)
REVELATION®
Tx Cardiac Ablation System
Contents
sterile in unopened, undamaged package
CAUTION: This device is intended for one use only. Do
not re-sterilize or re-use the device.
CAUTION: Federal (U.S.A) Law restricts this device to
sale by, or on the order of a physician.
Description
The Cardima®
REVELATION®
Tx Microcatheter System consists of a single use, steerable, eight-electrode
ablation microcatheter (3.7F), the REVELATION®
Tx, with an atraumatic, flexible, non-electrically active tip, and a single
use, deflectable NavAblator™ "hot tip" (4mm) ablation catheter (8F)
with an electrically active tip. Both
catheters incorporate thermocouple sensors for temperature feedback.
Figure 1, Cardima
REVELATION®
Tx Microcatheter
Figure 2, Cardima®
NavAblator™
Intended Use
The Cardima®Cardima
Inc., REVELATION®
Tx Microcatheter with NavAblator™
RF Ablation System is indicated for the treatment
of Atrial Fibrillation in patients with drug refractory paroxysmal atrial
fibrillation by mapping, pacing
and ablating with a compatible radiofrequency generator, creating
a set of continuous linear lesions along the lateral and septal walls and along
the isthmus in the right atrium.
The REVLATION®
Tx is intended for the creation of continuous linear lesions for the purpose of
interrupting arrhythmia pathways.
The NavAblator™
is intended for the creation of linear lesions at the isthmus for the purpose
of interrupting arrhythmia pathways.
Contraindications
This procedure is
contraindicated in patients with active systemic infection.
The catheters in
this system should not be used to create lesions in conditions where the
catheter would be unsafe (e.g., intracardiac thrombus).
Warnings
• This
device is not intended for ablation from within the coronary vasculature.
• Use
of RF energy may interfere with proper function of pacemakers and implantable
cardioverter/defibrillators. Refer to
PPM/ICD manufacturer’s instruction on use of RF energy with these devices
mentioned.
• Never
advance or retract device against unknown resistance or damage to device or its
components may occur.
• Improper
handling or use including reuse of this device may result in device failure
and/or possible complications.
Precautions
• Catheter
placement should be accomplished under fluoroscopic imaging.
• The
long-term risks of fluoroscopic exposure have not been established.
• The
long-term risks of radiofrequency ablation have not been established.
• Use
in conjunction with the Tx SELECT™
switchbox and Tx Catheter Cable. (See
technical specification and requirements)
• Excessive
bending or kinking of the device may cause damage to the device or its
components.
• Always
consult the RF-Generator Operating Manual and follow precautions prior to
delivery of RF-Energy.
• The
safety and effectiveness of the use of this system in treating children or
pregnant women have not been established.
• This
device should only be used by physicians thoroughly trained in the techniques
of transvenous intracardiac studies and/or electrophysiology studies.
Technical
Specifications And Requirements
Cardima REVELATION®
Tx Dimensional Specifications
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Tx RFG Cables for
these commercially available RF Generators:
Directions
A. REVELATION®
Tx System Setup (see Figure 3)
Figure 3,
REVELATION®
Tx Ablation System Set-up
1. Attach
the RF generator ground pad securely to the patient’s skin per manufacturers
instructions.
2. Connect
the Cardima Tx SELECT™
Switchbox to the electrocardiograph, pacing stimulator, and RF generator using
the appropriate connecting cables as specified in the Cardima Tx SELECT™
Switchbox Instructions For Use.
NOTE: Adaptor
cables are available for the Stockert 70, Medtronic Atakr and in Europe, the
Osypka HAT 300 Smart generator. Please consult a Cardima representative.
a
Select the appropriate NAVIPORT®
French size, curve reach and length.
b. Connect
an RHV (Rotating Hemostatic Valve) adapter to the NAVIPORT®
hub.
c. Connect
a pressurized, heparin/ saline flush bag to the RHV. Maintain a continuous drip.
Introduce an
appropriate size angiographic guidewire (e.g., .038”) into the NAVIPORT®.
4. Prepare
the REVELATION®
Tx catheter for use.
a. Flush
catheter with a heparin/saline solution while it is still in its protective
dispensing coil.
Remove catheter
from dispensing coil and confirm electrode coil integrity.
B. Atrial
Access
1. Place
the NAVIPORT®/guidewire
assembly through the introducer sheath and advance to the targeted area into
the atrium under fluoroscopic guidance.
Remove the
guidewire from the NAVIPORT®.
3. Place
the introducer over distal tip of the REVELATION®
Tx to cover electrodes, then insert into RHV.
Advance the REVELATION®
Tx through the introducer into the NAVIPORT®.
4. Remove
or pull back the introducer.
5. Place
the REVELATION®
Tx at the targeted area under fluoroscopic guidance and then connect it to the
Cardima REVELATION®
Tx Catheter Cable.
Hand off opposite
end (male end) to be connected to switchbox.
C. Determination
of Catheter/Tissue Contact
1. Observe
the catheter on the fluoroscope to confirm correct positioning.
2. Record
bipolar electrical signals from the REVELATION®
Tx.
In general, sharp
electrograms with high frequency components and large relative amplitudes are
suggestive of good contact.
RF Energy Delivery
1. Consult
the appropriate RF generator operating manual before starting, and configure
using the following settings:
Control Mode: Constant
Temperature
Set Temperature: Initially
50° C
Maximum Power: 35
W
Differential
Impedance
Setting: Switch
on if available and adjust to 20Ω.
If not available,
monitor impedance and stop RF energy delivery if impedance increases by more
than 20Ω.
Timer Set: 60
seconds
These settings
will allow power to be delivered up to a maximum of 35 W during the course of
the burn. RF energy will shutoff
automatically after 60 seconds unless the impedance rises to a user-determined
level in which case the shutoff will occur immediately.
2. Determine
which electrodes will receive RF energy based on the tissue contact
assessment. Energy will be delivered to
each electrode individually.
3. Set
the switchbox to correspond with the electrode receiving energy.
4. If
RF energy delivery automatically terminates (due to sudden rise in impedance)
before 60 seconds, remove the REVELATION®
Tx at the completion of the burn line and inspect for coagulum on the
electrodes. Loosely adherent coagulum
may be carefully cleaned off the catheter electrodes with a saline-soaked 4 x 4
gauze. Do not apply force to the tip
coil when wiping the electrodes. If
strongly adherent char is not easily wiped off, or if any damage is observed,
use another REVELATION®
Tx catheter.
NOTE: Following RF
ablation electrogram amplitudes should decrease at least 25-50%.
Note: To avoid
phrenic nerve damage, prior to ablation, pace with a stimulator setting of 10
mA at 2 ms. Palpate the patient for a
diaphragmatic stimulation. Do not apply
RF energy at any location where diaphragmatic stimulation is detected in this
manner.
5. Repeat
steps D2-D4 above for the remaining electrodes with sufficient tissue contact.
6. Repeat
section C above to assess changes that have occurred as a result of the RF
energy application. Repeat RF energy applications along a given trajectory as
necessary. The set temperatures may be
increased to a maximum of 60° C at the physician’s discretion.
7. Reposition
the catheter in the next desired location and repeat sections C and D above
until RF lesions are created in all desired trajectories.
NOTE: If frequent
impedance rises during RF delivery are noted and/or an excessive amount of coagulum appears on the
electrodes, it may be advisable to reduce the temperature setting or reposition
the catheter prior to the next RF application.
NOTE: If bi-directional block is not achieved at
the isthmus, the NavAblatorNavAblator™
may be used for this lesion.
E. NavAblatorNavAblator™
Preparation
3. Prepare
the NavAblator™
for use.
a. Remove
the NavAblator™ from the sterile package under sterile
conditions. As with all medical
devices, always inspect prior to use to ensure no damage has occurred during
shipping.
b. Prior
to use, activate the deflection mechanism of the catheter by pulling the
control knob. Then push the control
knob distally to straighten the tip before inserting.
c. Place
the NavAblator™
through the vascular introducer and advance to the atrium.
4. Set the switchbox to electrode position 1 only.
5. Follow
the steps in B through D to create a line of block at the isthmus. The duration of RF energy delivery may be
increased from 20 to 120 seconds at the physician's discretion.
Potential
Complications
Risks to patients
include all those risks currently associated with electrophysiology diagnostic
procedures and radiofrequency catheter ablation procedures, such as:
• Bleeding
• Cardiac
or vessel wall injury or perforation
• Cerebrovascular
accident
• Conduction
system abnormalities
• Death
• Hematoma
at entry site
• Local
or systemic infection
• Pericardial
effusion
• Permanent
atrioventricular block
• Phrenic
nerve damage
• Pneumothorax
• Thromboembolic
events
Reports Of Adverse
Events
There have been 57
occurrences of adverse events reported.
REPORTS OF
CLINICAL STUDIES
Clinical studies
were conducted of more than 80 subjects treated with the investigational
ablation system at approximately 20 investigational sites. The Study Design was a prospective,
non-randomized, single arm, controlled study in which the patients serve as
their own control. The
"control" consisted of a baseline model for each patient based upon
the number of symptomatic atrial fibrillation episodes documented by that
patient in a 30-day period (before treatment).
The study subjects
were required by inclusion criteria to have documented paroxysmal atrial
fibrillation that did not respond to antiarrhythmic drugs. If the patient was taking Amiodarone, he or
she need be unresponsive (refractory) to that one drug, otherwise, the patient
was required to be unresponsive to two antiarrhythmic drugs.
The objective of
the study was to determine the safety and effectiveness of the treatment system
based upon a reduction in the number of symptomatic AF episodes each patient
had during the follow up period compared to the number of episodes the patient
had during the baseline period. If the
patient was found to have demonstrated a reduction of 50% or more from the
reported number of baseline episodes, he was deemed to be a clinical success.
Eligible patients
were treated and followed for 24 months, with assessments at 1, 3, and 6, month
intervals for the number of symptomatic atrial fibrillation episodes they
recorded and transmitted and for the number and type of complications reported
during the follow up period.
Table 1, Mean
Episode Reduction
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a p<0.0001, paired paired
t-test
Table 2, Clinical
Success
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a ³75% for 3-4
baseline episodes b p<0.0001
b Statistics do not include five subjects with
disputed numbers of baseline episodes.
c Includes those
with “no reduction” as a subset of the <50% reduction group. In the >50% reduction group, those with
100% reduction are included.
Patients were
evaluated for Quality of Life on two established scales: SF-36 and AFSS. The results for the SF-36 are illustrated in Figure 4, below.
Figure 4, SF-36
Results Over Six Months
The Atrial
Fibrillation Severity Scale results are illustrated in Figure 5, below.
Figure 5, AFSS
Mean Scores Over Six Months
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Information
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