U.S. patent application number 13/838534 was filed with the patent office on 2015-10-01 for ablation catheter system with safety features.
The applicant listed for this patent is Todd J. COHEN. Invention is credited to Todd J. COHEN.
Application Number | 20150272664 13/838534 |
Document ID | / |
Family ID | 49581914 |
Filed Date | 2015-10-01 |
United States Patent
Application |
20150272664 |
Kind Code |
A9 |
COHEN; Todd J. |
October 1, 2015 |
ABLATION CATHETER SYSTEM WITH SAFETY FEATURES
Abstract
A medical system for delivering treatment or therapy to a
patient has a kill switch for interrupting the delivery. The kill
switch, which can disrupt the delivery directly or can cause an
error message to be generated that disrupts the delivery, can be
activated by the operator or remotely. In an ablation catheter
system, a kill switch mechanism immediately and abruptly terminates
delivery of ablation treatment or therapy.
Inventors: |
COHEN; Todd J.; (Port
Washington, NY) |
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Applicant: |
Name |
City |
State |
Country |
Type |
COHEN; Todd J. |
Port Washington |
NY |
US |
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Prior
Publication: |
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Document Identifier |
Publication Date |
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US 20130310829 A1 |
November 21, 2013 |
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Family ID: |
49581914 |
Appl. No.: |
13/838534 |
Filed: |
March 15, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13415454 |
Mar 8, 2012 |
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13838534 |
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61450236 |
Mar 8, 2011 |
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Current U.S.
Class: |
606/34 |
Current CPC
Class: |
A61B 2017/00734
20130101; A61B 2017/00212 20130101; A61B 2018/00886 20130101; A61B
2018/00351 20130101; A61B 2018/00898 20130101; A61B 2018/00708
20130101; A61B 2017/00123 20130101; A61B 2018/00577 20130101; A61B
18/1233 20130101; A61B 2018/00928 20130101; A61B 2018/00916
20130101; A61B 2018/00648 20130101; A61B 2017/00203 20130101; A61B
18/1492 20130101 |
International
Class: |
A61B 18/14 20060101
A61B018/14 |
Claims
1. In an improved ablation catheter system comprising a
longitudinally extending catheter having a proximal end and a
distal end, a handle attached to the proximal end of the catheter,
a mechanism at the distal end of the catheter for delivering
ablation therapy to a desired location, and a generator or
controller of ablation therapy in communication with the handle and
the distal end of the catheter, the improvement wherein the
ablation catheter system comprises a switching mechanism which is
capable of causing abrupt termination of ablation therapy by manual
operation, wherein the switching mechanism is positioned between
the generator or controller of ablation therapy and the catheter
handle, and wherein the switching mechanism has a button or other
activation means to manually terminate ablation therapy.
2. The ablation catheter system of claim 1 in which the switching
mechanism comprises a casing having circuitry and a button in order
to manually terminate therapy and cables at each end of the casing
attaching to connectors specific to a particular ablation catheter
on one end and an ablation therapy delivery system on the other
end.
3. The ablation catheter system of claim 2, wherein the switching
mechanism casing is standard for a variety of ablation systems and
is configured either in the connector cable or as a device which
itself connects between the ablation catheter and the connector
cable.
4. The ablation catheter system of claim 1, wherein the ablation is
a cardiac ablation.
5. The ablation catheter system of claim 1, wherein the switching
mechanism is a powered kill switch.
6. The ablation catheter system of claim 5, wherein the switching
mechanism is powered by a disposable battery.
7. The ablation catheter system of claim 6, wherein the switching
mechanism is powered by a disposable battery which also powers at
least one visible LED light in order to indicate system
functionality.
8. The ablation catheter system of claim 7, wherein the switching
mechanism contains two LEDs: one color LED indicating therapy
delivery, and another color LED indicating therapy termination.
9. The ablation catheter system of claim 8, wherein the battery or
ablation catheter system powers an internal timer which limits the
amount of time the medical device can operate in order to prevent
inadequate resterilization and to maintain a high level of quality
control with respect to the operation of the switching
mechanism.
10. The ablation catheter system of claim 9, wherein the timer
starts when the battery or the ablation system is activated by
pulling or moving a tab attached to the switching mechanism.
11. A method of controlling the use of a medical product used in a
surgical or clinical procedure, which comprises providing a medical
product that comprises a digital timer set to a predetermined time
period of operability that begins timing when the timer is
activated, that deactivates the medical product at the end of the
predetermined period, and that cannot be reset once started;
recovering the used medical product; resetting or replacing the
digital timer; sterilizing and repackaging the recovered product;
and selling the recovered product at a cost less than when new.
12. The method of claim 11 which also includes the step of
replacing the battery and its activation system.
13. The method of claim 12, wherein the medical product is an
ablation catheter.
14. A switching mechanism for an ablation catheter system
comprising a longitudinally extending catheter having a proximal
end and a distal end, a handle attached to the proximal end of the
catheter, a mechanism at the distal end of the catheter for
delivering ablation therapy to a desired location, and a generator
or controller of ablation therapy in communication with the handle
and the distal end of the catheter, wherein the switching mechanism
comprises: a casing having an upper surface and two lateral
surfaces; a button or other activation means positioned on the
upper surface; at least one light to reflect the status of the
ablation catheter system; a timer to limit the duration of use of
the switching mechanism; and a power source to drive the timer and
power the indicator light, wherein pushing the button or other
activation means terminates the delivery of ablation therapy.
15. The switching mechanism of claim 14, wherein the switching
mechanism is incorporated directly in and on an ablation catheter,
and the casing is that of the ablation catheter, wherein the switch
is located in an ergonomic position for easy manual control of said
switch without disruption while manually manipulating said
catheter.
16. The switching mechanism of claim 14, wherein the switching
mechanism is located between the ablation catheter and the ablation
therapy provider or generator and contains at least two connectors
with or without cables in order to provide manual control by the
catheter operator to terminate therapy.
17. The switching mechanism of claim 14, wherein a second, separate
button is connected through a wire or cable to the switching
mechanism, which second button is capable of being placed in an
ergonomic position on the handle of the ablation catheter in an
easily accessible position to provide immediate manual control by
the catheter operator to terminate therapy.
18. The switching mechanism of claim 13, wherein the switch
mechanism includes an additional wired button which attaches to the
ablation catheter, and both the button on the upper surface of the
switching mechanism casing and the wired button attached to the
ablation catheter can terminate therapy once activated.
19. The switching mechanism of claim 18, wherein the additional
wired button is hard-wired to the encased switching mechanism with
a strain-relief mechanism.
20. The switching mechanism of claim 18, wherein the additional
wired button is an attachable and removable accessory, which
connects to the switching mechanism itself.
21. The switching mechanism of claim 16, wherein a second, separate
button is remotely connected wirelessly to the switching mechanism,
such that the second button is capable of being placed in an
ergonomic position on the handle of the ablation catheter in an
easily accessible position to provide immediate manual control by
the catheter operator to terminate therapy.
22. The switching mechanism of claim 18, wherein a rubber polymer
or foam catheter ablation handle covering is applied over or to
include the wired second button control switch in order to enhance
catheter manipulation comfort without applying force directly on
the button's wire connection.
23. An ablation catheter system, wherein the ablation catheter
system comprises a digital timer set to a predetermined time period
of operability, wherein the digital timer begins timing when the
digital timer is activated and can only be reset by the ablation
catheter system's manufacturer, in order to provide a method of
quality controlled device reuse.
24. The ablation catheter system of claim 23, wherein the digital
timer has been inserted into the ablation catheter itself or
another part of the ablation catheter system.
25. The ablation catheter system of claim 23, wherein the digital
timer is powered by a battery and begins timing when the battery is
activated by either pulling a tab, pressing a button, or moving a
lever, or some other means which removes a connection disrupter
located between the battery and at least one of its electrical
connections in order to initiate timing.
26. The ablation catheter system of claim 25, wherein the battery
powers both the timer and a switching mechanism contained within
the ablation catheter, and said timer can be restarted but not
reset by the ablation catheter operator.
27. The ablation catheter system of claim 23, wherein the digital
timer is powered by a power source from the ablation delivery
system and begins timing when connected to said powers source,
wherein the timer can be restarted but not reset by the ablation
catheter operator.
28. The ablation catheter system of claim 23, wherein the digital
timer is activated when the ablation catheter system is removed
from sterile packaging by a member connected to the sterile
packaging that causes the activation.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This patent application is a continuation-in-part of
co-pending, commonly assigned, U.S. patent application Ser. No.
13/415,454, filed Mar. 8, 2012, which in turn is based upon and
claims the benefit of the priority of the filing date of
co-pending, commonly assigned U.S. Patent Application Ser. No.
61/450,236, filed Mar. 8, 2011, each of which applications is
incorporated herein in its entirety.
FIELD OF INVENTION
[0002] The present invention relates generally to systems,
catheters, and methods for performing targeted tissue ablation in a
subject. More particularly, the present invention provides an
ablation system having a quick cut-off mechanism, also known as a
"kill switch".
BACKGROUND OF THE INVENTION
[0003] Tissue ablation is used in numerous medical procedures to
treat a patient. Ablation can be performed to remove undesired
tissue such as cancer cells. Ablation procedures may also involve
the modification of tissue without removal, such as to interfere
with or stop electrical propagation through cardiac tissue in a
patient with an arrhythmia. Often the ablation is performed by
passing energy, such as electrical energy, through one or more
electrodes to cause the tissue in contact with the electrodes to
heat up to an ablative temperature. Other electrical energies such
as laser, microwave, ultrasound, etc., can effect change in tissue.
Alternatively, non-electrical therapies such as medications, stem
cells, biologics, or cryotherapy can be used to alter the structure
and function of tissue.
[0004] Atrial fibrillation refers to a type of cardiac arrhythmia
where there is disorganized electrical conduction in the atria
causing rapid uncoordinated contractions that result in ineffective
pumping of blood into the ventricle and a lack of synchrony. During
atrial fibrillation, the atrioventricular node receives electrical
impulses from numerous locations throughout the atria (such as the
pulmonary veins) instead of only from the sinus node. This
condition overwhelms the atrioventricular node, resulting in an
irregular and rapid heartbeat. As a result, blood pools in the
atria and increases the risk of blood clot formation.
[0005] Atrial fibrillation treatment options are limited. Three
known treatments, lifestyle change, medical therapy and electrical
cardioversion, all have significant limitations. Electrical
cardioversion attempts to restore sinus rhythm but has a high
recurrence rate. In addition, if there is a blood clot in the
atria, cardioversion may cause the clot to leave the heart and
travel to the brain or to some other part of the body, which may
lead to a stroke.
[0006] Various ablation techniques have been proposed to treat
atrial fibrillation, including the Cox-Maze procedure, linear
ablation of various regions in the atrium, and circumferential
ablation of pulmonary vein ostia. Other linear lesions can target
the roof of the left atrium, the mitral valve isthmus, superior
vena cava, and the ligament of Marshall.
[0007] Certain types of arrhythmias have critical components that
require ablation near the normal conduction system of the heart (AV
junction and/or His bundle). These arrhythmias typically include
paraseptal bypass tracts, AV node reentrant tachycardia, and
certain atrial and ventricular tachycardias. Inadvertent ablation
misapplications in treating such problems may result in complete
heart block and require implantation of a permanent pacemaker, a
known possible complication of the procedure. In addition, other
untoward events may occur during ablative procedures in which the
body may exhibit early signs (such as a change in heart rate,
oxygen saturation, and/or blood pressure), which may indicate
perforation. When this occurs, the device or catheter creates a
hole in the heart wall leading to fluid accumulation in the
pericardial sac and a life-threatening condition called cardiac
tamponade. Blood needs to be rapidly removed from the pericardial
sac by a needle or surgical window along with any supportive
measures (blood and/or fluids) as well as possible surgical repair.
Each and every untoward event has the potential for medical legal
action in which any delay in terminating therapy may be highly
scrutinized.
[0008] In applying ablation techniques to treat arryhthmias, the
distal tip of an ablation catheter is advanced to a desired
location in a patient's heart. Radiofrequency or laser energy, for
example, is transmitted to the distal tip of a catheter from a
point adjacent and/or external to a catherization laboratory upon
signal from the doctor or operator to a technician or nurse who
operates a generator (such as an RF generator) or a laser, to
deliver ablation therapy or energy. Whenever the doctor or operator
wants the ablation therapy or energy to be discontinued, the doctor
or operator signals the technician or nurse, usually by voice
command ("Stop!!!" or "Off!"). However, there is an inherent delay
in this procedure, which could result in damage to a patient, such
as heart block, perforation, or phrenic nerve paralysis, if the
ablation energy is not terminated quickly enough. In addition, it
is not very practical for the sterile catheter operator to have
direct and immediate control over any switching mechanism contained
on the non-sterile generator or console to terminate therapy as
they are concurrently configured. Also, these ablation generators
and consoles are typically not easily accessible to the operator
and, if placed in such a location, would potentially be disruptive
to lab staff and operations. Alternatively there could be foot
control for the doctor or operator to terminate the ablation
energy, but using a foot control may be awkward and difficult to
control (especially because two foot pedals would potentially be
used in concert: one for fluoroscopy and the other for an on/off
switch). In addition, accidentally stepping on the on/off foot
pedal switch as it currently functions can potentially turn on
therapy and cause inadvertent ablative therapy delivery with
unintended injury to the heart, its conduction, and other
structures.
[0009] Medical devices having on/off or cut-off mechanisms are
known. See, for example, U.S. Pat. Nos. 5,951,461, 6,165,206,
6,235,022, 6,808,499, 7,717,932, and 7,763,033 and U.S. Published
Patent Applications Nos. 2007/0233044, 2008/0245371, and
2009/0182325. However, none of these medical devices is an ablation
catheter system useful for a cardiac ablation procedure, nor do any
of the devices meet the unique demands characteristic of use of an
ablation catheter in a catherization laboratory setting. In
addition, a method and switching mechanisms have been developed
which are compatible with a number of different ablation/therapy
systems to prevent inadvertent therapy delivery and provide
immediate manual control to the operator.
OBJECTS OF THE INVENTION
[0010] It is an object of the invention to provide an improved
steerable ablation catheter system.
[0011] It is also an object of the invention to provide an improved
steerable ablation catheter system where the energy at the distal
tip of the ablation catheter can be terminated immediately and
abruptly.
[0012] It is a further object of the invention to provide an
improved steerable ablation catheter system having a kill
switch.
[0013] It is yet a further object of the invention to provide an
improved steerable ablation catheter with a kill switch located in
an ergonomic location on the catheter handle.
[0014] It is yet a further object of the invention to provide an
improved steerable ablation catheter with a kill switch located in
an ergonomic location on the handle of the ablation catheter to
provide direct and immediate manual access to abruptly terminate
delivery of ablation therapy.
[0015] It is yet a further object of the invention to provide an
improved steerable ablation catheter system with a kill switch
located in a cable supplying ablative therapy.
[0016] It is yet a further object of the invention to provide a
shorter kill switch attached to a male connector at one end and a
female connector at the other, to interface with an ablation
catheter and a connector cable.
[0017] It is yet a further object of the invention to provide a
kill switch located on a remote controller or a joy stick with
which the operator is manually manipulating a remote navigation or
robotic system.
[0018] It is yet a further object of the invention to provide a
specific and uniquely identifiable voice command system that can
activate a kill switch mechanism coupled with an ablation therapy
delivery system.
[0019] It is yet a further object of the invention to provide an
improved steerable ablation catheter system with a foot-operated
kill switch.
[0020] It is yet a further object of the invention to provide an
improved steerable ablation catheter system where the distal
portion of the ablation catheter comprises pressure sensors and/or
shock absorbing means.
[0021] It is yet a further object of the invention to provide a
system for providing catheter ablation wherein the system has one
or more safety features to minimize the risk of inadvertent damage
to heart tissue, such as, for example, perforation or damage to the
conduction system or other cardiac structure.
[0022] It is yet a further object of the invention to provide an
improved system for delivering treatment or therapy to a patient
where a kill switch interrupts the treatment or therapy to minimize
or avoid damage to a patient.
[0023] It is yet a further object of the invention to provide an
improved system for delivering treatment or therapy to a patient in
a system having an instrument that is in communication with a
hand-operated or foot-operated control, where a kill switch
interrupts the treatment or therapy to minimize or avoid damage to
a patient.
[0024] It is yet a further object of the invention to provide a
medical system for delivering treatment or therapy to a patient
that has a kill switch for interrupting the delivery, where the
kill switch can disrupt the delivery directly or can cause an error
message to be generated that disrupts the delivery.
[0025] It is yet a further object of the invention to provide a
medical system for delivering treatment or therapy to a patient
that has a kill switch for interrupting the delivery, where the
kill switch can disrupt the delivery of therapy by opening the
circuit of one or more feedback or sensed ablation system functions
such as temperature, impedance, or the like.
[0026] It is yet a further object of the invention to provide a
medical system for delivering treatment or therapy to a patient
that provides the functionality described above via an on/off
switch for controlling delivery of therapy.
[0027] It is yet a further object of the invention to provide an
on/off switch attached to connectors and a cable or just connectors
which attach between a medical device and a therapy delivery
system.
[0028] It is yet a further object of the invention that an entire
array of switches or cable-switches is created and customized to
the particular type of ablation system, such as cryoablation and/or
a particular manufacturer and/or catheter/device type.
[0029] It is yet a further object of the invention to provide a
connector switch for an ablation system that has a cable and
connector as part of the catheter ablation device.
[0030] It is yet a further object of the invention to provide a
connector cable switch for an ablation system that does not have a
cable as part of the catheter ablation device to permit catheter
maneuverability.
[0031] It is yet a further object of the invention to provide a
longer connector cable switch to an ablation system in which
phrenic nerve stimulation is occurring to permit the operator to
directly sense and feel diaphragm contraction and at the same time
to be able to immediately and manually terminate ablation
therapy.
[0032] It is yet a further object of the invention to provide
immediate manual control of a variety of different ablation systems
using a connector system interposed between a medical device and
it's therapy generator or controller.
[0033] It is yet a further object of the invention to provide
automatic and computer controlled control of a variety of different
ablation systems to detect early signs of inadvertent events and
immediately terminate therapy.
[0034] It is yet a further object of the invention to provide
automatic sensing of phrenic nerve conduction to the diaphragm and
immediately cut off therapy when phrenic nerve conduction and/or
diaphragm contraction is slightly diminished by a predetermined
value.
[0035] It is yet a further object of the invention to provide
automatic sensing of cardiac conduction such that early evidence of
a change in conduction would shut off the system before the
development of heart block.
[0036] It is yet a further object of the invention to provide
automatic sensing of early signs of perforation such that a system
would immediately cut off therapy upon detection of those
findings.
[0037] It is yet a further object of the invention to provide
multiple safety features in a catheter ablation system including
(1) the ability to immediately and manually terminate therapy by
the operator and (2) the ability to monitor and record contact
force and pressure of the catheter tip.
[0038] It is yet a further object of the invention to provide
multiple safety features in a catheter ablation system including
(1) the ability to immediately and manually terminate therapy by
the operator and (2) the ability to absorb and control the contact
pressure and/or force of said catheter as it makes contact with the
heart.
[0039] It is yet a further object of the invention to provide an
improved steerable ablation catheter system with a kill switch
having a battery-operated timer to limit use of the kill
switch.
[0040] It is yet a further object of the invention to provide an
improved steerable ablation catheter system with a kill switch
having lights that indicate when the ablation system has been
activated and when the ablation system has been deactivated due to
the kill switch or other event.
[0041] It is yet a further object of the invention to provide an
improved steerable ablation catheter system with a kill switch
having two or more sensors or buttons to activate the kill
switch.
[0042] It is yet a further object of the invention to provide an
improved steerable ablation catheter system with a kill switch in a
cable and having a remote sensor or button for activating the kill
switch.
[0043] It is yet a further object of the invention to provide an
improved steerable ablation catheter system with a kill switch
where lights on the kill switch indicate when the ablation system
has been activated and when the kill switch has been activated to
terminate therapy.
[0044] These and other objects of the invention will become more
apparent from the discussion below.
SUMMARY OF THE INVENTION
[0045] The term "kill switch" as used herein refers to a switching
mechanism that can immediately and abruptly terminate therapy but
cannot initiate therapy by itself. This is in contrast to an
"on/off" switching mechanism, which has the ability both to
initiate therapy on its own as well as to terminate therapy. Also,
the term "kill switch" can refer to a switch or button on a
catheter handle or casing as well as to the kill switch system
itself.
[0046] According to the invention, a medical system for delivering
ablative treatment or therapy has been provided where the delivery
of ablation treatment or therapy can be terminated abruptly and
immediately by an operator to prevent heart block and/or other
possible procedural complications. In one embodiment of the
invention, a kill switch is located on or in the handle of a
steerable ablation catheter, preferably in an ergonomic location to
provide convenient and easy access by a thumb of the operator.
Preferably the kill switch is a button that is depressible and
operates to terminate delivery of ablation therapy upon being
depressed.
[0047] Ablative treatment or therapy can be delivered to a patient
for several different purposes. Those purposes include, but are not
limited to, cardiac, cardio-vascular, urological, and gynecological
applications where tissue would be treated.
[0048] A typical ablation catheter handle has deflecting levers or
controls on the handle for steering the distal portion of the
ablation catheter. Preferably a kill switch is located on the
handle between the deflecting levers or controls to provide
ergonomic thumb access from the catheter handle controlling hand or
finger access from the auxiliary hand. This location is
advantageous to permit the direct ablation catheter controller the
ability to most rapidly terminate the delivery of therapy.
[0049] Preferably a kill switch is located in a place or position
such that other fingers on the handle, besides the thumb, and the
auxiliary hand can stabilize the catheter to a position, while
still allowing the additional digit of that hand or the auxiliary
hand to depress the kill switch most rapidly and efficiently.
[0050] In another embodiment of the invention, a kill switch is
positioned on a member integral with the cable that supplies the
ablative therapy or energy. For example, the section, member, or
casing containing a kill switch can be an integral part of the
cable that supplies the ablative therapy and that is connected to
the ablation catheter handle. Alternatively, the kill switch can be
located in a separate member into which the cable that supplies the
ablative therapy and the ablation catheter are connected.
[0051] In another embodiment of the invention, a kill switch is
positioned between two connectors which would interface at one end
with the ablation catheter, and the other end would interface with
the connector cable and/or with the ablation therapy generator.
[0052] In another embodiment of the invention, the kill switch of
the ablation catheter system is positioned on a remote controller
in which the operator can have immediate and remote access to
immediately terminate therapy. The kill switch could be between
connectors or between connectors and cables and could be remotely
triggered by a remote controller or computer-based system. In
addition, the kill switch could be independent and remote and
provide signals to the ablation catheter system. Or it could be
integrated on a remote controller, handle controller, computer
controller, or joy stick to provide remote navigation or
manipulation of an ablation catheter or other procedure-related
functions.
[0053] In another embodiment of the invention, a specific and
uniquely identifiable voice command can activate a kill switch
mechanism coupled with an ablation therapy delivery system. The
switch could be integrated between the catheter and the generator
and operate via voice command, or the switch could operate via a
voice controller at or near the generator or at computer
terminal/remote control device/workstation remotely.
[0054] In another embodiment of the invention a kill switch
comprises a button that is configured so that when an ablation
catheter is "hot" or energized, electricity travels through the
cable or the catheter handle to light the button or to activate a
light, LED, or visual or audible alert on or in a casing in the
cable or in the catheter handle, so that the operator is aware that
the catheter is delivering ablation therapy. The button is
positioned on or in the casing or ablation catheter handle so that
other features of catheter manipulation via manual means are not
disrupted. That is, the operator can easily advance, withdraw,
deflect, reverse deflect, and/or rotate the catheter distal portion
without interfering with the button function.
[0055] A light or audio signal on the cable casing or the ablation
catheter handle may provide immediate feedback to the operator to
alert him or her that therapy is being delivered. When the button
is pressed and the delivery of ablation energy is immediately
stopped or killed, the light or audio signal shuts off, an
indication that the ablation catheter is no longer ablating.
[0056] In another embodiment of the invention, a foot pedal
functioning as a kill switch is operatively connected to a source
of ablative therapy, a cable supplying ablative therapy, the
ablation catheter, a grounding patch or element, or a combination
thereof. The foot pedal is positioned to be readily accessible by
an operator's foot.
[0057] The catheter system according to the invention is designed
to enhance the operator's reaction, manually, to prevent or
minimize inadvertent delivery of therapy and related complications
during catheter ablation. With respect to cardiac catheter
ablation, some of these complications include damage to the
conduction system (heart block), perforation of the heart tissue
itself, and/or damage to adjacent structures such as the phrenic
nerve, which powers contraction of the diaphragm and helps with
respiration.
[0058] In another embodiment of the invention, a kill switch
contains a deactivator that deactivates after 8 to 24 hours, making
the kill switch non-functional and thereby ensuring that it is
disposable. The deactivator could be, for example, a digital timer
that is activated when power to the system is initiated or a
battery is engaged.
[0059] In normal catherization or electrophysiology lab operations,
the ablation therapy may be initiated from a position at some
distance from the ablation catheter. This could be at the end of
the procedural table or even in another adjacent or distant control
room. Such distant locations may include a generator/control
console, remote control, remote controller/controller computer
terminal, or the like. The kill switch only becomes engaged when
the ablation therapy has been activated or enabled; it is not
otherwise operable. Preferably there will be an alert mechanism
such as a light or LED on or around a kill switch button when the
ablation therapy has been energized and is well into the distal tip
of the ablation catheter. In one embodiment, depressing the kill
switch button can open up the circuit (normal closed, once
depressed the circuit is an open kill switch), terminating the
ablation therapy, and shutting off the light. The ablation therapy
may only be re-initiated when the technician or nurse restarts the
radiofrequency generator or laser, at which time the kill switch or
alert mechanism, or both, will be reset. Alternatively, a "normal
open kill switch" could also function such that therapy could only
be delivered if the kill switch is activated by pushing a button
and releasing said button would then terminate therapy.
[0060] In another embodiment of the invention, the distal end of an
ablation catheter comprises pressure sensors and compressible,
shock absorbing means, to minimize the chance of perforation or
internal damage. The shock absorbing material, such as small
springs (or an elastic/flexible ablation contactor), is positioned
proximal to the distal electrode. Pressure sensors positioned on or
near the proximal surface or edge of the distal electrode measure
the forces exerted on the myocardium by the distal section of the
ablation catheter.
[0061] In another embodiment of the invention, the ablation
catheter system will contain at least two safety mechanisms,
including an operator-operated manual kill switch and a
pressure/force controlling system to optimize the safety to the
patient.
[0062] In another embodiment of the invention, the ablation system
will provide automatic detection capabilities to detect at least
one early sign of inadvertent therapy such as phrenic nerve injury,
perforation, and/or heart block with the ability to immediately
terminate therapy.
[0063] There are a variety of kill switches which could be employed
in concert with an ablation therapy delivery system. The invention
described herein could utilize a myriad of buttons, controls, or
switches with indicators that function and/or provide information
including LEDs, the flow of electricity notification, audible
tones, etc. Many of these have been well described in the
electrical engineering literature. The invention also encompasses
on/off and kill switches that sense pressure, temperature, or any
other parameter.
[0064] A normal closed momentary kill switch is one in which the
electrical circuit is opened immediately upon depressing the switch
itself (typically in the form of a button, although other
configurations may exist) and the circuit's impedance would become
infinite and ablation therapy delivery would immediately terminate.
Once the switch is released, that is, not depressed, the circuit
would immediately close and pacing and sensing function from the
therapy delivery tip (typically an electrode) would be restored.
However, the ability to deliver ablation therapy could not be
re-engaged without turning on therapy at the generator source
itself. This type of mechanism is ideal for preventing inadvertent
delivery of ablation therapy and pacing/sensing function from the
therapy electrode or electrodes would only be "momentarily"
disrupted during the kill switch deployment and immediately
restored upon release of the switch. As above, normal open
momentary kill switches could also function in a manner that
therapy delivery could only occur with the switch engaged, and
therapy termination would occur with release of said switch.
[0065] In a preferred embodiment of the invention the kill switch
is a mechanical kill switch which is normally in the closed
position and, when depressed, transiently stays open. Said kill
switch is capable of withstanding 100 watts and 500 kHz with a
typical 250 vac and 3 amp rating.
[0066] Alternatively, a multi-function switch could control the
opening and closing of the kill switch upon each depression or
contact. The down side of the latter configuration is the potential
for longer disruption of the distal therapy sensing and pacing
function. A parallel circuit could separate out therapy delivery
disruption from pacing and electrode signal recognition/sensing
(i.e., kill switch functionality without disrupting pacing or
sensing). In fact, the kill switch can deliver a signal to alter
impedance and stop ablation therapy delivery without any effect of
sensing or pacing. It can be envisioned that there are numerous
ways of providing effective and immediate operator control over
therapy delivery via use of a kill switch without having any
significant impact (if at all) of electrode functionality (i.e.,
pacing and electrode signal visibility or sensing). In addition,
the kill switch could sense some other function or feedback
required for effective therapy delivery and/or function, if this
signal is disrupted via the kill switch an error could be detected
at the generator and therapy terminated. This is the case with the
Medtronic Cardiac CryoAblation System (ARCTIC FRONT.RTM.) in which
liquid nitrogen is delivered to a balloon/or catheter to freeze
tissue. If the electrical connector and some of its functions are
disabled (i.e., open circuit) the CryoConsole immediately shuts
down. All of these are encompassed in the invention described
herein.
[0067] In another embodiment of the invention, a kill switch could
be positioned on a remote control in order to remotely terminate
therapy. This could either be a stand-alone remote control or one
that is integrated into a remote control station or remote
controller in order to provide control over other aspects of the
ablation procedure. It is even possible for this switch mechanism's
remote control to be integrated with the controller for remote
navigation of an ablation catheter. The kill switch could be
located on a handle controller or joy stick or computer controller
distal to the catheter manipulator. Alternatively, the kill switch
can open the circuit of any signal that is critical to therapy
delivery and send an error message to the signal or therapy
generator, console, computer (CPU), or the like, in order to
terminate the delivery of any type of therapy.
[0068] In another embodiment of the invention, the kill switch can
create an error signal terminating therapy, for example, by
changing impedance, disrupting feedback communications, or the
like. Alternatively, a kill switch on a ground cable would
interrupt the grounding function and cause an error message to be
sent that would disrupt the therapy.
[0069] In another embodiment of the invention, an on/off switch can
function in each of the above embodiments, in a similar manner
and/or configuration as the kill switch configurations above. The
"on" component of the switch could be configured to sense human
contact prior to being engaged thereby preventing inadvertent
therapy by being dropped or leaned against. Other implementations
of said on/off switch similar to the kill switch above in a
connector-cable or as a connector-switch could provide manual
access to the operator in a similar fashion customized to a variety
of different ablation systems and manufacturers.
[0070] Electricity is necessary to travel from point A to point B
to provide ablation therapy (either directly as is the case with
radiofrequency energy, or indirectly, as is a controlling or
feedback signal monitoring balloon pressure and temperature in a
cryoablation balloon). If a switching mechanism such as a kill
switch were interposed between the electrical circuit of point A to
point B, it could be configured such that the circuit is normally
closed and momentarily manually depressing the switch would open up
the circuit and thereby prevent electricity from proceeding,
thereby terminating therapy (normally closed momentary kill
switch). Alternatively, the kill switch could be configured to be
normally open and depressing said switch would be necessary prior
to delivery of ablative therapy initiated by traditional means
(normally open momentary kill switch). Releasing the depressed kill
switch in this latter configuration would terminate therapy.
[0071] In both examples, the kill switch, unlike an on/off switch
is incapable of turning on therapy itself. Therefore, the unique
application of the kill switch to catheter ablation is its ability
to prevent inadvertent therapy delivery. You cannot step or
accidentally press a kill switch and turn on ablation therapy. The
kill switch described herein is a mechanical momentary kill switch.
The momentary kill switch may be preferable for the application of
terminating ablation therapy, but it is not absolutely necessary.
The kill switch can be depressible and lock into position. A tested
catheter handle version contained such a switch that, once
depressed, held the closed position, and when depressed again,
opened the circuit to terminate therapy. Each depression
mechanically reset the circuit accordingly.
[0072] Other types of configurations could include an automatically
triggered kill switch based on a sensed algorithm for early
detection of adverse events such as phrenic nerve injury. The
phrenic nerve could be stimulated and phrenic nerve conduction
and/or diaphragm contraction could be recorded. A predetermined
minimal change in threshold could trigger the kill switch to
automatically terminate therapy in this instance. Similarly, early
signs of perforation and/or changes in conduction could trigger the
kill switch to terminate therapy thereby reducing the chance of a
significant complication. In addition, the kill switch or an on/off
switch could function via a remote controller (using a
transmitter/receiver configuration such as a television remote
control using infrared or radio wave signals). Alternatively, these
switches could also function via voice or sound command and can
have some preprogrammed actuators, signals, and voice programs.
[0073] Regardless of whether the switching mechanism is an on/off
switch of kill switch many variations are possible, including a
depressible button, toggle switch, temperature or infrared sensor,
or switch button, for example. For standard radiofrequency a
switching mechanism would typically need to be rated for at least
100 Watts at 500 kHz with a 250 vac/3 amp rating. Error signals and
other types of sense signals may have different and perhaps less
energy requirements to function appropriately. In addition,
standard radiofrequency ablation typically delivers therapy from
the distal ablation electrode to a grounding patch. A single pull
kill switch may operate effectively interposed between the
conductor or wire that goes to that electrode. However, more
complicated and future ablation systems may deliver energy through
more than one electrode and a multiple pull kill switch would be
necessary to disrupt all therapy immediately. The same goes for
critical error signals necessary for feedback and surveillance of
non-radiofrequency energy (e.g., cryoablation). These signals may
require more than one pull (or one open conductor) to shut down
therapy. In addition, it is conceivable that the switching
mechanism itself can produce its own error signal and disrupt the
controller/generator and terminate therapy as well. A number of
different switching mechanisms and configurations can achieve the
goal of this novel therapy intended as a more efficient means of
rapidly terminating therapy and avoiding unnecessary
complications.
[0074] In another embodiment of the invention, in an improved
ablation catheter system comprising a longitudinally extending
catheter having a proximal end and a distal end, a handle attached
to the proximal end of the catheter, a mechanism at the distal end
of the catheter for delivering ablation therapy to a desired
location, such as tissue, and a generator or controller of ablation
therapy in communication with the handle, the handle and the distal
end of the catheter, or the handle, the catheter, and the distal
end of the catheter, the ablation catheter system comprises a
switching mechanism which is capable of causing abrupt termination
of delivery of ablation therapy by manual, automatic, remote, or
voice-operated operation.
[0075] In another embodiment of the invention, the switching
mechanism is positioned between the ablation catheter distal tip
and the generator or controller of ablation therapy, including on
or in the therapy-producing generator or controller.
[0076] In another embodiment of an ablation catheter system of the
invention, the kill switch is interposed on or in communication
with one or more conductor wires contained within the ablation
catheter, an electrical connector cable, a separate device
connected between the catheter and a therapy-producing generator or
controller, or the therapy-producing generator or controller.
[0077] In another embodiment of an ablation catheter system of the
invention, the switching mechanism is an on/off or kill switch
which is contained on and/or within the handle, which is in or in
communication with a connector cable, a separate device connected
between the catheter and the therapy-producing generator or
controller, or the therapy-producing generator or controller.
[0078] In another embodiment of an ablation catheter system of the
invention, the switching mechanism comprises wires, connectors, a
switch, and a protective enclosure to permit operation on a sterile
medical field.
[0079] In another embodiment of an ablation catheter system of the
invention, the switching mechanism is interposed on or in
communication with at least one conductor wire contained within the
catheter and a cable which leads from the catheter to a
therapy-producing generator or controller and which operation of
the switching mechanism permits therapy, terminates therapy, or
permits and terminates therapy.
[0080] In another embodiment of an ablation catheter system of the
invention, the switching mechanism comprises a depressible button,
a touch sensitive switch, a toggle switch, a pressure- or
temperature-sensitive sensor, or the like.
[0081] In another embodiment of an ablation catheter system of the
invention, the switching mechanism is positioned between steerable
levers on the handle and/or catheter body to provide ergonomic
thumb, finger, or thumb and finger access.
[0082] In another embodiment of an ablation catheter system of the
invention, wherein the determination of whether a switching
mechanism is to be positioned on the handle of the catheter, in a
cable having a distal end that is inserted into the handle or rigid
portion of a handle of a catheter, in a short cable segment to be
attached to the proximal end of a cable extending from the handle
of a catheter and the proximal end of a cable from a therapy
generator or controller, or in a long cable segment to be attached
to the proximal end of a cable extending from the handle of a
catheter and the proximal end of a cable from a therapy generator
or controller, is based upon factors such as the design and
configuration of the catheter, the ablation therapy, and the
location of the site to be ablated.
[0083] In another embodiment of an ablation catheter system of the
invention, wherein the location of the switching mechanism as well
as its mode of incorporation into the catheter ablation system is
determined by accessibility to a manufacturer's platform, the type
of catheter and its design and presence or absence of a built in
cable at the end, the type of procedure, position of the patient's
catheter access site, the operator's position, and the operator's
necessity to immediately monitor for adverse effects of the therapy
on the patient.
[0084] In another embodiment of an ablation catheter system of the
invention, the design, configuration, and position of said
switching mechanism and its application is determined by the type
of procedure, type of catheter and its design, catheter access
point, position of the patient, position of the operator,
maneuverability of the medical device (i.e., catheter), as well as
the operators ability to monitor for inadvertent therapy while
performing said procedure. Such a design may consider a longer
cable with the switch mechanism positioned more proximal to the
operator such that the operator could perform a cryoablation
procedure from the groin and have access to the switch in order to
manually feel the contraction of the diaphragm during phrenic nerve
stimulation and at the same time have manual control of the therapy
with the ability to immediately shut off therapy if diaphragm
contraction (or its surrogate) diminishes in order to avoid
permanent phrenic nerve damage. A shorter connector switch could
attach directly to a Boston Scientific BLAZER.RTM. radiofrequency
ablation catheter since that device already has approximately 8
inches of cable at the end of said catheter permitting manual
manipulation. Other radiofrequency ablation catheters such as the
Medtronic RF ablation catheter, the Johnson & Johnson Biosense
Webster THERMOCOOL.RTM. ablation catheter, and the St. Jude Medical
SAFIRE TX.TM. ablation catheter have handles which terminate with
just a connector. Each of these handles has an integral plug for
receiving a connector from a cable or device. A switching mechanism
device, which includes enough of a cable, would help such that
those catheters could be easily rotated without making manipulation
awkward.
[0085] In another embodiment of an ablation catheter system of the
invention, the switching mechanism is positioned in a long cable
segment to be attached to the proximal end of a cable extending
from the handle of a catheter and the proximal end of a cable from
a therapy generator or controller for cryoablation, so that an
operator can operate the switching mechanism and feel a patient's
diaphragm contractions to prevent phrenic nerve paralysis.
[0086] The variety of connectors and cables useful with ablation
catheters according to the invention means that one carrying out
the invention herein will have to select the appropriate cable,
device, and/or connector to match up to the handle of the ablation
catheter used. The ablation catheter described above which
terminate without any built-in cable may require a cable plus
switching mechanism to permit catheter maneuverability. The Boston
Scientific ablation catheter which has approximately 8 inches of
cable built in at the end can utilize a connector switch with or
without a cable. A longer cable may be required for a cryoablation
procedure performed from the groin, if the operator is to feel
diaphragm contraction force while at the same time feeling a switch
attached to a catheter. A remote control could trigger the switch
mechanism itself. Such a control could have a transmitter/receiver
configuration and operate the switching mechanism in a catheter,
connector, cable, generator, computer controller, or combination
thereof.
[0087] In another embodiment of an ablation catheter system of the
invention, the switching mechanism is located so that other fingers
on the handle and the auxiliary hand can stabilize catheter
positioning while still allowing an additional digit of that hand
or the auxiliary hand to depress the switching mechanism most
rapidly and effectively.
[0088] In another embodiment of an ablation catheter system of the
invention, the location of the switching mechanism as well as its
mode of incorporation into the catheter ablation system are
determined by accessibility to a manufacturer's platform, the type
of catheter and its design and presence or absence of a built in
cable at the end, the type of procedure, position of the patient's
catheter access site, the operator's position, and the operator's
necessity to immediately monitor for adverse effects of the therapy
on the patient.
[0089] In another embodiment of an ablation catheter system of the
invention, the switching mechanism is positioned in a long cable
segment during cryoablation, so that an operator can manually
operate the switching mechanism and feel a patient's diaphragm
contraction at the same time to prevent phrenic nerve
paralysis.
[0090] In another embodiment of an ablation catheter system of the
invention, the switching mechanism is in the most appropriate place
to allow an operator to both manually perform an ablation procedure
and to manually terminate therapy.
[0091] In another embodiment of an ablation catheter system of the
invention, the switching mechanism is positioned between two
connectors and wires in either a cable plus enclosure or just an
enclosure, all intended to transmit and/or control ablation
therapy.
[0092] In another embodiment of an ablation catheter system of the
invention, the switching mechanism can be engaged only after
ablation therapy has been initiated from the therapy-producing
generator and/or computer controller.
[0093] In another embodiment of an ablation catheter system of the
invention, the switching mechanism has an alert function.
[0094] In another embodiment of an ablation catheter system of the
invention, the switching mechanism can receive a signal from a
remote controller to terminate therapy.
[0095] In another embodiment of an ablation catheter system of the
invention, the switching mechanism is voice-, touch-, or
sound-activated and is coupled either directly or remotely to the
ablation therapy delivery system.
[0096] In another embodiment of an ablation catheter system of the
invention, a receiver has been programmed to recognize an
operator's voice, a certain command or commands, or a combination
thereof.
[0097] In another embodiment of an ablation catheter system of the
invention, the switching mechanism is controlled remotely, wired or
wirelessly, to permit immediate and remote therapy termination.
[0098] In another embodiment of an ablation catheter system of the
invention, the switching mechanism is a kill switch that either (1)
is normally a closed circuit and when the switch is engaged it
opens the circuit, forcing the ablation catheter system to shut off
its therapy, and then closes immediately, thereby restoring full
functionality of the system without re-initiation of therapy
delivery or (2) is normally an open circuit which requires the
switch to be engaged such that the circuit is closed thereby
permitting the transmission of ablation therapy, whereas
disengaging said switch immediately terminates therapy.
[0099] In another embodiment of an ablation catheter system of the
invention, the kill switch can operate as a fixed switch such that
engaging the switch performs one function such as closing an
electrical circuit in order to permit ablation therapy delivery and
re-engaging said switch opens an electrical circuit thereby
terminating therapy; or a momentary mode such that an electrical
circuit is either open or closed as long as the switch is manually
engaged.
[0100] In another embodiment of an ablation catheter system of the
invention, the switching mechanism works directly through the
therapy generator or controller.
[0101] In another embodiment of an ablation catheter system of the
invention, the switching mechanism is a kill switch that
momentarily opens, forcing the ablation catheter system to shut off
its therapy, and then closes immediately, thereby restoring full
functionality of the system without re-initiation of therapy
delivery.
[0102] In another embodiment of an ablation catheter system of the
invention, the switching mechanism or kill switch comprises
parallel circuitry in which ablation therapy delivery can be
immediately disrupted without interrupting any of the system's
electrical capabilities.
[0103] In another embodiment of an ablation catheter system of the
invention, the switch mechanism is depressible and resettable.
[0104] In another embodiment of an ablation catheter system of the
invention, in an improved ablation catheter system comprising a
longitudinally extending catheter having a proximal end and a
distal ends, a handle attached to the proximal end of the catheter,
a mechanism at the distal end of the catheter for delivering
ablation therapy, and a source of ablation therapy in communication
with the handle, the catheter, and the distal end of the catheter,
the improvement wherein the system has a switching mechanism and
one or more additional safety features to minimize the risk of
inadvertent damage to tissue, especially heart tissue.
[0105] In another embodiment of an ablation catheter system of the
invention, shock absorbing materials are interposed between the
distal tip of the catheter and the catheter to help absorb the
contact force and minimize pressure delivered to tissue and the
risk of inadvertent damage. Alternatively, the tip may be made of
an elastic and or flexible material in order to help absorb and
cushion the contact.
[0106] In another embodiment of an ablation catheter system of the
invention, one or more contact sensors are interposed between the
ablation therapy delivery tip and the absorbent material to measure
the degree of contact.
[0107] In another embodiment of an ablation catheter system of the
invention, one or more contact sensors measure pressure, force, or
both pressure and force and the operator has direct manual access
to terminate therapy.
[0108] In another embodiment of an ablation catheter system of the
invention, haptics are coupled to the handle to provide feedback to
an operator as to the amount of contact pressure that is being
delivered to the tip of the ablation delivery system within the
human body.
[0109] In another embodiment of the invention, a system for
preventing inadvertent damage to heart tissue comprises an
immediately accessible kill switch and features to detect and
minimize excessive force delivered to the tip of an ablation
catheter system within the heart.
[0110] In another embodiment of an ablation system of the
invention, a system for preventing inadvertent damage to the heart
and/or circulatory system and/or pericardial space during delivery
of ablative treatment or therapy comprises a plurality of safety
features, including (1) an immediately accessible on/off or kill
switch and (2) one or more force or pressure sensors to detect and
minimize excessive force delivered to the tip of an ablation
catheter system.
[0111] In another embodiment of an ablation system of the
invention, the system is an operator-controlled system which
permits the operator to have immediate manual control over (1) the
amount of force applied to the end or ends of an ablation system
and (2) permitting ablation therapy, terminating ablation therapy,
or permitting and terminating ablation therapy.
[0112] In another embodiment of the invention, a medical device
which fastens over a first connector and a connectable second
connector of a connection cable linked to a medical device for
delivering medical treatment or therapy, contains a mechanism for
easily separating the first and second connectors and thereby
interrupting treatment or therapy.
[0113] In another embodiment of a medical device of the invention,
the medical device also permits easy reconnection of the
connectors.
[0114] In another embodiment of the invention, a rapid cable
connect/disconnect device for immediate separation of a male cable
connector and a female cable connector, comprises a component which
grasps both connectors, maintains alignment of the connectors to
one another, unlocks any locking mechanism, and separates said
connectors, and is also capable of mechanically reconnecting or
re-coupling the cable connectors in an aligned manner to restore
continuity.
[0115] In another embodiment of the invention, a device can be used
in concert with an ablation catheter system such that rapid cable
disconnection results in termination of ablation therapy to
minimize damage from inadvertent therapy delivery and rapid cable
reconnection can restore full functionality of the ablation
catheter system.
[0116] In another embodiment of the invention, a switching
mechanism for use with an ablation catheter system comprises:
[0117] a first wired or wireless component for direct manual
activation, which is capable of being attached to or placed
adjacent to an ablation catheter handle, and
[0118] a second wired or wireless component coupled to the first
component to receive, transmit, or receive and transmit a switching
signal generated by the first component, to provide direct manual
control of the delivery of ablation therapy.
[0119] In another embodiment of the invention, the first component
can be attached to the catheter handle with a stretchable sleeve, a
clip, a connector, or sterile adhesive.
[0120] In another embodiment of the invention, a rapid cable
connect/disconnect device having a kill switch provides for
immediate connection or separation of a male cable connector and a
female cable connector. The rapid cable connect/disconnect device
comprises a component with male and female receptors which grasp
the respective female and male ends of the connectors, maintains
alignment of the connectors to one another, and optionally unlocks
any locking mechanism. The female receptor of the rapid cable
connect/disconnect device engages the male connector and the male
receptor of the rapid cable connect/disconnect device engages the
female connector, so as to separate the connectors, and the rapid
cable connect/disconnect device is also capable of mechanically
reconnecting or re-coupling the cable connectors in an aligned
manner to restore continuity.
[0121] In another embodiment of the invention, a rapid cable
connect/disconnect device with a kill switch can be used in concert
with an ablation catheter system such that rapid cable
disconnection results in termination of ablation therapy to
minimize damage from inadvertent therapy delivery and rapid cable
reconnection can restore full functionality of the system.
[0122] In another embodiment of the invention, a device for
immediate separation of first and second cable connectors comprises
a first tubular or substantially tubular member that is capable of
encircling and grasping the first cable connector, a second tubular
or substantially tubular member that is capable of encircling and
grasping the second cable connector, and a bridge member connecting
the first and second tubular or substantially tubular members,
wherein, when a portion of the bridge member is pushed downward, a
latch disengages and the tubular or substantially tubular members
move away from each other and cause the cable connectors to
disengage or disconnect.
[0123] In another embodiment of the invention, the device
facilitates easy reconnection of the first and second cable
connectors.
[0124] In another embodiment of the invention, an on/off switch or
kill switch is positioned between two connectors in a component.
The component can be positioned relative to an ablation catheter
handle based on one or two cable connectors of varying lengths. The
component may be attached to two variable length cable connectors,
one of which is attached directly to the ablation catheter handle,
or, dependent upon which model ablation catheter is used, the
component may be attached directly to the proximal end of the
handle of the ablation catheter. The lengths of the cable
connectors may vary depending upon where the operator wants the
component (with the on/off or kill switch) to be positioned
relative to the ablation catheter handle. If there is a cable
connector between the ablation catheter handle and the switching
component, that switching component would preferably be disposable,
and the cable connectors could each be reusable/resterilizable.
However, it is possible that the switching component and cables
could be either disposable or reusable/resterilizable.
[0125] In another embodiment of the invention, a component
comprising a kill switch is configured for dual use, that is, to be
convertible from manual to foot operation. More particularly, the
component would be configured so that it could be functionally
connected to an ablation catheter and be positioned within the
sterile field for manual operation by the operator to kill ablation
function and so that it could alternatively be positioned for foot
operation. For example, the component could operate on a sterile
field in a first mode of operation as a manual kill switch (with a
kill switch on the top surface of the component for manual
operation), and the component could operate and be positioned in a
second mode such that the switch component could be opened up and
placed on the floor (non-sterile) such that the foot could control
a pedal inside the component in order to trigger the kill switch
and terminate therapy.
[0126] In another embodiment of the invention, an on/off switch or
kill switch can be attached directly onto an ablation catheter
handle via suitable means, such as a sterile adhesive, a clip, or a
sleeve (that would slide over the front or back of the catheter
handle). If the switch is connected to the ablation therapy system
via a connector cable--either contained therein or as a separate
device interposed between connector cables--the switch could double
back toward the catheter handle and clip on, slide on, or adhere to
the handle by a number of means to the catheter handle such that
the switch itself functions on the handle.
[0127] In another embodiment of the invention, a connector cable
could be configured such that all of the wires are contained within
the connector cable and the wire or wires necessary for switching
off therapy separately branch off to connect to an on/off or kill
switching mechanism. That switching mechanism can be attached to an
ablation catheter handle in a number of different ways, such as by
adhesive, a sleeve, or a clip. The input and output wires of the
switching mechanism could be contained within a thinner sleeve that
could reach the ablation catheter handle and adhere to the ablation
catheter handle to permit catheter manipulation and have the
switching mechanism on the ablation catheter handle itself. The
connector cable will consist of a thicker and stiffer cable at its
proximal end which connects to a generator or control console and a
distal member containing a thinner, more flexible wiring to the
switching mechanism which can be placed on the ablation catheter
handle. The separate switching mechanism could essentially be a
thin wire that can extend from the end of the connector cable
proximal to the catheter and easily attach to the ablation catheter
handle without tangling during manipulation and permit easy access
to the switch on the ablation catheter handle to terminate therapy
manually.
[0128] In another embodiment of the invention, a connector cable
looks like a regular cable and has a separate terminus for a
thinner switching mechanism which could attach to the connector
cable. This mechanism if not engaged would allow the connector
cable to operate like a regular connector cable, but if the
switching mechanism is attached, it then has the ability to
terminate therapy. The switching mechanism can operate off the
handle or it can attach directly to the ablation catheter
handle.
[0129] In another embodiment of the invention, a switching
mechanism attaches directly onto an ablation catheter handle. The
switching mechanism can look similar to FIG. 1A such that it can be
placed in an easily accessible position on the ablation catheter
handle to provide easy ergonomic access to the switching mechanism
to easily terminate therapy. The switching mechanism itself can be
wireless (i.e., no direct wires terminate from the switch directly
into the ablation catheter or its connector cable). However, the
switching mechanism can adhere to the ablation catheter by a number
of ways, such as adhesive, a clip, or a flexible stretchable
sleeve, and can terminate therapy by transmitting a signal to the
receiver switching mechanism incorporated in a connector cable,
separate device, generator, console, or computer controller.
Alternatively, the switching mechanism can create a signal which
could interrupt therapy by creating an error signal. For example, a
stretchable sleeve slid over the proximal end of the handle may
contain many turns of an electrical coil. When the sleeve is
depressed (engaged), it could send a current throughout the coils
to create an electrical current through the ablation wires
contained in the handle via inductance, changing the signal enough
that an error could be detected by the generator or controller
console and terminate therapy. Other types of error and/or jamming
signals could also terminate therapy. In essence the method
provides a free standing, sterile method to achieve an on/off
switch or kill switch functionality with a wireless mechanism,
which can adhere or attach to the ablation catheter handle.
[0130] In another embodiment of the invention, a sealed reusable
connector cable could contain a kill switch which looks and feels
like a more standard cable (though it may have a bulge for the
separate kill switch mechanism). This switch/cable could be
reusable and resterilized (as well as disposable). This switching
mechanism contained within the cable has a receiver function. A
separate sterile disposable switch which could clip to the handle,
slide over the front or back as an elastic or stretchable sleeve,
or attach to the handle by some other adherent mechanism and could
serve as a transmitter switch which when activated (i.e., depressed
for example) it would send a signal to the transmitter and
terminate therapy. In addition, the kill switch receiver could be
contained within the ablation generator, console, or computer
controller.
[0131] In another embodiment of the invention, an on/off or kill
switch mechanism could be built-in to a device which attaches to or
rides over the proximal end of an ablation catheter handle which
terminates with only a connector and no cable. Examples of such
catheters include Medtronic's RF catheter, St. Jude Medical's
SAFIRE catheter, and Biosense Webster's THERMOCOOL catheter. The
device could comprise a separate component that (1) has an integral
switching mechanism, (2) plugs into the proximal end of the
ablation catheter handle, and (2) has a male or female receptacle
for receiving a connector from a cable. Alternatively, the device
could comprise the distal end of a cable that (1) has an integral
switching mechanism to attach to the ablation catheter handle and
(2) plugs into the proximal end of the ablation catheter handle. In
essence, this device can permit the switching mechanism to appear
as if it is part of the ablation catheter handle itself.
[0132] In another embodiment of the invention of an improved
ablation catheter system comprising a longitudinally extending
catheter having a proximal end and a distal end, a handle attached
to the proximal end of the catheter, a mechanism at the distal end
of the catheter for delivering ablation therapy to a desired
location, and a generator or controller of ablation therapy in
communication with the handle and the distal end of the catheter,
the improvement comprises a switching mechanism which is capable of
causing abrupt termination of ablation therapy by manual operation,
wherein the switching mechanism is positioned between the generator
or controller of ablation therapy and the catheter handle, and
wherein the switching mechanism has a button or other activation
means to terminate ablation therapy and one or more lights that
reflect the state of the ablation catheter system.
[0133] In another embodiment of the invention, a second, separate
button or other activation means is connected through a wire or
cable to the switching mechanism, which second button or other
activation means is capable of being placed in an ergonomic
position on the handle of the ablation catheter in an easily
accessible position to provide immediate manual control by the
catheter operator to terminate therapy.
[0134] In another embodiment of the invention, a second, separate
button or other activation means is connected through a fixed wire
to the switching mechanism, which second button or other activation
means is capable of being placed in an ergonomic position on the
handle of the ablation catheter in an easily accessible position to
provide immediate manual control by the catheter operator to
terminate therapy.
[0135] In another embodiment of the invention, a second, separate
button or other activation means is connected through a removal
wire to the switching mechanism (much like a headphone jack), which
second button or other activation means is capable of being placed
in an ergonomic position on the handle of the ablation catheter in
an easily accessible position to provide immediate manual control
by the catheter operator to terminate therapy.
[0136] In another embodiment of the invention, a sleeve or
stretchable sleeve or rubber/foam handle cover is configured to fit
over or around a catheter handle and provide enhanced grippability
and/or comfort. Said sleeve or cover also provides an encasement
for a second, separate button or other activation means attached to
a cable-mounted switching mechanism and attached to the distal
portion of an ablation catheter.
[0137] In another embodiment of the invention, a sleeve or
stretchable sleeve or rubber/foam handle cover is configured to fit
over a catheter handle such as the sleeve or cover has a button or
other activation means contained within it in order to terminate
the ablative therapy.
[0138] In another embodiment of the invention, a switching
mechanism for an ablation catheter system comprising a
longitudinally extending catheter having a proximal end and a
distal end, a handle attached to the proximal end of the catheter,
a mechanism at the distal end of the catheter for delivering
ablation therapy to a desired location, and a generator or
controller of ablation therapy in communication with the handle and
the distal end of the catheter, comprises:
[0139] a casing having an upper surface and two lateral
surfaces;
[0140] a button or other activation means positioned on the upper
surface; and
[0141] at least one light to reflect the status of the ablation
catheter system,
[0142] wherein pushing the button or other activation means
terminates the delivery of ablation therapy.
[0143] In another embodiment of the invention, a switching
mechanism for an ablation catheter system comprising a
longitudinally extending catheter having a proximal end and a
distal end, a handle attached to the proximal end of the catheter,
a mechanism at the distal end of the catheter for delivering
ablation therapy to a desired location, and a generator or
controller of ablation therapy in communication with the handle and
the distal end of the catheter, comprises:
[0144] a casing having an upper surface and two lateral
surfaces;
[0145] a button or other activation means positioned on the upper
surface; and
[0146] at least two lights to reflect the status of the ablation
catheter system,
[0147] wherein one of the lights is red and the other is green,
[0148] wherein the normal button function when electricity flows
through the switch and the green switch light is
activated/illuminated,
[0149] wherein pushing the button or other activation means
terminates the delivery of ablation therapy and the red switch
light is activated/illuminated,
[0150] wherein inactivation of the switch is indicated by neither
light being illuminated.
[0151] In another embodiment of the invention, the switching
mechanism also contains a digital timer with a predetermined
shutoff period.
[0152] In another embodiment of the invention, the timer is powered
by a battery within the casing or power from the ablation catheter
system.
[0153] In another embodiment of the invention, the timer starts
when the battery or the ablation system is activated.
[0154] In another embodiment of the invention, the timer can be
restarted but not reset.
[0155] In another embodiment of the invention, a method of
controlling the use of a medical product used in a surgical or
clinical procedure, comprises inserting into the medical product a
digital timer that is set to a predetermined time period of
operability, that begins timing when the timer is activated, and
that cannot be reset.
[0156] In another embodiment of the invention, the digital timer is
powered by a battery and begins timing when the battery is
activated.
[0157] In another embodiment of the invention, the digital timer is
powered by the medical product and begins timing when the medical
product is activated.
[0158] In another embodiment of the invention, a method of
controlling the use of a medical product used in a surgical or
clinical procedure, comprises
[0159] providing a medical product that comprises a digital timer
set to a predetermined time period of operability that begins
timing when the timer is activated, that deactivates the medical
product at the end of the predetermined period, and that cannot be
reset once started;
[0160] recovering the used medical product;
[0161] resetting or replacing the digital timer;
[0162] sterilizing and repackaging the recovered product; and
[0163] selling the recovered product at a cost less than when
new.
[0164] Reuse of manufactured ablation catheters has been
problematic specifically as it relates to the quality control of
the ablation catheter and its electronic components (temperature
sensors, electrodes, connectors, etc.). There is a need to have
better quality control and prevent haphazard reuse of said
catheters. In addition, there is a need to improve on the
functionality and manual control contained within the ablation
catheter itself. It is intuitive that the switching mechanism
should be ideally located within or on the ablation catheter and in
an ergonomic location such as the distal component, which is in the
front of the catheter near the normal location of the thumb when
the catheter handle is gripped. By placing the switching mechanism
in the ablation catheter, it would be important to prevent random
resterilization in order to assure the functionality of said
catheter as well as the performance of the switch.
[0165] Therefore, a routine ablation catheter could contain a
battery and a powered timer which could limit catheter operation
time. The battery, could have a protector or tab or piece of
insulation between itself and its electrical connector. Once the
catheter is pulled out of its sterile packaging, said insulation
could be remove or dislodged and the battery engaged directly with
its connector in order to initiate a digital timer. The timer could
function for a predetermined amount of time, and after which the
catheter itself would become nonfunctional. It could be impossible
for the facility that purchased said catheter to reset the clock or
timer without going back to the original manufacturer. The battery
could have a limited lifespan (say for example 8 hours and the
timer may last for a similar amount of time or even up to 24
hours). Only the manufacturer could potentially refurbish, replace,
and resterilize, reset, and reuse the original ablation catheter
and/or its components and resell them at a discount back to the
original facility or some other facility.
[0166] In addition, an ablation catheter if powering a timer via a
battery, could also power a built-in switching mechanism such as a
kill switch. The battery could also power one or more LEDs, which
could display the functionality of said switch in the device. For
example, a green LED could indicate that ablation therapy is turned
on and being delivered; a red LED could indicate that the ablation
therapy is turned off.
[0167] Each and every functionality and component described above
could be operational all within or on a standard ablation catheter
and together would prevent routine and random resterilization by
outside facilities and/or the operator's medical institution. Only
the original manufacturer would be able to reset the timer
contained within the device, replace the battery, evaluate each and
every component, resterilize and repackage and resell said catheter
at a discount. Overall, this would provide a significant quality
control measure as well as a potential cost saving to the
facility.
[0168] It is understood that this exact functionality as described
in the above paragraphs could also be applied to a separate
switching mechanism positioned between the ablation catheter and
the ablation therapy generating or producing system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0169] FIG. 1A is an oblique view of the handle of an ablation
catheter, which handle represents an embodiment of the
invention;
[0170] FIG. 1B is a lateral view of the handle shown in FIG.
1A;
[0171] FIG. 2 is a schematic representation of an embodiment of the
invention where a kill switch is positioned in a member that can be
positioned between a cable supplying ablative energy and an
ablation catheter;
[0172] FIG. 3 is a schematic representation of an embodiment of the
invention where a kill switch is positioned in a cable supplying
ablative energy;
[0173] FIG. 4. is a schematic representation of a foot pedal that
can act as a kill switch;
[0174] FIGS. 5 and 6 are schematic representations of the distal
end of an ablation catheter according to the invention;
[0175] FIG. 7 is a schematic of the kill switch on a remote handle
controller which can remotely manipulate an ablation catheter
and/or system;
[0176] FIG. 8 shows a schematic diagram of voice command activated
kill switch mechanism for remotely activating the kill switch with
a precise and learned verbal command;
[0177] FIG. 9 is a view of an end of a plug for a radiofrequency
cable useful according to the invention;
[0178] FIGS. 10A and 10B are schematic drawings of a simple
mechanical disconnector according to the invention;
[0179] FIG. 11 is a schematic drawing of a variation of the manner
in which a kill switch can be positioned on and in communication
with a catheter handle and a cable;
[0180] FIGS. 12A and 12B are schematic drawings of flexible sleeves
that can be positioned over catheter handles;
[0181] FIG. 13 is a schematic drawing of another embodiment of the
invention where a kill switch can be positioned on and in
communication with a catheter handle and a cable;
[0182] FIG. 14 is a schematic representation of on/off or kill
switch that can be positioned on a catheter handle;
[0183] FIGS. 15A and 15B are schematic lateral and top views of an
alternative to the embodiment of the invention shown in FIG. 3;
[0184] FIG. 16 is a schematic drawing of a variation of the
embodiment of the invention shown in FIGS. 15A and 15B;
[0185] FIG. 16A is a detail of the schematic drawing shown in FIG.
16;
[0186] FIG. 17 is a schematic drawing of a second kill switch
button useful according to the invention; and
[0187] FIG. 18 is a schematic drawing of a handle gripper useful
according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0188] The invention can perhaps be more appreciated from the
embodiments of the invention set forth in the drawings. In FIGS. 1A
and 1B, a steerable ablation catheter handle 2 has a proximal
portion 4 and a distal portion 6. Distal portion 6 engages a
distally extending ablation catheter 10, and a pivoting lever
mechanism 12 steers ablation catheter 10. A red depressible button
14 is positioned on the upper surface 18 of handle 2. When ablation
energy enters handle 2 from proximal cord or cable 20, button 14
lights up.
[0189] In the embodiment of the invention set forth in FIG. 2, a
connector 30 attached to a cable 32 from an ablation therapy supply
(not shown) can be connected to a first, male connector 38 of a
member 40 having a momentary mechanical or digital kill switch 42
with a button 43. A second, female connector 44 of member 40 can be
connected to connector 46 attached to a cable 50 of an ablation
catheter (not shown) or to a catheter such as the Biosense Webster
THERMOCOOL catheter that comprises a receptacle for connector 44 at
its proximal end (not shown).
[0190] With regard to kill switch 42, when kill switch 42 is in a
rest or closed position, that is, button 43 extends away from the
surface, the circuit between cable 32 and cable 50 is closed.
Pushing button 43 causes switch 42 to open the circuit between
cable 32 and cable 50, disrupting therapy. Switch 42 can be rated
at, for example, 250 vac and 3 amp. The lengths of cables 32 and 50
can be varied dependent upon factors such as the desired placement
of member 40, the catheter used, or the positions of other
equipment.
[0191] Member 40 may comprise a clam shell outer casing that is
sealed and water resistant. Alternatively, the casing could be
injection molded. Preferably member 40 has insulated copper wire 48
(dotted lines) connecting connector 38, switch 42, and connector
44. Connector 44 may be, for example, a Redell 10-pin connector,
which would be compatible with the Boston Scientific BLAZER
catheter. Other pin connectors may be chosen to be compatible with
other catheters available from, for example, Biosense Webster
(Johnson & Johnson), Medtronic, and St. Jude Medical.
[0192] FIG. 3 represents an alternative embodiment where a cable 52
from an ablation therapy source (not shown) comprises a section 54
with a kill switch 56. A connector 60 attached to cable 52 is
capable of connecting to a connector 62 of a cable 64 attached to
an ablation catheter (not shown). Catheters such as St. Jude
Medical catheters, Medtronic RF ablation catheters, and Biosense
Webster catheters that do not have any cable extending as part of
the ablation catheter may benefit from a connector-cable-kill
switch-cable-connector configuration rather than a straight
connector-kill switch-connector configuration to provide more
catheter maneuverability rather than a longer stiffer handle. The
customer could choose and select the particular length of cable,
location, and/or configuration that best meets their needs. The
Medtronic Cardiac CryoAblation catheter (ARCTIC FRONT) to freeze
pulmonary veins on the right side could be connected to a longer
cable-kill switch-cable system such that the operator could reach
and feel diaphragm contraction during phrenic nerve stimulation
while at the same time having the other hand on the kill switch to
immediately detect any adverse effects to the phrenic nerve and
immediately terminate therapy.
[0193] In the embodiment of the invention shown in FIG. 4, a foot
pedal 70 is operatively connected through a cable 72 connected at
connector 76 to an ablation therapy source 78. Stepping on foot
pedal 70 would cause therapy source 78 to immediately cease
delivery of therapy.
[0194] FIGS. 5 and 6 each are a schematic representation of the
distal section of an ablation catheter. In FIG. 5, a distal
electrode 80 is positioned distal to standard electrodes 82.
Pressure sensors 86 are positioned on the proximal surface 88 of
distal electrode 80, and a single shock absorber 90 is positioned
proximal to distal electrode 80. In FIG. 6, a distal electrode 92
is positioned distal to standard electrodes 94. Pressure sensors 96
are positioned on the proximal surface 98 of distal electrode 92,
and several shock absorbers 100 are positioned proximal to distal
electrode 92. It is conceivable that two or more safety features
could be incorporated into the same catheter such that the operator
would have the immediate ability to terminate therapy manually as
well as safely control the force and/or pressure delivered to the
heart. In the event that pressure sensed exceeds a predetermined
level or value, an operator would see that that level or value had
been exceeded and trip a kill switch. Alternatively, a controller
senses that a predetermined level or value has been exceeded and
automatically generates an error message or signal that will cause
therapy to cease.
[0195] In FIG. 7 a manual remote 110 comprises a kill switch 112.
Remote 110 is electrically connected either wired or wirelessly
with a receiver (not shown) that is functionally connected to an
ablation therapy delivery system. Activation of kill switch 112
results in interruption of therapy delivery by the ablation therapy
delivery system. In another embodiment, the kill switch could be
connected between the catheter and the therapy delivering generator
and/or console and triggered via a remote control device.
[0196] FIG. 8 is a schematic diagram of a voice activated kill
switch for an ablation therapy delivery system. A receiver 116
receives a voice command from an operator, where the receiver
preferably has been programmed to recognize the operator's voice, a
certain command or commands, or a combination thereof. Receiver 116
is functionally connected to a kill switch 118, which is interposed
between a therapy generator 120 and an ablation catheter 122.
Optionally kill switch 118 can be functionally connected directly
to either therapy generator 120 or ablation catheter 122.
[0197] It is conceivable that said configuration for the kill
switch could also be an on/off switch instead contained directly
within the catheter handle or adapted to a variety of connectors
and cables to provide manufacturer/catheter and operator optimized
functionality.
[0198] FIG. 9 is a view of the end of a cable plug or connector 130
where a rigid or semi-rigid cylindrical surface 132 surrounds pins
134. Pins 134 are further identified as "1" to "10" and have the
functions set forth as follows:
TABLE-US-00001 PIN NO. FUNCTION 1 Ablation electrode #1 2 Not used
3 Thermocouple (constantan) 4 Thermocouple (copper) 5 Band
electrode #2 6 Band electrode #3 7 Band electrode #4 8 Connection
check 9 Connection check 10 Not used
[0199] It is within the scope of the invention that a switching
mechanism will not interrupt all the cable functions but only
selected ones, so that other functions can continue. Here, for
example, interrupting the signals associated with pin 1 would
terminate the ablation function.
[0200] FIGS. 10A and 10B are top and lateral schematic
representations of an ablation therapy safety device where a safety
member 140 is positioned adjacent female end 142 and male 146 end
of a cable 148 and a cable 150, respectively. Safety member 140
comprises sleeve or support members 154 that engage respective ends
142, 146. A pressure point or button 156 is positioned on a bridge
member 158 connected to support members 154. When button 156 is
pushed in a downward direction, that is, toward bridge member 154,
a latch 160 on female end 142 is engaged/unlocked and support
members 154 push against cable ends 142 and 146 to cause them to
separate a predetermined distance, thus interrupting the flow of
therapy through cables 148 and 150. When ends 142 and 146 are
pushed back together, ablation therapy can flow through cables 148
and 150 once the ablation therapy generator or source (not shown)
is re-started.
[0201] FIG. 11 represents a top view of a cable 170 with a molded
cable connector 172 that is received in and engages a receptacle
176 in catheter handle 178. Cable connector 172 engages or extends
slightly over the proximal end 180 of catheter handle 178, to
provide support for, for example, a kill switch button 182 that is
functionally connected to cable connector 172 and/or cable 170.
[0202] FIGS. 12A and 12B are schematic representations of a
catheter handle 184 having a flexible gripper sleeve surrounding
the outer surface of catheter handle 184. In FIG. 12A, a gripper
sleeve 186 having a length approximately one-half of the length of
catheter handle 184 has been slipped over and is in position on
catheter handle 184. Sleeve 186 has a on/off or kill switch 188
that is in wired or wireless communication with catheter handle
184, cable 189, or some other component that can affect or
interrupt the delivery of ablation therapy. The gripper sleeve 190
shown in FIG. 12B has a length substantially the length of catheter
handle 184 and has been slipped over and is in position on catheter
handle 184. There is an opening 196 that fits around deflector 197.
Sleeve 190 has a on/off or kill switch 194 that is in wired or
wireless communication with catheter handle 184, cable 189, or some
other component that can affect or interrupt the delivery of
ablation therapy.
[0203] Sleeves 186 and 190 can comprise any medically acceptable
woven or non-woven flexible material, such as any flexible and
sterilizable polymeric member that can fit over and on a catheter
handle. Advantageously the sleeve material will provide comfort and
an enhanced gripping surface, that is, grippability, for the
operator's hand or fingers.
[0204] FIG. 13 represents a top view of a catheter handle 196 that
has a receptacle 198 in its proximal end 200 for receiving a cable
connector 202 of a cable 204. One or more wires 206 in
communication with the wires in cable 204 extend from cable
connector 202 or cable 204 to a support member 208 for supporting a
kill switch 210. Support member 208 is a flexible substrate that
can be positioned on or affixed to catheter handle 196, such as at
proximal end 200. For example, flexible member 208 could be glued
with a suitable sterile adhesive or tied or strapped to catheter
handle 196.
[0205] FIG. 14 is one embodiment of an on/off or kill switch that
could be positioned on a catheter handle or elsewhere. Switching
mechanism 214 comprises a button or switch 216 positioned on a
flexible or semi-flexible substrate 220 that can be tied, strapped,
adhered, or otherwise affixed to the distal end of a catheter
handle (not shown) or other structure or location, such as a
cabinet, table, or even the operator's person, such as a wrist.
Substrate 220 comprises a power source and electronics to generate
a signal, such as an inductive or other signal that will create
impedance or otherwise will interrupt ablation therapy in an
ablation catheter system. Alternatively, switch mechanism 214 may
transmit a signal to a component that is connected to or in a cable
transmitting ablation therapy where the component has a receiver
for receiving the signal and a mechanical or electronic switch for
interrupting the ablation therapy.
[0206] FIGS. 15A and 15B represent lateral and top views,
respectively, of an alternative to the embodiment of the invention
shown in FIG. 3, where a cable segment 230 from an ablation therapy
generator (not shown) or a generator breakout box, such as Boston
Scientific's Maestro Box (not shown) engages a proximal portion 232
of a clamshell or injection molded kill switch casing or member 234
having a button or other activation means 236, which can, for
example, be a membrane switch. Optionally button 236 could comprise
an IC connected to a microcontroller. Preferably there will be a
splash-proof or water-tight seam around button 236. A cable segment
238 extends from a distal portion 242 of kill switch casing 234 to
a connector (not shown) to connect to an ablation catheter handle
(not shown). The length of cable segments 230 and 238 in
combination with kill switch casing 234, together "the cable," will
vary dependent upon the ablation catheter system used and whether
there is a breakout box or similar connection device. The cable
used with an ablation catheter system with a breakout box or a
similar connection device tends to be shorter than a cable used
with an ablation catheter system without a breakout box or similar
connection device.
[0207] There is internal circuitry (not shown) that electrically or
electronically connects to button 236 and two lights 244, such as
LEDs. The colors and state of lights 244 reflect the status of the
system. For example, when the ablation therapy system is activated
and operating, one of lights 244 may glow green. And then, when
button 236 is pressed to "kill" the therapy, the green light 244
goes off and the other light 244 may glow red. Alternatively, there
could be only one light 244 that changes color from green to red,
or a single light could go on and off, or there could be more
lights and different colors.
[0208] Kill switch casing 234 comprises a digital timer 248 that is
in communication with a power source, such as a battery 250.
Digital timer 248 is preset for a predetermined time of
operability, such as from 8 to 24 hours. A primary purpose of timer
248 and the predetermined time of operability is to limit the use
of the kill switch and to prohibit re-use.
[0209] Battery 250 is mechanically connected to a switching
mechanism 254 that activates battery 250. Switching mechanism 254
may comprise a pull tab, that is, a piece of plastic tape or film
(not shown) that is withdrawn partly or completely through an
opening 258 in kill switch casing 234 from a space between a
battery terminal and a contact to complete a circuit.
Alternatively, movement of a simple slide or switch 256 could move
battery 250 or a contact so that battery 250 completes a circuit.
Preferably whatever mechanical means is employed to activate
battery 250 is designed so that it cannot disengage battery 250 and
thus interrupt timer 248.
[0210] Another embodiment of a kill switch according to the
invention is shown in FIG. 16, where a wire 260 extends from an
opening 262 in a kill switch casing 264. The distal end 266 of wire
260 comprises a kill switch button 270 to be positioned upon and
attached to an ablation catheter handle (not shown) or in a gripper
(rubber/foam handle cover; as shown below). Button 270 may have an
adhesive lower surface 272. A gripper handle cover could also
merely cover the wire which extends from the cable-based kill
switch to the second kill switch button attached to the proximal
portion of an ablation catheter.
[0211] Wire 260 can be integral to kill switch casing 264.
Alternatively the proximal end 274 of wire 260 can have a plug 276
that plugs into a jack 278 in kill switch casing 264, so that the
use of a second button is optional with this system. Similarly, a
handle cover or gripper could conceal any wires attaching this
second button to the cable-based connector kill switch.
[0212] FIG. 17 is an oblique view of a wire 280 that is secured
with clips or fasteners 282 along a cable segment 284 that extends
from a kill switch (not shown) to an ablation catheter handle (not
shown). Wire 280 may extend parallel to cable segment 284 or it may
spiral around cable segment 284. Connector 286 is compatible with
an opening or connector receptacle in a catheter handle (not
shown). Button 290, which can be, for example, a membrane switch,
has an adhesive or foam tape lower layer 292 to attach to a
catheter handle (not shown) or other curved surface. Wire 280 could
be unclipped from cable segment 284 for certain button applications
or locations.
[0213] As shown in FIG. 18, a standard catheter ablation handle 300
has been fitted with a flexible gripper (or handle cover) substrate
302 comprised of a sterilizable polymeric material. Gripper
substrate 302 has a proximally extending wire 304 that is
operatively connected to a kill switch casing (not shown), as
described above. Wire 304 extends through substrate 302 to a button
or other activation means 306 positioned distal of catheter control
knob 310. Gripper substrate 302 performs at least two functions: it
provides a comfortable surface for the operator's hand and it
provides a secure location for button 306. Gripper substrate 302 is
sized so that it securely and non-movingly encompasses catheter
handle 300. Optionally there may be fasteners or closure means that
fit gripper substrate 302 to catheter handle 300.
[0214] The embodiments shown in FIGS. 16 to 18 are effectively
"double" kill switch systems in that the operator has two separate
buttons in different locations to push to deactivate an ablation
catheter system. Only one button needs to be pushed; when one
button is pushed, the ablation system shuts down and deactivates
the other button. The utility of a catheter-based switching system
in which one of the switches of buttons resides on the catheter
itself (preferably in the thumb position) satisfies the needs of
physicians surveyed who prefer not to take their hand of the
catheter handle during the actual delivery of ablative therapy.
This embodiment allows for manual termination of ablation therapy
without having the operator's hand leave the ablation catheter.
[0215] If the external button, that is, the one not on the kill
switch casing, is plugged in, then the operator can use either
button to stop the ablation therapy. In one aspect of the
invention, removing a plug from a jack will stop the generator
immediately if the plug is unplugged after the ablation therapy
starts (in case the operator accidentally unplugs the external
button while moving around). Should that happen, either the plug
can be plugged back in and the ablation therapy generator
restarted, or the generator can just be restarted with the plug
unplugged. Optionally the external button will have a light,
preferably green, in or near the activation area to indicate
whether it is plugged in properly.
Example
[0216] A standard ablation catheter and a depressible red kill
switch was spliced into the main conductor leading to the distal
ablation electrode. The switch was positioned on the ablation
handle for immediate thumb control, and was reassembled so that all
the steerable components functioned according to design
specifications. The system was then tested in vitro utilizing raw
chicken and a standard approved RF ablation system.
[0217] FIGS. 1A and 1B represent a radiofrequency ablation catheter
system employing the kill switch on a standard handle, wherein, a
standard ablation catheter was modified to include a red button as
a kill switch. The system was tested multiple times and
consistently created in vitro ablation lesions with precise manual
control. Depressing the kill switch immediately terminated therapy
delivery thereby preventing inadvertent radiofrequency
delivery.
[0218] Conclusions: An ergonomic kill switch located in the thumb
position on a standard ablation catheter handle provides a novel
simple safety feature for rapid termination of inadvertent ablation
therapy. This study demonstrated the ease of operation of this
novel system with particularly utility during ablation procedures
proximal to the normal conduction system (thereby minimizing the
risk of inadvertent heart block).
[0219] While certain embodiments of the present invention have been
illustrated and described, it will be clear that the present
invention is not limited to these embodiments only. Numerous
modifications, changes, variations, substitutions and equivalents
will be apparent to those skilled in the art, without departing
from the spirit and scope of the present invention, as described in
the following claims.
* * * * *