Patent ID: 12220165

DETAILED DESCRIPTION

Embodiments of systems and methods for delivering energy to tissue of a patient in a controlled manner are discussed, and specifically, systems and methods for controlled delivery of radiofrequency (RF) energy to lung tissue, bronchial tissue or both. Embodiments of the systems and methods may be configured to consolidate and effectively communicate relevant information to a user of the systems, including detecting accessory connections (e.g. therapeutic device, footswitch, electrode return pad, or other) and serving as an automatic trouble shooting guide with user friendly instructions, information, indicators and the like.

FIG.1shows a schematic diagram of a system for delivering therapeutic energy10to tissue of a patient having an RF energy generator12, a controller14coupled to the energy generator, a user interface surface16in communication with the controller14and a therapeutic energy delivery device, in the form of an RF energy delivery catheter18, coupled to an interface coupler20on the user interface surface16. The controller14, which is coupled to the energy generator12and user interface surface16, is configured to control the energy output of the energy generator12. The user interface surface16may include switches, a digital display, visual indicators, graphical representations of components of the system and an audio tone generator as well as other features. The controller14includes a processor22that is generally configured to accept information from the system and system components, and process the information according to various algorithms to produce control signals for controlling the energy generator12. The processor22may also accept information from the system10and system components, process the information according to various algorithms and produce information signals that may be directed to the visual indicators, digital display or audio tone generator of the user interface in order to inform the user of the system status, component status, procedure status or any other useful information that is being monitored by the system. The processor22of the controller14may be digital IC processor, analog processor or any other suitable logic or control system that carries out the control algorithms. Some of the control alerts, information, feedback and testing routines are shown in the flow diagrams ofFIGS.5A and5B.

The system10also includes an electrode return pad24and a footswitch26, both of which are coupled to respective interface couplers28and30on the user interface surface16. The user interface surface16also includes a digital display32that may be used to display numeric data to a user of the system10. The arrangement of the user interface surface16provides a user friendly interface for the system10that provides feedback and system information to a user in an intuitive display format. System components that couple to the user interface surface16, such as the footswitch26, electrode return conductive pad24and energy delivery catheter18, couple to the user interface surface16adjacent graphical representations of the respective system components. In addition, visual indicators that are configured to display information about these various system components may also be disposed adjacent or within the respective graphical representation of each system component. This configuration allows a user to easily and intuitively couple system components to the proper interface on the user interface surface16and also allows a user to easily and intuitively correlate audio and visual system feedback to the appropriate system component.

Referring again toFIG.1, the energy delivery catheter18includes an elongate shaft34, a handle36secured to a proximal end of the elongate shaft34and a control cable38that extends from the handle36to a proximal coupler40that is configured to couple to the interface coupler20on the user interface surface16. A sliding actuator42on the handle36controls the radial expansion and contraction of a distal electrode basket44disposed on a distal end of the elongate shaft34. The elongate shaft34may have a variety of configurations, including stiff, flexible, steerable with distal tip deflection and the like. The elongate shaft34and distal portion may also be configured and sized to permit passage of the elongate shaft34through the working lumen of a commercially available bronchoscope. In addition, the controller14may also include an optional interface coupler (not shown) that is configured to couple to a bronchoscope camera trigger such that when the processor22of the controller14initiates a treatment cycle by switching the RF energy generator from a standby state to an activation state, a triggering signal is also generated by the controller to initiate video taping or displaying of an image produced by the bronchoscope camera which is coupled to a bronchoscope being used to position the energy delivery catheter18during a procedure or treatment cycle. Alternatively, an interface couple may provide the ability to send some or all of the controller output or feedback to the bronchoscope video processor or monitor. This feature allows display of information ordinarily on the controller's user interface surface to display on any of the bronchoscope video monitors. Additionally, additional controller output information that is not displayed on the controller's user interface surface can be displayed on any of the displays associated with the bronchoscope. This feature allow the physician to focus on the bronchoscope display monitor when performing a procedure.

The distal electrode basket44may be seen in more detail inFIGS.2and3. The distal electrode basket44is a flexible and resilient oval shaped basket that includes an energy emission element in the form of an electrode46that is formed from an exposed section of a basket leg48which is nominally coated with an electrical insulator material50in the areas outside of the exposed section. The distal electrode basket44also includes a temperature detection element in the form of a thermocouple52disposed on or adjacent the electrode46. The thermocouple52has leads54and thermocouple termination points56which are secured to the exposed section58of the basket leg or electrode46.

The leads54of the thermocouple52and a conductor (not shown) in electrical communication with the electrode46extend proximally from the distal basket44to the handle36and then proximally through the control cable38to the proximal coupler40. This configuration allows the electrode46and the thermocouple leads54to be electrically coupled in a modular arrangement with the controller14through the user interface surface16. The interface coupler20configured to accept the proximal coupler40of the energy delivery catheter18is disposed adjacent a graphical representation60of an embodiment of the energy delivery catheter18which is printed on the user interface surface16. This provides a useful visual prompt for a user who is setting up the system10. Once the proximal coupler40is connected to the interface coupler20for the energy delivery catheter18, the electrode46is now in electrical communication with the RF energy generator12, subject to control and modulation by the controller14which may switch the RF generator12back and forth between an active state and a standby state, during which no RF can be delivered. In addition, the leads54of the thermocouple52are also in electrical communication with the controller14so that the controller14may monitor the temperature of the tissue adjacent the electrode46. In this arrangement, the RF energy generator12, controller14and user interface16form a system for controlled delivery of activation energy to the energy delivery catheter18.

The electrode46may be monopolar or bipolar, however, if the electrode46is a monopolar electrode, a return electrode component62may be used with the system10in order to complete an electrical energy emission or patient circuit between the RF energy generator12and a patient (not shown). The electrode return62includes the conductive pad24, a proximal coupler64and a conductive cable66extending between and in electrical communication with the conductive pad24and proximal coupler64. The conductive pad24may have a conductive adhesive surface configured to removably stick to the skin of a patient and with a large enough surface area such that no burning or other injury to the patient's skin will occur in the vicinity of the conductive pad24while the system10is in use. The proximal coupler64is configured to couple to the interface coupler28on the user interface surface16. The interface coupler28for the electrode return62is disposed adjacent a graphical representation68of the electrode return62on the user interface surface16. Once again, this provides a useful visual prompt for a user who is setting up the system10.

Once the proximal coupler40of the energy delivery catheter18and the proximal coupler64of the electrode return62have been coupled to the controller14via the respective interface couplers20and28of the user interface surface16, RF energy may be generated by the RF generator12, i.e., the RF generator12is switched to an activation state, and emitted from the electrode46of the distal basket44of the energy delivery catheter18into target tissue of the patient adjacent the electrode46. The processor22may then adjust the output of the RF generator12in order to maintain a substantially constant temperature of tissue adjacent the electrode via a feedback loop between the thermocouple52and the processor22. The processor22may use a control algorithm to process the temperature feedback and generate control signals for the RF generator12. In addition, the control algorithm may be configured to set predetermined dwell or activation times for embodiments of treatment cycles. Embodiments of control algorithms and system components that may be used in conjunction with control device and method embodiments discussed herein may be found in U.S. patent application Ser. No. 10/414,411, titled “Control System and Process for Application of Energy to Airway Walls and Other Mediums”, filed Apr. 14, 2003, which is incorporated by reference herein in its entirety.

Additionally, devices and methods for treating airway walls are described in U.S. patent application Ser. No. 09/095,323 titled METHOD AND APPARATUS FOR TREATING SMOOTH MUSCLES IN THE WALLS OF BODY CONDUITS filed Jun. 10, 1998; Ser. No. 10/414,253 titled MODIFICATION OF AIRWAYS BY APPLICATION OF ENERGY filed Apr. 14, 2003; Ser. No. 09/436,455 titled DEVICES FOR MODIFICATION OF AIRWAYS BY TRANSFER OF ENERGY filed Nov. 8, 1999; Ser. No. 09/999,851 titled METHOD FOR TREATING AN ASTHMA ATTACK filed Oct. 25, 2001; Ser. No. 10/810,276 titled METHOD OF TREATING AIRWAYS IN THE LUNG filed Mar. 26, 2004; Ser. No. 10/640,967 titled METHODS OF TREATING ASTHMA filed Aug. 13, 2003; Ser. No. 10/809,991 titled METHODS OF TREATING REVERSIBLE OBSTRUCTIVE PULMONARY DISEASE filed Mar. 26, 2004; and Ser. No. 10/954,895 titled INACTIVATION OF SMOOTH MUSCLE TISSUE filed Sep. 30, 2004; and U.S. Pat. No. 6,411,852 titled CONTROL SYSTEM AND PROCESS FOR APPLICATION OF ENERGY TO AIRWAY WALLS AND OTHER MEDIUMS; and U.S. Pat. No. 6,634,363 titled DEVICES FOR MODIFICATION OF AIRWAYS BY TRANSFER OF ENERGY. Each of which of the above are incorporated by reference herein in their entirety

In one embodiment, the RF generator12generates RF energy at a frequency of about 400 kHz to about 500 kHz in with a wattage output sufficient to maintain a target tissue temperature of about 60 degrees C. to about 80 degrees C., specifically, about 60 degrees C. to about 70 degrees C. The duration of the activation state for an embodiment of a single treatment cycle may be about 5 seconds to about 15 seconds, specifically, about 8 seconds to about 12 seconds. Alternatively, the duration of the activation state of the RF generator may also be set to not more than the duration required to deliver about 150 Joules of energy to the target tissue, specifically, not more than the duration required to deliver about 125 Joules of RF energy to target tissue.

The initiation of the activation state of the RF generator12may be carried out by a variety of devices and methods, however, the embodiment ofFIG.1includes a user operated activation switch in the form the footswitch26. A conductive cable70is coupled to and disposed between the footswitch26and a proximal coupler72which is configured to be electrically coupled to the respective interface coupler30disposed on the user interface surface16. The interface coupler30for the proximal coupler72of the footswitch26is disposed adjacent a graphical representation74of the footswitch26on the user interface surface16. The footswitch26may be used in some configurations to initiate an activation state of the RF energy generator12if all components of the system10are functioning and connected properly. This can be defined as the controller entering into the ready mode.

Referring now toFIG.4, a more detailed view of an embodiment of the user interface surface16is shown. The user interface surface16may be a substantially rectangular and flat surface as shown inFIG.4, but may also have any other suitable shape, size or configuration. The user interface surface16may, in some embodiments, be any part of an energy delivery system, or component thereof, that a user may access or see in order to impart information or receive information therefrom. The controller14may have an alternating current (AC) power on/off switch that may be located anywhere on the controller14, or alternatively, on the user interface surface16. However, for the embodiment shown inFIG.4, the user interface surface16does not include an AC power on/off switch. The controller14or user interface surface16may include an audio tone generator (not shown) which may be used in conjunction with the various visual indicators of the system10to alert a user to the status of the various components of the system10. In one embodiment, the audio tone generator includes a speaker (not shown) which may be mounted on any suitable surface of the controller12or the user interface surface16.

The user interface surface16has a visual indicator in the form of a multi-colored LED (light emitting diode) ready indicator light76in the upper left hand corner of the user interface surface16. The ready indicator light76may be activated or lit with a first color, such as a green color, when the RF energy generator12is ready for use in a standby state. The LED indicator76, may be activated and lit with a second color, such as an amber color, when the RF energy generator12is switched on into an activation state at which time a brief audio tone may also sound upon the transition of the RF generator12from the standby or ready state to the activation state with RF energy being delivered to the energy emission element46of the energy delivery catheter18. Additionally, a separate LED indicator92may be activated and lit with a second color, such as a blue color, during RF energy delivery. Typically, a user activates the RF energy generator12for a treatment cycle by depressing and releasing the footswitch26. The color of the ready indicator light76may be switched back to the first color if, during an activation cycle, the footswitch26of the system10is depressed and released again so as to produce a footswitch shutoff response from the processor22which switches the RF energy generator12from the activation state to the standby state. The second color or amber color may also be displayed by the ready indicator light76when the system10is engaged in a power on self-test (POST) mode during which time the audio tone generator may be delivering a constant single pitch tone. In addition, the second amber color may also be displayed by the ready indicator when a fault with the energy delivery catheter18, such as a broken electrode46or broken thermocouple52, is detected by the controller14. The activation of the second color indicating a fault with the energy delivery catheter18may also be accompanied by an audible first error tone from the audio tone generator. The ready indicator light76may flash the first color, green, when the system10is conducting a cycling of the AC power to the controller14in order to reset the system10during which time the audible first error tone may also be produced. In essence, the ready indicator light76emits a first color when the system10is ready to use and a second color or amber color if the system10has detected a fault in the system10and is not ready to use.

Below the LED ready indicator76is the graphical representation74of the footswitch26which is printed on the user interface surface16. The graphical representation74of the footswitch26is directly above and adjacent to the interface coupler30which is configured to accept the proximal coupler72of the footswitch26assembly. The graphical representation74of the footswitch26adjacent the interface coupler30for the footswitch26provides an intuitive and user friendly prompt for the user to locate the plug in point for the footswitch26while setting up the system10.

To the right of the graphical representation74of the footswitch26is the graphical representation68of the electrode return assembly62which includes the conductive pad24, conductive cable66and proximal coupler64and which is printed on the user interface surface16. The graphical representation78of the proximal coupler64of the electrode return assembly62is disposed directly above and adjacent to the interface coupler28for the proximal coupler64of the electrode return assembly62. A visual indicator in the form of an amber colored LED light80is disposed within the graphical representation82of the conductive pad24of the electrode return assembly62and on the user interface surface16. The visual indicator80may be configured to be lighted in a steady state when the system10is proceeding through the POST which may also be accompanied by a single pitch audible tone from the audio tone generator. The visual indicator80may also be activated and lighted when the controller14measures an impedance in the patient circuit that is above a predetermined value after 3 or more attempts to activate the RF energy generator to the activation state. A second error tone may accompany the activation of the visual indicator in this circumstance. For some embodiments, the predetermined impedance value for the patient circuit may be above about 1000 Ohms, specifically, above about 900 Ohms. Such a high impedance measurement in the patient circuit indicates an open circuit and requires that the user check the patient circuit and try the system10another time. The patient circuit includes the electrode46and conductive cable38of the energy delivery catheter18, the patient (not shown) with the conductive pad24and electrode46in electrical communication with the patient's body, and the electrode return assembly62, The visual indicator80may also be activated or lighted in a flashing mode when a fault requiring the user to cycle AC power has been initiated by the processor22, during which time a first audible error tone may also be generated by the audio tone generator.

To the right of the graphical representation68of the electrode return62, the graphical representation60of the energy delivery catheter18is printed on the user interface surface16including the handle36, the elongate shaft34and the distal electrode basket44. The interface coupler20configured to accept the proximal coupler40of the energy delivery catheter18is disposed adjacent and directly below a graphical representation84of the handle36of the energy delivery catheter18. A first visual indicator in the form of an amber LED light86is disposed within the graphical representation88of the distal electrode basket44on the user interface surface16. A second visual indicator90, having a second color different from the first visual indicator, in the form of a red LED light90is disposed within the graphical representation84of the handle36.

The first visual indicator86may be activated and lighted for some embodiments of the system10when the controller14measures an impedance in the patient circuit that is above a predetermined value. For some embodiments, the predetermined impedance value for the patient circuit may be above about 1000 Ohms, specifically, above about 900 Ohms. A first audible error tone may also be generated during such an activation. The first visual indicator86may also be lighted or activated when the measured impedance of the patient circuit is above such a predetermined value during at least 3 or more attempts to activate the RF energy generator12to the activation state. In this circumstance, a second audible error tone may also be generated in conjunction with the activation of the first visual indicator86. The first visual indicator86may also be lighted in a steady state when the processor22of the system10is proceeding through the POST which may also be accompanied by a single pitch audible tone from the audio tone generator. The visual indicator86may also be activated or lighted in a flashing mode when a fault requiring the user to cycle AC power has been initiated by the processor22, during which time a first audible error tone may also be generated by the audio tone generator.

The second visual indicator90may be activated or lighted in a flashing or intermittent mode when a fault with the energy delivery catheter18, such as a broken electrode46or broken thermocouple52, is detected by the controller14. The activation of the second visual indicator90suggesting a fault with the energy delivery catheter18may also be accompanied by an audible first error tone from the audio tone generator. The second visual indicator90may also be lighted in a steady state when the processor22of the system10is proceeding through the POST which may also be accompanied by a single pitch audible tone from the audio tone generator. The second visual indicator90may also be activated or lighted in a flashing mode when a fault requiring the user to cycle AC power has been initiated by the processor22, during which time a first audible error tone may also be generated by the audio tone generator.

Another visual indicator92in the form of a graphical representation of a radiating electrode is disposed on the user interface surface16. This RF energy indicator92, which may be a third color or blue LED, is activated or lighted in a flashing mode during the time when the RF energy generator12is switched to the activation state and delivering RF energy to the energy delivery catheter18. The RF energy indicator92may also be lighted in a steady state when the processor22of the system10is proceeding through the POST which may also be accompanied by a single pitch audible tone from the audio tone generator. The RF energy indicator92may also be activated or lighted in a flashing mode when a fault requiring the user to cycle AC power has been initiated by the processor22, during which time a first audible error tone may also be generated by the audio tone generator.

A digital display94is disposed on the user interface surface16below the RF energy indicator92and is configured to display numerical information. The digital display94may be controlled or otherwise reset by a switch96disposed directly below the digital display94on the user interface surface16. In a normal mode, the digital display94will display the number of successful treatment cycles delivered by the system10performed by a user of the system10. If the switch96is depressed for less than about 2 seconds to about 4 seconds, the number of unsuccessful or incomplete treatment cycles is displayed for a brief period, such as about 5 seconds. After this brief period, the digital display94reverts back to a display of the number of completed treatment cycles. When the switch96is depressed and held for more than a brief period of about 2 seconds to about 4 seconds, the digital display94shows a “0” for a short period, such as about 1 second. If the switch96is held depressed during this short 1 second period, the count of the complete and incomplete treatment cycles is reset to 0. If the switch96is released during this short 1 second period, the digital display94reverts back to a display of the completed or successful treatment cycles without resetting the treatment cycle counter.

Referring toFIG.5, a variety of system process embodiments are shown in flow diagram form. In use, the system10for delivery of therapeutic energy is first supplied with power, such as AC power, which may be carried out by a switch (not shown) on the controller14or user interface surface16, as discussed above. Once AC power is supplied to the controller14, the processor22initiates the POST cycle, indicated by box100, which tests the integrity of the processor22, the controller14and the system10generally. If the POST fails, the user initiates a cycling of the AC power in order to reboot the controller14, and specifically, the processor22of the controller14. In addition, once AC power has been supplied to the controller14, the processor22continually runs a first background algorithm, indicated by the decision point “irrecoverable error”102. The irrecoverable error test checks for hardware and processor errors such as CPU configuration, COP timeout, ROM CRC error, RAM, illegal CPU instruction, software, non-volatile memory, RF current measurement errors. If such an error is detected, the user should initiate a cycling of the AC power, as indicated by box111, in order to reboot the controller14, and specifically, the processor22of the controller14. During the cycling of the AC power, the user will be informed of the cycling status by a flashing of all visual indicators on the user interface surface16as well as a flashing of the digital display94and the concurrent generation of an audible error tone.

If the POST is successful, the processor22will initiate a test algorithm that determines whether all connections of system components, such as the energy delivery catheter18, return electrode62and footswitch26are all properly coupled to the respective interface couplers20,28and30of the user interface surface16, as indicated by decision point104. If an error is detected during this routine, the ready indicator light76will remain in the second or amber color state, indicating that the RF energy generator12is not ready or in the standby state. Once the system components such as the energy delivery catheter18, electrode return62and footswitch26are properly coupled to the user interface16, the processor22will initiate an algorithm that determines whether the temperature detection element, or thermocouple52, of the energy delivery catheter18is properly functioning as indicated by box106.

During this test, the processor22measures the temperature indicated by the thermocouple52and compares the result to a predetermined temperature range, that encompasses room temperature for some embodiments. For example, the predetermined temperature range for some embodiments may be about 15 degrees C. to about 35 degrees C., specifically, about 20 degrees C. to about 30 degrees C. If the measured temperature indicated by the thermocouple52does not fall within the predetermined temperature range, the processor22indicates a broken thermocouple52by initiating an error message to the user which includes switching the ready indicator light76to the second or amber color in addition to initiating a flashing mode activation of the red LED second visual indicator90in the handle84of the graphical representation60of the energy delivery catheter18. An audible error tone may also accompany the error message generated by the visual indicators76and90. These error messages inform the user that it may be necessary to replace the energy delivery catheter18with a new one.

Once the thermocouple test has been successfully performed, the processor22will switch the ready indicator light76to the first color or green color indicating that the system10is now ready to perform a treatment cycle in a patient, as indicated by box108. At this point, the user may then position the distal electrode basket44of the energy delivery catheter18such that at least one emission element or electrode46is disposed adjacent target tissue of the patient, such as smooth muscle of the patients bronchial airways. Once the electrode46is properly positioned, the user depresses the footswitch26to initiate a treatment cycle, as indicated by user action/input box110. Upon depression of the footswitch26, the processor22immediately measures the impedance of the patient circuit, and if the impedance is below a predetermined maximum or within a predetermined impedance range, the processor22switches the RF energy generator12from the ready or standby state to the activation state wherein RF energy is being delivered to the target tissue of the patient for the initiation of a treatment cycle.

For some embodiments of a normal treatment cycle, as indicated by result box112, the processor22and algorithms run by the processor22are configured to maintain the RF energy generator12in the activation state for a dwell time of about 5 seconds to about 15 seconds, specifically, about 8 seconds to about 12 seconds. The duration of the treatment cycle may also be constrained by the total energy delivered to the target tissue during the cycle. For example, the processor22may execute an algorithm which terminates the treatment cycle when the total energy delivered to the target tissue is up to about 150 Joules, specifically, up to about 125 Joules. During the treatment cycle, the processor22controls the output of the RF energy generator12in order to maintain a substantially constant temperature of the target tissue. The temperature of the target tissue during a treatment cycle embodiment may be maintained at a temperature of about 60 degrees C. to about 80 degrees C., specifically, from about 60 degrees C. to about 70 degrees C. As discussed above, the processor22is able to maintain the substantially constant temperature of the target tissue by monitoring the temperature of the target tissue via the temperature measuring element or thermocouple52and processing the temperature information in a feedback loop with lowers the RF energy generator12output if the measured temperature is higher than desired and increasing the RF energy generator output if the measured temperature is lower than desired.

During the treatment cycle, the processor22will switch the blue RF energy visual indicator92to an activated solid or flashing mode and will activate the audio signal generator to generate a dual pitch audible tone from the audible tone generator that repeats a high pitch then low pitch audible tone during the treatment cycle, followed by a long single pitch tone at the end of a successful cycle. If an error occurs in the middle of a treatment cycle, an audible error tone will be generated and the visual indicator or indicators indicative of the error will be activated as discussed above. As discussed above, a treatment cycle may also be interrupted by the users depression of the footswitch26during the treatment cycle to initiate a footswitch shutoff, as indicated by user action box114. This may be done if the user feels that the system10is operating improperly for any reason, the user feels that the location of the electrode46is wrong, or for any other reason. A footswitch shutoff action by the user returns the system10to the RF generator ready state, indicated by box108, but does not log a completed or successful treatment cycle on the digital display94. If the treatment cycle is successfully completed, the digital display94will display a count of “1”, indicating one successfully completed treatment cycle.

If an error occurs during the treatment cycle, as indicated by result box116, or the footswitch shutoff option is used, a “0” will remain displayed. However, if the display control switch96is depressed for more than about 2 seconds to about 4 seconds, the digital display94will show a “1”, indicating one incomplete or unsuccessful treatment cycle. The user may continue to deploy the energy delivery catheter18to new locations within the patient's anatomy and activate the RF energy generator12to the activation state for any desired number of treatment cycles. If an error occurs during a treatment cycle, as indicated by result box116, the user interface16will then display via the appropriate visual indicators and audible tone indicators, the type of error that has occurred and will recommend a course of action for the user. After correction has been attempted by the user, the footswitch26may again be depressed, as indicated by user action/input box118, in order to initiate another treatment cycle.

If the impedance of the patient circuit is greater than a predetermined maximum or not within a predetermined impedance range upon depression of the footswitch26, as indicated by result box120, one of two error messages including visual indicators and audible tones may be generated by the system10. Specifically, if a high impedance is measured upon a first depression of the footswitch26or a second depression of the footswitch26, as indicated by box122, the error message “improve deployment and continue” will be generated, as discussed above, whereby the amber visual indicator86of the distal basket graphic88on the user interface16will be activated and lighted and a first error tone will be generated by the audible tone generator. In addition, an incomplete treatment cycle will be logged by the digital display94. Once attempted correction has been made, the footswitch26may again be depressed as indicated by user action/input box124, in which case the treatment cycle is reinitiated.

If on the third or subsequent depression of the footswitch26the same error is detected by the system10, the “check patient circuit” error message will be generated, as discussed above, whereby the amber visual indicator80of the return electrode graphic82and the amber visual indicator86of the electrode basket graphic88on the user interface surface16will be activated and lighted. Such an error message may also be accompanied by a second audible error tone generated by the audible tone generator. In addition, an incomplete treatment cycle will be logged by the digital display94. After attempted correction of the error, the footswitch26may again be depressed, as indicated by user action/input box126, in order to initiate another treatment cycle.

With regard to the above detailed description, like reference numerals used therein refer to like elements that may have the same or similar dimensions, materials and configurations. While particular forms of embodiments have been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the embodiments of the invention. Accordingly, it is not intended that the invention be limited by the forgoing detailed description.