Patent Description:
Electrocardiac signals acquired during a cardiac procedure, such as Electro-Physiological (EP) sensing procedure, are routed from electrodes at the heart of a patient to a system console, where the signals are recorded, analyzed, and displayed. The signals may be routed via a switching system which includes a digital-to-analog converter (DAC), which accepts acquired or "raw" digital signals from the electrodes and converts them into analog signals. The switching system may also perform other functions such as filtering and amplification. This manipulation overcomes the legacy problem that the console is only designed to accept a limited number of acquired signals.

<CIT> (<NUM>-<NUM>-<NUM>) and <CIT> (<NUM>-<NUM>-<NUM>) disclose switching systems for use in cardiac procedures.

The present disclosed subject matter will be more fully understood from the following detailed description of the examples thereof, taken together with the drawings, where corresponding or like reference numbers or characters indicate corresponding or like elements, in which:.

The present disclosed subject matter provides switching systems and methods for handling the high (and constantly growing) numbers of signals that are acquired over short time periods, e.g., simultaneously, and passed from electrodes at the heart of the patient to the console, while allowing pacing to proceed as normal.

The disclosed subject matter provides a switching system which includes a switch unit, which performs operations such as digital to analog signal conversion (by a digital to analog converted (DAC)) and other signal processing operations. The switching system is positioned along a bidirectional signal carrying line, also known as a bidirectional line. The bidirectional line extending between a catheter at the heart, the catheter including, for example, an electrode, and a console. The bidirectional line includes a main line, extending through the switch unit and a bypass line, around the switch unit, the main line and bypass lines enabled and disabled by switches, with the switches at the junctions of the main line and the bypass line. Pacing signals generated in the console cannot pass through the DAC and/or other signal processors of the switch unit, and accordingly, have to travel over the bypass line, which must be enabled by the switches changing states. The enabled bypass line provides an uninterrupted electrical connection from the console to the catheter, allowing for safe operation of the pacing signals.

<FIG> is a pictorial illustration of a system <NUM> for performing EP sensing, pacing and ablation procedures on a heart <NUM> of a living subject (e.g., patient <NUM>). The system <NUM> comprises a catheter <NUM>, which is percutaneously inserted by an operator <NUM> through the patient's <NUM> vascular system into a chamber or vascular structure of the heart <NUM>. An operator <NUM>, who is typically a physician, brings the catheter's distal tip <NUM> into contact with the heart wall.

Electrical activation maps may then be prepared, e.g., according to the methods disclosed in <CIT>, and <CIT>, and in commonly assigned <CIT>. One commercial product embodying elements of the system <NUM> is available as the CARTO®<NUM> System, available from Biosense Webster, Inc. , <NUM> Diamond Canyon Road, Diamond Bar, Calif.

Areas determined to be abnormal, for example, by evaluation of the electrical activation maps, can be ablated, e.g., by passage of radiofrequency electrical current through wires in the catheter to one or more electrodes at the distal tip <NUM>.

The catheter <NUM> typically comprises a handle <NUM>, having suitable controls on the handle to enable the operator <NUM> to steer, position and orient the distal end of the catheter as desired for the ablation. To aid the operator <NUM>, the distal portion of the catheter <NUM> contains position sensors (not shown) that provide signals to a positioning processor <NUM>, located in a console <NUM>.

Ablation energy and electrical signals can be conveyed to and from the heart <NUM> through an ablation electrode <NUM> located at or near the distal tip <NUM> via cable <NUM> to the console <NUM>. Sensing electrodes <NUM>, also connected to the console <NUM>, are disposed generally in the distal portion of the catheter <NUM>, and have connections to the cable <NUM>.

Electrocardiac signals, acquired, for example, from the sensing electrodes <NUM>, pass from the electrode <NUM> through the cable <NUM>, and are digitized by suitable Analog-to-Digital Converters (ADCs), for example of a patient interface unit (PIU) (not shown), this PIU in communication with the electrodes <NUM> and is positioned along the cable <NUM>, for example, proximate to the electrodes <NUM>. The resulting digital signals are referred to herein as "acquired electrocardiac signals", "acquired signals", or "raw signals" - these terms used interchangeably herein. The digital signals are provided to the switching system <NUM>, to the switch unit <NUM>, and then to the console <NUM>. While in the switch unit <NUM>, the acquired digital signals are typically subjected to processing, including modification, such as digital to analog conversion, filtering, amplification and other processes.

In addition, pacing signals and various other signals may be conveyed from the console <NUM> through the cable <NUM> (and the catheter <NUM>) and the electrodes <NUM>, <NUM> to the heart <NUM>, through the switching system <NUM>. Many configurations of the electrodes <NUM>, <NUM> are possible. For example, the ablation electrode <NUM> may be disposed at the distal tip <NUM>. The console <NUM> typically contains one or more ablation power generators <NUM> for generating the ablation signals.

The positioning processor <NUM> is an element of a positioning system <NUM> of the system <NUM> that measures location and orientation coordinates of the catheter <NUM>. In one example, the positioning system <NUM> comprises a magnetic position tracking arrangement that determines the position and orientation of the catheter <NUM> by generating magnetic fields in a predefined working volume its vicinity and sensing these fields at the catheter <NUM> using field generating coils <NUM>, and may include impedance measurement, as taught, for example, in <CIT>. The positioning system <NUM> may be enhanced by position measurements using the impedance measurements described in the above-noted <CIT>. In such position tracking arrangements, wire connections <NUM> link the console <NUM> with body surface electrodes <NUM>.

As noted above, the catheter <NUM> is coupled to the console <NUM>, which enables the operator <NUM> to observe and regulate the functions of the catheter <NUM>. Console <NUM> includes a processor 24x (<FIG>), which can be a computer with appropriate signal processing circuits. The processor 24x is coupled to drive a monitor <NUM>. The signal processing circuits in the console <NUM> typically receive, amplify, filter and digitize the received acquired or raw analog signals, processed by and transmitted from the switch unit <NUM>. The analog signals output by switch unit <NUM> are received and used by the console <NUM> and the positioning system <NUM> to compute the position and orientation of the catheter <NUM> and to analyze the electrical signals from the electrodes <NUM>, <NUM>.

At times during the procedure, such as abnormality in the procedure or stoppage of the heartbeat, as detected automatically by the system <NUM>, or manually by the physician <NUM>, the physician <NUM> may have to initiate the generation of pacing signals. The pacing signals are transmitted from the console <NUM> to the heart <NUM> over the same bidirectional line <NUM>, represented by the cable <NUM>, as the acquired signals. The pacing signals are triggered by the physician <NUM> on demand, for example, (by the physician <NUM> activating a pacing signal generator 24y (<FIG>) in the console <NUM>. This activation may, for example, include the physician <NUM> pressing a button or other similar structure (not shown), for example, on the console <NUM> (or on a device in communications with the console <NUM>), which communicates with the pacing signal generator 24y, to activate the pacing signals.

<FIG> shows the switching system <NUM> (represented by the broken line box), in accordance with an example of the present disclosure. The switching system <NUM> includes the switch unit <NUM>, which is positioned along a bidirectional signal carrying line <NUM>, also known as a bidirectional line. The bidirectional line <NUM>, is, for example, a single physical line, extending from an electrode <NUM> (in communication with the heart <NUM> of the patient <NUM>) to the console <NUM>, also known as an external console. The electrode <NUM> is representative of the multiple electrodes including those detailed above (e.g., electrodes <NUM>, <NUM>), and the console <NUM>. The bidirectional line <NUM> includes the main line <NUM>, which extends through the switch unit <NUM>, and the bypass line <NUM>.

The console <NUM> includes a processor 24x, also known as an operations processor, for receiving and analyzing received signals from the bidirectional line <NUM>, including the main line <NUM>. The console <NUM>, for example, also includes a pacing signal generator 24y, which is typically in communication with the processor 24x, and which may be manually triggered by the physician <NUM>. The generated pacing signals are transmitted to the bidirectional line <NUM> to the electrode <NUM>, via the bypass line <NUM>, as detailed below.

Switches 206a, 206b are, for example, positioned at the junctions of the main line <NUM> and the bypass line <NUM>, beyond the switch unit <NUM>, along the bidirectional line <NUM>. The switches 206a, 206b are configured to operate by changing their states to the same state together, in unison, and at the same time, for example, contemporaneously or simultaneously.

The switches 206a, 206b switch between states which, include, for example, a first state, where the main line <NUM> is enabled, activated/active, open or connected (these terms used interchangeably herein), and the bypass line <NUM> is disabled, deactivated or disconnected (these terms used interchangeably herein), and, a second state, where the bypass line <NUM> is enabled, activated/active, open, or connected (these terms used interchangeably herein), and the main line <NUM> is disabled, deactivated or disconnected (these terms used interchangeably herein). For example, the first state may be the default state for the switches 206a, 206b.

When the switches 206a, 206b are in the first state, the main line <NUM> is enabled, and the acquired signals travel from the electrode <NUM> to the console <NUM>, via the switch unit <NUM>. The acquired signals are typically processed in the switch unit, as detailed herein. While the main line <NUM> is enabled, the bypass line <NUM> is disabled or otherwise disconnected. Conversely, when the switches 206a, 206b are in the second state, the bypass line <NUM> is enabled or otherwise connected, and carries the pacing signals to the electrode <NUM> directly from the console <NUM>, thus bypassing the switch unit <NUM>. The main line <NUM> is disabled or otherwise disconnected, such that acquired or raw signals are cut off from traveling over the bidirectional line <NUM>.

The switches 206a, 206b may be either mechanical switches, or solid-state switches. Mechanical switches switch by physically moving or "toggling" between positions corresponding to the first and second states, respectively. Solid-state switches switch by electronically changing settings or resetting, the settings corresponding to the respective first and second states.

The switch unit <NUM> includes a processor <NUM>, also known as a switch unit processor, associated storage media <NUM>, a digital to analog converter (DAC) <NUM> and a sensor <NUM>, both of which communicate with a processor <NUM>. The processor <NUM> communicates with the switches 206a, 206b over wired links. The switch unit <NUM> may include other components, such as filters and/or amplifiers for filtering and/or amplifying the signals after digital-to-analog conversion, in addition to the components described herein, depending on the signal processing that the switch unit <NUM> is to perform.

The processor <NUM> includes one or more processors and may be a microcontroller or a central processing unit (CPU). The processor <NUM> is programmed to control the state of the switches 206a, 206b, switching the switches 206a, 206b when appropriate, in response to signals received from the sensor <NUM>.

The storage/memory <NUM> (which in some examples is an internal memory of processor <NUM>) stores machine executable instructions for execution by the processor <NUM>. The storage/memory <NUM> also includes storage media for temporary storage of data. The storage/memory <NUM> also includes machine executable instructions associated with the operation of the DAC <NUM> and the sensor <NUM>.

The DAC <NUM> converts digital signals, such as the acquired or raw signals, received over the main line <NUM> of the bidirectional line <NUM>, from the electrode <NUM>, into analog signals. The now-converted analog signals are transmitted to the console <NUM>, over the main line <NUM> of the bidirectional line <NUM>.

The sensor <NUM> includes a detector, which, for example, detects analog pacing signals. The detector is positioned along the main line <NUM>, typically intermediate the console <NUM> and the switch unit <NUM>, and for example, intermediate the console <NUM> and the switch 206b. The sensor <NUM> and detector are collectively referred to hereinafter as the "sensor", and represented by element number <NUM>.

For example, the sensor <NUM> operates by continuously monitoring the main line <NUM> of the bidirectional line <NUM> for pacing signals, and instantaneously reporting any detected pacing signals to the processor <NUM>. The detection of the pacing signals, as reported to and obtained by the processor <NUM>, allows the processor <NUM> to take action by signaling the switches 206a, 206b to change (switch) their states, from the first state to the second state, to enable the bypass line <NUM>, or alternately, maintain the switches 206a, 206b at the second state, to keep the bypass line <NUM> enabled, should the switches 206a, 206b already be at the second state.

For example, once a pacing signal is detected in the switching system <NUM> by the switching unit <NUM>, the switching system <NUM> disconnects or otherwise disables the main line <NUM> over which the acquired or raw signals travel from the heart <NUM> to the console <NUM>, through the switch unit <NUM>. The disconnecting is immediate, e.g., instantaneously, and is immediately, e.g., instantaneously followed by the switching unit <NUM>, enabling or otherwise connecting (opening) a bypass line <NUM>, over which the pacing signals travel. The pacing signals travel directly over the bypass line <NUM>, from the console <NUM> to the electrodes at the heart <NUM>. As a result of the now-enabled bypass line <NUM>, the pacing signals bypass and thus avoid the switch unit <NUM>, and signals travel over the bypass line <NUM> directly to catheter <NUM>, bypassing switching unit <NUM> entirely.

Attention is now directed to <FIG>, <FIG> and <FIG>, which illustrate example operations for the switching system <NUM>.

<FIG> illustrates operation of the switching system <NUM>, where acquired signals <NUM> are traveling from the electrode <NUM> to the console <NUM>, through the switch unit <NUM>, over the main line <NUM> of the bidirectional line <NUM>. The switches 206a, 206b are in the first state, such that the main line <NUM> of the bidirectional line <NUM> is enabled and open, to allow the aforementioned signal <NUM> flow. As the acquired signals are, for example, digital signals (as obtained from the electrode <NUM> by an analog to digital converter of the PIU (not shown) associated and in communication with the electrode <NUM> along the bidirectional line <NUM> portion proximate to the electrode <NUM>), these digital signals are processed in switch unit <NUM>, by at least being converted to analog signals, by the DAC converter <NUM>.

In <FIG>, pacing signal generation and transmission has been started or initiated by the physician <NUM> (for example, pressing a button on the console <NUM> or on a device in communications with the console <NUM> to activate the pacing signal generator 24y). The pacing signals <NUM> are generated by a generator 24y in the console <NUM> and transmitted by a transmitter (not shown) in the console <NUM>, over the bidirectional line <NUM>. The pacing signals <NUM> are, for example, analog signals, which once triggered at the console <NUM>, are to immediately reach the patient <NUM> via the electrode <NUM> (traveling over an uninterrupted electrical connection in the bidirectional line <NUM>). In this figure, the pacing signals <NUM> are detected by the sensor <NUM>. The sensor <NUM> signals the processor <NUM> that pacing signals <NUM> have been detected in the bidirectional line <NUM>. The processor <NUM> responds to these received signals, by signaling the switches 206a, 206b, to switch from the first state, to the second state, enabling or opening the bypass line <NUM> of the bidirectional line <NUM>.

As shown in <FIG>, with the bypass line <NUM> enabled, the pacing signals <NUM> travel directly from the console <NUM> to reach the electrode <NUM>, bypassing the switch unit <NUM>. The switching to the bypass line <NUM> has caused the switches 206a, 206b to switch, resulting in the disabling or otherwise disconnecting of the main line <NUM> of the bidirectional line <NUM>, such that acquired signals are cut off from flowing through the main line <NUM> of the bidirectional line <NUM>.

As the pacing signals <NUM> continue to be generated by the console <NUM>, and are detected by the and the sensor <NUM>, the sensor <NUM> continues to signal the processor <NUM> of the presence of the pacing signals <NUM>. In response, the switches 206a, 206b are maintained in the second state, where the bypass line <NUM> remains enabled and open, allowing the pacing signals to travel directly from the console <NUM> to the electrode <NUM>.

Once the pacing signals <NUM> are no longer detected by the sensor <NUM>, for example, for a predetermined amount of time, the sensor <NUM> signals this condition to the processor <NUM>. The processor <NUM> responds by signaling the switches 206a, 206b to switch from the second state to the first state, where the main line <NUM> is again enabled, and the bypass line <NUM> is disabled or disconnected, as shown, for example, in <FIG>.

<FIG> is a flow diagram of an example process performed by the switching system <NUM>. The example process allows for the immediate transmission of pacing signals, upon being manually triggered or activated by the physician <NUM>. The pacing signals are generated at a console <NUM> and transmitted to an electrode <NUM> at the catheter <NUM> at the patient's heart <NUM>. Once the pacing signals are no longer being transmitted, the switching system <NUM> reverts to its previous state, prior to the pacing signals having been detected. In this process, reference is made to the switching system <NUM> elements, as described above. The process is, for example, performed automatically and in real time, and may include manual subprocesses. The process may be performed for as long as desired.

The process begins at a START block <NUM>, where the switches 206a, 206b, are in the first state, which is also the default state here, as shown, for example, in <FIG>. Here, the digital to analog converter of the PIU (not shown) associated with the electrode <NUM> is transmitting acquired signals (obtained by the electrode <NUM>) to the console <NUM>, via the switch unit <NUM>, over the enabled main line <NUM> of the bidirectional line <NUM>. The acquired signals, upon reaching the switch unit <NUM> are processed, for example, by being converted to analog signals, by the DAC <NUM>. During the transmission of the acquired signals, the bypass line <NUM> is disabled and disconnected.

The process moves to block <NUM>, where the sensor <NUM> monitors the bidirectional line <NUM>, proximate to the console <NUM> for pacing signals, transmitted from the console <NUM>. The monitoring is, for example, continuous.

The process moves to block <NUM>, where the sensor <NUM> determines whether pacing signals are detected. If no, the sensor <NUM>, for example, does not signal the processor <NUM>, and the switch 206a, 206b state is maintained in the first or default state. The process returns to block <NUM>, from where it resumes.

However, at block <NUM>, should the sensor <NUM> detect pacing signals in the bidirectional line <NUM>, which are, for example, traveling from the console <NUM> toward the switch unit <NUM>, as shown, for example, in <FIG>, the sensor <NUM> signals this information to the processor <NUM>. The processor <NUM> signals the switches 206a, 206b to instantaneously change (switch) states, from the first state, to the second state, at block <NUM>, and as shown, for example, in <FIG>. With the switches 206a, 206b now in the second state, the bypass line <NUM> is immediately enabled or open, and pacing signals are transmitted directly from the console <NUM> to the electrode <NUM>, avoiding the switch unit <NUM>.

The process moves to block <NUM>, where it is determined, by the sensor <NUM>, whether pacing signals are being transmitted (and generated) from the console <NUM>. If yes, the process returns to block <NUM>, from where it resumes. The switch 206a, 206b state at the second state is maintained.

If no at block <NUM>, pacing signals are not being detected, and the process moves to block <NUM>. At block <NUM>, the processor <NUM> determines whether pacing signals have not been detected for a predetermined time period. For example, the processor <NUM> may not have received any signals from the sensor <NUM> indicating the detection of pacing signals. If no at block <NUM>, the time period has not expired, and the process moves to block <NUM>, from where the process resumes.

At block <NUM>, should the time period have expired, the process moves to block <NUM>, where the processor <NUM> signals the switches 206a, 206b to change (switch) from the second state to the first state, which is, for example, the default state. This switching returns the switching system <NUM> to its previous or default state, as the pacing signals are no longer being transmitted, and the main line <NUM> is again enabled, for carrying the acquired signals, from the electrode <NUM> to the console <NUM>, via the switch unit <NUM>, shown, for example, in <FIG>.

From block <NUM>, the process moves to block <NUM>, where it ends. The process may be repeated as desired.

The aforementioned disclosed subject matter may, for example, also be in the form of a computer software product. The product comprises, for example, a tangible non-transitory computer-readable medium in which program instructions are stored, which instructions, when read by a processor <NUM>, cause the processor <NUM> to signal switches 206a, 206b to switch to the same state together, in order to enable and open a bypass line <NUM> in a bidirectional line <NUM>, such that pacing signals may be transmitted directly from the console <NUM> to the electrode, rapidly and efficiently, upon being triggered or otherwise activated manually by the physician <NUM>. The bypassing of the switch unit <NUM> avoids any processing delays in the switch unit <NUM>. During the time the bypass line <NUM> is enabled or open, the main line <NUM>, over which acquired signals travel from the electrode <NUM> to the console <NUM>, is disabled and disconnected.

Claim 1:
A switching system (<NUM>) for use in a cardiac procedure on a subject (<NUM>) comprising:
a bidirectional line (<NUM>) configured for extending from an electrode (<NUM>) at the heart (<NUM>) of the subject (<NUM>) to an external console (<NUM>);
a switch unit (<NUM>) for communicating with the bidirectional line (<NUM>), the switch unit (<NUM>) comprising a digital to analog signal converter, DAC, (<NUM>) in communication with the main line (<NUM>) of the bidirectional line (<NUM>), the bidirectional line (<NUM>) comprising:
a main line (<NUM>), extending through the DAC of the switch unit (<NUM>), for carrying signals comprising acquired signals from the electrode (<NUM>) to the external console (<NUM>); and
a bypass line (<NUM>), extending outside of the switch unit (<NUM>) for carrying signals comprising pacing signals from the external console (<NUM>) to the electrode (<NUM>); and
a first switch (206a) and a second switch (206b) each in communication with the switch unit (<NUM>), each of the first switch (206a) and the second switch (206b) in communication with and switching between the main line (<NUM>) and the bypass line (<NUM>), the first switch (206a) and the second switch (206b) changeable between: <NUM>) a first state, where the main line (<NUM>) is enabled for carrying the acquired signals, and the bypass line (<NUM>) is disabled, and, <NUM>) a second state, where the bypass line (<NUM>) is enabled for carrying the pacing signals and the main line (<NUM>) is disabled.