Patent Description:
Invasive techniques for mapping electrophysiological properties of cardiac tissue cardiac may find use, mutatis mutandis, in electromechanical switching concepts that were generally proposed. An example of an electromechanical switch is brought in <CIT> that describes a linear slide selector switch for multiple channels for selecting between several switch positions. Specifically, there is a housing having a hinged door with a latch lock, the door rotates to a closed position and is held in a closed position by the latch lock. The housing also contains a slide and a printed circuit board. The printed circuit board has rows of contacts. A contactor is mounted to the slide. As the slide is moved linearly, electrical connections are made and broken on the printed circuit board.

As another example, <CIT> describes an implantable electrode arrangement which includes an electrode line with a plurality of electrically conductive surface regions in the region of the distal end of the electrode line for outputting electrical signals to a heart and/or for receiving signals from a heart. The electrode arrangement can be electrically connected by way of the electrode line to a cardio-electric device such as a defibrillator or cardiac pacemaker, which device receives electrical signals and/or outputs pulses. The electrode arrangement may include switching means, optionally being mechanical switching elements, which are of such an arrangement and configuration that the connection between individual ones of the electrically conducting surface regions and the cardio-electric device can be permanently switched on or off in the region of the electrode line. <CIT> provides methods and devices for optimization of biventricular pacing in subjects suffering from heart failure. The invention provides for a method for selection of optimal parameters for permanent pacing, the method comprising: positioning one or more arrays of lead wires in the posterior pericardium of a subject, wherein the arrays are connected to a multiplexing switch, wherein the switch is connected to a computer processor and a biventricular pacemaker, from the computer processor, generating a randomized sequence of: (i) pacing sites (VPS), (ii) right ventricular-left ventricular delays (RLDs), (iii) heart rates (HR); (iv) atrioventricular delays (AVDs), (v) or any combination or permutation thereof; and determining cardiac output in real time, using aortic flow velocity, thereby allowing selection of optimal parameters for permanent pacing.

The invention provides pacing systems according to claims <NUM> and <NUM>, and methods of manufacture according to claims <NUM> and <NUM>.

In some embodiments, the electromechanical switch includes (a) a substrate patterned with multiple contacts arranged in an array, and each contact in the array is coupled to a respective output of the plurality of outputs, (b) a moving switch, which is configured to move over the array of contacts and to establish electrical contact with one contact only at any given time, and (c) a motor, which is configured to move the moving switch.

In some embodiments, the electromechanical switch further includes a screw that is configured to be rotated by the motor, and the moving switch of the electromechanical switch is coupled to the screw and is configured to move in a linear trajectory over a linear array of the contacts when the screw is rotated by the motor.

In some embodiments, the array of the contacts is arranged in a circular configuration, and the moving switch of the electromechanical switch is configured to move in a circular trajectory over the array of the contacts.

In an embodiment, the substrate of the electromechanical switch is made of a printed circuit board (PCB). In another embodiment, the motor of the electromechanical switch includes a stepper motor.

In an embodiment, the system further includes a processor, which is configured to apply a control loop that adaptively controls the motor to fine-tune a position of the moving switch, to optimize the electrical contact between the wheel and the contact. In another embodiment, the processor is configured to control the motor based on an electrocardiogram (ECG) sensed via the electrode associated with the contact.

In some embodiments, the moving switch includes a wheel that is configured to roll over the array of contacts. In an embodiment, the wheel is made of metal. In another embodiment, the wheel is made of an electrically conductive polymer. In yet another embodiment, the wheel is made of polymer and is disposed with electrically conducting strips.

In some embodiments, the electromechanical switch includes (a) a substrate disposed with multiple reed switches arranged in an array, wherein each reed switch in the array is coupled to a respective output of the plurality of outputs, (b) a moving switch comprising a magnet, which is configured to move over the array of reed switches and to cause only one reed switch to establish electrical contact at any given time, and (c) a motor, which is configured to move the moving switch.

In some embodiments, the pacing system further includes a processor, which is configured to command the pacing generator to generate the pacing signal and command the electromechanical switch to route the pacing signal according to a prespecified pacing protocol.

In some embodiments, the pacing signal is unipolar. In other embodiments, the pacing signal is bipolar, and the pacing system includes an additional electromechanical switch to form a double electromechanical switch together with the electromechanical switch. The dual electromechanical switch is configured to route the bipolar pacing signal to no more than a selected pair of the outputs at any given time, so as to pace the heart bipolarly using no more than a selected pair of the electrodes.

In an embodiment, the dual electromechanical switch includes (a) a substrate patterned with multiple contacts arranged in a first array, each contact in the first array is coupled to a respective output of the plurality of outputs, and multiple contacts arranged in a second array, and wherein each contact in the second array is coupled to a respective output of the plurality of outputs, (b) a first moving switch, which is configured to move over the first array of contacts and to establish electrical contact with one contact only of the first array at any given time, (c) a second moving switch, which is configured to move over the second array of contacts and to separately establish electrical contact with one contact only of the second array at any given time, and (d) one or more motors, which are configured to move the first moving switch and the second moving switch independently of each other.

In an embodiment, the first array of contacts and the second array of contacts of the dual electromechanical switch are spatially separated in space. In another embodiment, the first array and the second array of contacts are concentric circular arrays. In an embodiment, the first array and the second array of contacts are vertically overlaid over one another.

In some embodiments, the dual electromechanical switch includes (a) a substrate patterned with multiple reed switches arranged in a first array, wherein each reed switch in the first array is coupled to a respective output of the plurality of outputs, and multiple reed switches arranged in a second array, and wherein each reed switch in the second array is coupled to a respective output of the plurality of outputs, (b) a first moving switch comprising a magnet, which is configured to move over the first array of reed switches and to cause only one reed switch of the first array to establish electrical contact at any given time, (c) a second moving switch comprising a magnet, which is configured to move over the second array of reed switches and to separately cause only one reed switch of the second array to establish electrical contact at any given time, and (d) one or more motors, which are configured to move the first moving switch and the second moving switch independently of each other.

There is additionally provided, in accordance with an unclaimed embodiment of the present invention, a method for pacing a heart, the method including generating a pacing signal. Using an electromechanical switch having a plurality of outputs that are coupled to a plurality of electrodes inserted into the heart for, each output configured to deliver the pacing signal to a respective electrode, the pacing signal is routed to no more than a single selected one of the outputs at any given time, so as to pace the heart using no more than a single selected one of the electrodes.

There is further provided, in accordance with an embodiment of the present invention, a manufacturing method for manufacturing a pacing system, including patterning a substrate with multiple contacts arranged in an array. A moving switch is provided, which is configured to move over the array and to establish electrical contact with one contact only at any given time. One or more motors are provided, which are configured to move the moving switch.

There is additionally provided, in accordance with an embodiment of the present invention, a manufacturing method, including patterning a substrate with multiple contacts arranged in a first array, and multiple contacts arranged in a second array. A first moving switch is provided, which is configured to move over the first array and to establish electrical contact with one contact only of the first array at any given time. A second moving switch is provided, which is configured to move over the second array and to separately establish electrical contact with one contact only of the second array at any given time. One or more motors are coupled, which are configured to move the first moving switch and the second moving switch independently of each other.

In delivering signals to the heart using a catheter, such as during cardiac pacing session of an electrophysiological (EP) mapping procedure, it is medically critical to avoid incorrect delivery. Thus, delivery systems for a catheter with multiple electrodes, such as those on a diagnostic EP catheter, must avoid using semiconductor electrical devices in the delivery signal path, since semiconductors may not have sufficient electrical isolation between adjacent channels, as well as the possibility of electrical breakdown in the semiconductor of a particular channel.

Embodiments of the present invention that are described hereinafter provide pacing systems and pacing methods that are patient safe, for use with catheters having multiple electrodes.

In some embodiments, a pacing system is provided, that uses body surface patches as return electrodes in a unipolar pacing layout. The pacing system comprises (a) a signal generator configured to generate a pacing signal, and (b) an electromechanical switch having a plurality of outputs coupled to a plurality of electrodes inserted into a heart of a patient, each output configured to deliver the pacing signal to a respective electrode, wherein the electromechanical switch is configured to route the pacing signal to no more than a single selected one of the outputs at any given time, so as to pace the heart using no more than a single selected one of the electrodes. The disclosed electromechanical switch prevents any possibility of interelectrode leakage. Even if the system breaks down (e.g., the motor fails) there is no possibility of inter-channel leakage or of delivery of current to the wrong channel.

In an embodiment, the electromechanical switch comprises (i) a substrate patterned with multiple contacts arranged in an array, where each contact in the array is coupled to a respective output of the plurality of outputs, (ii) a moving switch, which is configured to move over the array of contacts and to establish electrical contact with one contact only at any given time, and (iii) a motor, which is configured to move the moving switch.

In the context of the disclosed inventions, a moving switch may: roll over the contacts by a wheel rolling over the contacts, or slide over the contacts by having a slidable contacting element. Both the wheel and the slidable contacting element are electrically conductive. In some embodiment, the wheel is made of metal, in other embodiments the wheel is made of a polymer that includes conductive element. A conductive element may cause the bulk of the wheel to conduct electricity or be a pattern of conducting material disposed on the surface of the polymer wheel. Examples of polymers that can be used include various types of rubbers.

In some embodiments, a non-contact moving electromechanical switching is implemented, as described below, by using an array of reed switches (i.e., an array of electrical switches operated by an applied magnetic field). A reed switch is described in <CIT>).

In some embodiments the pacing system is configured to pace with a bipolar signal, and comprises an additional electromechanical switch which moves independently of the first switch. The resulting dual electromechanical switch is configured to route the bipolar pacing signal to no more than a first and second single selected two of the outputs at any given time, so as to pace the heart bipolarly using no more than single selected first and second electrode of the electrodes. Typically, the dual electromechanical switch is realized on a same substrate as, for example, a double linear, concentric or side by side circular layouts, as described below.

In some embodiments, the dual electromechanical switch comprises (a) a substrate patterned with multiple contacts arranged in a first array, wherein each contact in the first array is coupled to a respective output of the plurality of outputs, and multiple contacts arranged in a second array, and wherein each contact in the second array is coupled to a respective output of the plurality of outputs, (b) a first moving switch, which is configured to move over the first array of contacts and to establish electrical contact with one contact only of the first array at any given time, (c) a second moving switch, which is configured to move over the second array of contacts and to separately establish electrical with one contact only of the second array at any given time, and (d) one or more motors which are configured to move the first moving switch and the second moving switch independently of each other. The two arrays are spatially separated in space, e.g., laterally and/or vertically.

In some embodiments, the disclosed electromechanical switch may switch a pacing signal from the signal generator between, for example, more than hundred receiving electrodes of a catheter. A delivery system, such as a cardiac EP mapping system using the disclosed electromechanical relaying, can be either in an "off" or "on" state, and it does not pose the problem of incorrect delivery of unipolar or bipolar signals if the electromechanical switch breaks down, as described below.

In an embodiment, moving switches of the dual electromechanical switch are each constrained to move in a linear trajectory by being coupled to a lead screw that is rotated by a processor-controlled motor, such as a stepper motor. In another embodiment, the moving switches of the electromechanical switch are each constrained to move in a circular trajectory by being rotated by a stepper motor, as described below. According to the type of motion (linear or circular), arrays of electrode contacts are formed on a line or a circle.

In some embodiments, the contact arrays are formed on a substrate, such as a printed circuit board (PCB), and the stepper motor is rotated until a moving contact of a moving switch aligns with the selected contact. The sizes of the moving contacts and array contacts are selected such that, regardless of the moving switch position, only one contact in each array can be connected at any given time.

In some embodiments, electrodes from two or more catheters may be connected to a single dual electromechanical switch, for example, for pacing with unipolar signals with one catheter and sensing resulting EP signals with the other catheter.

The disclosed pacing systems may comprise a processor, which is configured to command the pacing generator to generate the pacing signals and command the electromechanical switch routing the pacing signal according to a prespecified pacing protocol.

The disclosed electromechanical switching techniques thus provides a patient safe and flexible solution to enable either unipolar or bipolar pacing using catheters comprising multiple electrodes.

<FIG> is a schematic, pictorial illustration of an electrophysiological (EP) mapping system <NUM> comprising a concentric circular electromechanical switch <NUM>, in accordance with an embodiment of the present invention. Electromechanical switch <NUM> is described in <FIG>. As shown, a physician <NUM> uses an EP mapping catheter <NUM> to pace a heart <NUM> of a patient <NUM>. Catheter <NUM> comprises, at its distal end, as seen in inset <NUM>, multiple arms <NUM>, which may be mechanically flexible, to each of which are coupled multiple electrodes <NUM>.

During the pacing procedure, electrodes <NUM> inject to, and acquire signals from, the tissue of heart <NUM>. A processor <NUM> receives the acquired signals via an electrical interface <NUM>, and uses information contained in these signals to construct an EP map <NUM> of at least part of wall tissue of heart <NUM> of patient <NUM>. During and/or following the procedure, processor <NUM> may display EP map <NUM> on a display <NUM>.

In some embodiments, system <NUM> variably paces heart <NUM> by a processor <NUM> instructing a circular electromechanical switch <NUM> to route (i.e., switch) bipolar signals, which a pacing signal generator <NUM> generates. The bipolar signals are outputted to a plurality of electrodes <NUM> by a plurality of outputs <NUM> of electromechanical switch <NUM> that electrodes <NUM> are coupled to. Electromechanical switch <NUM> switches the outputted signals between multiple different pairs of electrodes <NUM>. System <NUM> may measure resulting electrical activity of a heart <NUM> using some or all of electrodes <NUM>.

In some embodiments, to pace heart <NUM> in a bipolar manner via sequential selection of numerous electrode-pairs <NUM>, processor <NUM> may apply a predefined automatic stimulation-routing protocol. Using the protocol, processor <NUM> commands concentric electromechanical switch <NUM> to route (i.e., to switch) between different electrode-pairs <NUM> according to a certain predetermined sequence. An example of a procedure that may benefit from automatic stimulation-routing is pulmonary vein isolation validation.

During pacing, the respective locations of electrodes <NUM> are tracked. The tracking may be performed, for example, using a Carto3® system produced by Biosense-Webster (Irvine, California). Such a system measures impedances between electrodes <NUM> and a plurality of external conducting patches <NUM> that are coupled to the body of patient <NUM>; for example, three external conducting patches <NUM> may be coupled to the patient's chest, and another three external electrodes may be coupled to the patient's back. For ease of illustration, only the chest electrodes are shown. The disclosed pacing system may use conducting patches <NUM> as return electrodes in a unipolar pacing layout.

The example illustration shown in <FIG> is chosen purely for the sake of conceptual clarity. Other sensing geometry types, such as that in the Lasso® Catheter (produced by Biosense Webster Inc. ) may also be employed.

Processor <NUM> uses software stored in a memory <NUM> to operate system <NUM>. The software may be downloaded to processor <NUM> in electronic form, over a network, for example, or it may, alternatively or additionally, be provided and/or stored on non-transitory tangible media, such as magnetic, optical, or electronic memory. In particular, processor <NUM> runs a dedicated algorithm that enables processor <NUM> to perform the functions described above.

<FIG> are schematic, top view illustrations of a dual linear electromechanical switch <NUM>, of concentric circular electromechanical switch <NUM> of <FIG>, and of a side-by-side circular electromechanical switch <NUM> layout, respectively, in accordance with embodiments of the present invention. The disclosed electromechanical dual switches are configured to route bipolar pacing signals.

As seen in <FIG>, dual linear electromechanical switch <NUM> comprises two linear contact arrays 50a and 50b that are aligned in parallel to each other. First linear array 50a comprises contacts <NUM> and, second linear array 50b comprises contacts <NUM>. The electrodes are disposed on a substrate made of a printed circuit board (PCB) <NUM>.

Moving switches <NUM> and <NUM> are each constrained to move in a linear trajectory between contacts <NUM> and between contacts <NUM> by being coupled to lead screws <NUM> and <NUM>, respectively. Each of screws <NUM> and <NUM> is independently rotated by stepper motors 55a and 55b, respectively. First moving switch <NUM> comprises a moving contact 56a, and second moving switch <NUM> comprises a moving contact 58a, where moving contacts 56a and 58a independently move on contact arrays 50a and 50b, respectively. Only a single contact at each of arrays 50a and 50b can be connected to a moving contact at any given time, which ensures electrical isolation between adjacent channels of system <NUM> used for pacing heart <NUM>.

Moving contacts 56a and 58a are connected to a pacing signal source included on system <NUM> (connections and source not shown). The bipolar signals are outputted to a plurality of electrodes <NUM> (seen in <FIG>) by a plurality of outputs 38a of electromechanical switch <NUM> that electrodes <NUM> are coupled to. Electromechanical switch <NUM> outputs the pacing signal to the selected electrodes in catheter <NUM> via leads 56b and 58b of switch <NUM>, respectively.

As seen in <FIG>, concentric circular electromechanical switch <NUM> comprises a first, outer, circular array 40a of contacts <NUM> and a second, inner, circular array 40b of contacts <NUM>, disposed on a substrate made of a printed circuit board (PCB) <NUM>. The two circular arrays are concentrically aligned.

Moving switches <NUM> and <NUM> are each constrained to move in a circular trajectory between electrode contacts, by being coupled to circular rails <NUM> and <NUM>, respectively. Each of moving switches <NUM> and <NUM> are coupled to a stepper motor (an exemplary coupling mechanism and a stepper motor are shown in <FIG>) that rotates each moving switch over its respective circular rail. First moving switch <NUM> comprises a moving contact 46a, and second moving switch <NUM> comprises a moving contact 48a, that can respectively and independently move on contact arrays 40a and 40b. Only a single contact at each array can be connected to a moving contact at any given time, to ensure electrical isolation between adjacent channels of system <NUM> used for pacing heart <NUM>.

Moving contacts 46a and 48a are connected to a pacing signal source included on system <NUM> (connections and source not shown). The bipolar signals are outputted to a plurality of electrodes <NUM> (seen in <FIG>) by a plurality of outputs <NUM> of electromechanical switch <NUM> that electrodes <NUM> are coupled to. Electromechanical switch <NUM> outputs the pacing signal to the selected electrodes in catheter <NUM> via leads 46b and 48b of switch <NUM>, respectively.

As seen in <FIG>, side-by-side circular electromechanical switch <NUM> comprises a first circular array 60a of contacts <NUM>, which is disposed side-by-side to a second circular array 60b of contacts <NUM>. Both arrays are disposed on a substrate made of a printed circuit board (PCB) <NUM>.

Moving switches 66a and 66b are each constrained to move in a circular trajectory between contacts <NUM> and between contacts <NUM> by being coupled to rails 67a and 67b, respectively, where rails 67a and 67b are similar to rail <NUM> of <FIG>. Each of moving switches 66a and 66b are coupled to stepper motors 65a and 65b, respectively, by a coupling mechanism comprising respective discs 69a and 69b, via respective shafts 63a and 63b, where each shaft rotates each disc so as to rotate each moving switch over its respective circular rail.

A first moving switch 66a comprising a moving contact 660a, and a second moving switch 66b comprising a moving contact 660b, can respectively move on contact arrays 60a and 60b. Only a single contact at each array can be connected to a moving contact at any given time, to ensure electrical isolation between adjacent channels of system <NUM> used for pacing heart <NUM>.

Moving contacts 660a and 660b are connected to a pacing signal source included on system <NUM> (electrical connections and signal source not shown). The bipolar signals are outputted to a plurality of electrodes <NUM> (seen in <FIG>) by a plurality of outputs 38c of electromechanical switch <NUM> that electrodes <NUM> are coupled to. Electromechanical switch <NUM> outputs the pacing signal to the selected electrodes in catheter <NUM> via leads 68a and 68b of switch <NUM>.

The top view illustrations shown in <FIG> are brought by way of example, and are simplified for the sake of conceptual clarity. For example, motion mechanisms are sketched with minimal detail.

<FIG> is a schematic, side view illustration of a wheeled moving switch of the electromechanical switches of <FIG>, in accordance with an embodiment of the present invention. As seen, a moving switch <NUM> comprises a moving contact 458a that is rolled, using an electrically conducting wheel <NUM>, over an array of contacts <NUM>. Moving switch <NUM> is moved by a screw <NUM> that is rotated by a motor (such as by stepper motors 55a and 55b of <FIG>).

In some embodiments, wheel <NUM> is made metal. In other embodiments wheel <NUM> is made of an electrically conducting polymer, such as an electrically conducting rubber. Using rubber may extend the lifetime of the mechanical switch, by preventing erosion of the pads, such as due to metal to metal friction and metal to metal scratching. Using rubber may also improve the mechanical contact between wheel <NUM> and each of contacts <NUM>, e.g., by accommodating changing topography of the contacts.

In some embodiments, the polymer wheel is disposed with conductive strips <NUM> to establish an electrical contact separately with each of contacts <NUM>, as wheel <NUM> is rolling. For that, conductive strips <NUM> (e.g., gold strips) cover portion of circumference of the wheel. The wheel itself serves as a mechanical absorber and eliminate the high friction with the PCB pads, and accommodates for vertical miss alignments between moving switch <NUM> and the PCB for better mechanical contact. Strips <NUM> are drawn in <FIG> as sectors of a circle yet could have other suitable patterns.

In some embodiments, in order to establish firm electrical contact between wheel <NUM> and a contact <NUM>, processor <NUM> applies a control loop that adaptively controls the motor to fine-tune a position of moving switch <NUM> (e.g., by the wheel moving forwards\backwards). Processor <NUM> is configured to control the motor based on an electrocardiogram (ECG) sensed via the electrode associated with the contact. For example, when the system senses, via the respective electrode, an ECG of acceptable quality according to a prespecified criterion (e.g., of large enough signal), processor <NUM> determines that a good electrical contact was achieved for switching between wheel <NUM> on contact <NUM>. Using ECG to control quality of contact may assist in cases where, for example, a dust particle on a contact degrades the electrical contact, since the area of contact is small (e.g., a tangent line of a circle).

<FIG> is a schematic, illustration of a reed switch layout of the electromechanical switches of <FIG>, in accordance with an embodiment of the present invention. As seen, there is a gap, i.e., no mechanical contact between a moving switch <NUM> and an array of reed switches <NUM>. Instead, wherever moving switch <NUM> is located over a reed switch <NUM>, a magnet <NUM>, such as a fixed magnet, inside moving switch <NUM> causes the normally open reed switch <NUM> to close and pass the pacing signal. Moving switch <NUM> is moved by a screw <NUM> that is rotated by a motor (such as by stepper motors 55a and 55b of <FIG>).

As seen in the inset, a reed switch typically has two "sticks" in normally open mode and with the magnet these "sticks" can be connected. Using reed switches may extends the life of the disclosed pacing switch by eliminating issues of mechanical ware (e.g., destruction of PCB pads due to friction with a movable switch).

In some embodiments, magnet <NUM> is an electromagnet, that is kept off when moved over reed switches not intended to make contact. The electromagnet is thus operated only when it is positioned above a target reed switch, to close the circuit at the intended channel. More options are possible to avoid activation of wrong reed switches: for example, magnet <NUM> may be held flipped horizontally while moving over the array and be flipped vertically only over the target reed switch. Other means, such as disconnecting the reed switch using logic are also possible.

The illustration in <FIG> is brought by way of example. Other embodiments are possible using the reed switches, for example, by using an electromagnet instead of a fixed magnet to switch the reed switches.

Claim 1:
A pacing system (<NUM>), comprising:
a signal generator (<NUM>) configured to generate a pacing signal; and
an electromechanical switch (<NUM>) having a plurality of outputs that are configured to be coupled to a plurality of electrodes (<NUM>) inserted into a heart (<NUM>) of a patient, each output configured to deliver the pacing signal to a respective electrode, wherein the electromechanical switch (<NUM>) is configured to route the pacing signal to no more than a single selected one of the outputs at any given time, so as to pace the heart using no more than a single selected one of the electrodes,
wherein the electromechanical switch comprises:
a substrate patterned with multiple contacts (50a, 40a, 60a, <NUM>) arranged in an array, wherein each contact in the array is coupled to a respective output of the plurality of outputs,
a moving switch (<NUM>, <NUM>, <NUM>, <NUM>), which is configured to move over the array of contacts and to establish electrical contact with one contact only at any given time, and
a motor (<NUM>) configured to move the moving switch.