A medical device, assembly and system

Abstract

An apparatus (1, 50, 54) for subcutaneous implantation is disclosed. The apparatus (1, 50, 54) comprises a port (40) for receiving a percutaneous connector (55), the port (40) comprising an electrical contact (43) for providing electrical communication between the port (40) and the connector (55). Also disclosed is a percutaneous connector (55) for engaging a subcutaneously implanted port (40), an implantable control unit (1) for a medical device (60), a cardiac pump assembly (70) and an extracorporeal charging device (80).

Description

[0001] A MEDICAL DEVICE, ASSEMBLY AND SYSTEM

[0002] Technical Field

[0003] The present disclosure relates to a medical device, assembly and system, and is particularly, although not exclusively, concerned with an implantable control unit for a cardiac pump.

[0004] Background

[0005] Advanced heart failure is a major global health problem resulting in many thousands of deaths each year and those with the disease endure a very poor quality of life. The treatment options for advanced heart failure, for example drug therapy and cardiac resynchronization (pacemakers), have generally proved unsuccessful and the only option remaining for the patients is heart transplantation. Unfortunately, the number of donor hearts available only meets a fraction of the demand, leaving many people untreated.

[0006] In general terms, it is known to provide a cardiac pump, such as a Ventricular Assist Device (VAD), that is suitable for implantation into a ventricle of a human heart. The most common type of these implantable pumps is a miniaturised rotary pump, owing to their small size and mechanical simplicity and reliability. Such known devices have two primary components: a cardiac pump housing, which defines a cardiac pump inlet and a cardiac pump outlet; and a cardiac pump rotor, which is housed within the cardiac pump housing, and which is configured to pump fluid. VADs may be connected, via a percutaneous driveline, to an extracorporeal control unit for powering and controlling the VAD.

[0007] VADs have been gaining increased acceptance as a bridge to or an alternative therapy to heart transplantation. The use of VADs has shown that, in most cases, once the device has been implanted, the disease progression is slowed, the symptoms of heart failure are somewhat relieved, and the patient regains some mobility and a better quality of life.

[0008] Statements of Invention

[0009] The present inventors have determined that one of the continuing complications plaguing

[0010] VADs today is infection of the percutaneous driveline at a rate more than 18% that leads to pain, discomfort and poor quality of life. Infection can also contribute to hypercoagulability and even strokes. It may therefore be desirable to mitigate this risk.

[0011] Further, the present inventors have determined that an extracorporeal control unit may be cumbersome and inconvenient for the patient. It may therefore be desirable to provide a control unit which is less cumbersome and inconvenient for the patient.

[0012] According to an aspect of the present disclosure, there is provided an apparatus. The apparatus may be an apparatus for establishing a percutaneous or transdermal electrical current. The apparatus may be for subcutaneous implantation. The apparatus may comprise: a port for receiving a percutaneous connector. The port may comprise an electrical contact for providing electrical communication between the port and the connector. The present aspect may form part of and / or be used in conjunction with any other aspect.

[0013] According to an aspect of the present disclosure, there is provided an apparatus for subcutaneous implantation, the apparatus comprising: a port for receiving a percutaneous connector, the port comprising an electrical contact for providing electrical communication between the port and the connector. The present aspect may form part of and / or be used in conjunction with any other aspect.

[0014] The apparatus may comprise a charging port. The apparatus may comprise a control unit, of which the port may be a bail-out port (e.g., for emergencies).

[0015] The apparatus may be subcutaneously implantable, e.g., configured to be implanted subcutaneously. For example, the apparatus may be configured such that it is providable between a patient’s ribs and skin. The apparatus may comprise a skin-facing surface (e.g., a surface configured to face the skin once implanted). The port may be provided in the skin-facing surface.

[0016] The port may comprise a recess for receiving a protrusion of the connector. The recess may comprise an electrical contact (e.g., a plurality of electrical contacts, optionally five or eight).

[0017] The recess may comprise a septum for penetration by the connector. The septum may be configured to be penetrable, e.g., by a needle. The septum may be configured to maintain a fluid-tight seal within the recess, e.g., before and after penetration.

[0018] The recess may taper with depth. For example, the recess may comprise a mouth having greater dimensions than a deepest point. With depth from a mouth of the recess, the recess may comprise a first portion having tapered sides; a second portion having parallel sides; a third portion having tapered sides; and / or a fourth portion comprising parallel sides. The first to fourth portions may be provided immediately adjacent one another in consecutive order. The recess may comprise an abutment surface at its lowermost point, for arresting (e.g., abutting) a tip of a protrusion of the connector. The fourth or deepest portion may comprise an electrical contact, the electrical contact or a plurality of electrical contacts (e.g., eight electrical contacts).

[0019] The recess may be configured to receive a connector such that the connector engages the circumferential sides of the deepest portion.

[0020] The septum may be set back from a mouth of the recess (e.g., from the skin-facing surface of the apparatus). For example, the septum may be provided in the second portion having parallel sides. The septum may comprise a silicone plug. The septum may comprise a silicone plug with a backing of greater rigidity, e.g., such that the rigidity of the backing permits penetration of the silicone plug rather deflection. The backing may comprise an aperture for receiving a protrusion of a percutaneous connector, the aperture optionally centred therein.

[0021] The recess may comprise a locking mechanism for retaining a connector received by the recess. The locking mechanism may comprise a concave annulus or a convex annulus, e.g., provided about a circumference of the recess or concentrically with a longitudinal axis of the recess. The annulus (e.g., its central aperture) may be configured to engage the connector, e.g., such that a force required to remove the connector from the recess exceeds a force required to insert the connector. The rigid backing of the septum may comprise the annulus.

[0022] Additionally or alternatively, the locking mechanism may comprise a thread, e.g., a bayonet-type thread mechanism, optionally requiring less than a full rotation, such as a rotation of no more than 180 degrees (e.g., a half or a quarter turn), for engagement or locking in place.

[0023] The apparatus may comprise an RFID chip, e.g., proximate the recess. The RFID chip may be provided about the recess. The RFID chip may aid a user to locate the recess through the patient’s skin. The RFID chip may identify the apparatus.

[0024] The apparatus may comprise an implantable control unit for a medical device (e.g., for an active medical device, such as a cardiac pump). The control unit may comprise a controller, e.g., for controlling the medical device. The control unit may comprise a battery, e.g., for powering the medical device. The control unit may additionally comprise a charger coil for receiving energy transdermally (e.g., wirelessly through the skin). The apparatus may be provided as a standalone apparatus (e.g., with a driveline for communicating with a further implanted device). The apparatus may not be provided as part of a larger apparatus, such as a control unit. The apparatus may comprise an implantable charging port for transmitting energy received percutaneously to a further implanted device via an implanted driveline. For example, the apparatus may consist essentially of the port and a driveline for transmitting electrical communication with a further implanted device. The apparatus may not comprise a further means for receiving energy.

[0025] According to an aspect of the present disclosure, there is provided an implantable medical device (e.g., an implantable control unit such as for a further implantable medical device, such as a cardiac pump). The medical device may comprise: a controller, e.g., for controlling the further medical device; and / or a battery, e.g., for powering the further medical device. The medical device may comprise a port for receiving a percutaneous connector. The port may comprise an electrical contact for providing electrical communication between the port and the connector. The present aspect may form part of and / or be used in conjunction with any other aspect.

[0026] According to an aspect of the present disclosure, there is provided an implantable control unit for a medical device (e.g., an implantable medical device, such as a cardiac pump), the control unit comprising (e.g., housing): a controller for controlling the medical device; a battery; and a port for receiving a percutaneous connector. The port may comprise an electrical contact for providing electrical communication between the port and the connector. The present aspect may form part of and / or be used in conjunction with any other aspect.

[0027] According to an aspect of the present disclosure, there is provided an implantable control unit for a medical device (e.g., an implantable medical device, such as a cardiac pump), the control unit comprising: a controller for controlling the medical device; a battery; and a means for wireless transdermal energy transfer (e.g., a coil for wireless transdermal energy transfer or a capacitor plate for wireless transdermal energy transfer). The present aspect may form part of and / or be used in conjunction with any other aspect. For example, an implantable control unit may comprise a means for wireless transdermal energy transfer in addition to a port for receiving a percutaneous connector.

[0028] The control unit may comprise an external housing, casing or can, which may contain the controller, the battery and the port and / or the coil. For example, the battery, the controller and the means for wireless transdermal energy transfer may be provided within or attached to the same housing and / or as part of the same apparatus package, e.g., a unitary housing assembly.

[0029] The control unit may comprise a first major surface, e.g., providable subcutaneously. The first major surface may be a skin-facing surface (e.g., a surface configured to be provided beneath the skin once implanted, such as within a few centimetres beneath the skin).

[0030] The control unit may comprise a receiver coil. The control unit may comprise a plurality of receiver coils. A coil may be provided on the skin-facing surface. The port and / or a coil may be provided on the skin-facing and / or first major surface.

[0031] The coils (e.g., a plurality of the coils and / or two of the coils) may be at least partially stacked; at least partially interlaced; and / or inclined relative to one another. The battery may be charged using a single coil, and a second coil may be used in case of a fault on the first coil. Alternatively, two (e.g., both) coils may be used to charge the battery, and if a fault occurs on one of the coils, the battery may be charged using the other coil.

[0032] The control unit may comprise a circumferential minor surface. A coil may be provided about the circumferential minor surface. A plurality of coils may be provided about the circumferential minor surface. One or more coils may be provided inclined to one another. For example, the coil on the circumferential surface may be provided inclined to the major surface. Coils on the circumferential minor surface may be inclined to one another and inclined to the major surface. One or more of the receiver coils may be 3D-printed. A port or the port may be provided in the circumferential minor surface.

[0033] The battery may comprise a plurality of cells, optionally arranged in series. The cells may be provided in containers each housing a subset of the cells. The containers may be selectively connectable to the circuit by mechanical (e.g., relay) or electronic switches. Accordingly, the cells may be arranged in subsets, and each subset of cells may be selectively (dis)connectable to / from the circuit.

[0034] The first major surface may comprise an RFID chip. The RFID chip may be located within the coil (e.g., centred relative to the coil). The RFID chip may be provided proximate the port, e.g., proximate the recess. The RFID chip may be provided about the recess, e.g., such that their centres coincide. The RFID chip may aid a user to locate the port through the patient’s skin.

[0035] The first major surface may comprise a permanent magnet, optionally a plurality of permanent magnets. The magnet or plurality of magnets may aid a patient or user to locate the coil and / or the port. The magnet or plurality of magnets may be configured to retain an extracorporeal charging device in position, e.g., during charging. The control unit may comprise an electromagnet, e.g., on the first major surface. The electromagnet may be activatable (e.g., configured to be activated) during charging of the battery. The electromagnet may be configured to retain an extracorporeal charging device in position, e.g., during charging. The control unit may comprise magnetic (e.g., ferromagnetic) material for attraction towards a magnetic or electromagnet provided as part of an extracorporeal charger device.

[0036] The control unit may comprise a second major surface opposite the first major surface. The second major surface may comprise an internally- or ribs-facing surface. The second major surface may comprise a plurality of tabs extending therefrom, e.g., for attaching the control unit to the ribs of a patient.

[0037] The implantable control unit may be distinct (e.g., separate from) the further medical device. For example, the further medical device may comprise an implantable cardiac pump which may not comprise the control unit. The cardiac pump may be implantable at least partially within the heart; the control unit may be implantable subcutaneously. The pump and control unit may communicate by means of a driveline or mutually interconnected drivelines.

[0038] The control unit may comprise a driveline (e.g., an integral driveline) for electrical communication with the cardiac pump. The driveline may comprise an interconnector at its distal end for engaging an interconnector of the cardiac pump and thereby providing electrical communication with the cardiac pump.

[0039] The control unit may comprise a substantially oblate spheroid geometry. The control unit may comprise a substantially bi-frusto-spheroidal shape, e.g., a substantially frusto- hemispherical shape. The first major surface and / or the second major surface may be substantially elliptical. The first and second major surfaces may be substantially parallel. The circumferential minor surface may comprise an arc of revolution between the first and second major surfaces.

[0040] The control unit may comprise one or more LEDs configured to emit light towards, e.g., through, the skin. The skin-facing surface of the control unit may comprise the one or more LEDs. The LEDs may indicate a successful connection of an extracorporeal charging device. The LEDs may indicate a location of a feature of the control unit. The LEDs may change colour depending on the connection status.

[0041] The control unit may be configured to communicate wirelessly with an extracorporeal computer, such as a smart watch, a smart phone or a tablet. For example the receiver coil, a part thereof, and / or a smaller secondary receiver coil may be used as an antenna for transdermal communication with an external device. In this manner, the control unit 1 may transmit data (e.g., live, near real-time and / or historical data) through the skin to an extracorporeal device or to the cloud. Further, the antenna may permit a user (e.g., a cardiologist) to adjust the settings or parameters of the controller without requiring invasive techniques.

[0042] The control unit may be configured to determine a parameter of the patient. The parameter may comprise: an activity level of the patient; a heart rate of the patient; an electrical activity of the patient’s heart; a temperature of the tissues surrounding the control unit; an impedance of the tissues surrounding the control unit; and / or a blood oxygen saturation level of the patient.

[0043] The control unit may comprise a sensor, optionally a plurality of sensors. A, the or each sensor may be provided inside or on an exterior of the control unit. A, the or each sensor may be configured to determine a parameter of the patient, such as a parameter from the list above. The control unit may have a sensor comprising an exposed region of the control unit housing; a sensor provided within the housing, optionally electrically isolated from the exposed region of the control unit housing; and / or a sensor provided on a feedthrough connector.

[0044] On an exterior, the control unit may comprise any combination of the following sensors; an electrical contact; an optical sensor and / or a temperature sensor. Within an interior, the control unit may comprise any combination of the following sensors: a temperature sensor; a current sensor; a voltage sensor; an accelerometer; and / or a magnetic field sensor (e.g., Hall sensor). The control unit may comprise any combination of internal and external sensors.

[0045] The control unit may be configured to determine a change in a heart rate and / or an electrical activity of the patient’s heart. In response to determining a change, the control unit may be configured to: transmit a signal to the medical device for causing the medical device to change an operating condition (e.g., a speed of a motor of a cardiac pump or VAD) and / or change a power provided to the associated medical device. For example, in response to determining an increased heart rate or electrical activity of the patient’s heart, the control unit may cause the cardiac pump to operate at a greater speed (e.g., by increasing the speed of the motor of the cardiac pump or VAD).

[0046] The control unit may be configured to determine whether a parameter of the patient is outside of a predetermined range. In response to determining that a parameter of the patient is outside of a predetermined range, the control unit may be configured to transmit a signal including metadata describing the parameter and the value of the parameter. The signal may be transmitted to an extracorporeal device (e.g., via a Bluetooth antenna).

[0047] According to an aspect of the present disclosure, there is provided a connector. The connector may be a percutaneous or transdermal connector. The connector may be configured to penetrate the skin (e.g., penetrate unbroken skin or a piercing-like opening provided within the skin). The connector may be configured to provide a connection (e.g., a wired and / or electrical connection) between an extracorporeal device and a subcutaneously implanted device. The connector may comprise: an electrical contact for providing electrical communication between the port and the connector. The present aspect may form part of and / or be used in conjunction with any other aspect.

[0048] According to an aspect of the present disclosure, there is provided a percutaneous connector for engaging a subcutaneously implanted port, the connector comprising: an electrical contact for providing electrical communication between the port and the connector. The present aspect may form part of and / or be used in conjunction with any other aspect.

[0049] The connector may be configured to penetrate the skin. The connector may comprise a protrusion for penetrating the skin. For example, the connector may be configured to penetrate unbroken skin. The protrusion may comprise a needle. Additionally or alternatively, the connector may be configured to penetrate a piercing-type opening in the skin. The protrusion may comprise a blunt tip.

[0050] The protrusion may comprise an electrical contact, e.g., a plurality of electrical contacts, optionally five or eight. The electrical contacts may comprise a material which is different from the predominant material of the material (e.g., gold electrical contacts provided on a medical grade steel protrusion).

[0051] According to an aspect of the present disclosure, there is provided an assembly comprising: the percutaneous connector; and the apparatus or the control unit. The present aspect may form part of and / or be used in conjunction with any other aspect.

[0052] The recess of the port may be configured to receive the protrusion such that upon engagement (e.g., full engagement): the electrical contacts align (e.g., an electrical contact of the port aligns with an electrical contact of the protrusion); and / or the connector is releasably locked within the recess. For example, a plurality of (e.g., all) electrical contacts of the port may align with a plurality of (e.g., all) electrical contacts of the connector. Full engagement may comprise the connector abutting a surface of the recess such that the connector may not be inserted any further. According to an aspect of the present disclosure, there is provided an implantable cardiac pump. The cardiac pump may comprise a VAD. The cardiac pump may comprise a driveline, e.g., an integral driveline. The present aspect may form part of and / or be used in conjunction with any other aspect.

[0053] According to an aspect of the present disclosure, there is provided a cardiac pump assembly (e.g., an implantable cardiac pump assembly) comprising: an implantable cardiac pump. The cardiac pump may have a driveline (e.g., an integral driveline). The driveline may have an interconnector at its distal end. The driveline may be fully implantable (e.g., configured to be fully implanted). The interconnector may be configured to be implanted, e.g., such that the interconnector may not extend percutaneously / extracorporeally. The present aspect may form part of and / or be used in conjunction with any other aspect.

[0054] According to an aspect of the present disclosure, there is provided a cardiac pump assembly comprising: an implantable cardiac pump having a driveline (e.g., an integral driveline) with an interconnector at its distal end. The driveline may be fully implantable (e.g., configured to be fully implanted). The present aspect may form part of and / or be used in conjunction with any other aspect. For example, the interconnector may be configured to be implanted, e.g., such that the interconnector may not extend percutaneously / extracorporeally.

[0055] The assembly may further comprise an implantable control unit. The control unit may comprise a driveline (e.g., an integral driveline) with an interconnector, e.g., at its distal end. The interconnector may be connectable to the interconnector of the implantable cardiac pump for providing electrical communication therebetween. The control unit may comprise a header or socket for receiving a driveline (e.g., a non-integral or external driveline).

[0056] The cardiac pump may comprise a plurality of interconnectors, e.g., on the same or different drivelines. The or each interconnector may be configured to interconnect with different onward cables, e.g., the driveline of an implantable control unit and / or the percutaneous driveline of an extracorporeal control unit. An interconnector of the plurality of interconnectors (e.g., all but one of the plurality of interconnectors) may be left disconnected and / or not mated with a corresponding interconnector after implantation.

[0057] The cardiac pump assembly may further comprise an implantable driveline extension. The driveline extension may be fully implantable, e.g., from end to end. The driveline extension may have an interconnector at either end configured to interconnect with the interconnector of the control unit and / or the interconnector of the cardiac pump. For example, both interconnectors of the driveline extension may be of male type. The driveline extension may have sufficient length to interconnect the interconnectors of the control unit and the cardiac pump.

[0058] According to an aspect of the present disclosure, there is provided an extracorporeal device for charging an implanted medical device. The extracorporeal device may comprise a transmitter coil (e.g., a plurality of transmitter coils) configured to transmit energy transdermally to a receiver coil provided subcutaneously. The extracorporeal device may comprise its own battery pack and / or may be connectable to the mains during charging of the implanted device. The extracorporeal charging device may comprise a garment. The garment may support the transmitter coil such that upon wearing of the garment, the transmitter coil is located proximate the implanted device (e.g., sufficiently proximate so that energy transfer is achieved). The extracorporeal device may comprise a percutaneous connector for engaging an implanted port. The extracorporeal charging device may comprise a magnetic view film for visualising any permanent or electromagnets of the control unit and thereby facilitate user alignment of the charging device with the implanted device. The extracorporeal charging device may comprise an electromagnet energisable during charging to attract the extracorporeal charging devie to an implanted control unit. The present aspect may form part of and / or be used in conjunction with any other aspect.

[0059] According to an aspect of the present disclosure, there is provided a system. The system may comprise an apparatus (e.g., control unit), a cardiac pump (e.g., cardiac pump assembly), a percutaneous connector, an extracorporeal charging device, and / or an extracorporeal control unit. The system may additionally comprise a percutaneous driveline, a bailout driveline, and / or an implantable driveline extension. The present aspect may form part of and / or be used in conjunction with any other aspect.

[0060] According to an aspect of the present disclosure, there is provided a method. The method may comprise inserting a percutaneous connector into a port. The present aspect may form part of and / or be used in conjunction with any other aspect. The method may comprise providing electrical communication with an implanted apparatus. The method may comprise charging an implanted apparatus.

[0061] According to an aspect of the present disclosure, there is provided a method. The present aspect may form part of and / or be used in conjunction with any other aspect. The method may comprise implanting a control unit for a medical device. The control unit may comprise: a controller for controlling the medical device; a battery; a charging coil for transdermal wireless energy transfer; and / or a port. The method may comprise implanting a cardiac pump. The method may comprise connecting the cardiac pump to the control unit (e.g., via drivelines and interconnectors). The method may comprise charging the control unit, e.g., by a wireless transdermal energy transfer and / or by a bail-out port.

[0062] The method may comprise performing a first operation implanting one of a cardiac pump and a control unit. The method may comprise performing a second operation implanting the other of the cardiac pump and the control unit. The method may comprise implanting no further associated medical devices.

[0063] According to an aspect of the present disclosure, there is provided a method. The present aspect may form part of and / or be used in conjunction with any other aspect. The method may comprise locating an interconnector at a distal end of a driveline of a cardiac pump. The method may comprise inserting an interconnector (e.g., of an extracorporeal control unit or a second implantable control unit) into an interconnector of a cardiac pump, e.g., a redundant or unoccupied interconnector of the cardiac pump. The method may comprise removing an interconnector of an implanted control unit from the interconnector of a cardiac pump, e.g., after inserting the other interconnector. The method may comprise interchanging a connector of a first power source by a connector of a second power source from a single interconnector of the cardiac pump.

[0064] According to an aspect of the present disclosure, there is provided a method. The present aspect may form part of and / or be used in conjunction with any other aspect. The method may comprise inserting a blunt protrusion of a percutaneous connector through a piercing hole in a patient’s skin and into a port implanted subcutaneously.

[0065] According to an aspect of the present disclosure, there is provided a method. The method may form part of and / or be used in conjunction with any other aspect. The method may comprise controlling a medical device using a control unit according to any other aspect.

[0066] The method may comprise determining a parameter of the patient, e.g., using the control unit of any other aspect. The method may comprise determining that the parameter of the patient is outside of a predetermined range. The method may comprise transmitting, to an extracorporeal device, a signal including the value of the parameter and metadata describing the parameter.

[0067] The method may comprise varying an operating condition (e.g., operating speed) of an implanted medical device (e.g., a ventricular assist device). The operating condition may be varied according to a parameter of the patient (e.g., a heart rate and / or an electrical activity of the patient’s heart) as determined by the control unit. According to an aspect, there is provided a control unit. The present aspect may form part of and / or be used in conjunction with any other aspect. For example, the present control unit may be provided as part of the control unit comprising a receiver coil, a battery, a controller, a port, internal sensors and external sensors.

[0068] The control unit may comprise a motor control arrangement, such as for controlling the motor of an associated medical device, such as an associated VAD. The controller of the control unit may comprise the motor control arrangement. The control unit may comprise a first motor drive configured to be electrically coupled to a first winding arrangement comprising a first plurality of windings. The control unit may comprise a second motor drive configured to be electrically coupled to a second winding arrangement comprising a second plurality of windings. The or each winding arrangement may form part of a stator of a motor of the medical device. The or each motor drive may be configured to: determine a positional parameter relating to an angular position of a rotor of the motor; and optionally provide a synchronisation signal (for use in the error state) corresponding to the determined positional parameter to the other motor drive.

[0069] The first motor drive may be configured to: apply a voltage to each winding of the first winding arrangement (e.g., based on the determined positional parameter and thereby drive the rotor); evaluate a fault criterion relating to whether the first winding arrangement, the first motor drive or an electrical coupling therebetween is in a fault condition; and / or in response to a determination that the fault criterion has been met: isolate a part of the first winding arrangement, the motor drive or the electrical coupling therebetween identified as being associated with the fault condition; and simultaneously apply a voltage to a subset of the windings of the first winding arrangement based on the synchronisation signal provided by the second motor drive.

[0070] The first motor drive may be configured to: in response to a determination that the fault criterion has been met: provide a fault and / or synchronisation signal to the other motor drive.

[0071] The first motor drive may be configured to evaluate the fault criterion based on: a monitored current passing through the motor drive or the first winding arrangement; and / or a monitored voltage within first motor drive or the first winding arrangement.

[0072] The control unit may comprise a motor drive configured to be electrically coupled to a winding arrangement comprising a plurality of windings, wherein: the plurality of windings are electrically coupled to each other at a centrepoint junction to form a wye configuration; the motor drive is configured to receive an input DC voltage from a power supply; and / or the motor drive is configured to supply an intermediate voltage to the centrepoint junction, the intermediate voltage being lower than the input DC voltage. The intermediate voltage may be substantially half (e.g., half) the input DC voltage.

[0073] According to an aspect, there is provided a method. The method may be a method of operating a motor drive, such as a motor drive of the motor control arrangement of the previous aspect. The method may comprise determining a positional parameter relating to an angular position of a rotor (e.g., of an associated medical device or VAD) relative to a stator, optionally as the rotor is driven. The method may comprise providing a synchronisation signal corresponding to a determined positional parameter to another motor drive via a synchronisation channel. The method may comprise applying a voltage (e.g., in a sequence) to the or each winding of a winding arrangement using one or more half-bridges, optionally so as to cause the rotor to be driven to rotate in accordance with at least one motor control reference parameter.

[0074] The method may comprise evaluating a fault criterion relating to whether a corresponding winding arrangement, a motor drive or an electrical coupling therebetween is in a fault condition. If it is determined that the fault criterion has not been met and thus that corresponding winding arrangement, the motor drive and the electrical coupling therebetween is not in the fault condition, the method may directly return to applying a voltage (e.g., in a sequence) to each winding of the winding arrangement so as to cause the rotor to be driven to rotate and continues thereafter.

[0075] If it is determined that the fault criterion has been met, the method may comprise identifying, a part of the first winding arrangement, the first motor drive or the electrical coupling therebetween as being associated with the fault condition. The method may comprise providing a fault signal on the fault channel.

[0076] The method may comprise isolating the part of the first winding arrangement, the first motor drive or the electrical coupling therebetween identified as being associated with the fault condition.

[0077] The method may comprise applying a voltage (e.g., in a sequence) to a subset of the windings of the winding arrangement based on a synchronisation signal received on the synchronisation channel from the other motor drive forming part of the motor control arrangement.

[0078] To avoid unnecessary duplication of effort and repetition of text in the specification, certain features are described in relation to only one or several aspects or embodiments of the invention. However, it is to be understood that, where it is technically possible, features described in relation to any aspect or embodiment of the invention may also be used with any other aspect or embodiment of the invention.

[0079] Brief Description of Drawings

[0080] For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

[0081] Fig. 1 is a perspective view of an implantable control unit of the present disclosure;

[0082] Fig. 2 is a front view of the control unit of Fig. 1 ;

[0083] Fig. 3 is a side view of the control unit of Fig. 1 ;

[0084] Fig. 4 is a cross-sectional view through the control unit of Fig. 1 showing a port;

[0085] Fig. 5A is a cross-sectional view through a port and a percutaneous connector of the present disclosure;

[0086] Fig. 5B is a cross-sectional view through a port and a protrusion of a percutaneous connector of the present disclosure;

[0087] Fig. 6 is a perspective view of a cardiac pump of the present disclosure;

[0088] Fig. 7 is an X-ray view of an implanted cardiac pump assembly of the present disclosure including the control unit of Fig. 1 and the cardiac pump of Fig. 6;

[0089] Fig. 8 is an X-ray view of an extracorporeal charging device of the present disclosure;

[0090] Fig. 9 is an exploded view of a VAD system of the present disclosure;

[0091] Fig. 10 is a schematic drawing of an implantable control unit comprising sensors;

[0092] Fig. 11 is a schematic diagram of a motor control arrangement of the present disclosure;

[0093] Fig. 12A is a diagram which shows an example motor drive and an example winding arrangement suitable for use with the motor control arrangement of Fig. 11 ;

[0094] Fig. 12B is a diagram which shows an example motor drive and an example winding arrangement suitable for use with the motor control arrangement of Fig. 11 ; and

[0095] Fig. 13 is a flowchart which shows an example method of operating a motor drive of the present disclosure. Detailed Description

[0096] With reference to Figs. 1 , 2 and 3, a control unit 1 according to the present disclosure is described. The control unit 1 is a control unit for powering and controlling an implantable active medical device to which it is connected, such as an implantable cardiac pump 60 (Fig. 6).

[0097] The control unit 1 comprises a substantially planar first major surface 2 and a substantially planar second major surface 3 (Fig. 3). A curved and continuous circumferential minor surface 4 extends between the first and second major surfaces 2, 3.

[0098] The second major surface 3 may oppose the first major surface 2 such that the first and second major surfaces 2, 3 are substantially parallel. The first and second major surfaces 2, 3 may each comprise an elliptical (e.g., circular) geometry. For example, the second major surface 3 may be provided along a plane of symmetry of a sphere, and the first major surface 2 may comprise a frustum of the sphere such that the circumferential minor surface 4 represents an arc of revolution provided therebetween.

[0099] The control unit 1 may thereby comprise a substantially frusto-hemispherical shape, such that the first major surface 3 may comprise smaller dimensions than the second major surface 4. Alternatively, as depicted in Fig. 3, the first and second major surfaces 2, 3 may represent sections through a sphere provided either side of a plane of symmetry of the sphere, such that the control unit 1 may comprise a substantially bi-frusto-spheroidal shape. The control unit 1 may comprise slightly square or angular sides or edges in order to permit the control unit 1 to be felt through the skin.

[0100] The shape of the control unit 1 may be selected so as to reduce its overall dimensions, minimise the number of sharp edges (particularly about the first major surface 2) and thereby improve its form factor for a patient. The shape may be the least traumatic for the patient with largest radii and most circular shape practicable for long term comfort and avoidance of implant erosion through the patient’s skin for instance.

[0101] The control unit 1 is configured to be subcutaneously implantable (e.g., fully implantable such that it does not extend extracorporeally), such as between a patient’s skin and ribs, proximate an armpit. For example, the control unit 1 may be implantable beneath the patient’s skin such that there may be some fat and / or muscle between the implant and the skin (e.g., to reduce the risk of erosion through the skin, and so the implant may not be implanted immediately beneath the skin). The first major surface 2 may be configured to face a patient’s skin (e.g., configured to be provided beneath the patient’s skin), such that the first major surface 2 may comprise a skin-facing surface. The second major surface 3 may be configured to face a patient’s ribs (e.g., for possible attachment thereto).

[0102] The second major surface 3 comprises a plurality of tabs 5 extending in a substantially coplanar manner therefrom such that the tabs 5 and the second major surface 3 may be contiguous. Each tab 5 comprises an aperture 5a for receiving a fastener. The tabs 5 are thereby configured to permit attachment of the control unit 1 to a patient’s ribs by means of the received fasteners. In the depicted embodiment, two tabs 5 are provided approximately 120 degrees apart. By providing tabs 5, the potential risk of migration of the control unit 1 after implantation may be reduced (e.g., avoided).

[0103] Tissue-incorporating pads (not shown) may be provided on the ribs-facing side of the tabs 5, on surface 2, and / or on surface 3. The tissue-incorporating pads may promote fixation of the control unit 1 to the patient’s tissue, e.g., by promoting growth and ingress of tissue into the pad. Additionally or alternatively, tissue-incorporating pads may be provided as part of the implant kit for the control unit 1. The tissue-incorporating pads may be felt, knitted or woven material for example and may be suitably marked using colour or optically reflective material that may identify the implant site of the control unit 1 if / when the implant is exchanged.

[0104] The control unit 1 comprises an external housing or can 8, housing a battery (not shown) for storing energy and powering an associated medical device (e.g., cardiac pump 60), a controller (not shown) for controlling the associated medical device, and a means for receiving energy from an extracorporeal charging device (e.g., device 80, Fig. 8). Accordingly, a unitary housing 8 may comprise a battery, a controller and a means for receiving energy, such that the control unit 1 may be the only device to which a cardiac pump 60 must be connected (e.g., a further external battery and / or charging unit may not be required to run the implantable pump for extended periods of time).

[0105] The means for receiving energy may comprise a receiver coil 9 for wirelessly receiving, through the patient’s skin (i.e. , transdermally), energy transmitted from a transmitter coil 82 of an associated charging device 80 (Fig. 8).

[0106] In one embodiment, the receiver coil 9 may be provided proximate the first major surface 2 of the control unit 1. For example, at least part of the first major surface 2 (e.g., an annulus thereof) may be formed by a magnetically permeable material housing the receiver coil 9. The receiver coil 9 may thereby be provided beneath the patient’s skin once the controller unit 1 is implanted. By providing a receiver coil 9 proximately or immediately beneath the patient’s skin, proximity to an extracorporeal transmitter charging coil 82 may be increased and the efficiency of wireless transdermal energy transfer may be improved.

[0107] Additionally or alternatively, as depicted in Fig. 1 , the control unit 1 may comprise a receiver coil 9 provided about the circumferential minor surface 4. For example, the receiver coil 9 may be wrapped around the circumferential minor surface 4, optionally inclined to the major surface 2. As the efficiency of energy transfer is improved when the alignment between transmitter and receiver coils is increased, inclining the receiver coil 9 to the first major surface 2 may increase the degree of alignment tolerance between the transmitter and receiver coils, improve efficiency of energy transfer, and / or reduce set-up difficulty for a patient.

[0108] Accordingly, the control unit 1 may comprise a plurality of receiver coils 9. A first receiver coil 9 may be provided proximate (e.g., provided within or on) the first major surface 2 and a second receiver coil 9 may be provided about / on the minor surface 4 inclined to the first major surface 2. A third receiver coil 9 may be provided about the minor surface 4 inclined to both the first major surface 2 and the second receiver coil 9.

[0109] Additionally or alternatively, a further receiver coil may be provided on the first major surface 2, either stacked beneath the first receiver coil 9 or interlaced with the first receiver coil 9.

[0110] The provision of multiple receiver coils 9 may provide redundancy in case a fault develops in a receiver coil 9. For example, the battery may be charged using a single coil, and a second coil may be used in case of a fault on the first coil. Alternatively, two (e.g., both) coils may be used to charge the battery, and if a fault occurs on one of the coils, the battery may be charged using the other coil. The control circuitry of the control unit 1 will be further described later.

[0111] In addition to or as an alternative to the one or more receiver coils 9, the means for receiving energy may comprise a port 40 (Fig. 4) for receiving a percutaneous connector 55 (Fig. 5A). In particular, the control unit 1 may comprise a port 40 for receiving the protrusion 56 of a percutaneous connector 55 so as to provide electrical communication between the port 40 and the percutaneous connector 55. In this way, a wired connection may be established between the control unit 1 and the associated extracorporeal charging device. The port 40 will be described in greater detail in relation to Figs. 4, 5 and 6.

[0112] In the embodiment shown in Fig. 1 , a port 40 is provided in the first major surface 2, specifically the centre thereof. Accordingly, once the control unit 1 is implanted in a patient, the port 40 will be provided beneath the patient’s skin such that the port 40 may be readily accessible through the patient’s skin, e.g., in case of emergencies. In an embodiment not shown, a port 40 may be provided in the circumferential minor surface 4 of the control unit 1 or elsewhere on surface 2. The port 40 may have tactile features, such as an indent, to enable and confirm port location by the patient or caregiver prior to use.

[0113] It will be evident from the foregoing that the control unit 1 may comprise a transdermal wireless energy transfer means (e.g., receiver coil 9) which is minimally invasive for a patient, and a wired energy transfer means (e.g., port 40) which may be used, e.g., during emergencies. The wired energy transfer means may be provided as a back-up in case the wireless means stops working or in case override of the controller is required. When provided as part of the control unit 1 , the port 40 may be termed a bail-out port in reference to its capacity for override of the internal battery and controller during an emergency. However, it will be understood that the port 40 when provided as part of the control unit 1 may be used for routine charging (e.g., in the absence of charging coils 9).

[0114] In order to improve the ease of locating the control unit 1 and / or particular features of the control unit 1 , the control unit 1 may comprise an RFID chip (not shown), such as in the first major surface 2. For example, the RFID chip may be provided about, and optionally centred on, the port 40 in order to permit a patient to readily determine the location of the port 40. Additionally or alternatively, the RFID chip may be centred relative to the receiver coil 9 to permit improved alignment between the transmitter coil of the extracorporeal device and the receiver coil(s) 9. In an embodiment not shown, the skin-facing surface 2 of the control unit 1 may comprise one or more LEDs configured to emit light towards (e.g., through) the skin in order to indicate a successful connection of an extracorporeal charging device 80.

[0115] Additionally or alternatively, the first major surface 2 may comprise at least one permanent magnet (not shown) for improving the ease of locating the control unit 1 and / or features thereof. The permanent magnet may be provided proximate the first major surface 2 such that a patient may readily locate the control unit 1 through the patient’s skin. Similarly, the extracorporeal charging device may comprise at least one permanent magnet (e.g. in addition to or instead of the at least one permanent magnet in the first major surface 2). The permanent magnet(s) may retain in situ the extracorporeal charging device.

[0116] Similarly, the first major surface 2 may comprise at least one electromagnet (not shown). The electromagnet may be activated during charging of the battery so as to attract and retain in situ the extracorporeal charging device. Similarly, the extracorporeal charging device may comprise at least one electromagnet (e.g., in addition to or instead of the at least one electromagnet in the first major surface 2). The at least one permanent magnet and / or the at least one electromagnet may be provided, for instance, in the center of the external charging ring. An electromagnet may be preferred in order to avoid having a permanent magnet sticking to things / attracting things when not in use.

[0117] The control unit 1 may be fully encased in silicone or another biocompatible material in order to improve its biocompatibility, e.g., to reduce or prevent adhesions. The housing 8 may be sealed, e.g., by hermetic sealing and / or the silicone coating or otherwise, such that bodily fluids are excluded from the interior of the housing 8, including the controller and the battery.

[0118] The control unit 1 comprises a driveline 6 extending therefrom. In the embodiment shown in Fig. 1 , the control unit 1 comprises an integral driveline extending from the circumferential minor surface 4, for example. The driveline 6 comprises an interconnector 7 at its distal end, the interconnector 7 configured to be connected to a corresponding interconnector, such as the interconnector 63 (Fig. 6) of the medical device’s driveline or connected via an implantable driveline extension cable 64 (Fig. 6) provided between interconnector 7 and interconnector 63. The driveline 7 is thereby configured to provide electrical communication with the medical device 60 (e.g., for powering and / or controlling the medical device).

[0119] The driveline 6 may be fully implantable such that it is configured to remain intracorporeally throughout its length. For example, the driveline 6 may be configured so as not to extend through the skin or otherwise be percutaneous. In particular, the interconnector 7 may thereby remain within the patient’s body after implantation.

[0120] The driveline 6 may comprise an RFID chip, optionally in the interconnector 7, in order to permit its location to be readily determined through a patient’s skin without requiring invasive surgery or exploratory investigation. The interconnector 7 may be male or female.

[0121] The control unit 1 may be configured to communicate wirelessly with an extracorporeal computer, such as a smart watch, a smart phone, a tablet or external control unit. For example, the receiver coil 9, a part thereof, or a smaller secondary receiver coil 9, may be used as an antenna fortransdermal communication with an external device. In this manner, the control unit 1 may transmit data to an extracorporeal device or to the cloud. Further, the antenna may permit a user (e.g., a cardiologist) to view live the performance of the associated medical device, to view a remaining charge level of the battery of the control unit 1 and / or to adjust the settings of the controller without requiring invasive techniques.

[0122] In use, a user may provide a powered transmitter coil 82 (Fig. 8) proximate the skin-facing surface 2 of the control unit 1 and thereby transmit energy to the receiver coil 9. The current induced in the receiver coil 9 is then transmitted to the battery of the control unit 1 , such that the battery is charged. Upon full charging, the transmitter coil 82 may be removed, and the battery may power the controller of the control unit 1 and the cardiac pump 60 via the driveline 6, the implantable driveline extension 64 and pump integral connected driveline 62.

[0123] Port

[0124] With reference to Fig. 4, a port 40 according to the present disclosure is described. Fig. 4 is a cross-section through the control unit 1 in an implanted position, showing the port 40 provided beneath the skin, with a percutaneous connector 55 (described in relation to Fig. 5A) at least partially inserted within the port 40.

[0125] The port 40 comprises a recess 41 for receiving a percutaneous connector 55 of an associated charging device. The recess 41 extends from a mouth, formed in the first major surface 2, in a depth direction towards the second major surface 3. The recess 41 generally tapers with depth, such that it may be narrowest at its deepest and widest at its mouth.

[0126] At its mouth, the recess 41 comprises a first portion having tapered sides. With increasing depth, the recess 41 comprises: a second portion having parallel sides and radius smaller than the first portion; a third portion having tapered sides of decreasing radius and radius smaller than the second portion; and a fourth or deepest portion comprising parallel sides and radius smaller than the third portion. The recess 41 comprises an abutment surface at its depth for abutting or otherwise arresting a tip of a protrusion 56 of the associated percutaneous connector 55.

[0127] The recess 41 comprises an electrical contact 43 for establishing electrical communication between the percutaneous connector 55 and the port 40. In the embodiment shown, the recess 41 comprises five electrical contacts 43 in the fourth or deepest portion.

[0128] The recess 41 , specifically the second portion thereof, comprises a septum 44 for maintaining a fluid-tight seal within the third and fourth portions of the recess 41. In particular, the septum 44 comprises a silicone plug possibly with a backing of greater rigidity. The rigid backing may be annular in shape, such that a central opening for receiving the percutaneous connector 55 is provided. The backing may be of sufficient rigidity that it does not significantly deflect during insertion and removal of the percutaneous connector, permitting the septum 44 to maintain a fluid-tight seal within the recess 41.

[0129] As the third portion of the recess 41 is narrower than the second portion, the walls of the third portion engage a circumference of the rigid backing of the septum 44 and so prevent the septum 44 from being pushed deeper into the recess 41 (e.g., during insertion of the connector 55). The first portion comprises an overhang of radius smaller than the second portion, such that the septum 44 is engaged by the overhang and so is prevented from being pulled towards the mouth of the recess 41 (e.g., during removal of the connector 55). The septum 44 is thereby retained in position by the relative dimensions and geometry of the recess 41 and the septum 44.

[0130] As the septum 44 is provided in the second portion (i.e. , is set back from the mouth of the recess 41), a patient or other user of the port 40 may determine the location of the port 40 by palpation of the patient’s skin. In particular, the first portion permits a clearance 10 between the septum 44 and the patient’s skin and subcutaneous tissue, such that the location of the recess 41 may be determinable by touch.

[0131] During insertion of the protrusion 56 of the connector 55 through the septum 44, the septum 44 may remove any bodily fluids or material present on the protrusion in order to exclude these materials from the fourth portion of the recess 41 . This may clean the electrical contacts of the protrusion 56 and so improve the electrical connection with the electrical contacts 43 of the port 40.

[0132] The port 40 may comprise a locking mechanism for retaining the percutaneous connector 55 within the recess during use / charging. For example, the locking mechanism may comprise the rigid backing of the septum 44. The rigid backing of the septum 44 may be convex or concave, such that upon insertion of the percutaneous connector 55, the protrusion 56 engages an inner circumference of the rigid backing. The force required for extraction of the connector 55 may exceed the force required for insertion. In this manner, the percutaneous connector 55 may be securely retained within the recess 41 , e.g., during use / charging.

[0133] Additionally or alternatively, the locking mechanism may comprise a screw thread (not shown) provided within the recess and a corresponding screw thread (not shown) provided on the protrusion 56 of the connector 55. The screw threads may be bayonettype threads, e.g., fully engageable by a half a turn.

[0134] As shown in Fig. 4, the port 40 may be provided as part of a larger apparatus such as the control unit 1. Alternatively, the port 40 may be provided as part of a standalone device, such as the apparatus 50 (Fig. 5A) or the apparatus 54 (Fig. 5B).

[0135] Fig. 5A shows an apparatus 50 comprising a port 40 in an implanted position beneath a patient’s skin. The port 40 of the apparatus 50 may comprise identical features to those of the port 50 of the control unit 1 .

[0136] For simplicity, the structures and features within the recess 41 have been omitted from Fig. 5A, but it will be understood that the features described above in relation to the port 40 of Fig. 4 may be provided in the port 40 of the apparatus 50. For example, the apparatus 50 may comprise a generally tapered recess 41 having a septum 44 and at least one electrical contact for providing electrical communication between the apparatus 50 and the percutaneous connector 55.

[0137] The apparatus 50 comprises a driveline 52 extending therefrom. The driveline 52 may be connectable to an associated medical device (e.g., a cardiac pump 60 or a control unit 1), in order to provide electrical communication between a medical device and an extracorporeal device.

[0138] In use, a percutaneous connector 55 may penetrate the skin and be inserted into the port 40, establishing electrical communication between the percutaneous connector 55 and the apparatus 50. As such, the apparatus 50 may provide a percutaneous electrical connection between an extracorporeal device and an implanted device, without the requirement for permanent percutaneous cables. For example, the apparatus 50 may be connected to a battery of the implanted medical device in order to charge the battery whilst the percutaneous connector 55 is received by the apparatus 50. The apparatus 50 may thereby act as a power port for an implanted active medical device 60.

[0139] Fig. 5B shows an alternative standalone apparatus 54 which is configured to be used for routine charging purposes. The apparatus 54 of Fig. 5B comprises the same features as the apparatus 50 of Fig. 5A with the following exceptions. The recess 41 of the apparatus 54 is again configured to receive a percutaneous connector 55 and generally tapered but the recess 41 comprises (e.g., consists essentially of) two portions. The lowermost portion of the recess 41 again comprises one or more electrical contacts and an abutment surface, but the first portion adjacent the mouth comprises the septum 44. As such, the septum 44 of the apparatus 54 may not be set back from the mouth of the apparatus 54.

[0140] The non skin-facing surface of the apparatus 54 comprises a radially extending flange to facilitate attachment to features within the patient’s body (e.g., ribs). For example, the flange may comprise a plurality of openings in a similar manner to the tabs 5 in order to permit fixation of the apparatus 54. It will be understood that a driveline, for providing electrical communication between the percutaneous connector 55 and the associated medical device to which the apparatus 54 is connected, has been omitted from Fig. 5B for simplicity. The housing of the apparatus may comprise titanium and / or plastic.

[0141] When the port 40 is provided as a standalone apparatus 50, 54 connected to a further implanted medical device, e.g., comprising a battery, the apparatus 50, 54 may be termed a plug-to-charge port.

[0142] Percutaneous connector Also shown in Figs. 4 and 5A and 5B is a percutaneous connector 55 according to the present disclosure. The percutaneous connector 55 comprises a body 57 from which extends a protrusion 56 for penetrating the skin of a patient. The protrusion 56 comprises an electrical contact (not shown), optionally a plurality of electrical contacts corresponding to the number of electrical contacts provided in the recess 41. The protrusion comprises a tip at its distal end, the electrical contacts being provided towards the tip of the protrusion 56.

[0143] The tip of the protrusion 56 is configured to penetrate the skin. For example, when the port

[0144] 40 is a bail-out port used for emergencies, e.g., in case the control unit 1 malfunctions or otherwise requires immediate electrical communication, and the protrusion 56 is used to penetrate unbroken skin, the protrusion 56 may comprise a needle tip configured to pierce the skin and provide electrical communication with the associated medical device.

[0145] Alternatively, when the port 40 is used for routine charging of an implanted battery (e.g., the battery of the control unit 1 or the battery of an associated medical device to which the apparatus 50 is connected), the protrusion 56 may not comprise a needle tip but a relatively blunt tip akin to an earring or other piercing. For example, as shown in Fig. 5B, routine use of the apparatus 54 may lead to the formation of an earring-type piercing in the skin. As such, with time, it may be possible to use a percutaneous connector having a blunter tip than a needle, as the opening within the skin may not heal over between charging events.

[0146] The percutaneous connector 55 may be insertable until it “bottoms-out” within the recess 41 . For example, a distal tip of the percutaneous connector may abut a deepest surface of the recess. Additionally or alternatively, an intermediate surface of the percutaneous connector 55 may abut an intermediate surface of the recess 41. Further, the body 57 may comprise a substantially planar surface from which the protrusion 56 extends, such that the planar surface abuts the patient’s skin upon bottoming-out within the recess 41.

[0147] Upon insertion, the electrical contact(s) of the percutaneous connector are configured to align with the electrical contact(s) of the port 40.

[0148] The percutaneous connector 55 comprises an electrical cable 58 in electrical communication with the protrusion 56 and for connecting to a power source, a controller, and / or a computer (not shown).

[0149] In use, a user may insert a percutaneous connector 55, specifically the protrusion 56 thereof, into the recess 41 of the port 40, the recess 41 of the apparatus 50 or the recess

[0150] 41 of the apparatus 54, such that the electrical contacts of the connector 55 align with the electrical contacts 43 of the port 40. Electrical communication may thereby be provided between the implanted control unit 1 or the implanted apparatus 50, 54 and the percutaneous connector 55. The percutaneous connector 55 may thereby be configured to interact with a port 40 provided as part of a larger apparatus such as the control unit 1 , and / or interact with a port 40 provided as part of a standalone implanted apparatus 50, 54.

[0151] Cardiac pump

[0152] With reference to Fig. 6, a cardiac pump or VAD 60 is described. The cardiac pump comprises an inlet 61 , an outlet (not shown) and a driveline 62.

[0153] The cardiac pump 60 is configured to be implanted at least partially within a patient’s heart. In particular, the inlet 61 is providable within the left ventricle of a patient’s heart and the outlet may be anastomosed to the patient’s aorta such that the cardiac pump 60 may pump blood from the left ventricle and around the patient’s body, thereby alleviating the symptoms of heart failure.

[0154] The cardiac pump 60 may be powered and controlled via the driveline 62 which comprises an interconnector 63 at its distal end for connecting to an associated controller and thereby forming an electrical communication between the controller and the cardiac pump 60. For example, the cardiac pump 60 may be connected to a control unit 1 by means of the interconnector 63 and the interconnector 7 (e.g., as shown in Fig. 7).

[0155] As the control unit 1 is implantable within a patient and the cardiac pump 60 is implantable within the patient, the driveline 62 and the driveline 6 may be configured to be fully implantable within the patient, e.g., such that neither driveline extends extracorporeally. For example, each driveline 6, 62 may be fully biocompatible along its length. One of the interconnectors 7, 63 may be male, and the other of the interconnectors 7, 63 may be female. In the embodiment of Fig. 6, the interconnector 7 is male and the interconnector 63 is female.

[0156] As shown in Fig. 6, the interconnector 63 may be interchangeably connectable to a control unit 1 (e.g., via a driveline 6 and an interconnector 7) or connectable to a percutaneous driveline 65 of an extracorporeal control unit. In this manner, the interconnector 63 of the cardiac pump 60 may permit improved configurability and flexibility of the cardiac pump 60. For example, if an exchange of the control unit 1 is required, the cardiac pump 60 may be connected to a percutaneous driveline 65 of an extracorporeal control unit 86 (Fig. 9).

[0157] In an embodiment not shown, the cardiac pump 60 may comprise a plurality of interconnectors 63 (e.g., provided on the same or different drivelines 62). Having a plurality of interconnectors 63 may permit an extracorporeal control unit to be connected to the cardiac pump 60 prior to disconnection of the implanted control unit 1 during routine exchange of the implanted control unit 1. In an embodiment not shown, the driveline 62 may comprise a plurality of interconnectors 63 at its distal end.

[0158] Cardiac pump assembly

[0159] Fig. 7 shows a simplified drawing of a cardiac pump assembly 70 according to the present disclosure once implanted within a patient. The cardiac pump assembly 70 comprises the control unit 1 and the cardiac pump 60.

[0160] The control unit 1 is implanted on the patient’s right, proximate the armpit and may be attached to the ribs. The cardiac pump 60 is implanted at least partially in the patient’s heart. A driveline 6, 62 connects the cardiac pump 60 and the control unit 1, thus providing electrical communication (e.g., power and / or control) therebetween.

[0161] Extracorporeal charging device

[0162] Fig. 8 shows an example extracorporeal charging device 80 according to the present disclosure. The charging device 80 comprises a transmitter charging coil 82 provided within a garment 84. In particular, the transmitter charging coil 82 is provided in a region of the garment 84 which, when worn, may be provided proximate, e.g. immediately proximate, the implanted control unit 1. As such, the garment 84 may be configured to retain the transmitter charging coil 82 sufficiently close to the receiver coil 9 of the control unit 1 so that the magnetic field of the transmitter coil impinges on the receiver coil 9 and so the battery of the control unit 1 is thereby charged. In the example shown, the garment 84 comprises a vest or waistcoat which may be worn beneath additional garments (e.g., immediately adjacent the patient’s skin). The material and thickness of the garment 84 may be selected such that the garment 84 does not substantially affect the strength of the magnetic field from the transmitter coil 82 impinging upon the receiver coil 9 of the control unit 1.

[0163] As shown in Fig. 8, the device 80 may additionally comprise a means for providing power to the transmitter coil 82, such as a battery pack. Alternatively, the transmitter coil 82 may be connected (e.g., indirectly) to the mains, and the garment 84 may conveniently retain the transmitter coil 82 in position proximate the receiver coil 9.

[0164] In an embodiment not shown, the extracorporeal charging device may comprise a magnetic viewing film for detecting the position of an implanted apparatus (e.g., the control unit 1) by visualising the magnetic fields caused by one or more permanent magnets or electromagnets of the implanted or external apparatus. The extracorporeal charging device may additionally comprise one or more LED lights or other user feedback features in order to confirm alignment and / or charging.

[0165] VAD system

[0166] Fig. 9 shows an exploded view of a VAD system of the present disclosure. The VAD system may comprise the cardiac pump assembly 60, including the cardiac pump 61 and the control unit 1. The VAD system may further comprise the percutaneous connector 55, the extracorporeal charging device 80 and an extracorporeal control unit 86.

[0167] The cardiac pump 61 is connectable to the control unit 1 , via pump driveline 62, interconnector 63, an implantable driveline extension 64, interconnector 7 and driveline 6. For example, the cardiac pump assembly 60 may comprise the implantable driveline extension 64. Both interconnectors 7, 63 may be of female type and / or of limited length, and so the driveline extension 64 may have an interconnector at either end of male type, and may have sufficient length to bridge the interconnectors 7, 63 in their implanted locations.

[0168] Additionally or alternatively, the cardiac pump 61 may be connectable to an extracorporeal control unit 86, via interconnector 63 and percutaneous driveline 65.

[0169] The bail-out driveline 58 comprises a percutaneous connector 55, to engage with bail-out port 40, when bypass of control unit 1 is needed. Driveline 58 may be connectable to control unit 86.

[0170] The external charging coil 82 is shown connected to the extracorporeal control unit 86 for charging and / or communicating with control unit 1

[0171] The extracorporeal control unit 86 is shown with a mains plug adapter, as well as two battery packs, e.g., for powering the charging coil 82 and thus charging the control unit 1 on-the-go.

[0172] Control unit sensors

[0173] As shown in Fig. 10, the control unit 1 may comprise a number of sensors provided on or within the control unit housing.

[0174] A sensor or sensor terminal may comprise an exposed region of the can forming the external housing of the control unit 1. For example, a portion of the titanium or stainless- steel housing may not be coated with a polyurethane or other insulating coating and so may be provided in electrical communication with the surrounding tissues once implanted. Additionally or alternatively, a sensor or sensor terminal may comprise a sensor electrically isolated from the can and exposed to the exterior of the device and so in electrical communication with the surrounding tissues once implanted. This sensor may be provided on the feedthrough connector which provides electrical connection between the interior of the housing and the driveline.

[0175] For example, a first sensor may comprise an exposed region of the can, a second sensor may be provided as part of the feedthrough connector and a third sensor may be provided elsewhere within the can but electrically isolated from the first sensor.

[0176] The sensors may be provided on a rear of housing, e.g., on an aspect of the housing opposite a major surface comprising the TETS coil(s) and / or port, such that the sensors are configured to face facing into the body rather than outwardly.

[0177] The control unit 1 may be configured (e.g., using any one or more of the above sensors) to detect one or more parameters of or relating to the patient, such as parameters of the patient’s heart. The sensors may be configured to detect electrical activity of heart (e.g., electrical impulses of heart nerves) such that the control unit 1 may be able to determine a pulse rate of the heart and so may determine an appropriate speed of the VAD. Accordingly, based determine whether to increase or decrease an operating speed of a motor of an associated VAD. For example, when the control unit 1 is a control unit for a VAD, the control unit 1 may, in response to a determination that the pulse / contraction rate of the heart has increased (if the patient walking or otherwise active rather than sedentary), increase a power transmitted to the VAD motor in order to increase its speed.

[0178] Additionally or alternatively, the control unit 1 may be configured to determine an impedance of the tissues surrounding the housing once implanted. For example, the control unit 1 may comprise at least two sensors across which an electrical potential difference can be measured. A first sensor may comprise an exposed region of the housing and a second sensor may be provided on the feedthrough connector or on an electrically isolated region of the housing. Accordingly, the two sensors may be spaced apart from one another and, using the surrounding tissues as the return, measure an impedance or resistance of the patient’s tissues. The impedance or resistance may indicate a hydration level of the patient, an electrolyte level of patient, and / or a blood volume of the patient. The determined impedance and / or associated hydration, electrolyte level and / or blood volume may be communicated to an extracorporeal device, such as by Bluetooth.

[0179] Additionally or alternatively, the control unit 1 may comprise an accelerometer. The accelerometer may be configured to detect an activity of the patient. For example, the accelerometer may be configured to determine whether the patient is moving normally, whether the patient is sedentary but awake, walking, has fallen or otherwise shocked the control unit. Depending on the sensitivity of the accelerometer, the control unit 1 may be configured to detect contractions of the heart muscles. For example, by filtering the received accelerometer data by frequency, the detected activity may be determined, e.g., signals in the range 40Hz to 120 Hz may indicate heart activity.

[0180] Additionally or alternatively, the control unit 1 may be configured to determine a temperature of the control unit (e.g., control unit housing). For example, the control unit may comprise a temperature sensor in direct thermal communication with the housing and / or the control unit 1 may be configured to determine a temperature of the control unit by momentarily pausing the charging process and measuring a resistance of the TETS coils.

[0181] The temperature of the control unit may indicate a health status of the patient. For example, the control unit 1 may have a known temperature for a given operating condition, and any substantial deviation from this temperature may indicate a health issue of the patient such as infection or dehydration. In this manner, an infection at the implant site may be determined long before generalised symptoms of infections appear in the patient, thus allowing earlier treatment.

[0182] Additionally or alternatively, the control unit 1 may be configured to determine a blood oxygen saturation (SpO2) of the patient. The control unit 1 may comprise an electrical sensor and / or optical sensor provided on the control unit housing and configured to determine the blood oxygen saturation of the tissues surrounding the control unit 1 once implanted.

[0183] Accordingly, for any or all of the above parameters, the control unit 1 may be configured to determine whether a parameter is outside of a predetermined range. In response to determining that the parameter is outside of the range, the value of the parameter and metadata relating to the parameter may be encoded into a signal, and the signal then transmitted to an extracorporeal device (e.g., by Bluetooth or other means). Additionally or alternatively, in response to determining that the parameter is within a predetermined range, the value of the parameter and metadata relating to the parameter may be encoded into a signal and transmitted to an extracorporeal device.

[0184] In this way, the patient may be alerted: if they are dehydrated or their blood volume is otherwise too low; and / or if their activity levels are insufficient. Similarly, a doctor may be alerted if: the patient has abnormal heart activity; if the patient’s activity levels are insufficient; if the patient is dehydrated; if the patient’s SpO2 is too low. Additionally or alternatively, in response to determining that a parameter of the patient is outside of a predetermined range, the controller of the control unit 1 may vary an operating condition (e.g., operating speed) of the VAD. For example, the control unit 1 may increase a power provided to the VAD motor in order to increase its speed, and / or send instructions to the VAD to increase its speed.

[0185] Electromagnetic shield

[0186] Beneath the receiver coils 9, port 40, RFID chip, permanent magnets and electromagnets, when any combination of these features is present, the control unit 1 may comprise an electromagnetic shield for reducing (e.g., preventing) the transmission of electromagnetic noise into the interior of the control unit which houses the control circuitry for the associated medical device.

[0187] The electromagnetic shield may comprise a number of apertures or cutouts for permitting communication through the shield, such as by means of an antenna for communication, or a magnetic pickup point.

[0188] The electromagnetic shield may comprise (e.g., may be formed from) ferrite, which may be moulded, 3D printed or otherwise shaped to conform to the ergonomic geometry of the control unit housing.

[0189] Control circuitry

[0190] As described previously, the control unit 1 may comprise a plurality of receiver coils 9 which may increase the resilience of the control unit 1 , e.g., to the development of faults or due to damage.

[0191] When the control unit 1 comprises a plurality of receiver coils 9, the control unit 9 may function by receiving energy via a single receiver coil 9 and switch over to a second coil in the case of a fault developing on the first coil 9. Alternatively, the control unit 9 may function by receiving energy via more than one coil, e.g., a pair of coils, and operating on the remaining coil(s) in case of a fault developing on a first coil. It will be understood by the skilled person that retuning for frequency may be required if switching between TET using a single coil and a plurality of coils 9. Additionally, the provision of a plurality of receiver coils 9 may permit the measurement of multiple parameters (e.g., the inductance, impedance and / or temperature) of a subset of coils 9 without stopping TET.

[0192] Battery

[0193] The battery may comprise a plurality of cells, optionally arranged in series. The cells may be provided in containers each housing a subset of the cells. The containers may be selectively connectable to the circuit by mechanical (e.g., relay) or electronic switches, such that each subset of cells may be selectively disconnected from the circuit as required. This may allow a faulty cell to be removed from the circuit and / or the condition (e.g., temperature, voltage) of the cells in each container to be determined. Protection to prevent cell short circuit in case a high temperature of the control unit is detected. e.g., may comprise three containers of two cells each, or two containers of three cells each.

[0194] Motor control arrangement

[0195] Fig. 11 is a diagram showing an example motor control arrangement 100. The motor control arrangement 100 may form part of the control unit 1 (e.g., the controller) described above. The motor control arrangement 100 comprises a first motor drive 230 and a second motor drive 330. The first motor drive 230 is configured to apply output voltages therefrom to a first winding arrangement 260 by means of an electrical coupling therebetween, whereas the second motor drive 330 is configured to apply output voltages therefrom to a second winding arrangement 360 by means of an electrical coupling therebetween. The first motor drive 230 and the second motor drive 330 are generally similar and include corresponding features. The configurations of the first motor drive and the second motor drive 330 may be substantially identical.

[0196] Each winding arrangement 260, 360 forms part of a stator of the same electronically commutated electric motor, which may also be referred to as a brushless direct current (BLDC) electric motor. The stator may be arranged with respect to a rotor of the electric motor in either an inrunner or an outrunner configuration. Namely, the winding arrangements 260, 230 form part of the electric motor of the cardiac pump described herein. In use, the motor drives 230, 330 provide electronic commutation to the respective winding arrangement 260, 360 of the stator. To this end, an input side of each motor drive 230, 330 is configured to receive an input DC voltage (VCC) from a DC power supply (e.g., the battery of the control unit 1) at a respective pair of input terminals 232, 234, 332, 334. An output side of each motor drive 230, 330 is configured to supply a respective plurality of output voltages to the corresponding winding arrangement 260, 360 through first, second and third output terminals 236, 237, 238, 336, 337, 338. As a result, the motor drives 230, 330 may be described as three-phase motor drives, as will be understood by those skilled in the art. Each winding arrangement 260, 360 is configured to receive the respective plurality of output voltages from the corresponding motor drive 230, 230 via respective first, second and third winding terminals 266, 267, 268, 366, 367, 368 which are coupled by respective conductors 246, 247, 248, 346, 347, 348 forming part of the electrical couplings between the motor drives 230, 330 and the winding arrangements 260, 360.

[0197] The first motor drive 230 and the second motor drive 330 are communicatively coupled with one another by means of a synchronisation channel (e.g., bus) 110 and a fault channel (e.g., bus) 120. Further, each motor drive 230, 330 is communicatively coupled with the corresponding winding arrangement 260, 360 by means of a respective feedback channel 280, 380.

[0198] Fig. 12A is a diagram showing an example motor drive 230 and an example winding arrangement 260 suitable for use as the first motor drive 230 and the first winding arrangement 260, respectively, in the motor control arrangement 100 shown by Fig. 11.

[0199] A first output voltage supplied through the first terminal 236 is denoted by Vlta second output voltage supplied through the second terminal 237 is denoted by 72, and a third output voltage supplied through the third terminal 238 is denoted by V3. A voltage between the first and second terminals 236, 237 is denoted by 712and is given by 14 - V2. In a similar way, a voltage between the second and third terminals 237, 238 is denoted by y23and is given by V2- V3. Further, a voltage between the third and first terminals 238, 236 is denoted by 731and is given by V3- V1.

[0200] The winding arrangement 260 is shown by Fig. 12A as comprising first, second and third windings 261, 262, 263, each of which may include an inductive load and, optionally, any suitable combination of a resistive load and a capacitive load. Nevertheless, it will be understood that each winding 261 , 262, 263 may be considered to primarily comprise an inductive load. In the specific example of Fig. 12A, the first, second and third windings 261, 262, 263 are electrically coupled to one another at a centrepoint junction 286 to form a wye configuration,. Also, in the example of Fig. 12A, the first winding 261 is configured to receive the voltage 712between the first and second terminals 236, 237, the second winding 262 is configured to receive the voltage 72I between the second and third terminals 237, 238, and the third winding 263 is configured to receive the voltage 731between the third and first terminals 238, 236.

[0201] An impedance of the first winding 261 is denoted and a current therethrough is given by I1, an impedance of the second winding 262 is denoted by Z2and a current therethrough is given by I2, while an impedance of the third winding 262 is denoted by Z3and a current therethrough is given by / 3. Each winding 261 , 262, 263 may form part of a stator 266 of the motor 260 and is proximal to a rotor 268 of the motor 260 per a typical motor (e.g., induction / asynchronous motor) arrangement, as will be recognisable to those skilled in the art.

[0202] The input side of the motor drive 230 comprises a plurality of switches. The plurality of switches are arranged as first, second and third input half-bridges 620, 630, 640. The first input half-bridge 620 comprises a first high-side switch 651 and a first low-side switch 652, the second input half-bridge 630 comprises a second high-side switch 653 and a second low-side switch 654, while the third input half-bridge 640 comprises a third high- side switch 655 and a third low-side switch 656. Therefore, the input side of the motor drive 230 comprises a plurality of high-side switches 651 , 653, 655 and a plurality of low- side switches 652, 654, 656. As will be recognisable to those skilled in the art, the plurality of switches of the motor drive 230 are mutually connected to each other in a typical H-bridge circuit arrangement.

[0203] A first half-bridge output node 612 is coupled to and between a terminal of the first motor winding 261 and a terminal of the second motor winding 262, a second half bridge output node 614 is connected to and between a terminal of the second motor winding 262 and a terminal of the third motor winding 263, and a third half bridge output node 616 is connected to and between a terminal of the third motor winding 263 and a terminal of the first motor winding 261. In this way, the half bridges 620, 630, 640 are each coupled to the windings 261, 262, 263 (i.e. , the wound arrangement).

[0204] A first input connection rail 231 extends between the first input terminal 232 and the first high-side switch 651 to provide an electrical connection between the first input terminal 232 and the plurality of high-side switches 651, 653, 655. Similarly, a second input connection rail 233 extends between the second input terminal 234 and the first low-side switch 652 to provide an electrical connection between the second input terminal 234 and the plurality of low-side switches 652, 654, 656. In use, the first input connection rail 231 is connected to a positive terminal of the DC power supply 220 via the DC bus 210 whereas the second input connection rail 233 is connected to a reference voltage (e.g. ground or negative) terminal of the DC power supply 220 via the DC bus 210. As a result, an electric potential of the first input connection rail 231 is higher than an electric potential of the second input connection rail 233 during use. Therefore, the first input connection rail 231 may be referred to as a positive input connection rail 231 and the second input connection rail 233 may be referred to as a negative input connection rail 233. The first input connection rail 231 and the second input connection rail 233 together form part of a DC link of the motor drive 230.

[0205] The motor drive 230 is functionally provided with (e.g., comprises) a controller 290 configured to control operation thereof. To this end, the controller 290 is communicatively coupled with each of the plurality of switches. In this example, the controller 290 is also communicatively coupled with a plurality of voltage transducers and a plurality of current transducers. The plurality of voltage transducers includes a multiplicity of voltage transducers each configured to monitor a voltage at a respective one of the output terminals 236, 237, 238. The plurality of current transducers includes a multiplicity of current transducers each configured to monitor a current through a respective one of the output terminals 236, 237, 238. Also in this example, the plurality of voltage transducers also includes a feedback voltage transducer configured to monitor a voltage at the centrepoint of the wye-configured windings 261 , 262, 263. The feedback voltage transducer is communicatively coupled to the controller 290 via the feedback channel 280.

[0206] Each half-bridge 620, 630, 640 is operable in at least a high-operating state (e.g., “HIGH”) and a low-operating state (e.g., “LOW”). In the high-operating state of each half-bridge, the relevant high-side switch 651 , 653, 655 is in a closed state (e.g., a conducting state or an activated state) and the corresponding low-side switch 652, 654, 656 is in an open state (e.g., a non-conducting state or a deactivated state). Conversely, in the low- operating state of each half-bridge, the relevant high-side switch 651 , 653, 655 is in the open state and the corresponding low-side switch 652, 654, 656 is in the closed state. Thus the high-operating state and the low-operating state of each half-bridge 620, 630, 640 may be described as complementary operating states. Each half-bridge 620, 630, 640 is also operable in a non-operating state (e.g., “OFF”) in which both the relevant high- side switch 651 , 653, 655 and the corresponding low-side switch 652, 654, 656 are in the open state. The controller 290 is configured to provide control signals to each of the switches 651-656 so as to cause the half-bridges 620, 630, 640 to be in the high- operating state, the low-operating state and the non-operating state as desired.

[0207] Fig. 13 is a flowchart showing an example method 400 of operating a motor drive 230, 330 forming part of a motor control arrangement 100 as described herein. The method(s) described herein may be carried out by a suitable data processing apparatus, such as the controller 290 described above with respect to Fig. 12A. In other words, the controller 290 may be configured to carry out the method(s) described herein (e.g., the method 400). For the sake of simplicity, the following description is made in the context of the first motor drive 230 and the first winding arrangement 260 for ease of understanding with reference to Fig. 12A. References to the other motor drive are therefore to be understood as references to the second motor drive 330. However, it will be appreciated that the method 400 implementable, mutatis mutandis, by the second motor drive 330 (e.g., a controller thereof). The method 400 comprises an action of determining, at block 410, a positional parameter relating to an angular position (e.g., an angle) of the rotor relative to the stator as the rotor is driven. As discussed above, each motor drive 230, 330 is configured to provide electronic commutation to the respective winding arrangement 260, 360 of the stator. Provision of electronic commutation in this way may make use of a determined angular position of the rotor so that the switches of the motor drive 230, 330 may be appropriately controlled so as to generate a rotating magnetic field which results in application of a torque to the rotor for driving thereof.

[0208] Determination of the positional parameter, at block 410, may be carried out based on: a monitored current through the winding arrangement 260; and / or a monitored voltage associated with the winding arrangement 260. Such techniques may include monitoring a back electromotive force (emf) induced in a winding 261 , 262, 263 of the winding arrangement which, at a given point in time, has no voltage applied thereto by the motor drive 230 (and which may be referred to as an non-driven winding). A zero-crossing point of the back emf may be used to infer the angular position of the rotor, as will be understood by those skilled in the art. Additionally or alternatively, a mathematical model may be used to predict the angular position of the rotor based on the monitored current and / or the monitored current discussed above. When the motor is performing a start-up routine (e.g., is not rotating), the positional parameter may be determined based on an assumed predetermined value stored in a memory of the apparatus carrying out the method 400 (e.g., the controller 290).

[0209] Additionally, the method 400 comprises providing, at block 420, a synchronisation signal corresponding to the determined positional parameter (i.e. , the positional parameter determined at block 420) to the other motor drive 330 via the synchronisation channel 110 (e.g., transmitting the synchronisation signal to the other motor drive 230, 330 along the synchronisation channel 110). Provision of the synchronisation signal to the other motor drive 330 enables the other motor drive 330 to use the synchronisation signal for its own control purposes (e.g., in a similar way to that described below with reference to block 480). In turn, this is associated with an increased ability of the motor control arrangement 100 to continue operation despite the presence of a fault condition therein, as is described below.

[0210] The method 400 comprises an action of applying, at block 430, a voltage (e.g., in a sequence) to each winding 261 , 262, 263 of the winding arrangement 260 using the halfbridges 620, 630, 640 so as to cause the rotor to be driven to rotate in accordance with at least one motor control reference parameter. The motor control reference parameter may be, for example, a speed of the motor (as discussed above). Application, at block 430, of the voltage(s) to the winding(s) 261, 262, 263 is based on the positional parameter determined by the same motor drive 230, at block 410, so as to provide appropriate electronic commutation to the stator using the half-bridges 620, 630, 640.

[0211] The method 400 further comprises an action of evaluating, at block 440, a fault criterion relating to whether the corresponding winding arrangement 260, the motor drive 230 or the electrical coupling therebetween is in a fault condition. Evaluation, at block 440, of the fault criterion is based on information (e.g., signals) relating to operation of the windings 261, 262, 263 and / or the half-bridges 620, 630, 640. Such information may include: a monitored current through one or more of the windings 261 , 262, 263 or one or more of the half-bridges 620, 630, 640; and / or a monitored voltage associated with one or more of the windings 261, 262, 263 or one or more of the half-bridges 620, 630, 640.

[0212] By way of example, if a signal received from one or more of the plurality of current transducers is indicative of a current through one or more of the windings 261 , 262, 263 being above an upper current threshold, it may be determined that the fault criterion has been met. The upper current threshold being exceeded corresponds to an excessive current being present within the winding arrangement 260, the motor drive 230 or the electrical coupling therebetween. Such an excessive current is indicative of a short-circuit type fault having developed within the first winding arrangement 260, the motor drive 230 or the electrical coupling therebetween.

[0213] By way of further example, if a signal received from one or more of the plurality of current transducers is indicative of a current through one or more of the windings 261 , 262, 263 being below a lower current threshold, it may be determined that the fault criterion has been met. The lower current threshold not being exceeded corresponds to insufficient current passing through at least part of (e.g., one of the windings 261, 262, 263) of the winding arrangement 260, the motor drive 230 or the electrical coupling therebetween. Such an insufficient current is indicative of an open-circuit type fault having developed within the winding arrangement 260, the motor drive 230 or the electrical coupling therebetween.

[0214] By way of another example, if a signal received from the feedback voltage transducer is indicative of the voltage at the centre-point of the wye-configured windings being outside of an expected range, it may be determined that the fault criterion has been met. The expected range for the voltage at the centre-point of the windings may be predetermined and stored in the memory of the apparatus carrying out the method 400. In particular, the expected range for the voltage at the centre-point of the windings may be predetermined based on the impedances Z , Z2, Z3, of the windings 261, 262, 263. For example, but without wishing to be bound by theory, if the windings 261, 262, 263 each have substantially the same impedance, the voltage at the centre-point of the wye-configured windings may be expected to be approximately half the input DC voltage (VCC). The voltage at the centre-point of the windings falling outside of this expected range may thus be indicative of a fault being present within the winding arrangement 260, the motor drive 230 or the electrical coupling therebetween. Signals received from the other voltage transducers discussed above may be similarly used to determine whether the fault criterion has been met. That is, the voltages V12, 723> ^3i> between terminals 236, 237, 238 may be compared with expected values so as to determine whether abnormal behaviour is being exhibited and thus is the fault criterion has been met. By way of yet another example, signals received from the other voltage transducers discussed above may be used in other ways to ascertain whether the fault criterion has been met. Namely, if a signal received from a voltage transducer configured to monitor a voltage at a respective one of the output terminals 236, 237, 238 is indicative of there being substantially no voltage for a predetermined time period at the relevant output terminal despite the controller 290 having provided control signal(s) to the switches 651-656 to as to cause the respective half-bridge 620, 630, 640 to be in the high-operating state or the low-operating state, it may be determined that the fault criterion has been met. In such a scenario, the lack of or late voltage response at the relevant output terminal 236, 237, 238 is indicative of the corresponding half-bridge 620, 630, 640 being unable to appropriately respond to control signals from the controller 290 (e.g., due to a failure or one or more of the switches 651-656 thereof). This may be referred to as a responsivity fault.

[0215] If it is determined, at block 440, that the fault criterion has not been met and thus that corresponding winding arrangement 260, the motor drive 230 and the electrical coupling therebetween is not in the fault condition, the method 400 directly returns to applying, at block 410, a voltage (e.g., in a sequence) to each winding 261 , 262, 263 of the winding arrangement 260 so as to cause the rotor to be driven to rotate and continues thereafter. Contrastingly, if it is determined, at block 440, that the fault criterion has been met and thus that the corresponding winding arrangement 260, the motor drive 230 or the electrical coupling therebetween is in the fault condition, the method 400 proceeds to: identifying, at block 450, a part of the first winding arrangement 260, the first motor drive 230 or the electrical coupling therebetween as being associated with the fault condition; providing, at block 460, a fault signal on the fault channel 120; isolating, at block 470, the part of the first winding arrangement 260, the first motor drive 230 or the electrical coupling therebetween identified (at block 450) as being associated with the fault condition; and then applying, at block 480, a voltage (e.g., in a sequence) to a subset of the windings of the winding arrangement 260, 360 based on a synchronisation signal received on the synchronisation channel 110 from the other motor drive 330 forming part of the motor control arrangement 100.

[0216] Identifying, at block 450, the part of the first winding arrangement 260, the first motor drive 230 or the electrical coupling therebetween as being associated with the fault condition includes analysing the information relating to operation of the windings 261, 262, 263 and / or the half-bridges 620, 630, 640 discussed above with reference to block 440. For instance, the part of the first winding arrangement 260, the first motor drive 230 or the electrical coupling therebetween associated with the fault condition may include analysing the monitored current(s) and / or the monitored voltages to determine whether an opencircuit type fault has developed in the first half-bridge 620, the first conductor 246 or the first winding 261. Such a fault may be identified if the monitored current through the first terminal 236 is below the lower current threshold discussed above. Short-circuit type faults may be similarly identified if the monitored current through one of the terminals 236, 237, 238 is above the upper current threshold discussed above. Further, a responsivity fault in the first half-bridge 620 may be identified by observing a lack of change in voltage at the first output terminal 236 despite control signals being provided from the controller 290 to the switches 651 , 652 of the first-half bridge 620 to move between a non-operating state and an operating state.

[0217] Providing, at block 460, the fault signal to the other motor drive 330 on the fault channel 120 enables the other motor drive 330 to take mitigating action to include synchronisation signals to compensate for the first winding arrangement 260 and / or the first motor drive 230 being in the fault condition.

[0218] Isolating, at block 470, the part of the winding arrangement 260, 360 (e.g., the winding 261, 262, 253), the motor drive (e.g., the half-bridge 620, 630, 640) or the electrical coupling (e.g., the conductors 246, 247, 248) identified as being associated with the fault condition includes preventing the supply of a voltage to the relevant part. If the identified part is one of the windings 261 , 262, 263 or one of the conductors 246, 247, 248, at least one of the half-bridges 620, 630, 640 may be caused to be in the non-operating state (e.g., “OFF”) thereof to this end. For example, with reference to Fig. 12, if the first winding 261 or the first conductor 246 has been identified (at block 450) as being associated with the fault condition, the first winding 261 and the first conductor 246 may be isolated by causing the first half-bridge 620 to be OFF.

[0219] Additionally or alternatively, one or more dedicated isolators (e.g., contactors) may be provided to the motor drive 230 for the specific purpose of causing the identified part of the first winding arrangement 260, the motor drive 230 or the electrical coupling therebetween to be isolated as part of the action represented by block 470. Advantageously, this does not rely on use of the half-bridges 620, 630, 640 so as to isolate the identified part (e.g., if the part identified as being associated with the fault condition is one of the half-bridges 620, 630, 640, the identified part may still be isolated).

[0220] Isolation of the part of the motor drive (e.g., the half-bridge 620, 630, 640) or the electrical coupling (e.g., the conductors 246, 247, 248) identified as being associated with the fault condition has the direct effect of at least part of the first winding arrangement 260 being effectively deactivated. For example, if the first half-bridge 620 and / or the first conductor 246 is isolated, the first winding 261 is not usable by the motor control arrangement 100 and is therefore effectively deactivated. Isolation of the part of the first winding arrangement 260 identified as being associated with the fault condition naturally has the effect of the same part of the first winding arrangement being effectively deactivated.

[0221] The method 400 then comprises an action of applying, at block 480, a voltage (e.g., in a sequence) to a subset of the windings 261 , 262, 263 of the winding arrangement 260 using the half-bridges 620, 630, 640 based on the synchronisation signal provided by the other motor drive 330 along the synchronisation channel 110. Due to the isolation, at block 470, of the part of the winding arrangement 260, 360, the motor drive or the electrical coupling identified as being associated with the fault condition, the application of the voltage(s) at block 480 can only be to a proper subset (i.e. , not all) of the windings 261 , 262, 263 of the first winding arrangement 260. Moreover, due to the effective deactivation of the part of the first winding arrangement 260, the positional parameter of the rotor cannot be reliably determined in the same way as described above with reference to block 410. Instead, the method 400 involves, at block 480, using the synchronisation signal received from the other motor drive 330 along the synchronisation channel 110 in place of any positional parameter determined by the first motor drive 230 for the purpose of providing appropriate electronic commutation. This allows continued operation (in part) of the first winding arrangement 260 to aid driving of the rotor despite the fault condition.

[0222] Fig. 12B shows an alternative embodiment of the example motor drive 230 and example winding arrangement 260 suitable for use as the first motor drive 230 and the first winding arrangement 260, respectively, in the motor control arrangement 100 shown in Fig. 11. It will be understood that an arrangement corresponding to that shown in Fig. 12B may also be provided as part of the second motor drive 330 and second winding arrangement 360.

[0223] The embodiment of Fig. 12B is substantially identical to the embodiment of Fig. 12A, with the addition of terminal 281 , and conductors 282, 283, 284, 285. The terminal 281 is provided at an intermediate voltage (e.g., a mid voltage of the input terminals 232, 234 ((232-234)72)) , by being connected to a potential divider (e.g., the midpoint of the potential divider) provided between the input terminals 232, 234. The terminal 281 is connected to the centrepoint junction 286 by conductor 282, and the conductors 283, 284, 285 each connect a winding 261 ,262, 263 to the controller 290.

[0224] By connecting the centrepoint junction 286 of the winding arrangement 260 to the terminal 281 at the mid voltage of input terminals 232 and 234 ((232-234)72)) , if the windings 261 , 262, 262 are balanced, then in a non-fault condition, very little if any current will flow via conductor 282 due to the connection to 281 . However, in the event of a fault (e.g., Zi open or short circuit, open or short circuit in the connection (e.g., 246 or 260)) then the remaining two windings (e.g., Z2 and Z3) can be driven with the current flowing through 281 , 282 rather than via the faulty winding.

[0225] To this end, an input side of each motor drive 230, 330 is configured to receive an input DC voltage (VCC) from a DC power supply and a half voltage (VCC / 2) or other intermediate voltage at 281 (e.g., the battery of the control unit 1) at a respective pair of input terminals 232, 234, 332, 334. As a result, the motor drives 230, 330 may be described as three-phase motor drives. However if the centrepoint junction (wye point) is connected to the half voltage 281 then it is possible to drive a single or pair of windings in the event that one or more of the windings or connections has a fault. Accordingly, rather than straight redundancy of drive 230, 260 and 330,360, this design can enable two out of the phases in a single fault to be operational, and therefore maintain a higher output than if just one of the two winding arrangements operating (260,360). For example, two of the windings 261 , 262, 263 can still be driven in the event of a fault in one of the windings, meaning that the faulty winding arrangement can still be driven at two-thirds capacity, while the other non-faulty winding arrangement can be driven at full capacity, giving a total output at around 83% of capacity. In this manner, a voltage may be applied to a subset of the windings of Fig. 12B in accordance with block 480 of Fig. 13.

[0226] Although a potential divider is illustrated in Fig. 12B, it will be understood by the skilled person that means other than a potential divider may be used to select the intermediate voltage provided to the terminal 281. Similarly, it will be understood by the skilled person that, if the windings are not balanced, an intermediate voltage other than the mid voltage may be used.

[0227] Although described largely in relation to cardiac pump, it will be understood that the present disclosure may be equally applicable to other implanted active medical devices, e.g., a pacemaker.

[0228] It will be appreciated by those skilled in the art that although the invention has been described by way of example, with reference to one or more exemplary examples, it is not limited to the disclosed examples and that alternative examples could be constructed without departing from the scope of the invention as defined by the appended claims.

Claims

Claims1. An implantable control unit for a medical device, the control unit comprising: a controller for controlling the medical device; a battery; and a coil for wireless transdermal energy transfer.

2. The control unit of claim 1 , wherein the control unit comprises an external housing containing the controller, the battery and the coil.

3. The control unit of claims 1 or 2, wherein the control unit comprises a plurality of coils stacked, interlaced or inclined relative to one another.

4. The control unit of any preceding claim, wherein the control unit comprises a first major surface providable subcutaneously, wherein the first major surface comprises a coil.

5. The control unit of any preceding claim, wherein the control unit comprises a circumferential minor surface and a coil is provided about the circumferential minor surface.

6. The control unit of claim 5, wherein the coil provided about the circumferential minor surface is provided inclined to a major surface of the control unit.

7. The control unit of any preceding claim, wherein the first major surface comprises an RFID chip, optionally provided centred within a coil provided on a first major surface.

8. The control unit of any of claims 4 to 7, wherein the first major surface comprises a permanent magnet or an electromagnet configured to be activated during charging of the battery.

9. The control unit of any of claims 4 to 8, wherein the control unit comprises a second major surface opposite the first major surface, the second major surface comprising a plurality of tabs extending therefrom for attaching the control unit to the ribs of a patient.

10. The control unit of any preceding claim, wherein the control unit comprises a driveline for electrical communication with the medical device, optionally wherein the driveline comprises an interconnector at its distal end for providing electrical communication with the medical device.

11. The control unit of any preceding claim, wherein the control unit comprises one or more LEDs.

12. The control unit of any preceding claim, wherein the control unit comprises a sensor on its exterior, the sensor comprising: an exposed region of the control unit housing; a sensor provided within the housing, optionally electrically isolated from the exposed region of the control unit housing; and / or a sensor provided on a feedthrough connector.

13. The control unit of any preceding claim, wherein the control unit is configured to determine a parameter of the patient, wherein the parameter comprises: an activity level of the patient; a heart rate of the patient; an electrical activity of the patient’s heart; a temperature of the tissues surrounding the control unit; an impedance of the tissues surrounding the control unit; and / or a blood oxygen saturation of the patient.

14. The control unit of any preceding claim, wherein in response to determining a change in heart rate and / or electrical activity of a patient’s heart, the control unit is configured to transmit a signal to the medical device for causing the medical device to change an operating condition.

15. The control unit of any preceding claim, wherein in response to determining that a parameter of the patient is outside of a predetermined range, the control unit is configured to transmit a signal, optionally to an extracorporeal device, including the value of the parameter and metadata describing the parameter.

16. The control unit of any preceding claim, wherein the control unit further comprises a port for receiving a percutaneous connector, the port comprising an electrical contact for providing electrical communication between the port and the connector.

17. The control unit of claim 16, wherein the port comprises a recess for receiving a protrusion of the connector, the recess comprising an electrical contact and a septum for penetration by the connector, the septum configured to maintain a fluid-tight seal within the recess before and after penetration, wherein the septum is set back from a mouth of the recess.

18. The control unit of claim 17, wherein the recess comprises a locking mechanism for retaining a connector received by the recess, wherein the locking mechanism comprises: a concave annulus provided about a circumference of the recess and configured to engage the connector such that a force required to remove the connector from the recess exceeds a force required to insert the connector; and / or a thread requiring a rotation of less than 180 degrees for engagement.

19. The control unit of any preceding claim, comprising:a first motor drive configured to be electrically coupled to a first winding arrangement comprising a first plurality of windings; and a second motor drive configured to be electrically coupled to a second winding arrangement comprising a second plurality of windings, wherein each winding arrangement forms part of a stator of a motor of the medical device, and wherein each motor drive is configured to: determine a positional parameter relating to an angular position of a rotor of the motor; and provide a synchronisation signal corresponding to the determined positional parameter to the other motor drive.

20. The control unit of claim 19, wherein the first motor drive is configured to: apply a voltage to each winding of the first winding arrangement based on the determined positional parameter and thereby drive the rotor; evaluate a fault criterion relating to whether the first winding arrangement, the first motor drive or an electrical coupling therebetween is in a fault condition; and in response to a determination that the fault criterion has been met: isolate a part of the first winding arrangement, the motor drive or the electrical coupling therebetween identified as being associated with the fault condition; and simultaneously apply a voltage to a subset of the windings of the first winding arrangement based on the synchronisation signal provided by the second motor drive.

21. The control unit of claim 20, wherein the first motor drive is configured to: in response to a determination that the fault criterion has been met: provide a fault and / or synchronisation signal to the other motor drive.

22. The control unit of claim 20 or claim 21 , wherein the first motor drive is configured to evaluate the fault criterion based on: a monitored current passing through the motor drive or the first winding arrangement; and / or a monitored voltage within first motor drive or the first winding arrangement.

23. The control unit of any preceding claim, comprising a motor drive configured to be electrically coupled to a winding arrangement comprising a plurality of windings, wherein: the plurality of windings are electrically coupled to each other at a centrepoint junction to form a wye configuration; the motor drive is configured to receive an input DC voltage from a power supply; and the motor drive is configured to supply an intermediate voltage to the centrepoint junction, the intermediate voltage being lower than the input DC voltage24. An implantable assembly comprising: a ventricular assist device; and a control unit for the ventricular assist device, the control unit being according to any of claims 1 to 23.

25. A method comprising: determining a parameter of the patient using the control unit of any of claims 12 to 15; determining that the parameter of the patient is outside of a predetermined range; transmitting, to an extracorporeal device, a signal including the value of the parameter and metadata describing the parameter.

26. The method of claim 25, comprising:varying an operating condition of a ventricular assist device in response to determining that the parameter is outside a predetermined range.

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