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Technical field

The disclosure relates to sensing cardiac function .

One or more embodiments may relate to a cardiac function sensor adapted for implantation at a valvular annulus of a patient's body.

Background

Various sensors have been proposed for detecting e.g. the dynamics of opening and closing of leaflets in heart valve prostheses, optionally by detecting physiological parameters such as blood pressure or blood flow, acoustic signals, pH or other parameters.

Such sensors and the related detection techniques may be exposed to various factors which may affect e.g. long term reliability when implanted chronically.

This may be due, e.g. to the implantation environment and the inflammatory response of the human body: for instance, a fibrotic capsule grown around the sensor may lead to progressive alteration in the sensor response .

A sensor may thus be unable to provide reliable and correct operation over time, so that operation of an associated monitoring system may be adversely affected. Object and summary

The object of one or more embodiments is to provide improved sensing devices, e.g. for overcoming the problems outlined above.

In one or more embodiments, that object is achieved by means of a sensor and/or an implant device having the features set forth in the claims that follow .

The claims are an integral part of the disclosure of one or more embodiments as provided herein.

One or more embodiments may be configured to sense the kinematics of the valvular plane of the heart by using at least one kinematic sensor.

In one or more embodiments such a sensor may be configured to sense the kinematics of the valvular plane of the heart, e.g. by being coupled with an implant device located at or in proximity of the valvular plane of the heart.

One or more embodiments may sense displacement of the valvular plane during the cardiac cycle also in the presence of a fibrotic capsule.

One or more embodiments may make it possible e.g. to monitor and measure the displacement in space and time of the valvular plane, thus providing information on functionality of the heart and/or of an implant device such as e.g. a heart valve prosthesis.

One or more embodiments may include a sensor device, adapted to be coupled e.g. to a prosthetic heart valve or an annuloplasty ring, for implanting at a valvular annulus site of a patient's heart, in combination with a tracking system (for instance, wireless e.g. RF) which may permit to track the sensor device within the patient's body and sense kinematic parameters of the sensor device implanted e.g. at a valvular annulus site in the body of a patient.

In one or more embodiments the kinematic parameters sensed may be any of e.g. position, speed, acceleration and a kinematic sensor may be a sensor capable of sensing (and possibly measuring) such parameters with these parameters indicative of the motion of the patient's valvular plane. One or more embodiments may include an implant device, such as e.g. a prosthetic heart valve or an annuloplasty ring, for implanting at a valvular annulus site of a patient's heart, in combination with a tracking system (for instance, wireless e.g. RF) which may permit to track the implant device within the patient's body and sense kinematic parameters of the implant device implanted at a valvular annulus site in the body of a patient.

In one or more embodiments, function of a patient's heart may be tested, with possible malfunction detected, by sensing the motion of the patient's valvular plane as a function of the kinematic parameters sensed.

Brief description of the figures

One or more embodiments will now be described, by way of example only, with reference to the annexed figures, wherein:

- Figures 1 and 2 are exemplary of displacement of the valvular plane of the heart,

- Figures 3 to 7 are exemplary schematic views of sensing apparatus for use with one or more embodiments,

- Figure 8 is an exemplary block diagram of a sensing system for use with one or more embodiments,

Figures 9 to 11 are exemplary diagrams of signals which may be generated in one or more embodiments ,

Figure 12 is exemplary of use of a device according to one or more embodiments,

Figure 13 is a partly exploded view of the portion of Figure 12 indicated by the arrow XIII, reproduced on an enlarged scale,

Figure 14 is exemplary of use of a device according to one or more embodiments, - Figure 15 is a partly broken plan view of the device of Figure 14,

- Figure 16 is an enlarged perspective view of one of the elements shown in Figure 15,

- Figure 17 is a perspective view exemplary of a variant of the element of Figure 16,

- Figure 18 is a view exemplary of a variant of a portion of the element of Figure 17,

Figure 19 is exemplary of use of a device according to one or more embodiments, and

- Figure 20 is sectional view along line XX-XX of Figure 19 reproduced on an enlarged scale.

Detailed description

In the ensuing description various specific details are illustrated, aimed at providing an in-depth understanding of various examples of embodiments. The embodiments may be obtained without one or more of the specific details, or with other methods, components, materials, etc. In other cases, known structures, materials, or operations are not illustrated or described in detail so that the various aspects of the embodiments will not be obscured.

Reference to "an embodiment" or "one embodiment" in the framework of the present description is intended to indicate that a particular configuration, structure, or characteristic described in relationship to the embodiment is comprised in at least one embodiment. Hence, phrases such as "in an embodiment" or "in one embodiment" that may be present in various points of the present description do not necessarily refer to one and the same embodiment. Moreover, particular conformations, structures, or characteristics may be combined in any adequate way in one or more embodiments. Non-limiting and non-exhaustive embodiments are described with reference to the figures, wherein like references relate to like parts throughout the various figures unless otherwise specified. The references used herein are provided merely for convenience and hence do not define the extent of protection or the scope of the embodiments. The sizes and relative positions of elements in the figures are not necessarily drawn to scale. For example, the shapes of various elements and angles are not drawn to scale, and some of these elements may be enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn are not intended to convey any information regarding the actual shape of the particular elements and have been solely selected for ease of recognition in the drawings.

The myocardium fibres exhibit a complex structure with a helical structure e.g. left-handed helix in the sub epicardium and right-handed helix in the sub endocardium.

Various types of deformation of the myocardium may mutually interact during the cardiac cycle to contribute to cardiac output e.g. longitudinal shortening, circumferential shortening, wall thickening and torsion or rotation. For instance, the longitudinal function currently referred to as longitudinal shortening of the ventricle may be related to cardiac output .

Figures 1 and 2 are schematic vertical cross sections of a heart during the diastolic and the systolic phases, respectively.

The figures schematically show the locations of the heart valves, namely the tricuspid valve TV and the mitral valve MV located between the atria RA (right) and LA (left) and the ventricles RV (right) and LV (left), as well as the pulmonary valve PV and the aortic valve AV through which blood flows from the ventricles RV and LV into the pulmonary artery PA and the aorta AV, respectively.

The valves TV, MV, PV, AV may be regarded as notionally lying in a common plane, called the valvular plane VP.

In passing from the diastolic phase (Figure 1) to the systolic phase (Figure 2) the valvular plane VP undergoes a movement VPD towards the apex A of the heart (e.g. at least approximately "downwards", in a human standing upright) by pumping blood from the left ventricle LV towards the aorta AO and from the right ventricle RV towards the pulmonary artery PA, while facilitating return of blood into the right and left atria RA and LA, respectively.

In passing from the systolic phase (Figure 2) to the diastolic phase (Figure 1) also due to elastic recoil of the myocardial fibres previously contracted, the ventricles LV, RV relax, and the valvular plane VP returns to its initial position (e.g. moving at least approximately "upwards", in a human standing upright) by facilitating ventricles filling with blood coming from the atria.

The valvular plane displacement VPD and the velocity of the valvular plane VPV contribute to the cardiac mechanism in manner which may be compared to the operation mechanism of a piston in a (rectilinear) volumetric pump.

In a healthy heart, the valvular plane displacement VPD may have a value of 15-25mm; this may correspond to a reduction of the length of the ventricles RV, LV of about 25% from the diastolic phase to the systolic phase.

Due to the helical structure of the myocardium fibres, the valvular plane displacement VPD may be associated with the torsional (e.g. twisting) movement of the heart about its longitudinal axis during systole which may be compared to the wringing of a linen cloth to squeeze out the water.

In the presence of cardiac dysfunction, the mechanism described in the foregoing may be altered. In patients suffering from heart failure, the valvular plane displacement VPD may be reduced more than 50% with respect to healthy subjects.

Heart failure is one of the main causes of death and hospitalization of the whole world population bound to further increase due to the progressive aging of the population .

Patients affected by heart failure or with a tendency to develop such disease may have indication for heart valve repair or replacement by implanting implant devices of various types, such as e.g.:

implant devices including a purely annular structure, that is without prosthetic leaflets, aiming at restoring the correct anatomical shape and size of a natural valve which has been altered due to pathologies; annuloplasty rings may be exemplary of such implant devices,

- implant devices including one or more leaflets adapted to act as obturators to control blood flow through the prosthesis; prosthetic heart valves may be exemplary of such implant devices.

Leaflets of such implant devices may include a variety of structures e.g. flexible leaflets (optionally including biological tissue of animal origin, in so-called "biological" valves) or tilting obturators in the case of "mechanical" valves.

Also, such heart valve prostheses may include an armature or stent e.g. to support the leaflet (s); in so-called "stentless" valves such a support structure is not present.

Implantation techniques for such devices may be various and include e.g. by conventional open-heart surgery, or various types of non-invasive or minimally- invasive surgery, such as transapical-surgery or transcatheter techniques.

One or more embodiments may rely on the recognition that - irrespective of their structure, principle of operation and implantation technique such implant devices may be implanted at or in proximity of the valvular plane VP and thus undergo the same displacement VPD of the valvular plane VP.

Sensing (e.g. monitoring) kinematic parameters, that is parameters of motion such as e.g. one or more of displacement, velocity, acceleration, and so on at the implanted device may permit to sense corresponding parameters of the valvular plane VP.

Figures 3 to 7 are schematically representative of various systems which may permit to sense kinematic parameters of an implant device 100 (e.g. a prosthetic heart valve) implanted at a valvular annulus site in the body of a patient P.

Kinematics is the branch of mechanics that deals with motion (e.g. pure motion, without reference to the masses or forces involved) . Kinematic parameters are thus the parameters of motion (position, speed, acceleration, and so on) and a kinematic sensor is a sensor capable of sensing (and possibly measuring) such parameters.

For instance, Figure 3 is exemplary of a "wireless" system with an electromagnetic transceiver array 300 including e.g. excitation/receiving coils embedded in a, possibly removable, pad set between the backrest of a chair C and the back of a patient P sitting in that chair. The implant device 100 may include (coupled therewith as better detailed in the following) a sensor including a "beacon" transponder (e.g. of an inductive type) which may be electromagnetically tracked via the transceiver array 300.

Figure 4 is exemplary of a wireless system where an electromagnetic transceiver array 300 including e.g. excitation/receiving coils embedded in a, possibly removable, pad set between the surface of a bed B and the back of a patient P lying on that bed. The implant device 100 may again include (coupled therewith as better detailed in the following) a sensor including a "beacon" transponder (e.g. of an inductive type) which may be electromagnetically tracked via the transceiver array 300.

Figure 5 is exemplary of an tracking system with an external unit 400 including e.g. a pad including antennas for Transcutaneous Energy Transfer (TET) , e.g. for ASIC powering, and/or data transmission; such a pad may be conveniently held by the patient P himself or herself, e.g. when sitting in a chair C. The implant device 100 may then include (coupled therewith as better detailed in the following) a sensor such as an accelerometer plus associated signal processing circuitry (e.g. ASIC) which permit "inertial" tracking of the sensor via the external unit 400.

Figures 6 and 7 are illustrative of the possibility of arranging (e.g. embedding) an external unit 400 as discussed previously in a removable band G worn by the patient P, e.g. around the chest. Again, the implant device 100 may include a sensor suited for being tracked "inertially" via the external unit 400.

Tracking systems as considered in the foregoing are commercially available from various sources. Systems such those available under the commercial designations of 3D Guidance TrackSTAR from Ascension Technology Inc. of Burlington, VT, USA (see www . ascension-tech . com/ ) , Aurora from Northern Digital Inc. of Waterloo, Ontario Canada (see www . ndigital . com/medical/products/aurora/ ) , Fastrack from Polhemus Inc. of Colchester, VT, USA (see www . polhemus . com) , or Calypso 4D Localization system from Varian Medical Systems of Palo Alto, CA, USA (see www .varian . com/euit/oncology/ imaging solutions/calypso/ are exemplary of electromagnetic tracking systems (EMTS) .

Other integrated EMTS solutions include, e.g.

CARTO XP from Biosense-Webster Inc. of Diamond Bar, USA, InstaTrak (ENTrak) from General Electric of

Fairfield, CT, USA, the AxiEM add-on to the

StealthStation from Medtronic of Minneapolis, MN, USA or Syncro-Blue Tube form SyncroMedical Innovations,

Inc. of Macon , GA, USA.

Such systems may employ e.g. AC-driven tracking, pulsed DC-driven tracking or passive or transponder systems .

Also, such systems may be of the "wired" type including a field generator to create an electromagnetic field as the coordinate reference system and a set of wired sensor coils forming a transponder in the reference field or of "wireless" type where the transponder cannot send out the signal collected from the reference field and the tracking process involvers an excitation step followed by a "ring-back" step.

Inertial tracking systems may include various types of e.g. accelerometric sensors.

The sensors available under the commercial designations of Micropower 3-Sensor (e.g. ADLX335) from Analog Devices, the MEMS LIS2DE sensor from ST Microelectronics or the SCG12S, SCG14S, SCG10X, or SCG10Z MEMS elements from Murata are exemplary of sue sensors .

The diagrams of Figures 9 and 10 are exemplary of the possible time behaviour of the sensing signals which may be generated in a electromagnetic tracking system (EMTS) including a motion sensor (kinematic sensor) having plural motion detection axes, e.g. X, Y and Z forming a three-dimensional Cartesian system, that is with three mutually orthogonal axes.

The diagrams of Figure 9 refer to an alternate, approximately sinusoidal movement of an amplitude of about 16 mm taking place along the Z axis (ΔΖ ¾ 16 mm), while motion along the two other axes is negligible (ΔΧ = ΔΥ ¾ 0 mm) .

By way of comparison, the diagrams of Figure 10 refer to a signal generated by the same system for an alternate, approximately sinusoidal movement of substantially the same amplitude taking place primarily along the Z axis (ΔΖ ¾ 15 mm) , with motion components also along the two other axes (ΔΧ ¾ 3 mm; ΔΥ ¾ 5 mm) .

The foregoing indicates that even if the modulus of the sensing signal (e.g. (ΔΧ ² +ΔΥ ² +ΔΖ ² ) ^1/2 ) is considered, the accuracy of detection may be primarily dictated by the coupling of the sensor to the device 100, that by the ability of the sensor to follow and sense faithfully the movement of the implant device with the valvular plane.

By way of reference, the diagrams of Figure 11 report the time behaviour of various kinematic signals such as e.g. an acceleration signal (diagram a) mm/s ² ) , a velocity signal (diagram b) - mm/s) and a displacement signal (diagram c) - mm) detected by means of an ADXL335 sensor from Analog Devices. A corresponding displacement signal as detected by using an inductive sensor is shown in diagram d) .

The block diagram of Figure 8 is generally exemplary of an electronic circuit 3 adapted to be coupled with an implant device 100 and an associated data transmission system 30 adapted to cooperate with the circuit 100 in order to permit transmission of information (e.g. data) from - and possibly towards - the device. In one or more embodiments as exemplified herein remote powering (e.g. via Transcutaneous Energy Transfer or TET) of the circuit is provided.

It will be appreciated that the exemplary disclosure provided in connection with Figure 8 is essentially functional, in that exemplary processing functions which may be performed by the electronic circuit coupled with the implant device 100 and the associated data transmission system will be described.

How such data/signal transmission may be effected at the "physical" level, that is what types of electromagnetic signals will be transmitted, may be dictated by the technology adopted e.g. EMTS/inertial, wired/wireless, AC-driven, DC-driven, passive and so on .

In one or more embodiments, the circuit 3 may include at least one antenna 103 (e.g. radio-frequency or RF antenna) for permitting signal transmission with respect to the system 30 as described in the following.

In one or more embodiments, the antenna 103 may extend over the whole of the, e.g. annular, structure of the implant device 100. In one or more embodiments, the antenna 103 may extend over a part of the structure of the implant device 100.

In one or more embodiments, the electronic circuit 3 may include at least one integrated circuit (microchip) 203 which may be coupled to a kinematic sensor 4, i.e. a sensor adapted to detect kinematic, that is motion parameters such as displacement, velocity, acceleration, and so on along one or more motion detection axis axes X, Y, Z (see e.g. Figs 9 to 11) .

In one or more embodiments, such a cardiac function sensor 4 may sense cardiac function at a cardiac valvular annulus site traversed by blood in a blood flow direction. In one or more embodiments, the sensor 4 may include a kinematic sensor having at least one motion detection axis, the sensor configured to be arranged at a cardiac valvular annulus site with the at least one motion detection axis aligned with the blood flow direction.

In one or more embodiments, an implant device for implanting at a valvular annulus site may be provided having a longitudinal axis (adapted to extend in the blood flow direction) between a blood inflow end and a blood outflow end, the device including a kinematic sensor 4 having at least one motion detection axis, the sensor arranged with said at least one motion detection axis aligned with said longitudinal axis.

In one or more embodiments, coupling of the sensor 4 to the microchip 203 may be through a block 5 such as an Application-Specific Integrated Circuit or ASIC block configured for cooperation with a radio- frequency (RF) transmitter/receiver (transceiver) 6. In one or more embodiments, the transceiver 6 may be configured for receiving and transmitting signals via the antenna 203. In one or more embodiments, a power feed unit (e.g. of a capacitive type) 7 may be included in order to provide energization of the circuit 3.

In one or more embodiments the exchange of signals (information) between the circuit 3 (to be coupled with the device 100 and thus implanted within the body of a patient P) the system 30 (external to the patient's body) may be via a detector 8 adapted to be located (e.g. via a handling fixture 108) at the thorax portion T of the patient's body at e.g. a distance D to the circuit 3.

The detector 8 may include at least one antenna 9 (e.g. a RF antenna such as the antenna 103 of the circuit 3) coupled with a radio-frequency (RF) transmitter/receiver (transceiver) 10. In one or more embodiments the transceiver 10 may include an amplifier (e.g. of the Monolithic Microwave Integrated Circuit - MMIC type) coupled with a microprocessor 11.

In one or more embodiments, the processor 11 may be coupled with a detection/display module/circuit 12 for detecting and possibly displaying the displacement VPD of the valve plane VP (see e.g. Figures 1 and 2) .

In one or more embodiments, the system 30 may optionally also include any of a memory block 13, an apparatus (e.g. a modem) 14 for remote transmission of the data as detected and a power supply unit 15.

In one or more embodiments, the system 30 may be incorporated to a single instrument optionally of the hand-held type (essentially resembling a cellular phone or tablet) .

In one or more embodiments, the system 30 may be incorporated to a single entity with an electromagnetic transceiver array 300 or an external unit 400 as depicted in Figures 3 to 7 : see e.g. the hand-held pad illustrated in Figure 5.

In one or more embodiments, the system 30 may operate as a transmitter whereby e.g. the unit 10 (acting under the control of the microprocessor 11) may transmit via the antenna 9 a radio frequency (RF) signal 16.

In one or more embodiments, signals (e.g. RF) sent from the control unit 30 (e.g. the detector 8) to the circuit 3 implanted in the patient's body may include RF power feed energy for the circuit 3.

In one or more embodiments such signal may include, in addition to information (i.e. query) signals directed towards the circuit 3, also electromagnetic energy for energizing the circuit 3. The signal 16, once received via the antenna 103 of the unit 6 may produce on the module 7, via electromagnetic induction, the energy for powering the circuit 3 and permit operation thereof. In one or more embodiments this may also include energy for powering the sensor 4.

In one or more embodiments, the unit 5 may detect kinematic signals related to the spatial movement of the sensor 4 (which may be indicative of the displacement of the valvular plane VP) for transmission to the system 30.

In one or more embodiments the transmission of such information (116) may be via the antenna 103 transmitting signals to the unit 30.

Such signals may be captured by the antenna 9 and received by the unit 10, optionally to be processed by the microprocessor 11 to produce information related to the displacement of the valvular plane VP.

In one or more embodiments the related information may be displayed via the unit 12, stored in the unit 13 and/or transmitted via the unit (e.g. modem) 14 to a remote control unit e.g. for diagnostic purposes .

Those of skill in the art will appreciate that the description of the circuit 3 and the control unit 30 as provided herein is for exemplary purposes only.

Some or all of the modules/ functions exemplified herein may be differently implemented in hardware, software, firmware, or a combination or sub-combination of hardware, software, and firmware e.g. by a hardwired or firmware-configured circuit such as e.g. an ASIC, an FPGA, or any other circuit/system described via VHDL and synthetized.

In one or more embodiments, signals as those exemplified in Figures 9 to 11 (displacement, velocity, acceleration, and so on) may be obtained from a kinematic sensor 4 either as a signal directly output from the sensor 4 or a signal resulting from processing an output from the sensor 4 before and/or after this is transmitted to the control unit 30.

For instance, in one or more embodiments, corresponding displacement-velocity-acceleration signals as exemplified in parts a) , b) and c) of Figure 11 may be the outcome of processing (e.g. integration) as performed e.g. in the microprocessor 11.

In one or more embodiments, a sensor 4 integrated in an implant device 100 may provide, in addition to a signals related to the valvular plane displacement, also other parameters related to the functionality of the heart and/or of the implant device 100.

In one or more embodiments, processing of such signals may involve e.g. calculating (e.g. as the derivative of the displacement) the velocity at which the valvular plane VP displaces, optionally at each point of the displacement movement.

In one or more embodiments, such signals may include peaks, e.g. negative peaks, corresponding to the heart beat. The amplitude of those peaks with respect to a base (e.g. zero) level of the signal may be indicative of the characteristics of displacement of the valvular plane VP.

The parameters (e.g. the amount) of the valvular plane displacement may provide an indication of the cardiac functionality of a patient and/or of the correct operation of the implant device 100 e.g. a heart valve prosthesis.

Effective operation of one or more embodiments may then be related to factors such as:

- the capability of coupling the sensor 4 (and the circuit 3) to the implant device 100 without affecting the implantation process (which may involve e.g. collapsing the device 100 onto a delivery instrument for positioning at the implantation site, deploying and anchoring the device 100 at such site) and the ability of the device to perform its intended function (e.g. as a prosthetic valve),

- the ability of the sensor 4 to sense in an accurate manner, e.g. without "spurious" displacement, the movement of the device 100 primarily in the directions of its longitudinal axis extending between the blood inflow end and the blood outflow end.

Implant devices for implanting at a valvular annulus site may be implanted with such longitudinal axis substantially perpendicular to the valvular plane

VP.

One or more embodiments may thus provide for such a device including a kinematic sensor 4 having at least one motion detection axis (e.g. axis Z in the diagrams of Figure 9 and 10) aligned with the longitudinal axis extending between the blood inflow end and the blood outflow of the device.

Figures 12 to 20 are exemplary of various types of implant devices adapted to include such a sensor 4.

For instance, Figures 12 and 13 (Figure 13 being a partly exploded view of the portion of Figure 12 indicated by the arrow XIII, reproduced on an enlarged scale) are exemplary of a heart valve prosthesis HV which may be implanted at a valvular annulus site (e.g. aortic) with the capability of facilitating blood flow along a main axis A from a blood inflow end IF to a blood outflow end OF while countering flow in the opposite direction, that is from the blood outflow end OF to the blood inflow end IF.

In one or more embodiments, such a heart valve prosthesis HV may include an e.g. meshed stent structure S to support one or more (e.g. three) valve leaflets VL .

In one or more embodiments the stent structure S may be of an expandable type (e.g. balloon-expandable or self-expanding) from a radially collapsed insertion condition to an expanded condition at the implantation site .

Such a heart valve prosthesis HV (adapted for implantation e.g. by conventional open-heart surgery, or various types of non-invasive or minimally-invasive surgery, such as transapical-surgery or transcatheter techniques) may be of a conventional type in the art: this makes it unnecessary to provide a more detailed description herein.

In one or more embodiments, a kinematic sensor 4 as discussed in the foregoing may be coupled to the heart valve prosthesis HV in such a way that the sensor 4 may have at least one motion detection axis (e.g. Z) aligned with (e.g. parallel to) the inflow-outflow longitudinal axis A of the heart valve prosthesis HV.

In one or more embodiments, the stent structure S of the heart valve prosthesis HV may include a plurality (e.g. three) longitudinal struts SI, S2, S3 angularly aligned with the valve "commissures" defined by the valve leaflets VL .

In one or more embodiments, the kinematic sensor 4 may be coupled with one of the longitudinal struts (e.g. SI ) .

In one or more embodiments, coupling may be e.g. by adhesion (glueing) , soldering and/or form coupling, optionally to provide rigid coupling of the sensor 4 to the stent structure S, that is the support structure of the device HV.

For instance, in one or more embodiments one of the struts (e.g. SI) may be provided with a longitudinal channel-like formation 40 including two side walls 40a adapted to receive and retain therebetween the sensor 4, with the channel-like formation 40 extending parallel to the longitudinal axis L of the valve prosthesis HV.

In one or more embodiments, the sensor 4 may be in the form of (small) cylindrical bar adapted to be inserted (e.g. slid axially) between the side walls 40a.

In one or more embodiments, the motion detection axis (e.g. Z) of the sensor 4 may be aligned with the axis of the cylindrical shape. In that way, inserting the sensor between the side walls 40a of the longitudinal channel-like formation 40 will lead to the motion detection axis (e.g. Z) of the sensor 4 being aligned with the inflow-outflow longitudinal axis A of the heart valve prosthesis HV.

In one or more embodiments, location of the sensor 4 at one of the valve commissures may thus be obtained .

Also, in one or more embodiments, the arrangement just described will make it possible to obtain that the sensor 4 may not be exposed (at least directly, due to the presence of the valvular sheath including the valve leaflets VL) to blood flow within the valve prosthesis HV. Avoiding direct exposure to blood flow was found to improve accuracy of the sensing action.

While coupling (only) one sensor 4 with the valve prosthesis HV is exemplified herein, one or more embodiments may contemplate coupling plural sensors 4 with the valve prosthesis HV. Coupling three sensors, one for each longitudinal strut SI, S2, S3 may be exemplary of such an arrangement, which may increase sensing reliability due to sensor redundancy.

Figures 14 to 16 (with Figure 15 being a partly broken plan view of the device of Figure 14 and Figure 16 an enlarged perspective view of one of the elements shown in Figure 15) are exemplary of another heart valve prosthesis BV which may be implanted at a valvular annulus site.

This may be again with the capability of facilitating blood flow along a main axis A from a blood inflow end IF to a blood outflow end OF while countering flow in the opposite direction, that is from the blood outflow end OF to the blood inflow end IF.

In one or more embodiments, such a heart valve prosthesis BV may include a stent structure S, e.g. of a semi-rigid plastics material, to support one or more (e.g. three) valve leaflets VL.In one or more embodiments, the heart valve HV may include a sewing ring SR for sewing at the (annular) implantation site. In one or more embodiments, the sewing ring SR may include a resilient structure with an outer covering of a bio-compatible fabric such as e.g. Dacron ^(R) to permit passing sewing stitches through the sewing ring structure .

The prosthesis BV may be of a conventional type in the art (e.g. a so-called "biological" valve prosthesis, both of the stented type exemplified herein or of the stentless type) which makes it unnecessary to provide a more detailed description herein.

In one or more embodiments, a kinematic sensor 4 as discussed in the foregoing may be coupled to the heart valve prosthesis BV e.g. by locating it in the sewing ring SR, such that the sensor 4 may have at least one motion detection axis (e.g. Z) aligned with (e.g. parallel to) the inflow-outflow longitudinal axis A of the heart valve prosthesis HV: see e.g. the plan view of Figure 15.

In one or more embodiments, the sensor may be coupled with (e.g. carried by) a stabilizing platform 42 e.g. a small board or plate of a bio-compatible material (plastics or metal) .

In one or more embodiments, the stabilizing platform 42 may include a crescent-shaped member (e.g. to match the circular shape of the sewing ring SR) and/or be provided with openings such as holes 42a to permit passing of sewing stitches to secure the platform 42 to the sewing ring.

In that way the sensor may be located and retained in a stable, fixed condition on the sewing ring SR and the valve prosthesis BV with its motion detection axis (e.g. Z) aligned with the inflow-outflow longitudinal axis A of the heart valve prosthesis BV.

In one or more embodiments, the sensor 4 may be located at one of the valve commissures. In one or more embodiments, as illustrated in Figure 15, the sensor 4 may be located between, e.g. approximately midway, two adjacent commissures.

Again, in one or more embodiments, the arrangement just described will make it possible to obtain that the sensor 4 may not be exposed (at least directly, due to the presence of the valvular sheath including the valve leaflets VL) to blood flow within the valve prosthesis HV. As noted, avoiding direct exposure to blood flow was found to improve accuracy of the sensing action.

In one or more embodiments as exemplified in Figures 15 and 16, the sensor 4 may be in the form of (small) cylindrical bar adapted to be inserted into an annular receiving seat 42b in the platform 42, the seat 42b having its axis parallel to the longitudinal axis A of the heart valve prosthesis BV.

In one or more embodiments, the motion detection axis (e.g. Z) of the sensor 4 may again be aligned with the axis of the cylindrical shape. In that way, inserting the sensor 4 in the annular receiving seat 42b in the platform 42 will lead to the motion detection axis (e.g. Z) of the sensor 4 being aligned with the inflow-outflow longitudinal axis A of the heart valve prosthesis HV.

In one or more embodiments as exemplified in Figure 17 and 18, the sensor 4 may be in the form of a prismatic (e.g. cube-like) body adapted to be inserted into a quadrilateral receiving seat 42b in the platform 42.

In one or more embodiments, a "marker" 44, e.g. of a radiopaque material, may facilitate mounting the sensor 4 (e.g. inserting the sensor 4 in the annular receiving seat 42b in the platform 42) so that the motion detection axis (e.g. Z) may be aligned with the inflow-outflow longitudinal axis A of the heart valve prosthesis BV (or HV, in the case of embodiments as exemplified in Figures 12 and 13) .

In one or more embodiments, the marker 44 may be in the form of e.g. a small bar provided (e.g. glued or soldered) onto the casing of the sensor 4 in such a way that the orientation of the marker 44 indicates the direction of the axis Z. e.g. by being parallel thereto .

Again while coupling (only) one sensor 4 with the valve prosthesis BV is exemplified herein, one or more embodiments may contemplate coupling plural sensors 4 with the valve prosthesis BV e.g. in order to increase sensing reliability due to sensor redundancy.

Figures 19 and 20 (Figure 20 being a sectional view along line XX-XX of Figure 19 reproduced in an enlarged scale) are exemplary of an implant device in the form of an annuloplasty ring AR adapted to be implanted at a valvular annulus site. An annuloplasty ring for implantation at a mitral valve annulus site is exemplary of such an implant device.

An annuloplasty ring AR as exemplified in Figures 19 and 20 may be implanted at an annulus site with the patient's valve leaflets left in place to permit blood flow from an inflow end IF to a blood outflow end OF while countering flow in the opposite direction, that is from the blood outflow end OF to the blood inflow end IF.

While not provided with valve leaflets VL as the heart valve prostheses HV, BV discussed previously, the ring AR will again exhibit a longitudinal axis extending between a blood inflow end IF and a blood outflow end OF. Also, in one or more embodiments, such a ring AR may exhibit a sort of elliptical shape (which may be referred to as a "D" shape) thus having a longer axis and a shorter axis.

In one or more embodiments, such an implant device AR may include an e.g. D shaped ring-like support core K (closed ring or split-ring, plastic or metal), onto which a sewing fabric SF (e.g. Dacron ^(R) to permit passing sewing stitches) may be provided, possibly with the interposition of a soft "filler" F.

The annuloplasty ring AR may be of a conventional type in the art, which makes it unnecessary to provide a more detailed description herein.

In one or more embodiments, the kinematic sensor 4 may be coupled with the ring AR by being coupled to either of the sewing fabric SF (e.g. by resorting to a platform 42 as discussed previously in connection with Figures 14 to 17) or the support core K (e.g. as exemplified in Figures 19 and 20) .

In one or more embodiments, coupling may be e.g. by adhesion (glueing) , soldering and/or form coupling, optionally to provide rigid coupling of the sensor 4 to the core structure K.

For instance, in one or more embodiments the core K may be provided with a longitudinal channel-like formation 40 including two side walls 40a adapted to receive and retain therebetween the sensor 4. The formation 40 may be essentially as depicted in Figures 12 and 13 save for the provisions of two arms 48 for coupling to the core C in such a way that the channel- like structure of the formation 40 may extend in the direction of the axis A of the ring AR.

In one or more embodiments, the sensor 4 may be in the form of (small) cylindrical bar adapted to be inserted (e.g. slid axially) between the side walls 40a.

In one or more embodiments, the motion detection axis (e.g. Z) of the sensor 4 may be aligned with the axis of the cylindrical shape. In that way, inserting the sensor between the side walls 40a of the channel- like formation 40 will lead to the motion detection axis (e.g. Z) of the sensor 4 being aligned with the inflow-outflow longitudinal axis A of the heart valve prosthesis HV.

In one or more embodiments, the formation 40 may be provided at the outer side of the core C and/or at the longer axis of the quasi-elliptical (e.g. D-shape) core C.

Such arrangement will make it possible to obtain that the sensor 4 may not be exposed (at least directly to blood flow within the ring AR and/or that the sensor 4 is located at a position less exposed to ring deformation induced by the pulsating heart. Again, such an arrangement was found to improve accuracy of the sensing action.

While coupling only one sensor 4 with the implant device ( annuloplasty ring) AR is exemplified herein, one or more embodiments may contemplate coupling plural sensors 4 with the device AR, which may increase sensing reliability due to sensor redundancy.

One or more embodiments may thus include a cardiac function sensor for sensing cardiac function at a cardiac valvular annulus site traversed by blood in a blood flow direction, wherein the sensor includes a kinematic sensor having at least one motion detection axis (e.g. Z), the sensor configured (e.g. 100; HV; BV; AR) to be arranged at said cardiac valvular annulus site with said at least one motion detection axis aligned with said blood flow direction.

One or more embodiments may include a marker indicating the orientation of said motion detection axis to permit alignment with said blood flow direction .

One or more embodiments may thus include an implant device for implanting at a valvular annulus site, the device having a longitudinal axis extending between a blood inflow end (e.g. IF) and a blood outflow end (e.g. OF), the device including a kinematic sensor having at least one motion detection axis, the sensor arranged with said at least one motion detection axis aligned with said longitudinal axis.

One or more embodiments may include a support structure (e.g. S; C) wherein the kinematic sensor (4) is coupled, optionally rigidly, to said support structure .

One or more embodiments may include a channel- like formation (e.g. 40) for receiving the sensor therein, said channel-like formation optionally aligned with said longitudinal axis of the implant device.

One or more embodiments may include a cylindrical bar insertable in said channel-like formation.

One or more embodiments may include a heart valve prosthesis (e.g. HV) including valve leaflets (e.g. LV) having commissures therebetween, the sensor located either at one of said commissures or between two adjacent ones of said commissures.

One or more embodiments may include a heart valve prosthesis, wherein the sensor is located unexposed to blood flow within the valve prosthesis.

One or more embodiments may include an annuloplasty ring (e.g. AR) having a longer axis and a shorter axis, and the sensor may be located at said longer axis.

One or more embodiments may include a resilient sewing ring (e.g. SR) for sewing at said valvular annulus site, wherein the sensor is located at said sewing ring.

One or more embodiments may include a stabilizing platform (e.g. 42) supporting the sensor at said sewing ring .

In one or more embodiments the stabilizing platform may:

include a plate-like, preferably crescent- shaped, member and/or

- be provided with passageways (e.g. 42a) for stitches to secure the platform to a sewing ring.

In one or more embodiments the sensor may include a marker (e.g. 44) indicating the orientation of said motion detection axis to permit alignment with the longitudinal axis of the implant device.

Without prejudice to the underlying principles, details and embodiments may vary, even significantly, with respect to what has been described in the foregoing by way of example only without departing from the extent of the protection.

The extent of protection is determined by the following claims.