The present invention relates to an implantable medical device.

Generally, an implantable medical device may be any device which, in an implanted state, provides for a diagnostic and/or therapeutic function within the patient, such as a stimulation function, a sensing function, a monitoring function, a recording function and/or the like. The implantable medical device may be a device configured for cardiac applications such as a pacemaker or a cardiac stimulation device. However, it is not limited to cardiac applications, but for example may also be used for neuro-applications.

An implantable medical device may for example have the shape of a leadless stimulation device, such as a leadless pacemaker device. In this case a housing of the leadless pacemaker device encapsulates components of the leadless pacemaker device such as a processor, a data memory, a battery and other processing equipment to allow for operation of the leadless pacemaker device in an autarkic manner. The leadless pacemaker device may be implanted directly into a heart and may operate within the heart, for example within the right ventricle of the heart, without requiring any leads for placing an electrode at a location of interest within the heart.

The implantable medical device may also be a stimulation device which comprises a generator to be implanted for example subcutaneously at a location remote from the heart. In this case e.g. a lead extends from the generator into the heart to allow for a stimulation or a sensing of signals at a location of interest within the heart, for example within the right ventricle. An implantable medical device of this kind, for example a cardiac stimulation device such as a subcutaneous CRT device or a leadless pacemaker device, generally shall be implanted into the patient over a prolonged period of time, such that the implantable medical device remains operative within the patient over its lifespan. For this purpose, the implantable medical device typically comprises electrical components, such as an energy storage device in the form of a battery or a capacitor or a plurality of such devices, which shall power the implantable medical device for its operation.

Conventionally, an overall energy storage device of an implantable medical device is formed for example by an assembly of several electrical components such as battery or capacitor components. Therein, the multiple electrical components typically have to be electrically interconnected with each other and/or with an electronic module forming for example a core component of the medical device for implementing or controlling the intended diagnostic and/or therapeutic function. Accordingly, the electrical components forming energy storage devices may supply electricity to the electronic module.

Implantable medical devices of this kind shall be small in built such that they are easily implantable, for example subcutaneously or directly within the patient’s heart or in another vessel of interest. This requires electrical components comprised in the implantable medical device as well as their arrangement within the implantable medical device to be compact and space-efficient. Furthermore, a lifespan of an implantable medical device should be as long as possible. Accordingly, an energy storage capacity of electronic components forming an overall energy storage device for such medical device should be as large as possible. Generally, the energy storage capacity directly correlates with a volume of all electronic components forming the overall energy storage device. Furthermore, the electrical components shall generally be electrically interconnected in a manner such as to, on the one hand, enable sufficient power supply to the electronic module while, on the other hand, avoid significant energy losses for example due to electrical resistances. In addition, there is typically a desire to manufacture such electrical components as well as the entire implantable medical device in a cost-efficient manner while ensuring reliable operation of the implantable medical device over its lifespan. Unfortunately, at least some of the mentioned requirements are contradictory such that trade-offs may be needed. It is an object of the present invention to provide an implantable medical device which allows to beneficially fulfil the before mentioned requirements. Particularly, it is an object of the present invention to provide an implantable medical device allowing for a compact construction, a long lifespan, a high reliability and/or an easy manufacturing and assembling of the implantable medical device.

Such object may be met with the subject-matter of the independent claim. Advantageous embodiments are defined in the dependent claims as well as the corresponding specification and figures.

According to an aspect of the present invention, an implantable medical device comprising a housing, an electronic module, a plurality of electronic components and a plurality of interconnecting structures having an elongate extension is presented. The electronic module, the plurality of electronic components and the plurality of interconnecting structures are accommodated within the housing. The interconnecting structures are electrically connecting the electronic components with the electronic module. The housing comprises at least one partial volume in which a subgroup of the electronic components has a cross sectional area which fills between 80% and 99.5% of a cross section of the housing in the partial volume. At least one first interconnecting structure of the interconnecting structures extends from a first side of the partial volume through a remaining cross sectional area, which is not filled by the subgroup of the electronic components, to a second side of the partial volume opposite to the first side. Ideas underlying embodiments of the present invention may be interpreted as being based, inter alia, on the following observations and recognitions.

Briefly summarised in a non-limiting manner, embodiments of the implantable medical device presented herein may be particularly compact in construction. The compact construction may result from a beneficial arrangement and shape of multiple electronic components comprised in the housing of the medical device as well as from a beneficial configuration and arrangement of interconnecting structures for interconnecting the electronic components and the electronic module. Specifically, the configuration, arrangement and shape may be adapted such as to make optimal use of available space within the housing while at the same time enable limiting a number of different types of electronic components. In case the electronic components are energy storage devices such as batteries and/or capacitors, an available volume within the preferably rounded housing may be used efficiently such that a high energy storage capacity may be realized while at the same time reducing resistive energy losses in the interconnecting structures. Particularly, a partial volume within the housing is substantially filled with electronic components with regards to its cross sectional area while a remaining cross sectional area between neighbouring electronic components is used for accommodating interconnecting structures.

The medical device may be configured for being implanted into a human or animal body. Its size and shape may be adapted for being inserted into and accommodated in living tissue, e.g. in an available space or cavity in the body. The medical device may be configured for operating autonomously, i.e. without requiring energy from external sources.

The housing may form an outer shell of the medical device. It may enclose all components of the medical device including, inter-alia, the electronic module, the plurality of electronic components and the interconnecting structures as well as for example other components such as sensors, electrodes, etc. The housing may enclose the components in a tight, preferably hermetically sealed manner. The housing may be made from a sufficiently stable, non- corrosive material such as stainless steel or a plastic material. The housing may be made with a sheet material. Particularly, a wall forming the housing may have a substantially homogeneous thickness. Accordingly, an outer contour of the housing and an inside surface of the wall forming the housing may have a same or substantially same shape.

The housing preferably has a rounded shape. This means that at least some portions of the outer surface of the housing preferably have a rounded contour, i.e. are neither planar nor have sharp edges. The rounded portions of the housing may be curved in one or two dimensions. A curvature radius of the rounded portions may be in a same or similar order of magnitude of the dimensions of the housing. For example, with typical housing dimensions of between 2 cm and 20 cm, e.g. about 5 cm, typical curvature radii at the rounded portions may be between 1 mm and 3 m, preferably between 0.5 cm and 0.5 m. Having a rounded shape may mean that the housing preferably has no sharp edges along its entire outer surface. However, the characteristics of the shape does not necessarily exclude each and every sharp edge as long as the shape of the housing remains suitable for implantation applications. Due to the preferably rounded shape of its housing, the medical device may easily and without risks for injuries be inserted and accommodated in living tissue of the body.

The electronic module of the medical device may comprise electronic devices and/or circuitries configured for implementing and/or controlling functionalities of the medical device. For example, the electronic module may comprise a processor, a controller, data memory, a voltage transformer, a sensor, an electrode and/or other electronic devices for realizing therapeutic and/or diagnostic functionalities. The electronic module may comprise a printed circuit board (PCB) supporting and interconnecting the electronic devices mounted at the PCB. The electronic module may require a volume within the housing of the medical device, the volume having for example a rectangular cross-section.

The electronic components of the medical device may be components which support, cooperate and/or interact with the electronic module for establishing the functionalities of the medical device. Particularly, the electronic components may serve for supporting or enabling the autonomous operability of the medical device.

According to a specific embodiment, the electronic components are energy storage devices. Such energy storage devices may be for example primary batteries, i.e. non-rechargeable batteries, secondary batteries, i.e. rechargeable batteries, and/or capacitors. An energy storage capacity of such energy storage devices may be adapted for supplying enough electrical energy for the operation of the medical device during a typical lifespan of the medical device of for example several months or several years. Each of the electronic components is electrically connected to the electronic module, for example via interconnecting structures such as flexible electric wiring and/or rigid electric connectors.

The implantable medical device proposed herein differs from conventional medical devices, inter-alia, by the feature that its housing comprises at least one partial volume having specific characteristics. Such partial volume may contribute e.g. more than 20%, preferably more than 40% or even more than 60% to an entire inner volume within the housing. In the partial volume, a subgroup of the electronic components fills a substantial portion of the cross section of the housing. Specifically, a sum of cross-sectional areas of electronic components comprised in the subgroup shall fill at least 80%, preferably at least 90% or even more preferably at least 95% of the cross section of the housing in the partial volume. However, the electronic components of the subgroup shall not completely fill this cross-section. Instead, a remaining cross-sectional area shall be left unoccupied by electronic components. This remaining cross-sectional area shall be at least 0.5%, preferably at least 1% or at least 3% of the cross-sectional area of the housing in the partial volume. Such remaining cross- sectional area shall be used for accommodating at least one or some of the interconnecting structures in the medical device. Particularly, at least one first interconnecting structure shall be dimensioned and arranged such that it extends from a first side of the partial volume through the remaining cross-sectional area to an opposite second side of the partial volume. Accordingly, the at least one first interconnecting structure may primarily extend throughout the partial volume in a direction orthogonal to the plane in which the cross-sectional areas are measured.

Accordingly, such first interconnecting structure may establish an electrical connection between a first volume and a second volume within the housing, the first volume being arranged next to the first side of the partial volume and the second volume being arranged next to the second side of the partial volume. Therefore, for example further electronic components comprised in the first volume may be interconnected to the electronic module comprised in the second volume.

Particularly, the electronic components in the first volume may for example fill the first volume completely, i.e. to more than e.g. 99%, and their shape may be adapted to a shape of the first volume. The electronic components comprised in the partial volume arranged in between the first volume and the second volume may be configured with regard to their shapes and volumes such as to fill a substantial portion of this partial volume. However, their shapes and volumes shall be configured such that at least a minor remaining cross-sectional area is left unfilled in order to allow accommodating therein the at least one first interconnecting structure.

In other words, while the first volume may be completely filled with electronic components forming for example energy storage devices and the second volume may comprise the electronic module, the partial volume intermediate to these first and second volumes may be optimally filled with electronic components forming for example energy storage devices while leaving sufficient remaining cross-sectional area for accommodating the at least one first interconnecting structure for electrically interconnecting the electronic components in the first volume with the electronic module in the second volume.

According to an embodiment, at least some or preferably all of the electronic components of the subgroup have identical shapes. Therein, the term “identical shapes” may be interpreted in that an outer contour of the electronic components formed for example by a shell or housing is substantially identical within acceptable tolerances of for example less than 3% or less than 1%. However, in such embodiment, the electronic components may have different internal structures and/or functionalities.

According to a further specified embodiment, at least some of the electronic components of the subgroup have identical construction. Therein, the term “identical construction” may be interpreted in that the shapes, internal structures and functionalities of the electronic components are substantially identical.

Accordingly, of the plurality of electronic components comprised in the medical device, at least two electronic components included in the partial volume may be provided as electronic components being identical with regard to their shapes or their entire construction. The medical device may preferably exclusively comprise electronic components of such identical type within its partial volume. Alternatively, the medical device may comprise in its partial volume electronic components of two or more different types. The types may differ from each other with regard to their outer shape, their internal structure, their functionality and/or others physical characteristics. By providing at least some of the electronic components in the medical device as identical components, a number of different types of electronic components required for the medical device may be limited. Particularly, a number of different types of electronic components may be smaller than a number of electronic components in the medical device. For example, an overall energy storage capacity required for the medical device may be established with a multiplicity of energy storage devices of a limited number of types, preferably with only one or two or three or four types of energy storage devices.

Preferably, the identical electronic components of the same type are provided in the medical device in an even number, i.e. there are preferably 2, 4, 6, etc. identical electronic components of a same type comprised in the same housing. Accordingly, the identical electronic components of a same type may be provided and may preferably be arranged in pairs. Such pairs of electronic components may for example be arranged symmetrically within the housing of the medical device.

Each of the electronic components may be comprised in an individual shell. Such shell may enclose an inner volume of the electronic component. This shell may be rigid thereby giving the electronic component a specific outer contour. In the case of the electronic component being a battery or a capacitor, the shell may be formed by a housing enclosing internal structures such as electrodes of different polarity and/or an electrolyte.

In the medical device proposed herein, shapes of the shells of the electronic components may be specifically adapted to comply with the shape of the housing of the entire medical device. Specifically, at least one or preferably several or all of the electronic components may be arranged within the housing with a partial shell area of its shell being adjacent to a partial housing area of the housing. In other words, one or more of the electronic components may be comprised in the housing such that at least a portion of their shell abuts to or is mechanically supported by an inner surface of the wall forming the housing. The partial shell area may constitute for example more than 10%, preferably more than 20% or even more than 30% of the overall area of the shell of the electronic component. Therein, the shell or shells of the respective one or more electronic components may be specifically configured such that its partial shell area has a shape which is substantially complementary to the preferably rounded shape of the housing in the partial housing area.

Herein, “substantially complementary” may be interpreted in that an outer contour of the partial shell area may be complementary to an inner contour of the wall of the housing in the partial housing area to an extend such that the partial shell area may abut to the wall at least along more than 50%, preferably along more than 80% or even along more than 95% of its surface area. According to an alternative interpretation, “substantially complementary” may mean that any gaps between the outer contour of the partial shell area and the inner contour of the wall of the housing in the partial housing area may occur at most locally along the surface extension of the partial shell area and shall be smaller than for example 10%, 5% or even 1% of a dimension of the electronic component in the direction of the gap and/or smaller than for example 10 mm, 5 mm or even 1 mm. Furthermore, “substantially complementary” may mean that the outer contour of the partial shell area is substantially parallel to the inner contour of the wall of the housing in the partial housing area.

Due to the electronic components being provided with shells having a substantially complementary shape at least in partial areas with respect to the housing, the electronic components may be accommodated within the housing in a space saving manner. However, as the housing shall preferably have a rounded shape, this implies that also the shell(s) of the electronic component(s) may have a rounded shape at least in partial areas thereof. Generally, electronic components having a rounded shell shape may be more complex to design and/or fabricate than for example electronic components with planar surfaces. However, in order to use most of the available space within the housing of the medical device in order to for example maximise an energy storage capacity of energy storage devices forming the electronic components, additional efforts for designing and/or fabricating electronic components with complex rounded shapes may be acceptable.

According to an embodiment, at least one of the electronic components of the subgroup has a rounded lateral surface adjacent to the remaining cross sectional area. In other words, one or more of the electronic components forming the subgroup may have a rounded shape with rounded surfaces not only at a side directed to the housing of the medical device, such rounded surfaces being complementary to the inner surface of the housing, but with rounded surfaces also at a side directed to the remaining cross-sectional area. Accordingly, due to such rounded surfaces, a gap may form between one of the electronic components comprised in the partial volume and a neighbouring other one electronic component, this gap forming the remaining cross-sectional area through which the first interconnecting structure may extend. Particularly, the rounded lateral surface being adjacent and complementary to the shape of the housing and the rounded lateral surface adjacent to the remaining cross-sectional area may have identical or symmetrical shapes.

According to an embodiment, the at least one first interconnecting structure has a cross sectional area which fills at least 80% of a cross section of the remaining cross sectional area.

In other words, the cross-sectional areas of the electronic components comprised in the partial volume and the cross-sectional area of the at least one first interconnecting structure comprised in the partial volume may be adapted such that the at least one first interconnecting structure fills to a major extend, i.e. to at least 80%, preferably at least 90% or even at least 95%, the remaining cross-sectional area not being filled by the subgroup of electronic components. Accordingly, substantially the entire cross-sectional area of the housing in the partial volume may be filled with the combination of electronic components of the subgroup and the at least one first interconnecting structure. Thus, the available cross- section and volume within the partial volume in the housing may be used to a maximum.

According to an embodiment, the at least one first interconnecting structure comprises an elongate carrier element which at least in portions thereof laterally abuts to lateral surfaces of electronic components of the subgroup. Therein, the at least one first interconnecting structure further comprises an electric line accommodated within the carrier element.

Expressed differently, the at least one first interconnecting structure may be formed with an electric line embedded in a carrier element. The electric line may consist of an electrically conductive material such as a metal whereas the carrier element may comprise or may consist of an electrically isolating material such as a polymer. Accordingly, the carrier element may form an isolating coating or cladding enclosing the electric line. Therein, the carrier element may be dimensioned such that its cross-section substantially fills the remaining cross- sectional area between adjacent electronic components. Accordingly, the carrier element may abut with its outer lateral surface to lateral surfaces of adjacent electronic components of the subgroup comprised in the partial volume of the housing. Thereby, available space is used to a maximum while establishing sufficient electrical isolation as well as mechanical support between the electrical components and the first interconnecting structure.

According to an embodiment, neighbouring electronic components within the subgroup are separated from each other via an electric isolation structure. Therein, the at least one first interconnecting structure is embedded within such isolation structure. In other words, the electronic components comprised in the partial volume of the housing may be electrically isolated with regard to each other via intermediate electric isolation structures. Such electric isolation structures may have a substantial thickness such that the at least one first interconnecting structure may be incorporated therein. Thereby, the interconnecting structure may be accommodated within the partial volume in a very space saving manner.

According to an embodiment, electronic components of the subgroup are fixed at the housing via a fixation structure and/or are fixed at a neighbouring electronic components of the subgroup via a fixation structure. Therein, the at least one first interconnecting structure is embedded within such fixation structure.

In other words, the electronic components comprised in the partial volume of the housing may be fixed to the housing and/or neighbouring electronic component via a fixation structure. Such fixation structures may have a substantial thickness such that the at least one first interconnecting structure may be incorporated therein. Thereby, the interconnecting structure may be accommodated within the partial volume in a very space saving manner. According to an embodiment, the at least one first interconnecting structure comprises at least at one of opposite ends a contact structure for electrically contacting at least one of the electronic components and the electronic module. Expressed differently, the first interconnecting structure may comprise at one or both of opposite ends a contact structure. One or more of the electronic components and/or the electronic module of the medical device may electrically contact such contact structure. Accordingly, the interconnecting structure contacted via the contact structure to such electronic component or module may establish an electrical connection to another electronic component or module, respectively, arranged and contacted at the opposite end of the interconnecting structure. The contact structure may be configured such that the electrical contact may be established using for example soldering, welding, crimping or other contacting techniques. According to another embodiment, the at least one first interconnecting structure comprises at least at one of opposite ends a plug-in connector for electrically contacting at least one of the electronic components and the electronic module.

The plug-in connector may enable a releasable electrical connection between the first interconnecting structure and the electronic component or module. The plug-in connector may be e.g. one of a plug or a socket, i.e. a male or a female connector element, adapted for cooperating with a corresponding counterpart.

According to an embodiment, at least one of several following conditions may apply: (i) a minimum cross sectional dimension of the at least one first interconnecting structure is at least 0.05 mm, preferably at least 0.1 mm or at least 0.5 mm;

(ii) the at least one first interconnecting structure has an electrical resistance of less than 10 Ohm, preferably less than 1 Ohm or less than 0.1 Ohm, between opposite ends of its elongate extension; (iii) the at least one first interconnecting structure is configured to conduct electrical currents of more than 100 mA, preferably more than 1 A or more than 10 A. Due to such characteristics, the at least one first interconnecting structure may enable preventing resistive losses upon transmitting substantial electric power.

According to an embodiment, the at least one first interconnecting structure is configured for electrically connecting a first electric contact arranged at the first side of the partial volume with a second electric contact at the second side of the partial volume along a shortest possible path.

Thus, the first interconnecting structure preferably extends along a straight line for interconnecting the first electric contacts contacting for example an electric component at the one side of the partial volume to the second electric contacts contacting for example the electric module at the opposite side of the partial volume. Due to such electrical interconnection extending along a shortest possible path, electrical resistances and corresponding electrical resistance losses along the first interconnecting structure may be minimized.

According to an embodiment, windings of a coil extend through the remaining cross sectional area.

Such windings of a coil may extend through same portions of the remaining cross-sectional area which also accommodate the at least one first interconnecting structure. Accordingly, the windings may extend in parallel to such interconnecting structure and may be electrically isolated from such interconnecting structure. Alternatively, the windings may extend through separate portions of the remaining cross-sectional area, i.e. in a gap between neighbouring electric components where no first interconnecting structure is accommodated.

The coil may e.g. serve for establishing a wireless communication between the implantable medical device and a distant programming device. Alternatively, the coil may serve for establishing wireless transmission of electromagnetic energy, for example for recharging secondary batteries or capacitors. According to an embodiment, the electronic components are electrically connected to the electronic module but not mechanically supported to a major extend by the electronic module.

In other words, while each of the electronic components may supply electric energy to the electronic module for example via electric lines comprised in the interconnecting structures, the electronic component shall not be mounted or fixedly connected to the electronic module in a manner such that its weight or mass is held to a major extend by the electronic module. Instead, the electronic components may be substantially separate components with regard to a mechanical connection to the electronic module. The weight and mass of each electronic component may be mechanically supported to a major extend by a mechanical connection for example to the housing of the medical device. Such mechanical support may be easily established upon fabricating the medical device.

It shall be noticed that the applicant of the present application filed further applications simultaneously with the present application. These further applications have the titles “Implantable medical device with a compact construction” and “Method for fabricating an implantable medical device with a simplified interconnection scheme and corresponding implantable medical device”. Embodiments of an implantable medical device are described in these further applications and features and characteristics of such embodiments may be applied or adopted to embodiments of the implantable medical device described in the present application. Accordingly, the content of the further applications shall be incorporated herein in their entirety by reference.

It shall be noted that possible features and advantages of embodiments of the invention are described herein with respect to various embodiments of an implantable medical device. One skilled in the art will recognize that the features may be suitably transferred from one embodiment to another and features may be modified, adapted, combined and/or replaced, etc. in order to come to further embodiments of the invention. In the following, advantageous embodiments of the invention will be described with reference to the enclosed drawings. However, neither the drawings nor the description shall be interpreted as limiting the invention. Fig. 1 very schematically shows a sectional representation through an implantable medical device according to an embodiment of the present invention.

Figs. 2 to 6 show cross sectional representations through a partial volume of implantable medical devices according to embodiments of the present invention.

Fig. 7 represents various options of interconnecting structures for implantable medical devices according to embodiments of the present invention.

The figures are only schematic and not to scale. Same reference signs refer to same or similar features.

Fig. 1 shows a schematic representation of an embodiment of an implantable medical device 1. The medical device 1 comprises a housing 3 in which an electronic module 5, plural electronic components 7 and several interconnecting structures 9 are accommodated.

In the represented example, two different types of electronic components 7’, 7” are included in the housing 3, the electronic components 7’ of a first type having another geometry than the electronic components 7” of a second type. For example, electronic components 7’ of the first type may be capacitors 41, whereas electronic components 7” may be batteries 39. In the example, two identical electronic components 7’ of the first type and two identical electronic components 7” of the second type are comprised in the common housing 3. The electronic components 7 are electrically connected to the electronic module 5 via the interconnecting structures 9. An entire volume within the housing 3 may be regarded as comprising several regions. Therein, a partial volume 11 is centred between a lower volume at a first side 15, in which some 7” of the electronic components 7 are accommodated, and an upper volume at a second side 19, in which the electronic module 5 is accommodated. In the example shown in Fig. 1, the partial volume 11 forms more than 40% of an entire inner volume of the housing 3.

The partial volume 11 accommodates a subgroup 13 of the electronic components 7. A sum of all cross-sectional areas of all electronic components 7’ included in the subgroup 13 makes up more than 80% of a cross-sectional area of the housing 3 in the partial volume 11. In other words, the electronic components 7’ fill the partial volume 11 to a major extend such that their combined cross-sectional areas fill more than 80% of the cross section of the housing 3. Therein, the cross-sectional areas are regarded in a cross-sectional plane A-A as indicated in Fig. 1.

However, the electronic components 7’ of the subgroup 13 do not completely fill the partial volume 11. Instead, a remaining cross-sectional area 17 is left unfilled. Such remaining cross-sectional area 17 may provide between 0.5% and 20%, preferably between 0.5% and 5%, of the cross-sectional area of the housing 3. However, such remaining cross-sectional area 17 does not remain unused. Instead, such remaining cross-sectional area 17 includes at least one first interconnecting structure 10.

Therein, the first interconnecting structure 10 extends from the first side 15, where it is for example contacting one of the electronic components 7” comprised in the lower volume of the housing 3, to the second side 19 of the partial volume 11, where it is for example contacting the electronic module 5 comprised in the upper volume of the housing 3.

Preferably, the first interconnecting structure 10 extends linearly, thereby interconnecting an electric contact at the first side 15 with an electric contact at the second side 19 along a shortest possible path.

Figs. 2 to 6 show cross sectional representations along the plane A-A indicated in Fig. 1 through the partial volume 11 of implantable medical devices 1 according to embodiments of the present invention. As shown in the figures, some or preferably all of the electronic components 7’ comprised in the subgroup 13 filling the partial volume 11 have an identical shape or even an identical construction. Accordingly, with the exception of the remaining cross-sectional area 17, the entire partial volume 11 may be filled with a single type of electronic components 7’. This may substantially simplify fabricating and assembling the medical device 1, as no multiplicity of different electronic components 7 has to be provided and installed. In the example shown, two columns of electronic components 7’ are provided within the subgroup 13, each column comprising three electronic components 7’ stacked next to each other.

In the embodiments shown in Figs. 2 - 4, the housing 3 has a shallow shape with rounded lateral sides. The electronic components 7’ are provided with cross-sectional shapes which are specifically adapted to comply with such a rounded shape of the housing 3. Specifically, the electronic components 7’ comprise a rounded lateral surface 24, 25 at one of their lateral sides, the rounded lateral surfaces 24, 25 being substantially complementary to the rounded shape of the housing 3 at least in partial areas thereof.

In all embodiments shown in Figs. 2 - 4, uppermost and lowermost component 7’ in the two columns are arranged such that their lateral rounded surfaces 24 are directed towards a neighbouring rounded partial area of the housing 3. Thereby, the uppermost and lowermost components 7’ may fill the respective portion of the partial volume 11 to a maximum.

However, the electronic component 7’ in the middle of each of the two columns may not be arranged such as to completely fill the available space within the partial volume 11. Instead, a remaining cross-sectional area 17 is left unfilled. In the embodiments shown in Figs. 2 and 3, such remaining cross-sectional area 17 is arranged at a centre of the housing 3, whereas in the embodiment shown in Fig. 4, the remaining cross-sectional area 17 is arranged close to opposite lateral sides of the housing 3. In each case, the electronic components 7’ in the middle of the column are arranged such that the rounded lateral surface 25 of the electronic components 7’ is adjacent to the remaining cross-sectional area 17.

In the embodiments shown in Figs. 5 and 6, the housing 3 again has a shallow shape with rounded lateral sides. However, the electronic components 7’ comprised in the partial volume 11 do not have substantially rounded shapes but have a substantially rectangular cross-section. The electronic components 7’ are nevertheless arranged within the partial volume 11 such as to fill the cross section of the partial volume to more than 80%. For such purpose, the electronic component 7’ in the middle between an uppermost and a lowermost electronic component 7’ may for example be laterally offset such as to partially extend into the rounded lateral side of the housing 3. Accordingly, a remaining cross- sectional area 17’ may be generated at a centre between two of such middle electronic component 7’. Furthermore, remaining cross-sectional areas 17” may be generated between the uppermost and lowermost electronic components 7’ and a rounded portion of the housing 3 at its lateral side.

Alternatively, without laterally offsetting the middle electronic component 7’, a remaining cross-sectional area 17’” may be generated at the rounded lateral side of the housing 3.

The remaining cross-sectional area(s) 17 may be used for accommodating one, two or more first interconnecting structures 10. Therein, the first interconnecting structure 10 typically comprises an electrically conductive line 29. Such line 29 may be included in a carrier element 27. Such carrier element 27 may be electrically isolating. For example, the carrier element 27 may be a coating or a cladding or another flexible or rigid element laterally enclosing the line 29.

Preferably, the entire at least one first electronic component 7’ including the line 29 and the carrier element 27 may substantially fill the available cross-section of the remaining cross- sectional area 17, i.e. may have a cross-sectional area of e.g. more than 80% of the remaining cross-sectional area 17. Accordingly, the carrier element(s) 27 of the first interconnecting structure(s) 10 may laterally abut to lateral surfaces of the electronic components 7’ in the subgroup 13. Thereby, a cross-section of the line 29 may be maximised, thereby minimising its electrical resistance, and isolation provided by the carrier element 27 may be optimised and/or the first interconnecting structure(s) may mechanically stabilise the entire arrangement of electronic components 7’ and intermediate interconnecting structures 10 within the partial volume 11 of the housing 3.

Optionally, windings 43 of a coil may be comprised in at least one of the remaining cross- sectional areas 17. Such coil may transmit electromagnetic signals and/or electromagnetic energy.

As schematically visualised in Fig. 6, the electronic component 7’ of the subgroup 13 may be comprised in a mounting structure forming an isolation structure 21 and/or a fixation structure 22. The isolation structure 21 separates neighbouring electronic components 7’ from each other. The fixation structure 22 fixes the electronic components 7’ with regard to the housing 3 and/or with regard to neighbouring electronic components 7’ in the partial volume 11. Through-holes 23 may be included in such isolation/fixation structure 21, 22 and the at least one first interconnecting structure 10 may be embedded within the isolation/fixation structure 21, 22 in such through-holes 23.

Fig. 7 visualises various options for establishing electric contacts 30 at ends of an electrically conductive line 29 of a first interconnecting structure 10. While various options are shown in the same figure, only one or a small number of these options may be implemented in a real interconnecting structure 10.

For example, the first interconnecting structure 10 may comprise a contact structure 31 at one or each of opposing ends of the line 29. An electronic component 7 or the electronic module 5 arranged at one of the opposing upper and lower sides 15, 19 of the partial volume 11 may electrically contact the first interconnecting structure 10 via such contact structure 31. For example, corresponding contact structures of such electronic component 7 or electronic module 5 may be soldered, welded, crimped or connected in another manner to the contact structure 31.

Alternatively, the first interconnecting structure 10 may comprise a plug-in connector 37 at one or each of its opposing ends. Such plug-in connector 37 may be formed with a plug 33 or with a socket 35. Accordingly, the plug-in connector 37 may interact with a suitable counterpart provided for example at an adjacent electronic component 7 or at the electronic module 5. Thus, a releasable electrical connection may be established.

Finally briefly summarising, embodiments of the approach described herein may provide for an implantable medical device 1 being particularly compact due to a high packing density of its components. Simultaneously, more options are created for designing the shape of medical device 1. Electrically conductive lines 29 having a large cross-section may be included in the first interconnecting structures 10. This may enable arranging electronic components 7 such as energy storage devices at locations being remote to the electronic module 5, although high electric currents may have to be transferred between the electronic components 7 and the electronic module 5. Overall, this may enable adapting a shape of the electronic modules 7 comprised in the housing 3 to a preferably rounded shape of the housing 3 of the medical device 1. Finally, it should be noted that the term “comprising” does not exclude other elements or steps and the “a” or “an” does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.

List of Reference Numerals

I implantable medical device

3 housing 5 electronic module

7 electronic component

9 interconnecting structure

10 first interconnecting structure

I I partial volume 13 subgroup of electronic components

15 first side of the partial volume

17 remaining cross-sectional area

19 second side of the partial volume

21 isolation structure 22 fixation structure

23 through-hole

24 rounded lateral surface adjacent to housing

25 rounded lateral surface adjacent to remaining cross-sectional area

27 carrier element 29 electric line

30 electric contact

31 contact structure

33 plug

35 socket 37 plug-in connector

39 battery

41 capacitor

43 winding of a coil