DE202020107059U1 - Use of an electrically conductive thread to reduce the volume of an implantable heart monitor - Google Patents

Abstract

Implantable heart monitor (1), comprising:
- a housing (2) for surrounding an electronic circuit which is configured for recording an electrocardiogram of a patient,
- A first and a second electrode (3, 4) which are designed for deriving the electrocardiogram, the first electrode (3) being arranged at a free end (5a) of an elongated and flexible element (5) which is connected by a first End (21) of the housing (2) protrudes, and wherein the second electrode (4) is arranged at a second end (22) of the housing (2) opposite the first end (21).

Description

The present invention relates to an implantable cardiac monitor (also referred to as ICM for implantable cardiac monitor). Such devices are sometimes also referred to as loop recorders.

Smaller integrated circuits combined with smaller battery technology have made it possible in the past decade to significantly reduce the volume of such implantable cardiac monitors (ICM).

However, the continuation of this development will lead to ICMs with an increasingly shorter EKG vector. However, the quality of a surface EKG (SECG for surface electrocardiogram) recorded by an ICM depends in particular on the length of the EKG vector (the amplitude of the SECG signal is linearly proportional to the distance between the EKG poles), so that the aforementioned progressive miniaturization of ICMs in the classic form will lead to SECGs with a correspondingly poorer “signal-to-noise” ratio. In addition, if the housing of the heart monitor is very small, the device will more easily tend to move away from its original implantation site.

• - ein verlängerter SECG-Vektor wird zwischen der nicht isolierten Spitze (erster EKG-Pol 300) und dem gegenüberliegenden Ende 301 des Gehäuses 200, an dem eine Silikonbeschichtung entfernt wurde (zweiter EKG-Pol 301), erzeugt.
• - Die Verlängerung 100 dient zusammen mit dem Gehäuse 200 auch als Dipolantenne für die „Fernfeld“-HF-Telemetrie, hier im 402 - 405 MHz „MICS-Band“, zur Kommunikation mit einem weiteren medizinischen Gerät, das z.B. zur Auswertung und/oder Weiterleitung der vom Herzmonitor aufgenommenen Daten (z.B. SECG der den ICM tragenden Person) dient.

ICMs known in the prior art, for example in 1 shown, have a longitudinal extension 100 of the housing 200 serves the following purposes:

• - an extended SECG vector is placed between the non-isolated tip (first EKG pole 300 ) and the opposite end 301 of the housing 200 , from which a silicone coating has been removed (second EKG pole 301 ), generated.
• - The extension 100 serves together with the housing 200 also as a dipole antenna for the "far field" HF telemetry, here in the 402 - 405 MHz "MICS band", for communication with another medical device, for example for evaluating and / or forwarding the data recorded by the heart monitor (e.g. SECG of the the person wearing the ICM).

Based on this, the invention is based on the object of providing an implantable heart monitor which is improved with regard to the aforementioned problem of shortening the EKG vector, with a further aim to prevent movement of the device away from the implantation site.

This object is achieved by an implantable heart monitor with the features of claim 1.

Advantageous embodiments and further aspects of the invention are to be described below.

• - einem Gehäuse zum Einhausen einer elektronischen Schaltung des Herzmonitors, die zum Aufnehmen eines Elektrokardiogramms (z.B. SECG) eines Patienten dient,
• - einer ersten und einer zweiten Elektrode, die zum Ableiten des Elektrokardiogramms ausgebildet sind, (die Elektroden werden auch als erster bzw. zweiter EKG-Pol bezeichnet), wobei die erste Elektrode an einem freien Ende eines längserstreckten und flexiblen Elements des Herzmonitors angeordnet ist, wobei das längserstreckte und flexible Element von einem ersten Ende des Gehäuses abragt, und wobei die zweite Elektrode an einem dem ersten Ende gegenüberliegenden zweiten Ende des Gehäuses angeordnet ist.

According to claim 1, an implantable heart monitor is disclosed with:

• - a housing for housing an electronic circuit of the heart monitor, which is used to record an electrocardiogram (e.g. SECG) of a patient,
• - A first and a second electrode, which are designed to derive the electrocardiogram, (the electrodes are also referred to as the first and second EKG pole, respectively), the first electrode being arranged at a free end of an elongated and flexible element of the heart monitor, wherein the elongated and flexible element protrudes from a first end of the housing, and wherein the second electrode is arranged at a second end of the housing opposite the first end.

The housing of the heart monitor is preferably made of a metal, the metal preferably being titanium or a titanium alloy. The housing is preferably surrounded by electrical insulation, which leaves the second end of the housing free so that the second end can contact surrounding tissue and can accordingly act as a second electrode.

The fact that the flexible element is an elongated element means in the context of the invention, in particular, that the element has a significantly larger extension in the direction of its longitudinal extension than transversely to this direction, which corresponds to the outer diameter of the element. The direction of longitudinal extension of the element furthermore preferably coincides with the longitudinal axis of the housing.

The elongated and flexible element preferably has an outer diameter that is many times smaller than a corresponding outer diameter of the housing in the same direction. The outer diameter of the elongated and flexible element is preferably in a size range from μm to mm.

The elongated and flexible element can in particular be a thread which can consist of individual filaments or fibers, for example. The thread or the elongated and flexible element is preferably surrounded by electrical insulation apart from one end section, the end section (at the free end of the thread or the element) forms the said first electrode.

The elongate and flexible element or the thread can in particular be designed to be limp.

Furthermore, the implantable cardiac pacemaker can have an HF dipole antenna which is formed by the elongate and flexible element or the thread and by the conductive housing.

The relatively thin, elongated and flexible element or the thread can advantageously grow into the surrounding tissue after the implantation and thus stabilize the position of the implantable heart monitor at the implantation site. During explantation, the elongated element / thread can be pulled out of the tissue like a typical "suture thread" due to the small outer diameter.

The present invention thus compensates for the disadvantageous effects of miniaturization through the use of a conductive thread or a conductive, elongated and flexible element that serves as an EKG lead and RF antenna and also prevents the heart monitor (ICM) from moving away from its implantation site solves. Compared to the prior art, the volume of the extension of the housing is thus reduced, the length of the EKG vector being able to be maintained and, furthermore, a shape of the heart monitor resulting which helps the heart monitor to be held better at its implantation site.

Another aspect of the present invention relates to an implantation tool for implanting a heart monitor according to the invention.

According to the invention it is provided that the implantation tool has a distal first cutting tool for inserting the element (or thread) and a proximal second cutting tool for inserting the housing of the heart monitor.

The first cutting tool has, perpendicular to an insertion direction or longitudinal extension direction of the first cutting tool, an outside diameter that is smaller than an outside diameter of the second cutting tool.

The first cutting tool is preferably shaped such that it introduces the element or the thread having the first electrode. The first cutting tool can, for example, be designed as a needle that holds the element or the thread. If a particularly spherical body is attached to the distal end of the element / thread (see below), this first cutting tool can be forked in order to hold the body (“spherical cutter”). The second cutting tool is preferably shaped so that it introduces the housing of the ICM (“housing cutting tool”).

• 1 aus dem Stand der Technik bekannte ICMs, die eine Verlängerung des Gehäuses aufweisen, um einen entsprechend langen EKG-Vektor zu erfassen. Er dient auch als RF-Antenne im MICS-Band;
• 2 eine Ausführungsform eines erfindungsgemäßen implantierbaren Herzmonitors aufweisend einen dünnen und flexibler Faden, der als EKG-Pol und Antenne verwendet wird;
• 3 ein aus dem Stand der Technik bekanntes Implantationswerkzeug, insbesondere zur Verwendung mit dem in der 1 gezeigten ICM;
• 4 eine Ausführungsform eines Implantationswerkzeugs für einen erfindungsgemäßen implantierbaren Herzmonitor (z.B. gemäß 2); und
• 5 ein Zurückziehen des Implantationswerkzeugs nach Art der 4.

Embodiments of the invention and further features and advantages of the invention are to be explained below with reference to the figures. Show it:

• 1 ICMs known from the prior art which have an extension of the housing in order to record a correspondingly long EKG vector. It also serves as an RF antenna in the MICS band;
• 2 an embodiment of an implantable heart monitor according to the invention having a thin and flexible thread which is used as an EKG pole and antenna;
• 3 an implantation tool known from the prior art, in particular for use with the one in FIG 1 ICM shown;
• 4th an embodiment of an implantation tool for an implantable heart monitor according to the invention (for example according to 2 ); and
• 5 a retraction of the implantation tool in the manner of 4th .

2 shows an example of an embodiment of an implantable heart monitor (ICM) according to the invention 1 . An elongated and flexible element is used here 5 , e.g. in the form of a thread 5 , as the first electrode 3 and especially as part of an antenna. The element 5 is outside of an enclosure 2 of the ICM 1 except for a free end 5a that is the first electrode 3 forms, from electrical insulation 6th and can have an electrical feedthrough 7th (so-called feedthrough) into the housing 2 of the ICM 1 be led. The implementation 7th can optionally be in a header 8th of the housing 2 be arranged (the implementation 7th can also be done directly on the housing 2 be arranged). About the implementation 7th is the element 5 with an electrical circuit of the ICM 1 connected, which enables the recording of an EKG (e.g. SECG).

The element or the thread 5 is designed to be electrically conductive so that the element 5 Can conduct EKG or SECG signals and form an HF antenna dipole.

If desired, the conductive material can be biocompatible (e.g. titanium). Conductive stainless steel filaments are commercially available.

Simulations suggest that every part of the element or thread 5 that is more than 2 cm from the housing 2 distant, acts as a good RF antenna; the gain is expected to be ~ -30 dBi at both MICS and Bluetooth frequencies, which is good for an antenna implanted in body tissue.

Preferably there is the outer insulating layer 6th of the element / thread 5 made of a silicone.

This isolation 6th can at the distal (free) end 5a of the element / thread 5 , e.g. ~ 1 cm, can be removed during the production process. This end section 5a of the element / thread 5 serves as the first electrode 3 to record the EGK or SECG.

The element 5 or the thread 5 goes from a first end 21st or from the header 8th (if present) of the housing 2 from. A first end 21st or the header 8th opposite second end 22nd of the housing 2 forms a second electrode 4th that along with the first electrode 3 serves to derive the EKG or SECG. The case 2 is also, except for the second end 22nd , from electrical insulation 10 surrounded, which can for example consist of a silicone.

Furthermore, at the distal end of the element 5 or the thread 5 a small body 9 (e.g. a ball, especially with a diameter d ~ 1 mm) made of biocompatible material. This body 9 is used to hold or grasp the element / thread 5 during implantation (see 3 to 5 ) and also serves as an extension of the surface of the first electrode 3 especially if the body 9 has a fractal surface. Instead of a ball 9 another shape suitable for explantation (eg an ellipsoid) can also be used.

The header 8th of the ICM 1 is optional; it only serves as a rounded shape or outer surface to prevent any sharp edges of a classic implementation from touching the body tissue.

With regard to a heart monitor according to the invention 1 suitable implantation tool 11 there is the possibility of this according to the tool used for known ICMs 3 derive. Instead of the nozzle 12 (in the dashed box) could be the implantation tool 11 a needle at the distal end 13 (drawn as a solid line). Instead of a needle 13 Other geometries or cutting tools, for example in the form of a syringe, can also be used.

Exemplary details of the implantation tool 11 , especially parts of the tool 11 that are inserted into the patient's tissues are in the 4th (“Introducing the ICM”) and in the 5 ("Pulling out the implantation tool").

4th shows an embodiment of an implantation tool according to the invention 11 , in which 4th in particular the introduction of the heart monitor 1 represents in the patient's body.

According to 4th instructs the implantation tool 11 a first (thinner) cutting tool distally 13 on that is shaped to be the element 5 or the thread 5 (including insulation 6th , first electrode 3 and possibly body 9 ) into the patient's tissue. The first cutting tool 13 be designed as a needle (see also above) that the element 5 or the thread 5 holds. If for example a ball 9 (or an alternative body 9 ) on the element / thread 5 is attached, this first cutting tool 13 eg forked around the ball or the body 9 to hold (the first cutting tool can therefore also be used as a ball cutter 13 are designated). The second (larger) proximal cutting tool 14th is shaped so that it is the case 2 of the ICM 1 into the patient's tissue (by cutting free) (the second cutting tool is therefore also used as a housing cutter 14th designated).

5 particularly shows the process of withdrawing the implantation tool 11 . The cutting tools move here 13 , 14th away from the patient (here as an example to the right), with the element 5 or the thread 5 remains in the implanted position and the second cutting tool 14th opens in such a way that the housing 2 remains in its implanted position.

The goal of the implantation tool 11 is to cut (injure) as little body tissue as possible during insertion. According to 4th therefore has the first cutting tool 13 on the left of the 4th exactly the size to pave the way for the item 5 or the thread 5 to provide. This first cutting element 13 can, as already stated above, be designed like a needle, the element 5 or the thread 5 is threaded onto the needle, for example in an eyelet, wherein in particular the eyelet is arranged at the tip of the cutting tool, and the non-fixed part of the element 5 or the fade 5 protrudes into the interior of the cutting tool, preferably over a length of about 1 cm. When the end of the element 5 or the thread 5 a body 9 which preferably has a shape suitable for explantation, such as, for example, a sphere or an ellipsoid, is the cutting tool 13 designed to receive or hold the body. For example, the tip of the cutting tool can be forked or split in order to be able to receive or hold the body. The second cutting element 14th To protect the patient's tissue, it also has only one size which is dimensioned such that there is just a corresponding path for inserting the housing 2 of the ICM 1 can be created.

When the case 2 of the ICM 1 is completely inserted or implanted, the implantation tool 11 withdrawn, e.g. analogous to ICM implantation procedures. When removing the tool 11 (see. 5 ) becomes the needle or the first cutting tool 13 so withdrawn that the ball 9 and the thread 5 remain in their respective positions. The second cutting tool also opens 14th an outlet opening for the housing 2 that is, for example, on an abutment 15th of the tool 11 can support and remains in its implanted position.

The solution according to the invention has the advantages that the volume of the ICM according to the invention 1 while maintaining the length of the EKG vector and the antenna characteristic is reduced. The implantation along the element 5 or the thread 5 takes place with a needle or a first cutting tool 13 and is therefore simpler and associated with less tissue injury. By waxing the element 5 or the thread 5 prevents the ICM 1 leaves the implantation site. That way future ICMs 1 take full advantage of smaller batteries and electronics.

Claims (1)

Implantable heart monitor (1), comprising: - a housing (2) for surrounding an electronic circuit which is configured for recording an electrocardiogram of a patient, - A first and a second electrode (3, 4) which are designed for deriving the electrocardiogram, the first electrode (3) being arranged at a free end (5a) of an elongated and flexible element (5) which is connected by a first End (21) of the housing (2) protrudes, and wherein the second electrode (4) is arranged at a second end (22) of the housing (2) opposite the first end (21).

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