EP0806973A1

EP0806973A1 - Device for stimulating excitable tissue

Info

Publication number: EP0806973A1
Application number: EP96946169A
Authority: EP
Inventors: Dagmar Hartung
Original assignee: Cardiac Pacemakers Inc
Current assignee: Cardiac Pacemakers Inc
Priority date: 1995-12-04
Filing date: 1996-12-02
Publication date: 1997-11-19
Also published as: CA2212174A1; JPH11501852A; WO1997020595A2; WO1997020595A3; DE19545090A1

Abstract

The invention relates to an arrangement for stimulating excitable tissue. It comprises an electrical energy source, a pulse generator and electrodes electrically connected to the energy source. The electrodes are switched to create electrical fields, specifically, switched by one and the same pulse from the pulse emitter to create two overlapping electrical fields.

Description

"Arrangement for the Stimulation of Irritable Body Tissue"

The invention relates to an arrangement according to the preamble of claim 1

In the present invention, the term “stimulation” is distinguished from the term “defibrillation”. In the case of stimulation, irritable cells are selectively excited at a point from which the subsequent spread of excitation takes place. In the case of defibrillation, the largest possible and simultaneous area takes place Influencing cells in order to depolarize them and then to let them resume their natural stimulus conduction in an orderly manner

From DE 32 13 331 A1 it can be seen that an antistatic electrode should have a small geometric area, so that a high field strength results and the selective excitation desired for the stimulation is achieved

From DE 35 23 226 A1 it can be seen that the most uniform distribution of the field lines over the heart is desired during defibrillation Generic arrangements are known in the form of cardiac pacemakers with the associated electrode probes. In the known devices, two electrodes are used, with a pulse emitted by the pulse generator for generating an electric field or a dipole field between the two

Electrodes. These known arrangements serve to stimulate the heart tissue, that is, they are intended to cause a directed spread of the excitation from the electrodes by the pulse

Non-generic are known for example from EP 559 933 A1 arrangements for defibrillation, in which a synchronous discharge of cardiac cells is to be effected in the hope that normal activity of excitation can then be resumed or that excitation of the pacemaker is stimulated by a pacemaker Cardiac cells can take place undisturbed

Defibrillation will use three electrodes, two of which are arranged inside or outside the heart, while a third electrode is implanted under the patient's skin

In contrast, in the case of stimulation, that is to say when using cardiac pacemakers, the electrodes are arranged in the heart as wall-mounted electrodes, that is to say they have direct contact with the cells to be stimulated

In principle, when developing cardiac pacemakers or electrode arrangements for stimulation, it is desirable to achieve the lowest possible stimulation threshold. In addition, it is desirable to protect the patient as much as possible, ie to keep the number of electrodes to be implanted as low as possible

The invention has for its object to further develop a generic arrangement in such a way that when used using conventional impulses for stimulation, the use of wall-standing or floating electrodes is made possible

This object on which the invention is based is achieved by an arrangement with the features of claim 1

In other words, the invention proposes, using the electrode probes known per se, to change the connection between the pulse generator and the probe in such a way that the plurality of electrodes provided on one probe when a single one is dispensed

In this way, the stimulus threshold can be reduced in such a way that both wall-standing and floating electrodes can be used. Local concentrations of field lines are brought about by superimposing the electric fields or the dipole fields, with an increase, as is known The number of fields causes an increased irritation of the cells, so that even the electrodes which are remote from the wall, namely floating, can cause sufficient stimulation of the heart cells for stimulation

In addition to use in cardiac pacemakers, the application can be used, for example, for muscular / neuronal stimulation, for example for cardiomuoplasties cardiomy, for stimulating the urinary bladder, for skeletal muscle stimulation or for central or peripheral nerve stimulation

When used in the field of cardiac pacemaker therapy, implantable pacemakers, external temporary pacemakers or implantable AICD can be designed according to the invention both when using floating electrodes in the heart and when using wall-mounted electrodes in the heart

Advantageous refinements of the invention can be found in the subclaims Exemplary embodiments of an arrangement according to the invention are shown in the drawings FIGS. 1 to 10

1 schematically shows a heart silhouette with H, the left ventricle being indicated at the bottom right by V, while the atrium, ie the atrium, is indicated schematically further above by A_

A probe S_ is indicated within the heart silhouette H, which has three electrodes. The two floating electrodes 1 and

2 in the area of the atrium A and the wall-standing electrode 3 in the ventricle V

The probe S combines supply lines to the individual electrodes 1, 2 and 3, it being apparent from FIG. 1 that these supply lines branch out, each of the respective electrodes 1, 2 and

3 assigned supply line is designated with the same number as the respective electrode and these supply lines are connected to the electrical contacts 4a and 4v of an energy source 5, for example a battery of a pacemaker. The electrical contacts 4a serve to control the atrium electrodes 1 and 2, while the contacts 4v serve to control the ventricular electrode 3. The ventricular electrode 3 serves primarily as a fastening means for the probe S, however, it can also be used for unipolar stimulation of the heart cells, as is known from the circuitry with the minus pole of the energy source 5 can be seen, the plus pole being connected to an additional electrode

This additional electrode is referred to as "ground", wherein this electrode can be formed by the housing of the pacemaker or also by a third separate electrode on the actual pacemaker probe S or on an independent probe Below this schematically illustrated arrangement, four different interconnections of the electrodes are identified with the capital letters A, B, C and P_ in FIG. 1, and the field line course of the electrical fields is shown schematically above them. The overlap region of two electrical fields is shown with dashed lines

Lines indicated In this overlap area there is the massaging of field lines which, according to the invention, causes the particularly low stimulus threshold for the stimulation of the heart tissue

This results in the possibility of switching A to turn on the ground electrode negatively, electrode 1 likewise, electrode 2, however, positively. Circuit diagram B shows the fundamentally the same structure, but with an exactly opposite electrical view of the individual electrodes. The electrode "Ground" is positive. switched, the electrode 1 likewise, the electrode 2 negative in contrast. The course of the electrical field lines remains basically the same, so that the same point of a field concentration in the region of the electrode 2 results. However, the polarity changes, which the stimulus threshold Is known to influence and be able to influence behavior

The two electrical fields overlap over a substantially larger area as a result of the connection of the electrodes according to the circuit diagrams C and D. According to the connection option C, the two electrodes 1 and 2 are both connected negatively, while the electrode “Ground” is positive A fundamentally identical field line profile results from a negated connection of the electrodes, in which electrodes 1 and 2 are switched on positively, but the electrode “Ground” is negative, that is, through a change in polarity. Furthermore, the same field line profile results if - As indicated in the bottom right in FIG. 1, the electrodes 1 and “ground” are switched in the opposite direction to the electrode 2 than indicated in the circuit diagrams C and D. In this way, the polarities of the electrodes, the basic course of the field line and thus the one with dashed lines change Line drawn area of a massage of field lines remains the same, however, so that a particularly intense irritating effect for the surrounding tissue can be achieved in this area and thus a lowering of the stimulus threshold is achieved. In this way, the energy source 5 can either have a longer lifespan or be structurally smaller

The probe S shown in FIG. 1 represents a commercially available probe in which the electrodes 1 and 2 are used as sensors which merely register an atrial impulse in the case of commercially available cardiac stimulator arrangements

The cardiac pacemaker generates the output pulse with the help of the ventricle electrode 3, which is connected as a unipolar electrode, ie the opposite pole to the electrode 3 is not in the heart but outside, for example in the form of the “ground” electrode

2 is fundamentally similar to FIG. 1 and shows schematically the arrangement according to the invention in the upper region, but when using electrodes 1 and 2 with a wall, without a ventricular electrode, an energy source with only two electrical contacts 4 is used. The one shown in FIG The probe is a commercially available wall-mounted atrial probe that does not have to be modified according to the invention, but only has to be connected to the actual pacemaker in another way in order to achieve the advantages according to the invention. The configuration of the pulses with regard to pulse duration, pulse duration and pulse intensity can remain unchanged, nevertheless an improved stimulation of the tissue is effected. If necessary, the pacemakers can even be carried out more easily than hitherto. While for some applications the increase in tension was required compared to the tension that

The battery of the pacemaker supplies (with the aid of a so-called voltage doubler), in many cases, such an increase in voltage is dispensed with when the electrodes are connected according to the invention, so that energy-consuming circuit components of the stimulation arrangement can be dispensed with 3 shows an arrangement similar to FIG. 2, but using floating atrium electrodes. The use of floating electrodes is gentle on the patient, since the noting electrodes do not have to be implanted. When implanting electrodes, it is often necessary to select the implantation location several times in order to to look for a place with the lowest possible stimulus threshold In general, the implantation of electrodes in the heart tissue contains the risk of infection and puncturing, so that it is fundamentally desirable to keep the number of implanted electrodes as low as possible Disadvantageous that they require a lot of energy in order to ensure adequate stimulation despite the distance to the cells to be stimulated. This could lead to irritation of the threnic nerve, so that the stimulation could at the same time trigger dwarf jerks in the case of the invention External connections of the electrodes are excluded

4 shows an arrangement in which by using a large-area atrium electrode 2 a relatively wide and not only punctiform area can be achieved even in the circuit diagrams A and B, in which field lines are massaged

FIG. 5 shows that the ground electrode can be replaced if an additional atrium electrode 4 is used. The same arrangement shown on the right in FIG. 5 is shown in FIG. 6 together with the course of the electric fields and dipole fields that can be achieved with it, and with the circuitry possibilities A B, C and D are shown, similar to that in FIG. 1 also indicated at the bottom right in FIG. 6 that the two other electrodes, here the other two atrium electrodes 1 and 4, are each reversed relative to the second atrium electrode 2 can be switched, whereby in principle the same course of the electrical and the dipole fields can be achieved FIG. 7 shows an arrangement similar to that of FIG. 6 with an atomic electrode 2 which is enlarged in comparison therewith, so that even when the electrodes are connected in accordance with the circuit diagrams A and B, a comparatively broad and not only narrow or punctiform area of the field concentration results

FIG. 8 shows an arrangement in which the ventricular electrode 3 is arranged in a wall-like manner as in the preceding examples, but in the vicinity of which the third atom electrode 4 is arranged. The resultant field rhinoceros are as shown in the previous illustrations, wherein here, too, the area of an increased field line concentration and thus an improved irritating effect for the adjacent body tissue results within the framework of the lines shown in broken lines

A commercially available probe according to the prior art is also used in the arrangement according to FIG. 8. In the conventional application of this probe, the electrodes 1 and 2 serve as sensors which record the paging signals, so that the electrodes 3 and 4 then move the electrodes with a time delay Stimulation can take place. By connecting the electrodes according to the invention, lower stimulation thresholds can be achieved when using inexpensive conventional probes and inexpensive commercially available cardiac pacemakers

FIG. 9 shows a comparison of two different connection possibilities according to the invention, including a third electrode in the stimulation according to the invention. The illustration labeled “Bimos 1” shows two electrodes attached to a common probe, which are indicated in a rectangular manner, while those indicated oval and according to the invention required third electrode is formed by the circuit maker housing, as is known in a conventional unipolar stimulation configuration. The electrode spacing between the first and the second ring electrode (E1 and E2) is significantly smaller than that

Electrode distance between the second ring electrode E2 and third ring electrode E3, which is formed by the Schπttmacherergehause

In contrast, the representation "Bimos 2" shows three ring electrodes arranged on the common probe, the distance between the first and second ring electrodes E1 and E2 being either identical or different to the distance between the second and third ring electrodes E2 and E3 The third ring electrode E3 is always arranged intracardially or in the lower part of the vena karva supeπo

FIG. 10 shows the two circuit vanants “Bimos 1” and “Bimos 2”, a probe with three electrodes being shown in both cases, which are indicated as rectangular fields. As in FIG. 9, the circuit breaker housing is oval

In the configuration according to “Bimos 1 ', the three electrodes interconnected according to the invention are formed by two of the electrodes arranged on the probe and by the circuit breaker housing. In contrast, the circuit breaker housing in the electrode connection according to“ Bimos 2 ”is not in the electrode circuit involved

Below the two representations "Bimos 1" and "Bimos 2", the different ones are possible with the respective circuit concept

Political configurations shown. The blackened fields indicate not possible circuit mogch chains. In the configuration according to "Bimos 1", the light-colored electrode on the probe is always not involved in the connection, so that below this light-colored electrode all fields are blackened of the circuit arrangement according to “Bimos 2”, the pacemaker electrode is not included in the circuit arrangement in the case of the invention and in the case of bipolar circuits (A, B, C for the circuitry in accordance with the invention and bi 1 to bi 6 for bipolar circuitry). Unipolar circuitry arrangements are in one configuration however, according to "Bimos 2" Inclusion of the Schπttmachergehaus possible, as can be seen from the polarization representations according to uni 1 to uni 6

The bipolar circuit variants 2, 3, 5 and 6 and the unipolar circuit variants 3 and 4 cannot be implemented in an electrode arrangement according to "Bimos 1", so that the corresponding circuit variants are also blackened under the representation "Bimos 1"

Claims

1 arrangement for stimulating irritable body tissue,

5 with an electrical energy source,

as well as with a pulse generator,

10 and with electrodes which are electrically conductive with the

Energy source are connected

the electrodes being connected to achieve electrical fields,

15 characterized in

that the electrodes are connected to achieve two overlapping electric fields by means of one and the same pulse emitted by the 20 pulse generator

2 Arrangement according to claim 1, characterized by three

Electrodes

25 3 Arrangement according to claim 1 or 2, characterized gekenn¬ characterized in that an electrode is designed as a wall-standing electrode

4 Arrangement according to one of the preceding claims, 30 characterized in that two electrodes are designed as floating electrodes

5 Arrangement according to one of the preceding claims, characterized in that an electrode (Fig. 4 and

35 Fig 7 No. 2) is designed as a flat electrode 6 Arrangement according to one of the preceding claims _, characterized in that all electrodes are arranged on a single probe

7 Arrangement according to one of the preceding claims, characterized by electrodes arranged on a probe, the probe comprising fastening means for fixing to the body tissue

8 Arrangement according to claim 7, characterized in that the fastening means are designed as an electrode