WO2001064282A1

WO2001064282A1 - Temporary pacemaker lead

Info

Publication number: WO2001064282A1
Application number: PCT/EP2001/002175
Authority: WO
Inventors: Stefan Blume; Christoph Walther
Original assignee: Ethicon Gmbh
Priority date: 2000-03-01
Filing date: 2001-02-26
Publication date: 2001-09-07
Also published as: DE10009830C2; DE10009830A1; AU4243501A

Abstract

A temporary pacemaker lead (1) has a proximal end-section, which can be connected to an external electronic device outside the body of a patient, and a distal end-section (2). The distal end-section (2) has at least one electrode (20) which can be brought into electric contact with the myocardium of the patient, which electrode, relative to the local longitudinal axis of the lead (1), projects outwards on one side and elastically.

Description

Temporary pacemaker lead

The invention relates to a temporary pacemaker lead.

A temporary pacemaker lead is used to stimulate the heart muscle of a patient at times via an external electronic device (in particular an external pacemaker) or to monitor it by means of an external electronic device (e.g. an ECG monitor) . The distal end-section of such a temporary pacemaker lead has at least one electrode which can be brought into electric contact with the myocardium of the patient and is attached to the heart muscle of the patient during a surgical operation, usually with the help of a surgical needle which is attached to the distal end of the lead. The proximal end-section is guided through the chest wall of the patient by means of a surgical needle. Electric terminals are provided or can be attached in the proximal end-section, which serve as a connection to the external electronic device. Temporary pacemaker leads can be unipolar, bipolar or can have more than two poles (with the corresponding number of electrodes in the distal end-section) . Each electrode is connected to the proximal end-section of the temporary pacemaker lead in an elec- trically conductive manner, but insulated from the other electrodes, e.g. by means of separate wires.

US-A-4 530 368 shows a temporary bipolar pacemaker lead with two wires insulated from each other. A surgical needle is attached to the distal end of the lead. Shortly before this, the insulation is removed from one wire and also, somewhat further along in proximal direction, from the second wire. Between the two stripped sections, both wires are enclosed in a common additional sheath. In order to attach this temporary pacemaker lead to the heart muscle of a patient, the myocardium is punctured with the help of the needle and the lead pulled through until the electrode located further in proximal direction comes to lie in the myocardium. The additional sheath is then located outside the myocardium. The lead is bent there so that the myocardium can be penetrated again by the needle in order to introduce into the myocardium the electrode that is positioned distally further. A reliable contact between the electrodes and the myocardium is not always ensured with this temporary pacemaker lead. A further disadvantage is that two punctures must be made to attach the lead to the heart of the patient, which prolongs the operation.

A bipolar temporary pacemaker lead is known from EP 0 159 540 Bl, in which one of the two electrodes is designed as a sleeve. The other electrode is located at a distal distance from it and is formed as a flexible anchor for entry into the heart wall, either by fanning-out the stripped individual wires of the electric supply line in two directions away from the local longitudinal axis of the line, or by meander-shaped, wave-like or helical bending of a stripped section of the electric supply line. A surgical needle is attached to the distal end of the temporary pacemaker lead. In order to attach the electrodes to the heart muscle, it is sufficient to pierce the myocardium with this needle at one point and then to pull both electrodes into the myocardium. The quite bulky anchor-shaped electrode is intended to stick in the puncture channel and ensure a secure holding. It is however a disadvantage that the puncture channel is widened by the anchor-shaped electrode, whereby the tissue is also affected and more tissue fluid can enter the puncture channel, which impairs the electric contact. The anchor can also give rise to problems when the temporary pacemaker lead is to be removed from the body of the patient by pulling on the proximal end-section.

The object of the invention is to provide a temporary pacemaker lead, the electrode or electrodes of which can be inserted quickly and in a tissue-friendly manner into the myocardium of a patient, where they are attached securely and form a good and reliable electric contact, the temporary pacemaker lead however also being able to be removed from the patient without any problems .

This object is achieved by a temporary pacemaker lead with the features of claim 1. Advantageous designs of the invention emerge from the dependent claims .

The temporary pacemaker lead according to the invention has a proximal end-section which can be connected outside the body of a patient to an external electronic device (e.g. an external pacemaker or an ECG monitor) , and a distal end-section. The distal end-section has at least one electrode which can be brought into electric contact with the myocardium of the patient, and which projects outwards on one side and elastically, relative to the local longitudinal axis of the lead.

Because the electrode designed according to the invention projects outwards on only one side of the longitudinal axis, this electrode is less bulky than the previously known anchor-shaped electrodes. The distal end-section of the lead can therefore be easily introduced into the myocardium, preferably with the help of a surgical needle, attached to the distal end of the lead, which is severed afterwards . The tissue in the area of the puncture channel is under little stress, as the puncture channel is well defined. The temporary pacemaker lead can also be removed again later without any problems by pulling on the proximal end-section projecting from the patient. The small size of the puncture channel prevents the entry of larger amounts of tissue fluid (seromas) , or even the development of connective tissue between the electrode and the myocardial tissue. The electric contact between the electrode and the myocardial tissue is thus particularly good, which results in a lower stimulus threshold and an improved response behaviour to the connected external electronic device. Also, security against so-called exit blocks is high, i.e. security against a sudden failure of transmission of the electric signals . Surprisingly, it has proven that the electrode which projects outwards on one side and is outwardly elastic, effects a similarly good hold in the myocardium of a patient as a previously known anchor-shaped electrode. This is possibly because the puncture channel is not unnecessarily widened in the myocardium by the electrode and can thus counteract the elasticity of the electrode, so that the resulting friction forces prevent an unintended withdrawal from the heart muscle.

Preferably, the electrode designed according to the invention is arranged between two sections of the lead which are provided with an electric insulation. The electrode can be formed, e.g., from a stripped section of a wire of the lead. Preferably, the electric conduction proceeds via a litz wire so that the elec- trode consists of a stripped section of the litz wire in this case .

In a preferred version, the electrode designed according to the invention is formed arching outwards . This design is compact and effects relatively high elastic forces as well as a good electric contact. Furthermore, there are no protruding sharp edges or the like, so that no undesired damage is caused to the tissue of the patient.

If the lead is multipolar and an insulated section of a wire, to which a further electrode is assigned, runs alongside an electrode designed according to the invention, this insulated section of the wire can project pointing outwards away from the electrode designed according to the invention and be designed to be elastic, e.g. by having this section formed in the manner of an arc, just like the electrode designed according to the invention. This results overall in an even better anchorage in the tissue. In spite of this, the puncture channel is saved, as the wire alongside the electrode designed according to the invention is surrounded by insulation material which as a rule does not penetrate the tissue and thus give rise to injuries. Furthermore, at least two electrodes designed according to the invention can be arranged offset relative to each other in longitudinal direction of the lead. Also, such a version ensures a particularly good anchorage in the myocardium.

In a preferred version of a multipolar lead, apart from at least one electrode designed according to the invention, a sleeve-like electrode is provided which surrounds a section of the lead. Preferably, the sleeve-shaped electrode is arranged distally from an electrode designed according to the invention. One wire of the lead can be guided through the sleeve-shaped electrode in an electrically insulated manner.

As already mentioned, a severable surgical needle is preferably attached to the distal end of the temporary pacemaker lead. With the help of this needle, the distal end-section of the lead including the electrode or electrodes can be inserted into the heart muscle of the patient . When the electrode or electrodes are positioned in the myocardium by pulling on the needle or the lead, the needle as well as a distal end-section of the lead project out of the myocardium and can be cut off at a desired point. The proximal end-section of the temporary pacemaker lead is guided in conventional manner through the thorax of the patient, preferably with the help of a straight surgical needle, and connected to an external electronic device outside the body, optionally with the help of additional connection devices.

In the following, the invention is described in more detail by means of embodiments . The drawings show in

Figure 1 a schematic side view (partly in longitudinal section) of part of the distal end region of a first version of a pacemaker lead according to the invention,

Figure 2 a view as in Figure 1, the electric field formed between the two electrodes being shown in addition, Figure 3 a view as in Figure 1, the area of the temporary pacemaker lead with the two electrodes being inserted in a puncture channel in the myocardium of a patient,

Figure 4 a schematic side view (partly in longitudinal section) of a part of the distal end region of a second version of a temporary pacemaker lead according to the invention and

Figure 5 a schematic side view of a part of the distal end region of a third version of a temporary pacemaker lead according to the invention.

A part of a temporary pacemaker lead 1 is shown in Figure 1 in side view (and partly in schematic longitudinal section) , namely the section of the distal end-section 2 which contains the electrodes . These electrodes are brought into electric contact with the myocardium of a patient during a surgical operation. The temporary pacemaker lead 1 continues in the direction of the arrow 4 and leads to a proximal end-section which is not shown in the Figures. The proximal end-section is located outside the body of the patient after the operation. The temporary pacemaker lead 1 can be connected there to an external device, e.g. to an external pacemaker for stimulating the heart or to an ECG oni- tor for monitoring the heart.

The arrow 6 indicates that the temporary pacemaker lead 1 also continues further in distal direction. In the embodiment, a surgical needle is attached there which can be severed after the electrodes are inserted in the myocardium. The terminology is chosen here so that the terms "proximal" and "distal" indicate the-perspective of the surgeon, i.e. the proximal end-section of the temporary pacemaker lead is nearer to the surgeon, namely outside the body of the patient.

The temporary pacemaker lead 1 is bipolar and has a first wire 10 and a second wire 12, which are guided in parallel to each other, and the electric insulations of which are connected to each other. A litz wire serves to conduct electricity in both wires 10, 12. The lead 1 is thus flexible, but shown for simplicity's sake as a straight line in the Figures. In the lead 1, the local longitudinal axis runs, in the distal end-section 2, between the wires 10, 12 and parallel ( tangentially) to them.

The first wire 10 has a stripped section 14 which is located between two sections 16 and 18 which are provided with electric insulation. The section 18 continues in the direction of the arrow 6, the surgical needle mentioned being attached to its distal end.

In the area of the stripped section 14, the litz wire of the first wire 10 is shaped arching outwards so that it is elasti- cally pre-stressed and points away from the local longitudinal axis of the lead 1. A first electrode 20 is formed in this way.

The second wire 12 leads to a second electrode 22 which is desi- gned as a somewhat tapered sleeve and surrounds the end-section of the second wire 12 as well as the section 18 of the first wire 10. Whilst the second wire 12 is stripped at its end 24 and is in electric contact there with the second electrode 22, the section 18 of the first wire 10 is guided through the sleeve- shaped second electrode 22 in electrically-insulated manner.

Figure 2 illustrates in schematic manner the general course of the field lines of the electric field.26 which forms between the first electrode 20 and the second electrode 22, if e.g. electric pulses are applied to the lead 1 from an external pacemaker.

To connect the temporary pacemaker lead 1 to the heart muscle of a patient, the surgical procedure starts in conventional manner. Then, the above mentioned surgical needle is guided through the myocardium and the lead 1 is displaced until the first electrode 20 and the second electrode 22 are positioned in the puncture channel of the needle. This situation is represented in Figure 3 in which the puncture channel is numbered 28. The two electrodes 20 and 22 widen the puncture channel locally somewhat so that the myocardial tissue lies against the electrodes 20 and 22 and presses against them. In this way, a good electric contact results . Because of the elastic action of the first electrode 20, the lead 1 is also anchored safely to the myocardium. In spite of this, it can later be pulled out of the puncture channel 28 in proximal direction without any problems once the needle is severed.

Figure 4 shows a second version of a temporary pacemaker lead which is here numbered 1" . As this version is largely the same as the first version, the same reference numbers as in Figures 1 to 3 are otherwise used. In contrast to the first version, in the case of the temporary pacemaker lead 1' an insulated section 30 of the second wire 12 is formed arching outwards alongside the electrode 20 so that it points away from the local longitudinal axis of the lead 1' and from the electrode 20. The insulated section 30 is elastic just like the first electrode 20. The result of this is an even firmer fit for the temporary pacemaker lead 1' than with the version according to Figures 1 to 3.

Figure 5 shows a section of the distal end region 42 of a further version of a temporary pacemaker lead, here numbered 40. The temporary pacemaker lead 40 is likewise bipolar and has a first wire 44 and a second wire 45. A first electrode 46 which is arc- shaped and projects elastically outwards is formed on the first wire 44 and a corresponding electrode.47 on the second wire 45. The electrodes 46 and 47 are offset relative to each other in longitudinal direction of the lead 40 and otherwise designed similarly to the electrode 20 in the first two versions. The lead 40 continues further in distal direction in the direction of the arrow 48 and ends in a surgical needle.

In the three described versions of the temporary pacemaker lead, the respective force required to pull the lead out of the myocardium was measured on an explanted bovine heart . The section of the lead containing the electrodes was inserted into the myocardium as illustrated in Figure 3, and was pulled in proximal direction. The extraction forces (anchorage strengths) were between 75 cN and 145 cN. These values are comparable with the extraction forces for temporary pacemaker leads customary in the market, which have a yielding anchor electrode made of zigzag- shaped stainless steel litz wire, with which values of 64 cN to 143 cN were measured under comparable conditions.

Claims

1. Temporary pacemaker lead with a proximal end-section, which can be connected outside the body of a patient to an external electronic device, and with a distal end-section (2) , which has at least one electrode (20) which can be brought into electric contact with the myocardium of the patient, which electrode projects outwards on one side and elasti- cally relative to the local longitudinal axis of the lead (1) .

2. Temporary pacemaker lead according to claim 1, characterized in that the electrode (20) is arranged between two sections (16, 18) of the lead (1) which are provided with an electric insulation.

3. Temporary pacemaker lead according to claim 1 or 2 , characterized in that the electrode (20) is formed from a stripped section (14) of a wire (10) of the lead (1) .

4. Temporary pacemaker lead according to one of claims 1 to 3 , characterized in that the electrode (20) is formed arching outwards .

5. Temporary pacemaker lead according to one of claims 1 to 4 , characterized in that the lead (1' ) is multipolar and in that, alongside the electrode (20) , an insulated section (30) of a wire (12) assigned to another electrode (22) projects outwards on one side, pointing away from the electrode (20) and elastically.

6. Temporary pacemaker lead according to one of claims 1 to 5 , characterized in that the lead (40) is multipolar and at least two electrodes (46, 47) designed according to claim 1 are arranged offset relative to each other in longitudinal direction of the lead (40) .

7. Temporary pacemaker lead according to one of claims 1 to 6, characterized in that the lead (1) is multipolar and in that, apart from at least one electrode (20) designed according to claim 1, a sleeve-shaped electrode (22) is pro- vided, which surrounds a section of the lead (1) .

8. Temporary pacemaker lead according to claim 7, characterized in that the sleeve-shaped electrode (22) is arranged distally from an electrode (20) designed according to claim 1.

9. Temporary pacemaker lead according to claim 7 or 8 , characterized in that a wire (10) of the lead (1) is guided in an electrically insulated manner through the sleeve-shaped electrode (22) .

10. Temporary pacemaker lead according to one of claims 1 to 9, characterized in that a severable surgical needle is attached to the distal end of the lead (1) .