GB2065478A - Atrial-ventricular endocardial lead - Google Patents

Abstract

A single pass atrial-ventricular endocardial coaxial lead has a ring tip electrode 12 at the distal end for ventricular sensing and pacing and an electrode 20 for atrial sensing. The atrial electrode 20 includes an exposed cylinder of porous wire, the cylinder being 3 cm. long and at a spacing of 9 cm. from the ventricular electrode 12. The lead can be used for temporary or permanent transvenous ASVIP pacing. Coaxial inner and outer conductors 14, 22 are connected to electrodes 12, 20 respectively at their distal ends, and to inner 16 and outer 24 coaxial connectors at their proximal ends. Tines 18 are used for fixation. The 3 cm. length of the atrial electrode 20 permits use of the lead in different sized hearts without the lead having to be adjustable in respect of the spacing between electrodes 12, 20. <IMAGE>

Description

SPECIFICATION Atrial-ventricular endocardial lead The present invention pertains to a surgical electrical applicator, and more particularly, pertains to an atrial-ventricular endocardial lead.

In prior art atrial-ventricular pacing (ASVIP) applications, two transvenous pacing leads have been utilized, one transvenous pacing lead for pacing and sensing ventricular activity and the second transvenous pacing lead for sensing at least the atrial activity. The primary disadvantages of two transvenous pacing leads has been 1) increased risk of surgical complications and 2) surgical difficulty of passing two transvenous pacing leads of distinct physical size through the same vein, or having to cut open a vein to pass the second transvenous pacing lead.

Another problem with the prior art transvenous atrial-ventricular pacing leads has been thatthe type of lead which would use a standard sized ring electrode spaced a fixed distance from the distal electrode does not have general applicability because of the ring electrode being area sensitive with respect to the spacing between the distal electrode and the proximal electrode. The proximal ring electrodes have been usually fixed on the transvenous pacing lead and unable to be adjusted for the required sensing of the atrial activity.

In the prior art pacing leads, one would have to pick a transvenous pacing lead with the desired spacing between the distal electrode and the atrial electrode as determined during surgery. One problem with this concept is having such leads available to pick from and the second was the inability to provide micro-adjustability of the lead itself. While there have been prior art leads which have provided some adjustment, this adjustment for determining the desired spacing of the electrode resulted in a complex medical insertion and an extended medical operation procedure.

According to the invention there is provided an atrial-ventricular single pass endocardial coaxial lead comprising a coaxial lead, a ventricular electrode at the distal end of an inner conductor of said coaxial lead, an inner coaxial connector at a proximal end of said inner conductor of said coaxial lead, an atrial electrode having longitudinal exposed circumferential cylindrical surface spaced from said ventricular electrode and connected to an outer conductor of said coaxial lead, an outer coaxial connector at a proximal end of said outer conductor of said coaxial lead whereby said ventricular electrode provides for ventricular sensing and pacing and said atrial electrode provides for atrial sensing thereby providing a single pass lead for atrial synchronous ventricular inhibited pacing.

The present invention provides an atrialventricular single pass endocardial lead intended for atrial sensing, and ventricular pacing and sensing.

The invention allows the provision of a lead which can support unipolar modality for either chamber, which does not require adjustment, is coaxial, and is preferably provided with distal tines for stabilization within the ventricular chamber. The ventricular electrode may be a ring tip electrode configuration and the atrial electrode is preferably a continuous flexible porous wire mesh material extending from approximately 9 cm to 12 cm away from the ventricular electrode. An atrial electrode of such a wire mesh has a large area and is intended for sensing the atrial activity. The present invention is particu larly useful for atrial synchronous ventricular inhibited pacing (ASVIP).

According to one preferred embodiment of the present invention, there is provided an atrialventricularendocardial coaxial lead including an inner conductor covered with insulation, a ring tip electrode connected to the distal end of the inner conductor and an inner coaxial plug connected to the proximal end of the inner conductor, an outer conductor covered with insulation extending partially and coaxially along longitudinal length of the inner conductor and including a porous wire mesh longitudinal circumferential cylinder exposed at the distal end of the outer connector, the porous wire mesh being positioned a predetermined distance from the distal end of the ring tip electrode, and an outer coaxial plug at the proximal end of the outer connector whereby the ventricular distal ring tip electrode provides for ventricular sensing and pacing, and the porous wire mesh longitudinal circumferential cylinder provides for atrial sensing of atrial activity thereby providing a single pass atrialventricular endocardial lead.

The preferred embodiment of the invention substantially overcomes the disadvantages of the prior art by providing an atrial-ventricular endocardial lead with an atrial electrode which is of continuous flexible wire mesh material extending from approximately 9 cm to 12 cm from the ventricular distal tip electrode.

A significant aspect and feature of the preferred embodiment of the invention is the ability to achieve ASVIP pacing without lead adjustability with a single pass atrial-ventricular endocardial lead. By extending the longitudinal length of the atrial proximal electrode, the present invention achieves the ability to obtain P-wave or intracardiac amplitudes without adjustability in light of different sized hearts.

Because the atrial electrode does not affix to the endocardial structure, there is minimal fibrotic build up, and therefore the minimal detriment of the P-wave amplitude and slow rate.

A significant aspect and feature of the present invention is the provision of a single pass atrialventricular endocardial lead for both ventricular sensing and pacing, and atrial sensing in a singlepass coaxial lead which lends itself to simplified manufacture and easy insertion through a percutaneous lead introducer (e.g. subclavian stick).

A further significant aspect and feature of the preferred embodiment of the invention is an atrial ventricular single pass endocardial lead having the capability of chronic removability. Since the atrial electrode does not affix to the atrial chamber, and since the ventricular electrode can be stabilized by flexible tines, the lead is removable at a later time.

An additional significant aspect and feature of the preferred embodiment of the invention is an atrialventricular endocardial lead where the ventricular lead utilizes proven technology for ventricular sensing and pacing. The lead is positionable in a standard manner for ventricular leads. The atrial proximal electrode exposes a length of atrial electrode over a substantial circumferential area as opposed to a relatively small surface area of an electrode as in the prior art devices which were previously described.

An additional significant aspect and feature of the preferred embodiment of the invention is an atrial electrode which can be a porous wire mesh which is flexible, has a large surface area for sensing, and is readily manufacturable. The shape of the atrial electrode is a longitudinal cylindrical porous wire mesh member.

An embodiment of the invention will now be described by way of example and with reference to the accompanying drawing wherein: The sole figure 1 illustrates a plan view of an atrial-ventricular endocardial lead according to the invention.

An atrial-ventricular endocardial coaxial lead 10 comprises a ventricular electrode 12 such as a ring tip electrode, by way of example and for purposes of illustration only and not to be construed as limiting of the present invention, which connects to a distal end of a ventricular inner conductor 14 having a suitable outer insulation covering which can be MP 35N conductor coil by way of example and for purposes of illustration only and not to be construed as limiting of the present invention, and an inner coaxial connector 16 affixes to the proximal end of the inner conductor 14. A plurality of outwardly extending flexible tines 18 can surround the ventricular electrode 12 as illustrated in the figure.Atrial electrode 20, such as an exposed porous outer wire mesh circumferential cylinder illustrated in the figure connects to a distal end of an atrial outer coaxial conductor 22 having suitable body inert insulation covering which can be MP 35N conductor coil and an outer coaxial connector 24 connects to the proximal end of the outer coaxial conductor 22. The overall longitudinal length of the atrial conductor 22 is substantially shorter by about 12 cm than the length of the ventricular conductor 14 as later described in detail. The outer wire mesh 20 is affixed to the insu latin of the inner ventricular conductor 14 such as by silicone adhesive or other suitable fastening adhesive by way of example and for purposes of illustration only. The longitudinal length of the atrial electrode 20 is about 3 cm.The distal end of the atrial electrode 20 is spaced from the distal tip of the lead 10 by substantially 9 cm. The proximal end of the atrial electrode 20 is thus about 12 cm from the distal tip of the lead 10.

The atrial-ventricular endocardial lead 10 is introduced into a vein such as through a percutaneous vein introducer, subsequently pushed through the vein, and can be observed underfluoroscopy until the ventricular electrode 12 is positioned in the ventricular cavity of the heart. Concurrently, the atrial electrode 20, being affixed on the atrial-ventricular endocardial lead 10, is positioned and requires no further adjustment.

The preferred spacing of about 9 cm between the ventricular electrode 12 and the distal end of the atrial electrode 20 allows proper respective electrical connection to the ventricle and the atrium. The preferred form of the atrial electrode 20 of about 3 cm of porous wire mesh provides a large surface area permitting sustained and adequate electrical interface with the atrial tissue and also allowing adequate current densities and suitable impedance.

Various modifications can be made to the atrialventricular endocardial lead 10 of the present invention without departing from the apparent scope of the present invention.

Claims (8)

1. An atrial-ventricular single pass endocardial coaxial lead comprising a coaxial lead, a ventricular electrode at the distal end of an inner conductor of said coaxial lead, an inner coaxial connecter at a proximal end of said inner conductor of said coaxial lead, an atrial electrode having a longitudinal exposed circumferential cylindrical surface spaced from said ventricular electrode and connected to an outer conductor of said coaxial lead, an outer coaxial connector at a proximal end of said outer conductor of said coaxial lead whereby said ventricular electrode provides for ventricular sensing and pacing and said atrial electrode provides for atrial sensing thereby providing a single pass lead for atrial sync hronous ventricular inhibited pacing.

2. A lead as claimed in claim 1 wherein said ventricular electrode is a ring tip electrode.

3. A lead as claimed in claim 1 or 2 comprising a plurality of tines surrounding said ventricular electrode.

4. A lead as claimed in claim 1,2 or3, wherein said atrial electrode is an exposed porous wire mesh.

5. A lead as claimed in any preceding claim, wherein said atrial electrode has longitudinal length of substantially 3 cm.

6. A lead as claimed in any preceding claim wherein a distal end of said atrial electrode is spaced substantially 9 cm from a distal tip of said ventricular electrode.

7. An atrial-ventricular endocardial lead comprising a ventricular electrode, an inner ventricular conductor connected to said ventricular electrode, an outer atrial conductor positioned partially over said inner conductor, and an exposed porous wire mesh cylindrical atrial electrode connected to a distal end of said outer atrial conductor, and a coaxial connector connected to said inner and outer conductors at the proximal end of said conductors whereby said atrial-ventricular endocardial lead provides for ven tricular sensing and pacing, and atrial sensing.

8. An atrial-ventricular endocardial lead substantially as hereinbefore described with reference to the accompanying drawing.