Title:
Endocardial electrode
United States Patent 3911928
Abstract:
An endocardial electrode for effecting the intracardial stimulation of a heart, consisting of an elongated electrical conductor, which is provided with an electrical insulation, and an electrode head located at the end of the conductor proximate the heart for the transmission of stimulative impulses to the heart through the inserted electrode. The surface of the electrode head is constituted partly of an insulating material, and partly of an electrically conductive contact material which is electrically connected with the conductor.
US Patent References:
Electrode
Wappler - January 1924 - 1480353
Electrical contact pad
Zerne - November 1932 - 1889271
COMBINATION HEART CATHETER AND ELECTRODE
Woodson - October 1970 - 3533403
BODY IMPLANTABLE LEAD
Friedman - January 1974 - 3788329
MUSCLE STIMULATION AND/OR CONTRACTION DETECTION DEVICE
Denniston - June 1974 - 3815611
Electrode
Wappler - January 1924 - 1480353
Electrical contact pad
Zerne - November 1932 - 1889271
COMBINATION HEART CATHETER AND ELECTRODE
Woodson - October 1970 - 3533403
BODY IMPLANTABLE LEAD
Friedman - January 1974 - 3788329
MUSCLE STIMULATION AND/OR CONTRACTION DETECTION DEVICE
Denniston - June 1974 - 3815611
Application Number:
05/460211
Publication Date:
10/14/1975
Filing Date:
04/11/1974
View Patent Images:
Export Citation:
Assignee:
Lagergren, Hans (Stockholm, SW)
Primary Class:
Other Classes:
D24/167
International Classes:
A61B18/14; A61N1/05; A61N1/375; A61N1/372; A61N1/04
Field of Search:
128/404,407,408,418,419P,2.6E,2.1F,DIG.4
Primary Examiner:
Kamm, William E.
Attorney, Agent or Firm:
Waters, Schwartz & Nissen
Claims:
What is claimed is
1. Endocardial electrode for the intracardial stimulation of a heart, comprising an elongate electrical conductor; an electrical insulation encasing said conductor; and an electrode head being connected to said conductor at the end thereof proximate the heart for transmission of stimulative impulses to the heart upon insertion of said electrode, said electrode head having a surface area the major portion of which is constituted of an insulating material and the relatively smaller remaining surface area of an electrically conductive contact material forming a plurality of spaced electrically conductive minute surface areas, each of said last-mentioned areas being electrically connected with said conductor.
2. Endocardial electrode as claimed in claim 1, the surface of said electrode head having a maximum area of 15 mm2.
3. Endocardial electrode as claimed in claim 2, said surface area being 5 mm2.
4. Endocardial electrode as claimed in claim 1, said electrically conductive contact material being evenly distributed about the surface of said electrode head.
5. Endocardial electrode as claimed in claim 4, said contact material being in the form of strips extending along the surface of said electrode head.
6. Endocardial electrode as claimed in claim 4, said contact material being in the form of strips helically wound about the surface of said electrode head.
7. Endocardial electrode as claimed in claim 4, said contact material comprising a plurality of discrete dot-shaped areas dispersed about the surface of said electrode head.
8. Endocardial electrode as claimed in claim 1, said electrode head being of relatively large volume and weight, said volume being in the range of 15 mm3 to 60 mm3, and said weight being in the range of 0.30 p to 2.0 p.
9. Endocardial electrode as claimed in claim 8, said electrode head having a volume of 25 mm3 and a weight of 0.8 p.
10. Endocardial electrode as claimed in claim 1, said electrode head being essentially cylindrically shaped, said electrical conductor being fastened to one end of said cylindrically shaped electrode head, and the free end of said electrode head being of a rounded off configuration.
11. Endocardial electrode as claimed in claim 10, said contact material being constituted of a band-shaped material.
12. Endocardial electrode as claimed in claim 11, said band-shaped contact material being positioned in parallel spaced strips extending along the longitudinal axis of said cylindrically shaped electrode head.
13. Endocardial electrode as claimed in claim 12, the space between adjacent strips of said contact material being 0.5 mm to 5 mm wide.
14. Endocardial electrode as claimed in claim 13, said space between adjacent strips of said contact material being about 1.5 mm wide.
15. Endocardial electrode as claimed in claim 11, said band-shaped contact material being helically wound to form a plurality of spaced strips extending about the annular surface of said cylindrically shaped electrode head.
16. Endocardial electrode as claimed in claim 15, the space between adjacent helically wound strips of said contact material being about 0.5 mm to 5 mm wide.
17. Endocardial electrode as claimed in claim 16, said space between adjacent helically wound strips of said contact material being about 1.5 mm wide.
18. Endocardial electrode as claimed in claim 11, said band-shaped material having a width in the range of 0.01 mm and 0.4 mm.
19. Endocardial electrode as claimed in claim 14, said band-shaped material having a width of about 2 mm.
20. Endocardial electrode as claimed in claim 1, said electrode head comprising an electrically conductive material core having projecting portions forming interstitial spaces; and an electrically insulating material being filled in said interstitial spaces.
21. Endocardial electrode as claimed in claim 20, said projecting portions being essentially ridge-like in configuration.
22. Endocardial electrode as claimed in claim 20, said projecting portions having a helical screw-thread configuration.
23. Endocardial electrode as claimed in claim 1, said electrode head being formed of an electrically conductive basket-shaped wire mesh; and electrically insulating material filling the interior of said basket shape and wire mesh interstices.
24. Endocardial electrode as claimed in claim 23, said insulating material having a relatively high specific weight.
1. Endocardial electrode for the intracardial stimulation of a heart, comprising an elongate electrical conductor; an electrical insulation encasing said conductor; and an electrode head being connected to said conductor at the end thereof proximate the heart for transmission of stimulative impulses to the heart upon insertion of said electrode, said electrode head having a surface area the major portion of which is constituted of an insulating material and the relatively smaller remaining surface area of an electrically conductive contact material forming a plurality of spaced electrically conductive minute surface areas, each of said last-mentioned areas being electrically connected with said conductor.
2. Endocardial electrode as claimed in claim 1, the surface of said electrode head having a maximum area of 15 mm2.
3. Endocardial electrode as claimed in claim 2, said surface area being 5 mm2.
4. Endocardial electrode as claimed in claim 1, said electrically conductive contact material being evenly distributed about the surface of said electrode head.
5. Endocardial electrode as claimed in claim 4, said contact material being in the form of strips extending along the surface of said electrode head.
6. Endocardial electrode as claimed in claim 4, said contact material being in the form of strips helically wound about the surface of said electrode head.
7. Endocardial electrode as claimed in claim 4, said contact material comprising a plurality of discrete dot-shaped areas dispersed about the surface of said electrode head.
8. Endocardial electrode as claimed in claim 1, said electrode head being of relatively large volume and weight, said volume being in the range of 15 mm3 to 60 mm3, and said weight being in the range of 0.30 p to 2.0 p.
9. Endocardial electrode as claimed in claim 8, said electrode head having a volume of 25 mm3 and a weight of 0.8 p.
10. Endocardial electrode as claimed in claim 1, said electrode head being essentially cylindrically shaped, said electrical conductor being fastened to one end of said cylindrically shaped electrode head, and the free end of said electrode head being of a rounded off configuration.
11. Endocardial electrode as claimed in claim 10, said contact material being constituted of a band-shaped material.
12. Endocardial electrode as claimed in claim 11, said band-shaped contact material being positioned in parallel spaced strips extending along the longitudinal axis of said cylindrically shaped electrode head.
13. Endocardial electrode as claimed in claim 12, the space between adjacent strips of said contact material being 0.5 mm to 5 mm wide.
14. Endocardial electrode as claimed in claim 13, said space between adjacent strips of said contact material being about 1.5 mm wide.
15. Endocardial electrode as claimed in claim 11, said band-shaped contact material being helically wound to form a plurality of spaced strips extending about the annular surface of said cylindrically shaped electrode head.
16. Endocardial electrode as claimed in claim 15, the space between adjacent helically wound strips of said contact material being about 0.5 mm to 5 mm wide.
17. Endocardial electrode as claimed in claim 16, said space between adjacent helically wound strips of said contact material being about 1.5 mm wide.
18. Endocardial electrode as claimed in claim 11, said band-shaped material having a width in the range of 0.01 mm and 0.4 mm.
19. Endocardial electrode as claimed in claim 14, said band-shaped material having a width of about 2 mm.
20. Endocardial electrode as claimed in claim 1, said electrode head comprising an electrically conductive material core having projecting portions forming interstitial spaces; and an electrically insulating material being filled in said interstitial spaces.
21. Endocardial electrode as claimed in claim 20, said projecting portions being essentially ridge-like in configuration.
22. Endocardial electrode as claimed in claim 20, said projecting portions having a helical screw-thread configuration.
23. Endocardial electrode as claimed in claim 1, said electrode head being formed of an electrically conductive basket-shaped wire mesh; and electrically insulating material filling the interior of said basket shape and wire mesh interstices.
24. Endocardial electrode as claimed in claim 23, said insulating material having a relatively high specific weight.
Description:
FIELD OF THE INVENTION
The present invention relates to an endocardial electrode for effecting the intracardial stimulation of a heart, consisting of an elongated electrical conductor, which is provided with an electrical insulation, and an electrode head located at the end of the conductor proximate the heart for the transmission of stimulative impulses to the heart through the inserted electrode.
DISCUSSION OF THE PRIOR ART
In known endocardial electrodes of the above-mentioned type, the metallic electrode head is relatively small and lightweight whereby, on the one hand, it is difficult to position the head on an adequately stimulably sensitive portion of the myocardium while, on the other hand, there the danger is present in that the electrode head, due to its small size, may be displaced through movements of the heart so as to come at rest at a location of the endocardium/myocardium at which the energy level of the stimulating impulse will no longer be sufficient to stimulate the heart.
SUMMARY OF THE INVENTION
As a result of this situation encountered in the prior art, it is an object of the present invention to provide an endocardial electrode of the above-mentioned type which is not subject to the mentioned drawbacks and which may, nevertheless, be operated with impulses of relatively low energy levels. The inventive electrode, while having an extremely small contact surface with the endocardium/myocardium, should be relatively large and weighty, and locatable and removable in the absence of any problems.
The foregoing object is solved by the invention which provides an endocardial electrode in which the surface of the electrode head is constituted partly of an insulating material, and partly of an electrically conductive contact material which is electrically connected with the conductor.
In this inventive construction of the electrode, the surface of the contact material may be so dimensioned as to approximately correspond to the surface of the smallest known electrode heads. In that instance, the current density generated at the contact surface is correspondingly high. The increase in the surface of the electrode head due to the use of insulating material causes that the head to become larger, and mainly heavier, so as to be simply and securely positionable on the endocardium/myocardium, and remaining securely in the myocardium even during movements of the heart. The inventive construction of the electrode head also permits the contact material to be distributed about the surface of the electrode head, so that upon positioning of the head on the endocardium/myocardium affords a greater degree of probability that the contact areas may be located on a particularly stimulably sensitive portion of the myocardium.
Within the scope of the invention, the surface of the contact material does not exceed 15 mm 2 , and is preferably 5 mm 2 in size. Furthermore, the contact material is, as closely as possible, uniformly distributed over the entire surface of the electrode head, and preferably in strip form, spiral form, or in dots or punctiform. The electrode head may thus have a relatively large volume and high weight, in which the volume is in the extent of approximately 60 mm 3 to 15 mm 3 , and preferably approximately 25 mm 3 , while the weight is in the extent of between 0.30 p and 2.0 p, and preferably about 0.8 p, wherein p is measured in "ponds" or grams. In such a construction of the electrode head, the latter may essentially be cylindrically shaped, with the free end thereof being rounded off. In a preferred embodiment of the invention, the contact material is constituted of a band-shaped material. The width of the band is approximately between 0.01 mm and 0.4 mm, and is preferably 0.2 mm. The web is preferably mounted on the electrode head so as to extend in mutually parallel lines along the axial direction of the cylindrically shaped electrode head, or may be helically wound about the cylindrically shaped portion of the electrode head. In that case, the distance between the helical windings preferably lies between approximately 0.5 mm and 5 mm, and is preferably 2 mm.
The weight of the electrode head may readily be increased in a simple manner within the framework of the invention, so as to achieve secure positioning thereof in the right heart chamber, and its manufacture simplified, in that the electrode head may be constructed of a metallic core, or of an electrically conductive material with projecting portions, in which the interstitial spaces between the individual portions are filled with an electrically insulating material. The projecting portions may be ridge-shaped, in the style of screw threads, hedgehog-shaped or the like, so as to achieve the strip-shaped, spirally-shaped or punctiform dot-shaped arrangement of the contact material on the electrode head. In this constructional embodiment, the connection between the free end of the elongated conductor of the endocardial electrode and electrode head becomes particularly simple. The invention also encompasses solutions, in which the electrode head is either completely or partly constructed of insulating material, preferably ceramic or the like, wherein the contact surfaces or, respectively, contact area of the head may be vapor-deposited or galvanically formed thereon. Furthermore, another construction may be contemplated, within the scope of the invention, wherein the contact areas may be formed of a basket-shaped wire mesh which is then filled with the heaviest possible insulating material.
The connection of the contact areas or locations, which is basically the same for all of the embodiments, with the electrode conductor is suitably carried out by spot welding or soldering, or may be also accomplished by means of an electrically conductive adhesive.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference may now be had to the following detailed description of preferred embodiments of the invention, taken in conjunction with the accompanying drawing, in which:
FIG. 1 illustrates, in longitudinal section, an endocardial electrode according to the present invention;
FIG. 2 illustrates a second embodiment of the endocardial electrode;
FIG. 3 illustrates a third embodiment of the endocardial electrode; and
FIG. 4 illustrates a fourth embodiment of the endocardial electrode.
DETAILED DESCRIPTION
Referring in detail to the drawing, in which identical or similar components in the various embodiments are designated by the same reference numerals, FIG. 1 illustrates an elongate electrical conductor 1 of the endocardial electrode, which is provided with encompassing electrical insulation 2. At the electrode end which is proximate the heart, there is located an electrode head 3. The electrode head 3 is generally cylindrically shaped, and is rounded off or curved at its free end. The surface of the electrode head 3 is partly constructed of an electrically insulating material 4 which is not irritative to the body, and partly of an electrically conductive contact material 5. In the embodiments of FIGS. 1 and 2, the contact material 5, which lies on the surface of the electrode head, is band-shaped. Thus, in the construction of FIG. 1, the band-shaped contact material extends in mutually parallel lengths or strips along in the axial direction of the cylindrically shaped electrode head.
In the embodiment of FIG. 2, the contact surface of the band-shaped material extends in a helically wound manner about the cylindrically shaped portion of the electrode head. In the exemplary embodiment shown, the overall length of the electrode head in the axial direction thereof measures approximately 6 mm, and the diameter measures 3 mm. The total surface area of the contact material is approximately 5 mm 2 .
FIG. 3 illustrates another embodiment of the invention, in which the contact surfaces 5 of the electrode head 3 are essentially discrete dots or punctiforms distributed over the entire surface of the electrode head.
FIG. 4 illustrates still another embodiment of the invention, in which the contact surfaces 5 of the electrode head are constructed of an electrically conductive wire mesh material. The material is shaped into a basket-like configuration, with the interior thereof and the interstitial spaces of the wire mesh being filled with electrically insulating material 4.
Various plastic and insulating materials are readily adapted to be employed in the construction of the electrode head, as follows:
Specific Weight in gms/cm 3 Material Designation ______________________________________ 0.5 - 0.9 Insulating paper. 0.9 - 1.0 Polyethylene, polybutene, polypropylene, unfilled rubber, polyisobutylene. 1.0 - 1.2 Polystyrole, normally filled soft-and-hard rubber, cellulose ether, polymethacylate, polycarbonate, unfilled poly- ester and epoxy resins. 1.2 - 1.4 Vulcanized fiber, cellulose ester, polyvinyl ester, also hard-and-soft - PVC, phenolic resin, phenolic resin molded material with organic fillers, cardboard. 1.4 - 1.5 Aminoplast-molded materials with organic fillers, acetal resins. 1.5 - 1.8 Polyvinylide chloride, rubber chloride, anorganically filled molded materials, reinforced plastics, hardeners. 1.8 - 2.3 Silicon, polytetrafluoro- ethylene and other fluorine- containing polymers. 2.2 Quartz glass 2.3 - 2.5 Hard porcelain 2.6 - 2.8 Steatite 2.8 Mica 2.2 - 3.8 Technical glasses 3.1 - 3.9 Titanium oxide-containing ceramic insulating materials ______________________________________
While there has been shown what is considered to be the preferred embodiment of the invention, it will be obvious that modifications may be made which come within the scope of the disclosure of the specification.
The present invention relates to an endocardial electrode for effecting the intracardial stimulation of a heart, consisting of an elongated electrical conductor, which is provided with an electrical insulation, and an electrode head located at the end of the conductor proximate the heart for the transmission of stimulative impulses to the heart through the inserted electrode.
DISCUSSION OF THE PRIOR ART
In known endocardial electrodes of the above-mentioned type, the metallic electrode head is relatively small and lightweight whereby, on the one hand, it is difficult to position the head on an adequately stimulably sensitive portion of the myocardium while, on the other hand, there the danger is present in that the electrode head, due to its small size, may be displaced through movements of the heart so as to come at rest at a location of the endocardium/myocardium at which the energy level of the stimulating impulse will no longer be sufficient to stimulate the heart.
SUMMARY OF THE INVENTION
As a result of this situation encountered in the prior art, it is an object of the present invention to provide an endocardial electrode of the above-mentioned type which is not subject to the mentioned drawbacks and which may, nevertheless, be operated with impulses of relatively low energy levels. The inventive electrode, while having an extremely small contact surface with the endocardium/myocardium, should be relatively large and weighty, and locatable and removable in the absence of any problems.
The foregoing object is solved by the invention which provides an endocardial electrode in which the surface of the electrode head is constituted partly of an insulating material, and partly of an electrically conductive contact material which is electrically connected with the conductor.
In this inventive construction of the electrode, the surface of the contact material may be so dimensioned as to approximately correspond to the surface of the smallest known electrode heads. In that instance, the current density generated at the contact surface is correspondingly high. The increase in the surface of the electrode head due to the use of insulating material causes that the head to become larger, and mainly heavier, so as to be simply and securely positionable on the endocardium/myocardium, and remaining securely in the myocardium even during movements of the heart. The inventive construction of the electrode head also permits the contact material to be distributed about the surface of the electrode head, so that upon positioning of the head on the endocardium/myocardium affords a greater degree of probability that the contact areas may be located on a particularly stimulably sensitive portion of the myocardium.
Within the scope of the invention, the surface of the contact material does not exceed 15 mm 2 , and is preferably 5 mm 2 in size. Furthermore, the contact material is, as closely as possible, uniformly distributed over the entire surface of the electrode head, and preferably in strip form, spiral form, or in dots or punctiform. The electrode head may thus have a relatively large volume and high weight, in which the volume is in the extent of approximately 60 mm 3 to 15 mm 3 , and preferably approximately 25 mm 3 , while the weight is in the extent of between 0.30 p and 2.0 p, and preferably about 0.8 p, wherein p is measured in "ponds" or grams. In such a construction of the electrode head, the latter may essentially be cylindrically shaped, with the free end thereof being rounded off. In a preferred embodiment of the invention, the contact material is constituted of a band-shaped material. The width of the band is approximately between 0.01 mm and 0.4 mm, and is preferably 0.2 mm. The web is preferably mounted on the electrode head so as to extend in mutually parallel lines along the axial direction of the cylindrically shaped electrode head, or may be helically wound about the cylindrically shaped portion of the electrode head. In that case, the distance between the helical windings preferably lies between approximately 0.5 mm and 5 mm, and is preferably 2 mm.
The weight of the electrode head may readily be increased in a simple manner within the framework of the invention, so as to achieve secure positioning thereof in the right heart chamber, and its manufacture simplified, in that the electrode head may be constructed of a metallic core, or of an electrically conductive material with projecting portions, in which the interstitial spaces between the individual portions are filled with an electrically insulating material. The projecting portions may be ridge-shaped, in the style of screw threads, hedgehog-shaped or the like, so as to achieve the strip-shaped, spirally-shaped or punctiform dot-shaped arrangement of the contact material on the electrode head. In this constructional embodiment, the connection between the free end of the elongated conductor of the endocardial electrode and electrode head becomes particularly simple. The invention also encompasses solutions, in which the electrode head is either completely or partly constructed of insulating material, preferably ceramic or the like, wherein the contact surfaces or, respectively, contact area of the head may be vapor-deposited or galvanically formed thereon. Furthermore, another construction may be contemplated, within the scope of the invention, wherein the contact areas may be formed of a basket-shaped wire mesh which is then filled with the heaviest possible insulating material.
The connection of the contact areas or locations, which is basically the same for all of the embodiments, with the electrode conductor is suitably carried out by spot welding or soldering, or may be also accomplished by means of an electrically conductive adhesive.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference may now be had to the following detailed description of preferred embodiments of the invention, taken in conjunction with the accompanying drawing, in which:
FIG. 1 illustrates, in longitudinal section, an endocardial electrode according to the present invention;
FIG. 2 illustrates a second embodiment of the endocardial electrode;
FIG. 3 illustrates a third embodiment of the endocardial electrode; and
FIG. 4 illustrates a fourth embodiment of the endocardial electrode.
DETAILED DESCRIPTION
Referring in detail to the drawing, in which identical or similar components in the various embodiments are designated by the same reference numerals, FIG. 1 illustrates an elongate electrical conductor 1 of the endocardial electrode, which is provided with encompassing electrical insulation 2. At the electrode end which is proximate the heart, there is located an electrode head 3. The electrode head 3 is generally cylindrically shaped, and is rounded off or curved at its free end. The surface of the electrode head 3 is partly constructed of an electrically insulating material 4 which is not irritative to the body, and partly of an electrically conductive contact material 5. In the embodiments of FIGS. 1 and 2, the contact material 5, which lies on the surface of the electrode head, is band-shaped. Thus, in the construction of FIG. 1, the band-shaped contact material extends in mutually parallel lengths or strips along in the axial direction of the cylindrically shaped electrode head.
In the embodiment of FIG. 2, the contact surface of the band-shaped material extends in a helically wound manner about the cylindrically shaped portion of the electrode head. In the exemplary embodiment shown, the overall length of the electrode head in the axial direction thereof measures approximately 6 mm, and the diameter measures 3 mm. The total surface area of the contact material is approximately 5 mm 2 .
FIG. 3 illustrates another embodiment of the invention, in which the contact surfaces 5 of the electrode head 3 are essentially discrete dots or punctiforms distributed over the entire surface of the electrode head.
FIG. 4 illustrates still another embodiment of the invention, in which the contact surfaces 5 of the electrode head are constructed of an electrically conductive wire mesh material. The material is shaped into a basket-like configuration, with the interior thereof and the interstitial spaces of the wire mesh being filled with electrically insulating material 4.
Various plastic and insulating materials are readily adapted to be employed in the construction of the electrode head, as follows:
Specific Weight in gms/cm 3 Material Designation ______________________________________ 0.5 - 0.9 Insulating paper. 0.9 - 1.0 Polyethylene, polybutene, polypropylene, unfilled rubber, polyisobutylene. 1.0 - 1.2 Polystyrole, normally filled soft-and-hard rubber, cellulose ether, polymethacylate, polycarbonate, unfilled poly- ester and epoxy resins. 1.2 - 1.4 Vulcanized fiber, cellulose ester, polyvinyl ester, also hard-and-soft - PVC, phenolic resin, phenolic resin molded material with organic fillers, cardboard. 1.4 - 1.5 Aminoplast-molded materials with organic fillers, acetal resins. 1.5 - 1.8 Polyvinylide chloride, rubber chloride, anorganically filled molded materials, reinforced plastics, hardeners. 1.8 - 2.3 Silicon, polytetrafluoro- ethylene and other fluorine- containing polymers. 2.2 Quartz glass 2.3 - 2.5 Hard porcelain 2.6 - 2.8 Steatite 2.8 Mica 2.2 - 3.8 Technical glasses 3.1 - 3.9 Titanium oxide-containing ceramic insulating materials ______________________________________
While there has been shown what is considered to be the preferred embodiment of the invention, it will be obvious that modifications may be made which come within the scope of the disclosure of the specification.