US5257635A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical heating catheter
Assignee: LANGBERG JULIA M
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Filing: 1991-07-26
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Granted: 1993-11-02
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Expires: 2011-07-26
Abstract
Abstract The invention provides a thermal design of a catheter where the active electrode is partially covered by a heat conducting and electrically insulating heat-sink layer for localizing and controlling an electrical heating of tissue and cooling of the active electrode by convective blood flow. The invention further comprises a current equalizing coating for gradual transition of electrical properties at a boundary of a metallic active electrode and an insulating catheter tube. The current equalizing coating controls current density and the distribution of tissue heating.
Inventors
- 👤 Edwin Langberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 01:50
CPC Classifications
A; A61; A61N; A61N1/00; A61N1/40; A61N1/403; A61B; A61B18/00; A61B18/04; A61B18/08; A61B18/12; A61B18/14; A61B18/1492; A61B18/18; A61B18/1815; A61N1/02; A61N1/04; A61N1/05; A61N1/056; A61N1/0565; A61N1/06; A61N1/18; A61N1/20; A61N1/28; A61B18/1206; A61B18/1233; A61B2018/00005; A61B2018/00053; A61B2018/00059; A61B2018/00071; A61B2018/00083; A61B2018/00089; A61B2018/00095; A61B2018/00107; A61B2018/00148; A61B2018/00315; A61B2018/00345; A61B2018/00351; A61B2018/00571; A61B2018/00577; A61B2018/00636; A61B2018/00773; A61B2018/00839; A61M; A61M2230/00; A61M2230/04
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
86 words
An electrical heating catheter comprising: an electrical cable housed in an electrically insulating catheter tube; the electrical cable adapted to be connected at a proximal end to a source of electrical power; an active electrode including a metallic material; the electrical cable connected at a distal end to said active electrode; a graduated electrical impedance coating on the active electrode for providing a smooth transition of surface current density between said metallic material of the active electrode and a material of the electrically insulating catheter tube.
Claim 2
Dependent Claim
86 words
An electrical heating catheter comprising: an electrical cable housed in an electrically insulating catheter tube; the electrical cable adapted to be connected at a proximal end to a source of electrical power; an active electrode including a metallic material; the electrical cable connected at a distal end to said active electrode; a graduated electrical impedance coating on the active electrode for providing a smooth transition of surface current density between said metallic material of the active electrode and a material of the electrically insulating catheter tube.
Claim 3
Dependent Claim
22 words
An electrical heating catheter in claim 1 wherein said coating comprises a material with substantially uniform electrical properties and a varying thickness.
Claim 4
Dependent Claim
16 words
An electrical heating catheter in claim 2 wherein said material of said coating is conductive epoxy.
Claim 5
Dependent Claim
16 words
An electrical heating catheter in claim 2 wherein said material of said coating is a cermet.
Claim 6
Dependent Claim
16 words
An electrical heating catheter in claim 2 wherein said material of said coating is a plastic.
Claim 7
Dependent Claim
17 words
An electrical heating catheter in claim 2 wherein said material of said coating is a metal oxide.
Claim 8
Dependent Claim
64 words
An electrical heating catheter in claim 2 wherein said coating with said varying thickness comprises a conductive skirt surrounding a base of said active electrode, the skirt characterized by a wedge-shaped cross section with a wide face of the wedge against a junction with said electrically insulating catheter tube and a pointy end of the wedge against said metallic material of said active electrode.
Claim 9
Dependent Claim
28 words
An electrical heating catheter in claim 1 wherein said graduated electrical impedance coating comprises an electrical material of a substantially uniform thickness and a spatially varying electrical impedance.
Claim 10
Dependent Claim
33 words
An electrical heating catheter in claim 1 wherein said graduated electrical impedance coating comprises axially stratified layers, each layer of a substantially constant impedance, and an impedance value graduated from layer to layer.
Claim 11
Dependent Claim
121 words
In a catheter for electrical heating, comprising an active electrode formed of metallic material and a catheter transmission line having a proximal end and a distal end, said line being adapted to be connected at its proximal end to a source of electrical power and being connected at its distal end to said active electrode, said electrode in operation being immersed in a lossy medium, said catheter characterized by: a graduated impedance coating deposited on a surface of the said active electrode for shaping an electric field in the lossy medium outside of said electrode and coating being heat conducting and electrically insulating, said coating controlling an electrical heating of tissue and cooling of said active electrode by convective blood flow.
Claim 12
Dependent Claim
121 words
In a catheter for electrical heating, comprising an active electrode formed of metallic material and a catheter transmission line having a proximal end and a distal end, said line being adapted to be connected at its proximal end to a source of electrical power and being connected at its distal end to said active electrode, said electrode in operation being immersed in a lossy medium, said catheter characterized by: a graduated impedance coating deposited on a surface of the said active electrode for shaping an electric field in the lossy medium outside of said electrode and coating being heat conducting and electrically insulating, said coating controlling an electrical heating of tissue and cooling of said active electrode by convective blood flow.
Claim 13
Dependent Claim
31 words
A catheter for electrical heating in accordance with claim 10, wherein said graduated impedance coating comprises a resistive coating of a varying thickness deposited on the metallic material of said electrode.
Claim 14
Dependent Claim
30 words
A catheter for electrical heating in accordance with claim 10, wherein said graduated impedance heat sink coating comprises a dielectric coating of a varying thickness deposited on said metallic material.
Claim 15
Dependent Claim
28 words
A catheter for electrical heating in accordance with claim 10, further comprising a graduated electrical impedance coating located in a gap and electrically interacting with said active electrode.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-11-01 | 1997-05-03 | 1997-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-11-01 | 2001-05-03 | 2001-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-11-01 | 2005-05-03 | 2005-11-02 | $7700.00 | Window Closed / Lapsed |