Defibrillation electrode having smooth current distribution

• US 5,271,417 A
• Filed: 11/19/1991
• Issued: 12/21/1993
• Est. Priority Date: 01/23/1990
• Status: Expired due to Fees

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Lang, Douglas J., Swanson, David K., Dahl, Roger W.
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): SCHAETZLE, KENNEDY
• Application Number:
  US07/794,004
• Time in Patent Office: 763 Days
• Field of Search: 128/783, 128/784, 128/799, 128/419 P, 128/639, 128/642, 128/419 D, 128/786
• US Class Current: 607/122
• CPC Class Codes: A61N 1/0563 specially adapted for defibrillation or cardioversion

Abstract

A defibrillation electrode for implantation in the region of the heart and for connection to a defibrillation system. The electrode comprises multiple independent conductive segments spaced apart for defining a discharge surface of the electrode. In one embodiment, the electrode comprises a plurality of concentric conductive rings electrically connected together. To smooth the current distribution, the interface impedance of the inner conductive segments is made lower than that of the outer conductive segments. In one embodiment, the impedance is determined by the choice of the conductive material. In another embodiment, the impedance is determined by texturing the surface of the conductive segments. In yet another embodiment, the impedance is determined by the ratio of conductive edges to surface of the conductive segment. The discharge surface region can also take the form of a portion of a cardiac catheter.

Other ways to control the current distribution include the use of a floating conductive segment, and the use of discrete segments which receive defibrillating waveforms of different amplitudes and isolating the conductive segments to deliver higher amplitude waveforms to the inner segments than the outer segments.

Claims

1. An implantable cardioversion/defibrillation electrode for implantation in the region of the heart for connection to a defibrillation/cardioversion system, said electrode comprising:

means for effecting a predetermined discharge distribution across said electrode comprising a conductive discharge surface region having a predetermined surface area comprised of electrically conductive material for delivering energy to the heart, select portions of the electrically conductive material of said discharge surface region having different interface impedance characteristics from other portions of said discharge surface region for effecting said predetermined discharge distribution across said electrode, wherein said select portions correspond to central portions of said discharge surface region, and said other portions correspond to extreme portions of said discharge surface region, said select portions having a lower interface impedance than the other portions such that the interface impedance gradually increases from the central portions to the extreme portions across said discharge surface region.

2. An implantable cardioversion/defibrillation electrode for implantation in the region of the heart for connection to a defibrillation/cardioversion system, said electrode comprising:

means for effecting a predetermined discharge distribution across said electrode comprising a conductive discharge surface region having a predetermined surface area comprised of electrically conductive material for delivering energy to the heart, select portions of the electrically conductive material of said discharge surface region having different interface impedance characteristics from other portions of said discharge surface region for effecting said predetermined discharge distribution across said electrode, wherein said discharge surface region comprises multiple conductive segments connected in common, and select ones of said conductive segments are formed of electrically conductive material having a lower interface impedance of activation energy than the conductive segments of said other portions of said discharge surface region.

3. An implantable cardioversion/defibrillation electrode for implantation in the region of the heart for connection to a defibrillation/cardioversion system, said electrode comprising:

means for effecting a predetermined discharge distribution across said electrode comprising a conductive discharge surface region having a predetermined surface area comprised of electrically conductive material for delivering energy to the heart, select portions of the electrically conductive material of said discharge surface region having different interface impedance characteristics from other portions of said discharge surface region for effecting said predetermined discharge distribution across said electrode, wherein said discharge surface region comprises multiple conductive segments connected in common, wherein select ones of said conductive segments correspond to said select portions of said discharge surface region and are textured to increase the surface area of said select ones of said conductive segments for decreasing the interface impedance thereof, each of said plurality of conductive segments is a conductive screen formed of woven conductive filaments, and the diameter and spacing of the filaments comprising the screens of said select ones of said conductive segments are modified to change the interface impedance of said select ones of said conductive segments.

4. An implantable cardioversion/defibrillation electrode for implantation in the region of the heart for connection to a defibrillation/cardioversion system, said electrode comprising:

means for effecting a predetermined discharge distribution across said electrode comprising a conductive discharge surface region having a predetermined surface area comprised of electrically conductive material for delivering energy to the heart, select portions of the electrically conductive material of said discharge surface region having different interface impedance characteristics from other portions of said discharge surface region for effecting said predetermined discharge distribution across said electrode, wherein said discharge surface region comprises multiple conductive segments connected in common, select ones of said conductive segments correspond to said select portions of said discharge surface region and are textured to increase the surface area of said select ones of said conductive segments for decreasing the interface impedance thereof, and wherein the cross-sectional dimensions of select ones of said conductive segments are altered to modify the interface impedance thereof.

5. An implantable cardioversion/defibrillation electrode for implantation in the region of the heart for connection to a defibrillation/cardioversion system, said electrode comprising:

means for effecting a predetermined discharge distribution across said electrode comprising a conductive discharge surface region having a predetermined surface area comprised of electrically conductive material for delivering energy to the heart, select portions of the electrically conductive material of said discharge surface region having different interface impedance characteristics from other portions of said discharge surface region for effecting said predetermined discharge distribution across said electrode, wherein said discharge surface region comprises multiple conductive segments connected in common, and said select ones of said conductive segments are formed of multiple layers of conductive screens.

6. An implantable cardioversion/defibrillation electrode for implantation in the region of the heart for connection to a defibrillation/cardioversion system, said electrode comprising:

means for effecting a predetermined discharge distribution across said electrode comprising a conductive discharge surface region having a predetermined surface area comprised of electrically conductive material for delivering energy to the heart, select portions of the electrically conductive material of said discharge surface region having different interface impedance characteristics from other portions of said discharge surface region for effecting said predetermined discharge distribution across said electrode, wherein said discharge surface region comprises multiple conductive segments connected in common, and further comprising a catheter body, and wherein each of said plurality of conductive segments comprise spaced multiple turns of conductive ribbon around said catheter body.

7. The electrode of claim 6, wherein the dimensions of the conductive ribbon and the spacing between adjacent turns of the ribbon of said select ones of said conductive segments is altered to reduce the interface impedance thereof.