Capacitors with recessed rivets allow smaller implantable defibrillators

• US 6,385,490 B1
• Filed: 06/30/2000
• Issued: 05/07/2002
• Est. Priority Date: 12/16/1999
• Status: Expired due to Term

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Tong, Robert R., Rubin, Steven A., Christenson, Luke J., OʼPhelan, Michael J.
• Primary Examiner(s): Jastrzab, Jeffrey R.
• Assistant Examiner(s): Oropeza, Frances P.
• Application Number:
  US09/607,382
• Time in Patent Office: 676 Days
• Field of Search: 607/4, 607/5, 607/9, 607/119, 607/36, 361/302, 361/509, 361/520, 361/537
• US Class Current: 607/5
• CPC Class Codes: A61N 1/378 Electrical supply
• CPC Class Codes: H01G 9/08 Housing; Encapsulation

Abstract

Implantable defibrillators are implanted into the chests of patients prone to suffering ventricular fibrillation, a potentially fatal heart condition. Critical components in these devices are aluminum electrolytic capacitors, which store and deliver one or more life-saving bursts of electric charge to a fibrillating heart. These capacitors make up about one third the total size of the defibrillators. Unfortunately, manufacturers of these capacitors have paid little or no attention to reducing the size of these capacitors through improved capacitor packaging. Accordingly, the inventors devised a unique capacitor lid, or header, assembly that allows size reduction. Specifically, one embodiment of the header assembly includes two recesses, each with a depth that allows the head of a rivet (or other fastener) to be substantially flush, or coplanar, with the underside of the header. Another embodiment includes a single recess to receive two rivet heads. The recesses reduce the vertical space necessary to ensure separation of the rivets from internal components of the capacitor and thus allow reduction in the overall height of the capacitor and size of devices, such as implantable defibrillators, that use them.

Claims

1. An implantable heart rhythm management device comprising:

one or more leads for sensing electrical signals of a patient or for applying

electrical energy to the patient;

a monitoring circuit for monitoring heart activity of the patient through one

or more of the leads; and

a therapy circuit for delivering electrical energy through one or more of the

leads to a heart of the patient, wherein the therapy circuit includes

one or more aluminum electrolytic capacitors, each comprising;

one or more terminals;

a header having a header thickness and one or more recesses, with each recess having a depth less than the header thickness;

one or more aluminum fasteners, with each fastener fastening one of the terminals to the header and having a head at least partially within one of the recesses; and

an active element including one or more aluminum foils, with at least one of the foils electrically coupled to one of the aluminum fasteners.

2. The implantable heart rhythm management device of claim 1, wherein the header comprises first and second bonded layers, with the second bonded layer having a second thickness and with each recess having a depth less than the second thickness.

3. The implantable heart rhythm management device of claim 1, wherein the header comprises first and second bonded layers, with the first layer consisting essentially of rubber and the second layer consisting essentially of phenolic resin.

4. The implantable heart rhythm management device of claim 1, wherein the device is a defibrillator;

one or more of the aluminum fasteners is a rivet;

the active element includes one or more tabs coupled to one or more of the aluminum foils; and

the rivet is ultrasonically welded to at least one of the tabs.

5. The implantable heart rhythm management device of claim 1, wherein each recess has a depth less than on e half the header thickness.

6. The implantable heart rhythm management device of claim 1, wherein each recess faces the active element.

7. An implantable heart rhythm management device comprising:

one or more capacitors, with each capacitor comprising;

a tubular housing having a longitudinal axis and having an opening defining a plane intersecting the longitudinal axis;

a header filling or covering at least a portion of the opening, having a maximum thickness in a dimension parallel to the longitudinal axis, and having one or more recesses, each with a depth, measured in the dimension parallel to the longitudinal axis, which is less than the maximum thickness of the header; and

one or more terminals fastened to the header with one or one or more fasteners, each fastener having a head at least partly within one of the recesses.

8. The implantable heart rhythm management device of claim 7, wherein each recess has a depth less than one half the header thickness.

9. The implantable heart rhythm management device of claim 7, wherein each capacitor further comprises an active element within the tubular housing and wherein each recess faces the active element.

10. The implantable heart rhythm management device of claim 7, wherein the housing and terminals consist essentially of aluminum.

11. An implantable heart rhythm management device comprising:

one or more capacitors, with each capacitor comprising;

a tubular housing having a longitudinal axis and having a closed end and an open end, each defining a plane intersecting the longitudinal axis;

a header filling or covering at least a portion of the opening, having a maximum thickness in a dimension parallel to the longitudinal axis of the housing, and having one or more recesses, each with a depth, measured in the dimension parallel to the longitudinal axis, which is less than the maximum thickness of the header;

an active element within the tubular housing between the closed end and the header, the active element including one or more conductive members; and

one or more terminals fastened to the header with one or more conductive fasteners, each fastener having a head electrically coupled to one or more of the conducive members and at least partly within one of the recesses.

12. The implantable heart rhythm management device of claim 11, wherein each recess has a depth less than one half the maximum thickness of the header.

13. The implantable heart rhythm management device of claim 11, wherein each recess faces the active element.

14. An implantable heart rhythm management device comprising:

one or more capacitors, with each capacitor including;

capacitor casing means which defines an interior volume of the capacitor;

header means having a header thickness attached to the capacitor casing means and having one or more each recess having a depth less than the header thickness; and

terminating means fastened to the header with one or more fasteners, each fastener having a head at least partly within one of the one or more recesses.