Leadless Cardiac Pacemaker with Anti-Unscrewing Feature

• US 20120116489A1
• Filed: 10/12/2011
• Published: 05/10/2012
• Est. Priority Date: 10/13/2010
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Inventors: Khairkhahan, Alexander, Carroll, Kenneth J., Paspa, Paul, Varady, Eric
• Granted Patent: US 9,020,611 B2
• Time in Patent Office: Days
• US Class Current: 607/127
• CPC Class Codes: A61N 1/0573 chacterised by means penetrating the heart tissue, e.g. helix needle or hook
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/37512 Pacemakers
• CPC Class Codes: A61N 1/37518 Anchoring of the implants, e.g. fixation
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators

Abstract

A leadless cardiac pacemaker comprises a housing, a plurality of electrodes coupled to an outer surface of the housing, and a pulse delivery system hermetically contained within the housing and electrically coupled to the electrode plurality, the pulse delivery system configured for sourcing energy internal to the housing, generating and delivering electrical pulses to the electrode plurality. The pacemaker further comprises an anti-unscrewing feature disposed on either a fixation device of the pacemaker or on the housing itself. The anti-unscrewing feature can be configured to prevent the fixation device from disengaging the wall of the heart.

Claims

1. A leadless biostimulator, comprising:

a housing sized and configured to be implanted within a heart of a patient;

a primary fixation device attached to the housing and configured to affix the biostimulator to a wall of the heart; and

an anti-unscrewing feature disposed on the primary fixation device, the anti-unscrewing feature configured to prevent the primary fixation device from disengaging the wall of the heart.

2. The leadless biostimulator of claim 1 wherein the primary fixation device is a fixation helix.

3. The leadless biostimulator of claim 1 wherein the anti-unscrewing feature is at least one barb.

4. The leadless biostimulator of claim 3 wherein the at least one barb is pointed generally proximally away from a distal end of the fixation device.

5. The leadless biostimulator of claim 1 wherein a first torque required to insert the fixation device into the wall of the heart is less than a second torque required to remove the fixation device from the wall of the heart.

6. The leadless biostimulator of claim 1 wherein the anti-unscrewing feature is at least one rounded feature.

7. The leadless biostimulator of claim 1 wherein the anti-unscrewing feature is at least one through-hole.

8. The leadless biostimulator of claim 1 wherein the anti-unscrewing feature is at least one depression.

38. The leadless biostimulator of claim 1 wherein the anti-unscrewing feature is a suture.

39. The leadless biostimulator of claim 38 wherein the suture is bio-absorbable.

9. A leadless biostimulator, comprising:

a housing sized and configured to be implanted within a heart of a patient;

a primary fixation helix attached to the housing and configured to affix the biostimulator to a wall of the heart; and

an anti-unscrewing helix wound in an opposite direction of the primary fixation helix, the anti-unscrewing helix attached to the housing.

10. The leadless biostimulator of claim 9 wherein the primary fixation helix is a right-handed helix and the anti-unscrewing helix is a left-handed helix.

11. The leadless biostimulator of claim 9 wherein the primary fixation helix is longer than the anti-unscrewing helix.

12. The leadless biostimulator of claim 9 wherein the anti-unscrewing helix is positioned outside of the primary fixation helix.

13. The leadless biostimulator of claim 9 wherein the primary fixation helix is an electrode.

14. The leadless biostimulator of claim 9 wherein the anti-unscrewing helix is configured to compress against tissue as the primary fixation helix is affixed to the wall of the heart.

15. The leadless biostimulator of claim 9 wherein the anti-unscrewing helix is configured to engage the wall of the heart in the event the biostimulator unscrews from the wall of the heart.

16. A leadless biostimulator, comprising:

a housing sized and configured to be implanted within a heart of a patient;

a primary fixation device attached to the housing and configured to affix the biostimulator to a wall of the heart; and

an anti-unscrewing feature disposed on the housing, the anti-unscrewing feature configured to prevent the primary fixation device from disengaging the wall of the heart.

17. The leadless biostimulator of claim 16 wherein the primary fixation device comprises a fixation helix.

18. The leadless biostimulator of claim 16 wherein the anti-unscrewing feature comprises a plurality of teeth, barbs, or other sharpened features.

19. The leadless biostimulator of claim 18 wherein the teeth, barbs, or other sharpened features are disposed on a distal surface of the housing.

20. The leadless biostimulator of claim 18 wherein the teeth, barbs, or other sharpened features are disposed on a tapered surface of the housing.

21. The leadless biostimulator of claim 18 wherein the teeth, barbs, or other sharpened features are arranged asymmetrically to provide resistance only in an unscrewing direction of the primary fixation device.

22. The leadless biostimulator of claim 16 wherein a first torque required to insert the fixation device into the wall of the heart is less than a second torque required to remove the fixation device from the wall of the heart.

23. The leadless biostimulator of claim 16 wherein the anti-unscrewing feature is a cleat.

24. The leadless biostimulator of claim 23 wherein the cleat is positioned on the housing beneath the fixation device.

25. The leadless biostimulator of claim 24 wherein the cleat is directed towards the fixation device and configured to grab heart tissue between the cleat and the fixation device to resist unintentional detachment of the fixation device from the wall of the heart.

26. The leadless biostimulator of claim 16 wherein the anti-unscrewing feature is at least one through-hole.

27. The leadless biostimulator of claim 16 wherein the anti-unscrewing feature is at least one depression.

28. A leadless biostimulator, comprising:

a housing sized and configured to be implanted within a heart of a patient;

a primary fixation device attached to the housing and configured to affix the biostimulator to a wall of the heart; and

at least one through-hole disposed in the housing, the at least one through-hole configured to promote tissue in-growth into the through-hole to prevent the primary fixation device from disengaging the wall of the heart.

29. The leadless biostimulator of claim 28 wherein the at least one through-hole extends horizontally into the housing.

30. The leadless biostimulator of claim 28 wherein the at least one through-hole extends along a longitudinal axis of the housing.

31. The leadless biostimulator of claim 28 wherein the at least one through-hole has a diameter of approximately 0.005″

to 0.04″

.

32. The leadless biostimulator of claim 28 wherein the at least one through-hole extends partially across a diameter of the housing.

33. The leadless biostimulator of claim 28 wherein the at least one through-hole extends fully across a diameter of the housing.

34. The leadless biostimulator of claim 28 wherein the at least one through-hole is filled with a bioabsorbable material.

35. A method of preventing unintentional detachment of a leadless biostimulator from a heart of a patient, comprising:

applying torque to the leadless biostimulator in a first direction to affix the leadless biostimulator to heart tissue with a primary fixation device;

applying torque to the tissue in a second direction with an anti-unscrewing device to prevent disengagement of the leadless biostimulator from tissue.

36. The method of claim 35 wherein the torque in the second direction is greater than the torque in the first direction.

37. A method of preventing detachment of a leadless biostimulator from a patient, comprising:

implanting the leadless biostimulator into heart tissue of the patient;

preventing the leadless biostimulator from detaching from the heart tissue with a bioabsorbable anti-unscrewing feature; and

allowing the bioabsorbable anti-unscrewing feature to be absorbed by the patient in less than 3 months.