Search

EP-4736933-A1 - BIOSTIMULATOR HAVING A RADIOPAQUE MARKER

EP4736933A1EP 4736933 A1EP4736933 A1EP 4736933A1EP-4736933-A1

Abstract

A biostimulator (100) includes a housing (302) having a longitudinal axis (304) and containing an electronics compartment (306). A pacing element (108) is coupled to the housing (302). The pacing element (108) includes a flexible conductor (410) extending along the longitudinal axis (304). A fixation element mount (311) is mounted on the housing (302). The fixation element mount (311) includes a distal mount end (430). A fixation element (106) is mounted on the fixation element mount (311). The fixation element (106) extends about the longitudinal axis (304). A radiopaque marker (502) has a distal marker end (504) longitudinally aligned with the distal mount end (430) of the fixation element mount (311). Other embodiments are also described and claimed.

Inventors

  • TEAGUE, BRYAN
  • WELCH, MARK
  • KWON, Daniel
  • CHANTASIRIVISAL, STEVE

Assignees

  • Pacesetter, Inc.

Dates

Publication Date
20260506
Application Date
20251027

Claims (15)

  1. A biostimulator (100), comprising: a housing (302) having a longitudinal axis (304) and containing an electronics compartment (306); a pacing element (108) coupled to the housing (302), wherein the pacing element (108) includes a flexible conductor (410) extending along the longitudinal axis (304); a fixation element mount (311) mounted on the housing (302), wherein the fixation element mount (311) includes a distal mount end (430); a fixation element (106) mounted on the fixation element mount (311), wherein the fixation element (106) extends about the longitudinal axis (304); and a radiopaque marker (502) having a distal marker end (504) longitudinally aligned with the distal mount end (430) of the fixation element mount (311).
  2. The biostimulator of claim 1, wherein the radiopaque marker (502) is mounted on the fixation element mount (311) at the distal mount end (430).
  3. The biostimulator of claim 1, wherein the radiopaque marker (502) is embedded in the fixation element mount (311) at the distal mount end (430).
  4. The biostimulator of claim 1, wherein the radiopaque marker (502) is coupled to the pacing element (108).
  5. The biostimulator of claim 4, wherein the pacing element (108) extends through a central channel (702) of the radiopaque marker (502).
  6. The biostimulator of claim 4 or 5, wherein the radiopaque marker (502) is embedded in an insulation sleeve (412).
  7. The biostimulator of claim 4 or 5, wherein the radiopaque marker (502) is mounted on an insulation sleeve (412).
  8. The biostimulator of claim 1, wherein the radiopaque marker (502) includes a marker nut (802), and wherein the marker nut (802) is threaded onto a flange (308) of the housing (302) to capture the fixation element mount (311) between the flange (308) and the marker nut (802).
  9. The biostimulator of claim 8, wherein the marker nut (802) includes a radiopaque doped polymer.
  10. The biostimulator of claim 1, wherein the radiopaque marker (502) includes a radiopaque doped filler in a cavity (902) between the pacing element (108) and the fixation element mount (311).
  11. The biostimulator of claim 1, wherein the fixation element mount (106) includes a radiopaque doped polymer.
  12. The biostimulator of claim 11, wherein the radiopaque doped polymer includes polyether ether ketone loaded with less than 15% by volume of a radiopaque material.
  13. The biostimulator of claim 1, wherein the pacing element (108) includes a tip electrode (401) extending along a spiral axis (403) about the longitudinal axis (304), and wherein at a portion of the tip electrode (401) is coated with a radiopaque coating (1002).
  14. The biostimulator of any one of claims 1 to 13, wherein the fixation element (106) extends helically about the longitudinal axis (304), and wherein the fixation element (106) includes a flared section (1102) having an outer diameter (1104) that increases in a distal direction.
  15. The biostimulator of claim 1, wherein the housing (302) contains circuitry in the electronics compartment (306), wherein the fixation element (106) is electrically coupled to the circuitry, and wherein the fixation element (106) includes an insulative coating (1502) between a proximal exposed section (1404) and a distal exposed section (1406).

Description

TECHNICAL FIELD The present disclosure relates to biostimulators. More specifically, the present disclosure relates to leadless biostimulators useful for deep septal pacing. BACKGROUND Cardiac pacing by an artificial pacemaker provides an electrical stimulation of the heart when its own natural pacemaker and/or conduction system fails to provide synchronized atrial and ventricular contractions at rates and intervals sufficient for a patient's health. Such antibradycardial pacing provides relief from symptoms and even life support for hundreds of thousands of patients. Cardiac pacing may also provide electrical overdrive stimulation to suppress or convert tachyarrhythmias, again supplying relief from symptoms and preventing or terminating arrhythmias that could lead to sudden cardiac death. Leadless cardiac pacemakers incorporate electronic circuitry at the pacing site and eliminate leads, thereby avoiding shortcomings associated with conventional cardiac pacing systems. Leadless cardiac pacemakers can be anchored at the pacing site, e.g., in a right ventricle and, for dual-chamber pacing, in a right atrium, by an anchor. Cardiac pacing of the His-bundle is clinically effective and advantageous by providing a narrow QRS affecting synchronous contraction of the ventricles. His-bundle pacing in or near a membranous septum of a heart, however, has some drawbacks. The procedure is often long in duration and requires significant fluoroscopic exposure. Furthermore, successful His-bundle pacing cannot always be achieved. Pacing thresholds are often high, sensing is challenging, and success rates can be low. Deep septal pacing is an alternative to His-bundle pacing. Deep septal pacing involves pacing past the His-bundle toward the right ventricle apex. More particularly, deep septal pacing targets the left bundle branch below the His site. Deep septal pacing has been achieved using a lead in which the electrode penetrates several millimeters into the septum. Pacing thresholds associated with deep septal pacing are potentially lower than with His-bundle pacing, and clinical efficacy of the approach has been demonstrated. SUMMARY Deep septal pacing, e.g., left bundle branch area pacing (LBBAP) can require a pacing electrode to penetrate through a majority of a ventricular septal wall to extend into the left bundle branch or into a left bundle fascicular that resides on a left side of a septum. In the case of a leadless cardiac pacemaker, a body of the pacemaker can be affixed to the septum and the pacing electrode can penetrate to the target tissue. More particularly, the pacing electrode may be required to penetrate 10-12 mm into the ventricular septal wall. Affixation of the leadless cardiac pacemaker to the septal wall and a depth of the pacing electrode should be accurately performed for effective treatment. Existing leadless cardiac pacemakers are not well suited to ensuring affixation of the leadless cardiac pacemaker to the septal wall. Fluoroscopy may be used to visualize placement of the leadless cardiac pacemaker. A relative location between a fixation element and the septum may not be visible under such fluoroscopy, however. As a result, the leadless cardiac pacemaker may be over-torqued during implantation, which can lead to burrowing into the septal tissue too far and possible perforation of the septum, or under-torqued during implantation, which can lead to inadequate fixation of the leadless cardiac pacemaker to the septal wall. Accordingly, a form of feedback or indication under fluoroscopy to allow a physician to confirm that the leadless cardiac pacemaker is accurately affixed to the septal wall can be beneficial, e.g., by reducing a risk of dislodgement of the leadless cardiac pacemaker after implantation. Existing leadless cardiac pacemakers employ fixation elements that may not adequately anchor the leadless cardiac pacemaker in the septum. Insufficient capture of septal tissue can increase a risk of the leadless cardiac pacemaker becoming dislodged after implantation. Accordingly, a fixation element that maximizes tissue capture can mitigate a risk of dislodgment. Existing leadless cardiac pacemakers are not well suited to ensuring that a depth of the pacing electrode is accurate. A pacing electrode used to pace target tissue is commonly physically separated from a fixation element used to anchor the leadless cardiac pacemaker in the septum. The physical separation can make it difficult to burrow the electrically active electrode into the septum far enough to contact the left bundle branch without perforating into the left ventricle. Shallow burrowing, however, risks having poor anchoring in the septal tissue. Accordingly, a fixation element that can anchor the leadless cardiac pacemaker in the septal wall and deliver pacing impulses to the target tissue at an accurate depth can be beneficial. A biostimulator is described. In an embodiment, the biostimulator includes a housing having a longitudin