Leadless cardiac pacing devices including tissue engagement verification

Abstract

An implantable leadless cardiac pacing device including a housing having a proximal end and a distal end, an electrode positioned proximate the distal end of the housing configured to be positioned adjacent cardiac tissue, and a tissue anchoring member extending from the distal end of the housing configured to secure the housing to cardiac tissue. The device further includes a tissue engagement verification feature configured to provide feedback upon engagement of the tissue anchoring member in cardiac tissue.

What is claimed is: 
     
         1 . An implantable leadless cardiac pacemaker comprising:
 a housing having a proximal end and a distal end and defining an axis therebetween;   a first electrode positioned proximate the distal end of the housing, the first electrode configured and adapted to be positioned against and in electrical contact with cardiac tissue;   a second electrode located on the housing and electrically isolated from the first electrode;   a helical tissue anchor extending from the distal end of the housing, the helical tissue anchor configured and adapted to be inserted into the cardiac tissue to secure the housing to the cardiac tissue; and   a tissue engagement member surrounding the helical tissue anchor, the tissue engagement member being axially compressible from an axially extended configuration to an axially contracted configuration upon engagement with the cardiac tissue, wherein a distal end of the tissue engagement member is movable relative to the helical tissue anchor and the housing as the tissue engagement member is axially compressed from the axially extended configuration to the axially contracted configuration.   
     
     
         2 . The implantable leadless cardiac pacemaker of  claim 1 , wherein the tissue engagement member includes an annular ring at the distal end thereof. 
     
     
         3 . The implantable leadless cardiac pacemaker of  claim 2 , wherein the tissue engagement member includes one or deflectable struts extending proximally from the annular ring. 
     
     
         4 . The implantable leadless cardiac pacemaker of  claim 2 , wherein the annular ring includes a radiopaque material providing visual indication via fluoroscopy whether the tissue engagement member is in the axially extended configuration or the axially contracted configuration. 
     
     
         5 . The implantable leadless cardiac pacemaker of  claim 1 , wherein the axially extended configuration of the tissue engagement member is an equilibrium position. 
     
     
         6 . The implantable leadless cardiac pacemaker of  claim 1 , wherein the tissue engagement member is disposed coaxially around the helical tissue anchor. 
     
     
         7 . The implantable leadless cardiac pacemaker of  claim 1 , wherein the helical tissue anchor surrounds the first electrode. 
     
     
         8 . The implantable leadless cardiac pacemaker of  claim 3 , wherein the helical tissue anchor extends distally beyond the tissue engagement member in the axially contracted configuration. 
     
     
         9 . An implantable leadless cardiac pacemaker comprising:
 a housing having a proximal end and a distal end and defining an axis therebetween;   a first electrode positioned proximate the distal end of the housing, the first electrode configured and adapted to be positioned against and in electrical contact with cardiac tissue;   a second electrode located on the housing and electrically isolated from the first electrode;   a helical tissue anchor extending from the distal end of the housing, the helical tissue anchor configured and adapted to be screwed into the cardiac tissue to secure the housing to the cardiac tissue; and   a tissue engagement member surrounding the helical tissue anchor, the tissue engagement member having a proximal end secured to the housing and an opposite distal end;   wherein the distal end of the tissue engagement member is configured to engage the cardiac tissue as the helical tissue anchor is screwed into the cardiac tissue;   
     
     
         10 . The implantable leadless cardiac pacemaker of  claim 9 , wherein the distal end of the tissue engagement member is axially displaceable relative to the helical tissue anchor and the housing. 
     
     
         11 . The implantable leadless cardiac pacemaker of  claim 10 , wherein the distal end of the tissue engagement member is axially movable from an axially extended configuration in which the distal end of the tissue engagement member is positioned a first axial distance from the distal end of the housing to an axially contracted configuration in which the distal end of the tissue engagement member is positioned a second axial distance from the distal end of the housing, the second axial distance being less than the first axial distance. 
     
     
         12 . The implantable leadless cardiac pacemaker of  claim 11 , wherein the axially extended configuration is an equilibrium position of the tissue engagement member. 
     
     
         13 . The implantable leadless cardiac pacemaker of  claim 9 , wherein the tissue engagement member coaxially surrounds the helical tissue anchor. 
     
     
         14 . The implantable leadless cardiac pacemaker of  claim 9 , wherein the helical tissue anchor surrounds the first electrode. 
     
     
         15 . The implantable leadless cardiac pacemaker of  claim 9 , wherein the distal end of the tissue engagement member is configured to press against the cardiac tissue when the helical tissue anchor is screwed into the cardiac tissue. 
     
     
         16 . The implantable leadless cardiac pacemaker of  claim 9 , wherein the tissue engagement member includes an annular ring at the distal end thereof. 
     
     
         17 . The implantable leadless cardiac pacemaker of  claim 16 , wherein the tissue engagement member includes one or deflectable struts extending proximally from the annular ring. 
     
     
         18 . The implantable leadless cardiac pacemaker of  claim 16 , wherein the annular ring includes a radiopaque material providing visual indication via fluoroscopy whether the tissue engagement member is in engagement with the cardiac tissue. 
     
     
         19 . A method of implanting a leadless cardiac pacemaker, the method comprising:
 advancing a leadless cardiac pacemaker into a chamber of a heart while contained within the distal end of a delivery catheter, the leadless cardiac pacemaker including a housing having a distal end and a proximal end;   screwing a helical tissue anchor extending from the distal end of the housing into cardiac tissue to secure the leadless cardiac pacemaker to the cardiac tissue;   axially compressing a tissue engagement member of the leadless cardiac pacemaker from an axially extended configuration to an axially contracted configuration via engagement of a distal end of the tissue engagement member with the cardiac tissue as the helical tissue anchor is being screwed into the cardiac tissue; and   removing the delivery catheter from the chamber of the heart.   
     
     
         20 . The method of  claim 19 , wherein the tissue engagement member surrounds the helical tissue anchor.