Leadless cardiac stimulation systems

Abstract

Various configurations of systems that employ leadless electrodes to provide pacing therapy are provided. In one example, a system that provides multiple sites for pacing of myocardium of a heart includes wireless pacing electrodes that are implantable at sites proximate the myocardium using a percutaneous, transluminal, catheter delivery system. Each of the electrodes contains a source of electrical energy for pacing the myocardium and is adapted to receive electromagnetic energy from a source outside the myocardium. The system also includes a source adapted for placement outside the myocardium and that uses locally measured electrocardiograms to synchronize pacing of the heart by sending electromagnetic commands to the electrodes to pace the myocardium surrounding the electrodes. Also disclosed is various configurations of such systems, wireless electrode assemblies, and delivery catheters for delivering and implanting the electrode assemblies.

1 . A cardiac tissue stimulation system, comprising;
 an elongate member sized and shaped to access an interior of a heart via an intravascular route, and the elongate member including a proximal end configured to be manipulated by a user and a distal end sized and shaped for delivery to the interior of the heart;   a tether configured to traverse the intravascular route via a lumen defined by the elongate member; and   a leadless cardiac stimulation electrode assembly mechanically coupled to the tether, the leadless cardiac tissue stimulation electrode assembly configured for delivery to the interior of the heart using the elongate member, the leadless cardiac tissue stimulation electrode assembly including:
 an cardiac tissue stimulation circuit configured to generate an electrical stimulation for delivery to heart tissue; 
 an electrode electrically coupled to the cardiac tissue stimulation circuit and configured to deliver the cardiac tissue stimulation generated by the cardiac tissue stimulation circuit to heart tissue; and 
 an anchoring device configured to securely anchor the leadless cardiac tissue stimulation electrode assembly to heart tissue; 
   wherein the electrode of the leadless cardiac tissue stimulation electrode assembly is configured to deliver cardiac electrical stimulation to a first location within the heart while the electrode assembly is coupled to the tether;   wherein the leadless cardiac tissue stimulation electrode assembly is configured to be repositioned from the first location to a second location within the heart using the tether and in response to information indicative of a response to a delivered cardiac electrical stimulation; and   wherein the leadless cardiac tissue stimulation electrode assembly is configured to be released from the tether at the second location to implant the leadless cardiac tissue stimulation electrode assembly within the heart.   
     
     
         2 . The cardiac tissue stimulation system of  claim 1 , comprising a sensing circuit configured to sense electrical activity indicative of the response to the delivered cardiac electrical stimulation to provide the information indicative of the response to the delivered cardiac electrical stimulation. 
     
     
         3 . The cardiac tissue stimulation system of  claim 2 , wherein the sensing circuit is located at or near the proximal end of the elongate member and coupled to the electrode of the leadless cardiac tissue stimulation electrode assembly using a detachable conductive lead that traverses the intravascular route to the interior of the heart. 
     
     
         4 . The cardiac tissue stimulation system of  claim 3 , wherein the tether comprises the detachable conductive lead. 
     
     
         5 . The cardiac tissue stimulation system of  claim 2 , wherein the sensing circuit is included as a portion of an implantable assembly located outside the heart. 
     
     
         6 . The cardiac tissue stimulation system of  claim 1 , wherein the system includes a pusher sized and shaped to traverse the intravascular route through the lumen and configured to be manipulated by a user to deploy the leadless cardiac tissue stimulation electrode assembly from a distal end of the elongate member. 
     
     
         7 . A cardiac tissue stimulation system, comprising:
 an catheter defining a lumen, the catheter sized and shaped to access an interior of a heart via an intravascular route, and the catheter including a proximal end configured to be manipulated by a user and a distal end sized and shaped for delivery to the interior of the heart;   an actuator configured to access the interior of the heart via the lumen of the catheter; and   a leadless cardiac tissue stimulation electrode assembly mechanically coupled to the actuator, the leadless cardiac tissue stimulation electrode assembly configured for delivery to the heart chamber using the catheter, the leadless cardiac tissue stimulation electrode assembly including:
 an cardiac tissue stimulation circuit configured to generate an electrical stimulation for delivery to heart tissue; 
 an electrode electrically coupled to the cardiac tissue stimulation circuit and configured to deliver the electrical stimulation generated by the cardiac tissue stimulation circuit to heart tissue; 
   wherein the electrode of the leadless cardiac tissue stimulation electrode assembly is configured to deliver a cardiac electrical stimulation to a first location within the heart chamber while the electrode assembly remains coupled to the actuator;   wherein the leadless electrostimulation electrode assembly is configured to be repositioned from the first location to a second location within the heart using the actuator and in response to information indicative of a response to delivered cardiac electrical stimulation; and   wherein the leadless electrostimulation electrode assembly is configured to be detached from the actuator after repositioning.   
     
     
         8 . The cardiac tissue stimulation system of  claim 7 , wherein the leadless cardiac tissue stimulation electrode assembly includes a first fixation device. 
     
     
         9 . The cardiac tissue stimulation system of  claim 8 , wherein the first fixation devices includes the electrode. 
     
     
         10 . The cardiac tissue stimulation system of  claim 8 , wherein the leadless cardiac tissue stimulation electrode assembly is configured for manipulation by a user to provide a non-deployed configuration of the first fixation device during traversal of the lumen defined by the catheter, a partially-deployed configuration of the first fixation device to engage heart tissue for evaluation of a site for implantation of the leadless cardiac tissue stimulation electrode assembly, and a fully-deployed configuration of the first fixation device to engage heart tissue for chronic cardiac tissue stimulation and implantation. 
     
     
         11 . The cardiac tissue stimulation system of  claim 10 , wherein the actuator is configured to disengage from the leadless cardiac tissue stimulation electrode assembly after the leadless cardiac tissue stimulation electrode assembly is in the deployed configuration. 
     
     
         12 . The cardiac tissue stimulation system of  claim 8 , comprising a second fixation device located at or near an opposite end of the leadless cardiac tissue stimulation electrode assembly from the first fixation device. 
     
     
         13 . The cardiac tissue stimulation system of  claim 12 , wherein the second fixation device extends outward in a direction substantially opposite the first fixation device. 
     
     
         14 . The cardiac tissue stimulation system of  claim 12 , wherein the second fixation device is constrained by an inner wall of the catheter when located in a lumen defined by the catheter. 
     
     
         15 . The cardiac tissue stimulation system of  claim 14 , wherein the second fixation device is configured to self-deploy when exiting the lumen to securely anchor the leadless cardiac tissue stimulation electrode assembly. 
     
     
         16 . A cardiac tissue stimulation electrode assembly, comprising:
 a housing sized and shaped for delivery to an interior of the heart via an intravascular route and the housing sized to fit entirely within the heart;   a cardiac tissue stimulation circuit located within the housing and configured to generate an electrical stimulation for delivery to heart tissue;   an electrode electrically coupled to the cardiac tissue stimulation circuit and configured to deliver the electrical stimulation generated by the cardiac tissue stimulation circuit to heart tissue, the electrode configured to deliver a cardiac electrical stimulation to a first location within the heart chamber while the electrode assembly remains coupled to an actuator, the actuator including a distal end coupled to the electrode assembly and a proximal end configured for manipulation by a user; and   an anchoring device configured to securely anchor the leadless electrostimulation electrode assembly to heart tissue;   wherein the leadless electrostimulation electrode assembly is configured to be repositioned from the first location to a second location within the heart using the actuator and in response to information indicative of a response to delivered cardiac electrical stimulation; and   wherein the leadless electrostimulation electrode assembly is configured to be detached from the actuator after repositioning.   
     
     
         17 . The cardiac tissue stimulation electrode assembly of  claim 16 , wherein anchoring device includes a partially-deployed configuration for use when the leadless cardiac tissue stimulation electrode assembly is located at the first location for evaluation of the first location as an cardiac tissue stimulation site. 
     
     
         18 . The cardiac tissue stimulation electrode assembly of  claim 16 , wherein the anchoring device is configured to be manipulated from the partially-deployed configuration to a non-deployed configuration for repositioning of the leadless cardiac tissue stimulation electrode assembly to the second location. 
     
     
         19 . The cardiac tissue stimulation electrode assembly of  claim 16 , comprising a wireless communication circuit configured to receive information from a cardiac stimulation controller located elsewhere. 
     
     
         20 . The cardiac tissue stimulation electrode assembly of  claim 19 , wherein the wireless communication circuit is configured to wirelessly receive information indicative of a one or more of a cardiac stimulation amplitude or a cardiac stimulation pulse width.