Leadless cardiac stimulation device employing distributed logic

Abstract

Systems and methods involve an intrathoracic cardiac stimulation device operable to provide autonomous cardiac sensing and energy delivery. The cardiac stimulation device includes a housing configured for intrathoracic placement relative to a patient's heart. A fixation arrangement of the housing is configured to affix the housing at an implant location within cardiac tissue or cardiac vasculature. An electrode arrangement supported by the housing is configured to sense cardiac activity and deliver stimulation energy to the cardiac tissue or cardiac vasculature. Energy delivery circuitry in the housing is coupled to the electrode arrangement. Detection circuitry is provided in the housing and coupled to the electrode arrangement. Communications circuitry may optionally be supported by the housing. A controller in the housing coordinates delivery of energy to the cardiac tissue or cardiac vasculature in accordance with an energy delivery protocol appropriate for the implant location.

1 . (canceled) 
     
     
         2 . An implantable subcutaneous cardioverter defibrillator system for therapeutically stimulating a portion of a patient's body, comprising:
 a first implantable subcutaneous cardioverter defibrillator having a first electrode and being configured to deliver therapeutic energy in a first polarity through said first electrode; and   a second implantable subcutaneous cardioverter defibrillator having a second electrode and being configured to deliver therapeutic energy in a second polarity, opposite of said first polarity, through said second electrode; wherein:   said first implantable subcutaneous cardioverter defibrillator and said second implantable subcutaneous cardioverter defibrillator are configured to deliver therapeutic energy in concert with one another; and   said system is configured to synchronize delivery of said therapeutic energy by said first implantable subcutaneous cardioverter defibrillator and delivery of said therapeutic energy by said second implantable subcutaneous cardioverter defibrillator.   
     
     
         3 . The system of  claim 2  wherein said system is configured to wirelessly synchronize delivery of said therapeutic energy by said first implantable subcutaneous cardioverter defibrillator and delivery of said therapeutic energy by said second implantable subcutaneous cardioverter defibrillator. 
     
     
         4 . The system of  claim 2  wherein said first implantable subcutaneous cardioverter defibrillator operates as a coordinating device to synchronize delivery of said therapeutic energy by said second implantable subcutaneous cardioverter defibrillator operating as a subordinate device. 
     
     
         5 . The system of  claim 2  wherein said therapeutic energy delivery by said first implantable subcutaneous cardioverter defibrillator is additive to said therapeutic energy delivered by said second implantable subcutaneous cardioverter defibrillator. 
     
     
         6 . The system of  claim 5 , wherein:
 said first implantable subcutaneous cardioverter defibrillator has a first housing;   said second implantable subcutaneous cardioverter defibrillator has a second housing;   said first housing of said first implantable subcutaneous cardioverter defibrillator includes said first electrode; and   said second housing of said second implantable subcutaneous cardioverter defibrillator includes said second electrode.   
     
     
         7 . The system of  claim 5  wherein said system is configured to deliver said therapeutic energy of said first implantable subcutaneous cardioverter defibrillator simultaneous with said therapeutic energy delivered by said second implantable subcutaneous cardioverter defibrillator. 
     
     
         8 . The system of  claim 1  configured for delivering said therapeutic energy to a majority of myocardial tissue of said patient. 
     
     
         9 . The system of  claim 1  wherein said system is configured with said therapeutic energy from said first subcutaneous cardioverter defibrillator and said therapeutic energy from said second subcutaneous cardioverter defibrillator being applied to a majority of myocardial tissue of said patient. 
     
     
         10 . The system of  claim 1  wherein each of said first implantable subcutaneous cardioverter defibrillator and said second implantable subcutaneous cardioverter defibrillator comprises: an internal energy source; a therapeutic energy delivery module operatively coupled to said internal energy source; and control circuitry operatively coupled to said therapeutic energy delivery module configured to control delivery of said therapeutic energy. 
     
     
         11 . A method of delivering therapeutic energy to a portion of a patient's body utilizing a first implantable subcutaneous cardioverter defibrillator and a second implantable subcutaneous cardioverter defibrillator, the method comprising the steps of:
 subcutaneously implanting the first implantable subcutaneous cardioverter defibrillator having a first electrode and being configured to deliver therapeutic energy in a first polarity through said first electrode;   subcutaneously implanting the second implantable subcutaneous cardioverter defibrillator having a second electrode and being configured to deliver therapeutic energy in a second polarity, opposite of said first polarity, through said second electrode;   operatively coupling said first implantable subcutaneous cardioverter defibrillator and said second implantable subcutaneous cardioverter defibrillator to deliver therapeutic energy through said patient's body between said first electrode of said first implantable subcutaneous cardioverter defibrillator and said second implantable subcutaneous cardioverter defibrillator; and   synchronizing delivery of said therapeutic energy by said first implantable subcutaneous cardioverter defibrillator and with delivery of said therapeutic energy by said second implantable subcutaneous cardioverter defibrillator.   
     
     
         12 . The method of  claim 11  wherein said synchronization step is accomplished wirelessly. 
     
     
         13 . The method of  claim 11  wherein said synchronization step is accomplished by coordination of said first implantable subcutaneous cardioverter defibrillator as a coordinating device and said second implantable subcutaneous cardioverter defibrillator as a subordinate device. 
     
     
         14 . The method of  claim 11  wherein said synchronizing delivery step is accomplished with said therapeutic energy delivery by said first implantable subcutaneous cardioverter defibrillator being additive to said therapeutic energy delivered by said second implantable subcutaneous cardioverter defibrillator. 
     
     
         15 . The method of  claim 11  wherein said synchronized delivery step is accomplished simultaneously with both said first implantable subcutaneous cardioverter defibrillator and said second implantable subcutaneous cardioverter defibrillator. 
     
     
         16 . The method of  claim 15  wherein said therapeutic energy is delivered to a majority of myocardial tissue of said patient. 
     
     
         17 . The method of  claim 15  wherein the operatively coupling step is performed by establishing a communication link between said first implantable subcutaneous cardioverter defibrillator and said second implantable subcutaneous cardioverter defibrillator. 
     
     
         18 . An implantable medical device system comprising:
 a first leadless cardiac pacemaker (LCP) having at least first and second electrodes and an attachment feature for attaching to the myocardium of a patient, the first LCP being configured for use with first and second energy delivery protocols, the first LCP also including communications circuitry for communicating with a patient external device, wherein:
 the first energy delivery protocol is configured for use in a first heart chamber of a patient; and 
 the second energy delivery protocol is configured for use in a second heart chamber of a patient; and 
   programmer having communications circuitry for communication with the first LCP and configured to select a mode for the first LCP as between the first energy delivery protocol to configure the LCP for use in the first heart chamber, and the second energy delivery protocol to configure the LCP for use in the second heart chamber.   
     
     
         19 . The implantable medical device system of  claim 18  wherein the first heart chamber is an atrium and the second heart chamber is a ventricle. 
     
     
         20 . The implantable medical device system of  claim 18  wherein:
 the first energy delivery protocol defines a first escape interval such that the first LCP, if configured to use the first energy delivery protocol, will start the first escape interval upon sensing a first predetermined event and will deliver a therapy output if a second predetermined event is not identified before expiration of the first escape interval; 
 the second energy delivery protocol defines a second escape interval such that the first LCP, if configured to use the second energy delivery protocol, will start the second escape interval upon sensing a third predetermined event and will deliver a therapy output if a fourth predetermined event is not identified before expiration of the second escape interval; and 
 the first escape interval is shorter than the second escape interval. 
 
     
     
         21 . The implantable medical device system of  claim 18  wherein:
 the first energy delivery protocol defines a first escape interval such that the first LCP, if configured to use the first energy delivery protocol, will start the first escape interval upon sensing a first predetermined event and will deliver a therapy output if a second predetermined event is not identified before expiration of the first escape interval; 
 the second energy delivery protocol defines a second escape interval such that the first LCP, if configured to use the second energy delivery protocol, will start the second escape interval upon sensing a third predetermined event and will deliver a therapy output if a fourth predetermined event is not identified before expiration of the second escape interval; 
 the first predetermined event is a ventricular depolarization; 
 the second predetermined event is the occurrence of an atrial depolarization or a ventricular depolarization; 
 the third predetermined event is a ventricular depolarization; and 
 the fourth predetermined event is the occurrence of a ventricular depolarization.