System and Method for Mapping Electrophysiological Activation

Abstract

Electrical activation of tissue can be mapped from using electrophysiological data from a plurality of electrodes carried by a high density grid catheter. Each clique of three or more electrodes will define a pair of orthogonal bipoles as well as several unipoles. An electroanatomical mapping system can analyze the electrophysiological data such that, for each clique, an integral of an omnipolar electrogram the best morphologically matches a representative (e.g., average) unipolar electrogram for the clique is identified. The orientation of the best-fit omnipole is then defined as the activation direction for the clique. The conduction velocity magnitude can also be computed as a ratio of an amplitude of the unipolar electrogram for the clique to an amplitude of the integral of the omnipolar electrogram for the clique along the activation direction. The resulting activation map can also be output graphically.

What is claimed is: 
     
         1 . A method of mapping cardiac activation, comprising:
 receiving, at an electroanatomical mapping system, electrophysiological data from a plurality of electrodes carried by a multi-electrode catheter, the plurality of electrodes defining a plurality of cliques; and   for each clique of the plurality of cliques, the electroanatomical mapping system executing a process comprising:
 defining a clique unipolar electrogram; 
 identifying a best-fit omnipole integral to the clique unipolar electrogram; and 
 defining an orientation of the best-fit omnipole integral as a cardiac activation direction for the clique; 
   thereby determining a cardiac activation direction map.   
     
     
         2 . The method according to  claim 1 , wherein the process executed by the electroanatomical mapping system for each clique further comprises computing a clique conduction velocity magnitude using the best-fit omnipole integral and the clique unipolar electrogram, thereby determining a cardiac activation magnitude map. 
     
     
         3 . The method according to  claim 2 , wherein computing the clique conduction velocity magnitude using the best-fit omnipole integral and the clique unipole electrogram comprises computing the clique conduction velocity magnitude as a ratio of an amplitude of the clique unipolar electrogram to an amplitude of the best-fit omnipole integral. 
     
     
         4 . The method according to  claim 2 , further comprising outputting a graphical representation of the cardiac activation magnitude map. 
     
     
         5 . The method according to  claim 1 , wherein identifying a best-fit omnipole integral to the clique unipolar electrogram comprises:
 computing a clique E-field loop;   integrating the clique E-field loop; and   identifying the best-fit omnipole integral using the integrated clique E-field loop and the clique unipolar electrogram.   
     
     
         6 . The method according to  claim 1 , wherein the best-fit omnipole integral to the clique unipolar electrogram comprises a forward integral. 
     
     
         7 . The method according to  claim 1 , wherein the best-fit omnipole integral to the clique unipolar electrogram comprises a reverse integral. 
     
     
         8 . The method according to  claim 1 , wherein the best-fit omnipole integral to the clique unipolar electrogram comprises a weighted combination of a forward integral and a reverse integral. 
     
     
         9 . The method according to  claim 8 , wherein the best-fit omnipole integral to the clique unipolar electrogram comprises a smoothly time-varying convex combination of the forward integral and the reverse integral. 
     
     
         10 . The method according to  claim 1 , further comprising outputting a graphical representation of the cardiac activation direction map. 
     
     
         11 . The method according to  claim 1 , wherein each clique of the plurality of cliques comprises three electrodes that define two orthogonal bipoles. 
     
     
         12 . A method of mapping cardiac activation, comprising:
 receiving, at an electroanatomical mapping system, electrophysiological data from a plurality of electrodes carried by a multi-electrode catheter, the plurality of electrodes defining a plurality of cliques; and   for each clique of the plurality of clique, the electroanatomical mapping system executing a process comprising:
 defining a clique unipolar electrogram; 
 computing a clique E-field loop; 
 integrating the clique E-field loop; 
 identifying a projection of the integrated clique E-field loop that is a best fit to the clique unipolar electrogram; and 
 defining an orientation of the projection of the integrated clique E-field loop that is the best fit to the clique unipolar electrogram as a cardiac activation direction for the clique, 
   thereby determining a cardiac activation direction map.   
     
     
         13 . The method according to  claim 12 , wherein integrating the clique E-field loop comprises forward-integrating the clique E-field loop. 
     
     
         14 . The method according to  claim 12 , wherein integrating the clique E-field loop comprises reverse-integrating the clique E-field loop. 
     
     
         15 . The method according to  claim 12 , wherein integrating the clique E-field loop comprises:
 forward-integrating the clique E-field loop;   reverse-integrating the clique E-field loop; and   computing a weighted combination of the forward integral of the clique E-field loop and the reverse integral of the clique E-field loop.   
     
     
         16 . The method according to  claim 15 , wherein the weighted combination comprises a smoothly time-varying convex combination. 
     
     
         17 . The method according to  claim 12 , wherein the process executed by the electroanatomical mapping system for each clique further comprises computing a clique conduction velocity magnitude as a ratio of an amplitude of the clique unipolar electrogram to the projection of the integrated clique E-field loop that is the best fit to the clique unipolar electrogram. 
     
     
         18 . The method according to  claim 12 , wherein the clique unipolar electrogram comprises an average unipolar electrogram for the clique of electrodes. 
     
     
         19 . An electroanatomical mapping system for generating a cardiac activation map, comprising an activation mapping and visualization processor configured to execute a series of steps comprising:
 receiving electrophysiological data from a plurality of electrodes carried by a multi-electrode catheter, the plurality of electrodes defining a plurality of cliques; and   for each clique of the plurality of cliques, determining a cardiac activation direction according to a process comprising:
 defining a clique unipolar electrogram; 
 identifying a best-fit omnipole integral to the clique unipolar electrogram; and 
 defining an orientation of the best-fit omnipole integral as the cardiac activation direction for the clique. 
   
     
     
         20 . The electroanatomical mapping system according to  claim 19 , wherein the activation mapping and visualization processor is further configured to determine a conduction velocity magnitude for each clique of the plurality of cliques according to a process comprising:
 computing the conduction velocity magnitude as a ratio of an amplitude of the clique unipolar electrogram to an amplitude of the best-fit omnipole integral.