Esophagus position detection by electrical mapping

Abstract

A method of estimating a spatial relationship between at least a part of a patient esophagus and a heart chamber, including: measuring at least one electric parameter at one or more positions within the heart chamber to obtain measured values; and estimating the spatial relationship based on the measured values.

What is claimed is: 
     
         1 . A device for estimating esophagus position, comprising:
 at least one body surface electrode connectible to a field generator and configured to apply an electric field from said field generator to a heart chamber;   measuring circuitry configured to receive signal measurements of an electric parameter of the electric field applied by the at least one body surface electrode from an electrode probe navigating within the heart chamber; and   control circuitry, configured to estimate a position of at least part of an esophagus adjacent to the heart chamber, based on said signal measurements.   
     
     
         2 . The device of  claim 1 , further comprising:
 an interface circuitry, wherein said interface circuitry generates an indication of esophagus position based on said estimation of said esophagus position.   
     
     
         3 . The device of  claim 1 , further comprising:
 a digital computer memory;   wherein said control circuitry estimates said esophagus position by comparing a measured map constructed to associate the signal measurements with positions in the heart chamber to one or more reference maps, stored in said digital computer memory, wherein the reference maps associate predicted values of said electric parameter with the positions in the heart chamber.   
     
     
         4 . The device of  claim 3 , wherein at least one of the reference maps is a simulated map. 
     
     
         5 . The device of  claim 4 , wherein the simulated map also simulates effects of an esophagus at a simulated location on measurements of the reference map. 
     
     
         6 . The device of  claim 4 , wherein the simulated map omits effects of any esophagus on measurements of the reference map. 
     
     
         7 . The device of  claim 3 , wherein at least one of the reference maps is a map constructed using a measured map having a known position of the at least part of the esophagus adjacent to the heart chamber. 
     
     
         8 . The device of  claim 1 , wherein the control circuitry estimates said esophagus position by comparing a measured map of the shape of the heart chamber constructed using the signal measurements to one or more reference maps of the shape of the heart chamber; wherein the measured map is constructed using a method that allows distortions of an electric field due to the presence of an esophagus to distort a shape of the measured map. 
     
     
         9 . The device of  claim 8 , wherein at least one of the reference maps is a simulated map. 
     
     
         10 . The device of  claim 9 , wherein the simulated map also simulates effects of an esophagus at a simulated location on a heart chamber shape of the reference map. 
     
     
         11 . The device of  claim 9 , wherein the simulated map omits effects of any esophagus on heart chamber shapes of the reference map. 
     
     
         12 . The device of  claim 3 , wherein at least one of the reference maps is a map constructed using a measured map having a known position of the at least part of the esophagus adjacent to the heart chamber. 
     
     
         13 . The device of  claim 8 , wherein the control circuitry estimates the esophagus position using a template shape to match a shape of the measured map of the heart chamber. 
     
     
         14 . The device of  claim 1 , wherein said measuring circuitry is connected to a catheter system configured to be at least partly placed within a heart chamber to measure said electric parameter. 
     
     
         15 . The device of  claim 1 , further comprising:
 at least one electrode connectable to said measuring circuitry; wherein said electrode is shaped and sized to be placed within a heart chamber to measure said electric parameter.   
     
     
         16 . The device of  claim 1 , comprising:
 a field generator; wherein said field generator is configured to deliver an energy field to a heart chamber through an electrode placed in said heart chamber based on said esophagus position of said at least part of the esophagus.   
     
     
         17 . The device of  claim 1 , wherein the control circuitry is further configured to model the heart chamber based on the signal measurements. 
     
     
         18 . The device of  claim 1 , wherein the electric parameter of the electric field is electric potential. 
     
     
         19 . The device of  claim 1 , wherein said estimating comprises estimating that said esophagus is not within a certain range from a wall of said heart chamber.