Systems and methods for deriving electrical characteristics of cardiac tissue for output in iso-characteristic displays

A system for examining tissue within the heart comprising at least three spaced apart electrodes, at least two of the electrodes adapted for substantially constant contact with a region of endocardial tissue,

• an element establishing position of the electrodes in a first pair and in a second pair,
• an element substantially fixing position of the first pair,
• generator means operable in one mode for transmitting electrical current in a first path through a region of endocardial tissue between the first pair of the electrodes, at least one of which is within the heart, the generator means being operable in another mode for transmitting electrical current in a second path through endocardial tissue in the region between the second pair of the electrodes, at least one of which is within the heart, and
• means for deriving a tissue electrical characteristic based, at least in part, upon sensing impedances of tissue lying in the first and second paths, including means for arranging the derived electrical characteristics into groups of equal electrical characteristic values.

A system for examining heart tissue comprising

• a structure,
• an array of spaced apart electrodes carried by the structure, the structure. adapting all of the electrodes for substantially constant contact with endocardial tissue in a selected position,
• means for transmitting electrical current from the spaced apart electrodes in multiple paths through a region of heart tissue,
• means for deriving an electrical characteristic of tissue lying in the multiple paths based, at least in part, upon sensing tissue impedances in the multiple paths, including means for arranging the derived electrical characteristics into groups of equal electrical characteristic values, and
• means for creating an output displaying the groups of equal electrical characteristics in spatial relation to location of the electrodes on the structure.

A system for examining heart tissue comprising

• a three dimensional structure,
• an array of spaced apart electrodes carried by the structure, the structure adapting all of the electrodes for substantially constant contact with endocardial tissue in a selected position,
• means for transmitting electrical current from the spaced apart electrodes in multiple paths through a region of heart tissue,
• means for deriving an electrical characteristic of tissue lying in the multiple paths based, at least in part, upon sensing tissue resistivities in the multiple paths, including means for arranging the derived tissue resistivities into groups of equal tissue resistivity values, and
• means for creating and displaying in three dimensions an output of the groups of equal tissue resistivities in spatial relation to location of the electrodes on the structure.

A system for examining heart tissue comprising

• a three dimensional structure having a shape, an array of spaced apart electrodes carried by the structure, the structure adapting all of the electrodes for substantially constant contact with endocardial tissue in a selected position,
• means for transmitting electrical current from the spaced apart electrodes in multiple paths through a region of heart tissue,
• means for deriving an electrical characteristic of tissue lying in the multiple paths based, at least in part, upon sensing tissue impedances in the multiple paths, and
• means for creating an output displaying in three dimensions groups of equal electrical characteristics in spatial relation to location of the electrodes on the structure comprising
• first means for computing the location of the electrodes on the structure in a three dimensional coordinate system,
• second means for generating a pattern of intersecting horizontal and vertical lines forming a three dimensional mesh that conforms to the shape of the three dimensional structure, the points of intersection between the horizontal and vertical lines comprising nodes, the nodes that represent the locations of the electrodes comprising knots,
• third means for assigning values to the nodes that reflect:
• electrical characteristics by assigning to each knot the value of the electrical characteristic derived at the associated electrode and by interpolating between the knots to assign interpolated value,,;
• of electrical characteristics to the remaining nodes, and
• fourth means for creating an output display by assigning a first indicium to the node or nodes having the maximum electrical characteristic value, a second indicium to the node or nodes having the minimum electrical characteristic value, and intermediate indicia between the first and second indicia to the node or nodes having intermediate electrical characteristic values between the maximum and minimum electrical characteristic values.

A system for examining tissue within the heart comprising

• at least three spaced apart electrodes, at least two of the electrodes adapted for substantially, constant contact with a region of endocardial tissue and the remaining electrode adapted for location outside the heart,
• an element establishing position of the electrodes in a first pair and in a second pair,
• an element substantially fixing position of the first pair,
• generator means operable in one mode for transmitting electrical current in a first path through a region of endocardial tissue between the first pair of the electrodes, at least one of which is within the heart, the generator means being operable in another mode for transmitting electrical current in a second path through endocardial tissue in the region between the second pair of the electrodes, at least one of which is within the heart, and
• means for deriving a tissue electrical characteristic based, at least in part, upon sensing impedances of tissue lying in the first and second paths, including means for arranging the derived electrical characteristics into groups of equal electrical characteristic values.

A system for examining heart tissue comprising

• at least three spaced apart electrodes, all of the electrodes adapted for substantially, constant contact with a region of endocardial tissue,
• generator means operable in one mode for transmitting electrical current in a first path through the region of endocardial tissue between a first pair of the electrodes, the generator means being operable in another mode for transmitting electrical current:
• in a second path through endocardial tissue in the region between a second pair of the electrodes, and
• means for deriving a tissue electrical characteristic based, at least in part, upon sensing impedances of endocardial tissue lying in the first and second paths, including means for arranging the derived electrical characteristics into groups of equal electrical characteristic values.

A system for examining tissue within the heart comprising

• at least three spaced apart electrodes, all of the electrodes adapted for substantially, constant contact with a region of endocardial tissue,
• an element establishing position of the electrodes in a first pair and in a second pair,
• an element substantially fixing position of the first pair,
• generator means operable in one mode for transmitting electrical current in a first path through a region of endocardial tissue between the first pair of the, electrodes, at least one of which is within the heart, the generator means being operable in another mode for transmitting electrical current in a second path through endocardial tissue in the region between the second pair of the electrodes, at least one of which is within the heart, and
• means for deriving a tissue electrical characteristic based, at least in part, upon sensing impedances of tissue lying in the first and second paths, including means for arranging the derived electrical characteristics into groups of equal electrical characteristic values.

A method for examining heart tissue comprising the steps of

• positioning a array of spaced apart electrodes in contact with a region of endocardial tissue in a desired position with all of the electrodes in substantially constant contact with endocardial tissue,
• transmitting electrical current from the spaced apart electrodes in multiple paths through a region of heart tissue,
• deriving electrical characteristics of tissue lying in the multiple paths based, at least in part, to sensing tissue impedances in the multiple paths, and
• arranging the derived electrical characteristics into groups of equal electrical characteristic values.

A method for examining heart tissue comprising the steps of

• positioning a three dimensional array of spaced apart electrodes in contact with a region of endocardial tissue in a desired position with all of the electrodes in substantially constant contact with endocardial tissue,
• transmitting electrical current from the spaced apart electrodes in multiple paths through a region of heart tissue,
• deriving electrical characteristics of tissue lying in the multiple paths based, at least in part, upon sensing tissue impedances in the multiple paths,
• arranging the derived electrical characteristics into groups of equal electrical characteristic values, and
• outputting in a three dimensional display the groups of equal characteristic values in spatial relation to the location of the electrodes.

A method for examining heart tissue comprising the steps of

• positioning a three dimensional structure carrying an array of spaced apart electrodes in contact with a region of endocardial tissue in a desired position with all of the electrodes in substantially constant contact with endocardial tissue,
• transmitting electrical current from the spaced apart electrodes in multiple paths through a region of heart tissue,
• deriving an electrical characteristic of tissue lying in the multiple paths based, at least in part, upon sensing tissue impedances in the multiple paths,
• creating a display in three dimensions groups of equal electrical characteristics in spatial relation to location of the electrodes on the structure by
• computing the location of the electrodes on the structure in a three dimensional coordinate system;
• generating a pattern of intersecting horizontal and vertical lines forming a three dimensional mesh that conforms to the shape of the three dimensional structure, the points of intersection between the horizontal and vertical lines comprising nodes, the nodes that represent the locations of the electrodes comprising knots;
• assigning values to the nodes that reflect electrical characteristics by assigning to each knot the value of the electrical characteristic derived at the associated electrode and by interpolating between the knots to assign interpolated values of electrical characteristics to the remaining nodes;
• and
• creating an output display by assigning a first indicium to the node or nodes having the maximum electrical characteristic value, a second indicium to the node or nodes having the minimum electrical characteristic value, and intermediate indicia between the first and second indicia to the node or nodes having intermediate electrical characteristic values between the maximum and minimum electrical characteristic values.