System and method of identifying sources for biological rhythms

Abstract

Multiple cardiac signal pairs, each having an analysis signal and a reference signal, are selected from cardiac signals collected from a plurality of sensors associated with locations of the heart over a plurality of time points. At each time point, a relational characteristic is calculated between each cardiac signal pair. The relational characteristics are compared to determine whether a change occurs in the relational characteristics from one cardiac signal pair to other cardiac signal pairs. A matrix of the relational characteristics at the locations of the sensors is generated for the plurality of cardiac signal pairs. A direction of the source of the rhythm disorder is identified as progressing toward a location associated with an increase in variability based on the relational characteristics.

1 . A method of locating a source of a rhythm disorder of a heart, the method comprising using a computing device to:
 access cardiac signals from a plurality of sensors associated with locations of the heart over a plurality of time points;   select a plurality of cardiac signal pairs, each cardiac signal pair having an analysis signal and a reference signal;   at each time point, calculate a relational characteristic between each cardiac signal pair;   compare the relational characteristics for the plurality of cardiac signal pairs to determine whether a change occurs in the relational characteristics from one cardiac signal pair to other cardiac signal pairs;   generate a matrix of the relational characteristics at the locations of the sensors for the plurality of cardiac signal pairs; and   identify a direction of the source of the rhythm disorder as progressing toward a location associated with an increase in variability based on the relational characteristics.   
     
     
         2 . The method of  claim 1 , wherein the relational characteristic at each time point is calculated by taking a derivative of each signal within the cardiac signal pair. 
     
     
         3 . The method of  claim 1 , wherein the computing device further assigns an index of variability to each cardiac signal pair based on the relational characteristics. 
     
     
         4 . The method of  claim 3 , wherein the index of variability for each cardiac signal pair is based on one of a variability in signal timing and a variability in signal amplitude within each cardiac signal pair. 
     
     
         5 . The method of  claim 3 , wherein the index of variability for each cardiac signal pair is determined from variability in signal shape. 
     
     
         6 . The method of  claim 3 , wherein the index of variability is determined from the relational characteristics by one or more methods selected from a group consisting of standard deviation analysis, frequency analysis, entropy analysis, cross-correlation analysis, randomness analysis, Monte Carlo simulation methods, quantification of chaos, complex statistical analyses, and combinations thereof. 
     
     
         7 . The method of  claim 3 , wherein the computing device further generates a graph of indexes of variability for the plurality of cardiac signal pairs. 
     
     
         8 . The method of  claim 1 , wherein the analysis signal of the one cardiac signal pair and the analysis signals of the other cardiac signal pairs are a common signal and the reference signal of the one cardiac signal pair and the reference signals of the other cardiac signal pairs are different signals. 
     
     
         9 . The method of  claim 8 , wherein each pairing of the common analysis signal with all other reference signals generates a sub-plot, and wherein the computing device further:
 generates a plurality of additional sub-plots, each sub-plot corresponding to a different analysis signal; and   combines the plurality of sub-plots to generate a plot corresponding to the matrix.   
     
     
         10 . The method of  claim 1 , wherein the analysis signal of the one cardiac signal pair and the analysis signals of the other cardiac signal pairs are different signals and the reference signal of the one cardiac signal pair and the reference signals of the other cardiac signal pairs are a common signal. 
     
     
         11 . The method of  claim 3 , wherein the matrix comprises a grid having points corresponding to the locations of the sensors, each location of the grid having a visually-discernible value corresponding to the index of variability at that location. 
     
     
         12 . The method of  claim 11 , wherein the computing device further displays the grid as an array of colored pixels, wherein the index of variability is color-coded to distinguish lower indexes of variability from high indexes of variability. 
     
     
         13 . The method of  claim 3 , wherein the computing device further identifies from the matrix one or more locations of the heart associated with higher indexes of variability surrounded by regions of lower indexes of variability. 
     
     
         14 . A system for locating a source of a rhythm disorder of a heart, the system comprising:
 a computing device configured to:
 receive cardiac signals corresponding to a plurality of sensors associated with locations of the heart over a plurality of time points; 
 select a plurality of cardiac signal pairs, each cardiac signal pair having an analysis signal and a reference signal; 
 at each time point, calculate a relational characteristic between each cardiac signal pair; 
 compare relational characteristics for the plurality of cardiac signal pairs to determine whether a change occurs in the relational characteristics from one cardiac signal pair to other cardiac signal pairs; 
 generate a matrix of the relational characteristics at the locations of the sensors for the plurality of cardiac signal pairs; 
 identify a direction of the source of the rhythm disorder as progressing toward a location associated with an increase in variability based on the relational characteristics; and 
   a display device configured to display a clinical representation of the identified direction of the source of the rhythm disorder.   
     
     
         15 . The system of  claim 14 , wherein the relational characteristic at each time point is calculated by taking a derivative of each signal within the cardiac signal pair. 
     
     
         16 . The system of  claim 14 , wherein the computing device is further configured to assign an index of variability to each cardiac signal pair based on the relational characteristics. 
     
     
         17 . The system of  claim 16 , wherein the index of variability is determined from the relational characteristics by one or more methods selected from a group consisting of standard deviation analysis, frequency analysis, entropy analysis, cross-correlation analysis, randomness analysis, Monte Carlo simulation methods, quantification of chaos, complex statistical analyses, and combinations thereof. 
     
     
         18 . The system of  claim 16 , wherein the computing device is further configured to generate a graph of indexes of variability for the plurality of cardiac signal pairs. 
     
     
         19 . The system of  claim 14 , wherein the analysis signal of the one cardiac signal pair and the analysis signals of the other cardiac signal pairs are a common signal and the reference signal of the one cardiac signal pair and the reference signals of the other cardiac signal pairs are different signals. 
     
     
         20 . The system of  claim 19 , wherein each pairing of the common analysis signal with all other reference signals generates a sub-plot, and wherein the computing device is further configured to:
 generate a plurality of additional sub-plots, each sub-plot corresponding to a different analysis signal; and   combine the plurality of sub-plots to generate a plot corresponding to the matrix.   
     
     
         21 . The system of  claim 14 , wherein the matrix comprises a grid having points corresponding to the locations of the sensors, each location of the grid having a visually-discernible value corresponding to the index of variability at that location. 
     
     
         22 . The system of  claim 21 , wherein the computing device is further configured to cause the display device to display the grid as an array of colored pixels, wherein the index of variability is color-coded to distinguish lower indexes of variability from high indexes of variability. 
     
     
         23 . The system of  claim 16 , wherein the computing device is further configured to identify from the matrix one or more locations of the heart associated with higher indexes of variability surrounded by regions of lower indexes of variability.