Cardiac mapping system and method for voltage-based evaluation of electrograms

Abstract

Systems and methods for evaluating electrograms are described. An example method of evaluating an electrogram such as an atrial and/or ventricular electrogram containing a plurality of data samples each having a voltage includes selecting an activity interval for the electrogram, calculating an energy level for each window of a plurality of windows of the electrogram based on the voltages of the data samples in each window, assigning the calculated energy levels to a plurality of bins, and calculating an index based at least in part on a number of energy levels assigned to a particular bin of the plurality of bins.

What is claimed is: 
     
         1 . A computer implemented method for evaluating an electrogram containing a plurality of data samples each having a voltage, the computer implemented method comprising:
 defining a plurality of windows, each window of the plurality of windows being a length of time defined by an activity interval;   calculating respective energy levels for each window of the plurality of windows of the electrogram;   defining a first threshold and a second threshold;   determining a first count of the respective energy levels and corresponding windows below the first threshold;   determining a second count of the respective energy levels and corresponding windows above the second threshold;   calculating a value based on a ratio of a sum of the first count and the second count to a total number of the respective energy levels;   mapping the value to a three dimensional map of a heart; and   presenting the map to a user on a display to indicate fractionation of the electrogram.   
     
     
         2 . The computer implemented method of  claim 1 , wherein calculating the respective energy levels is based on a summation of absolute values of voltages of each data sample in each window. 
     
     
         3 . The computer implemented method of  claim 1 , wherein defining the plurality of windows comprises defining one window for each sample of data in the electrogram. 
     
     
         4 . The computer implemented method of  claim 1 , wherein the first threshold is a low energy level threshold and the second threshold is a high energy level threshold. 
     
     
         5 . The computer implemented method of  claim 1 , further comprising generating a histogram of the sum of the first count and the second count. 
     
     
         6 . The computer implemented method of  claim 1 , wherein calculating the value comprises computing an isoelectric index based on respective voltages of the plurality of data samples. 
     
     
         7 . The computer implemented method of  claim 6 , wherein calculating the value further comprises combining a first calculated index with a second calculated index for the electrogram to produce a fused index. 
     
     
         8 . The computer implemented method of  claim 7 , wherein the second calculated index is a complex fractionated electrogram (CFE) mean, and combining the first calculated index with the CFE mean comprises mapping the CFE mean to a same range of values as the first calculated index using a sigmoid function and combining the first calculated index with the mapped CFE mean using an F-measure function. 
     
     
         9 . The computer implemented method of  claim 1  further comprising receiving the activity interval for the electrogram from a user. 
     
     
         10 . The computer implemented method of  claim 1  further comprising determining the activity interval for the electrogram. 
     
     
         11 . A system for evaluating an electrogram containing a plurality of data samples each having a voltage, the system comprising:
 a computing device configured to receive the data samples, the computing device comprising:
 a processor; 
 a display coupled to said processor; and
 at least one memory device coupled to said processor, the memory device storing computer-executable instructions that, when executed by the processor, cause the computing device to: 
 determine an activity interval for the electrogram; 
 define a plurality of windows, each window of the plurality of windows being a length of time defined by the activity interval; 
 calculate respective energy levels for each window of the plurality of windows of the electrogram; 
 define a first threshold and a second threshold; 
 determine a first count of the respective energy levels and corresponding windows below the first threshold; 
 determine a second count of the respective energy levels and corresponding windows above the second threshold; 
 calculate a value based on a ratio of a sum of the first count and the second count to a total number of the respective energy levels; 
 map the value to a three dimensional map of a heart; and 
 present the map to a user on a display to indicate fractionation of the electrogram. 
 
   
     
     
         12 . The system of  claim 11 , wherein the memory device further stores computer-executable instructions that, when executed by the processor, cause the computing device to define one window for each sample of data in the electrogram. 
     
     
         13 . The system of  claim 11 , wherein the memory device further stores computer-executable instructions that, when executed by the processor, cause the computing device to calculate the energy level for each window by summing an absolute value of a voltage of each data sample in the window. 
     
     
         14 . The system of  claim 11 , wherein the first threshold is a low energy level threshold and the second threshold is a high energy level threshold. 
     
     
         15 . The system of  claim 11 , wherein the memory device further stores computer-executable instructions that, when executed by the processor, cause the computing device to receive a first user input value for the first threshold and a second user input value for the second threshold. 
     
     
         16 . The system of  claim 11 , further comprising a display device, wherein the memory device further stores computer-executable instructions that, when executed by the processor, cause the computing device to generate a histogram of the sum of the first count and the second count. 
     
     
         17 . The system of  claim 11 , wherein the memory device further stores computer-executable instructions that, when executed by the processor, cause the computing device to calculate the value by computing an isoelectric index based on respective voltages of the data sample. 
     
     
         18 . The system of  claim 17 , wherein the memory device further stores computer-executable instructions that, when executed by the processor, cause the computing device to calculate the value by combining a first calculated index with a second calculated index for the electrogram to produce a fused index. 
     
     
         19 . The system of  claim 18 , wherein the second calculated index is a complex fractionated electrogram (CFE) mean, and wherein the memory device further stores computer-executable instructions that, when executed by the processor, cause the computing device to map the CFE mean to a same range of values as the first calculated index using a sigmoid function and combine the first calculated index with the mapped CFE mean using an F-measure function. 
     
     
         20 . The system of  claim 11 , wherein the memory device further stores computer-executable instructions that, when executed by the processor, cause the computing device to receive a user value for the activity interval for the electrogram.