Method and apparatus for classifying and localizing heart arrhythmias

Abstract

Analyzes surface electrocardiographic and intracardiac signals to identify and separate electrical activity corresponding to distinct but superimposed events in the heart. Assesses the spatial phase, temporal phase, rate, spectrum and reproducibility of each event to determine uniformity of activation in all spatial dimensions. Uses numerical indices derived from these analyses to diagnose arrhythmias. Uses these indices to determine the location of an arrhythmia circuit, and to direct the movement of an electrode catheter to this location for ablation or permanent catheter positioning. Subsequently, uses these indices to determine whether ablation has successfully eliminated the circuit. Uses variability in these indices from the surface electrocardiogram to indicate subtle beat-to-beat fluctuations which reflect the tendency towards atrial and ventricular arrhythmias.

1 . A method of analyzing a signal, comprising: 
 providing a digital template and a digitized signal sufficient to facilitate identification of atrial fibrillatory components of activity as originating from a left side or a right side of the heart, the digitized signal comprising a plurality of amplitudes corresponding to consecutive time samples;    generating a plurality of correlation values correlating the digital template to successive time samples of the digitized signal, wherein a plurality of correlation values are generated sufficient to facilitate discernment of whether distinct components of activity have origins in the left or right sides of the heart;    mapping the correlation values; and    identifying a treatable condition, based upon the mapping of the correlation values.    
   
   
       2 . The method as set forth in  claim 1 , wherein the correlation values are mapped against time.  
   
   
       3 . The method as set forth in  claim 1 , wherein the providing comprises providing a digital template and a digitized cardiac signal sufficient to facilitate identification of atrial fibrillatory components of activity from distinct regions of the heart, the identification being sufficient to facilitate a separation of atrial tachycardia, atrial fibrillation, atrial flutter and ventricular tachycardia.  
   
   
       4 . The method as set forth in  claim 1 , wherein the time samples span a plurality of cardiac cycles  
   
   
       5 . The method as set forth in  claim 1 , wherein successive time samples are consecutive time samples.  
   
   
       6 . The method as set forth in  claim 1 , wherein the digitized signal is an ECG.  
   
   
       7 . The method as set forth in  claim 1 , wherein the digitized signal is an intracardiac electrogram.  
   
   
       8 . The method as set forth in  claim 1 , wherein the digitized signal is a digitized cardiac signal and the method further comprises: 
 comparing correlation values with a threshold value; and    identifying features as correlation values that exceed the threshold value.    
   
   
       9 . The method as set forth in  claim 8 , wherein the correlation values are derived from a template having a duration up to that of the digitized cardiac signal.  
   
   
       10 . The method as set forth in  claim 9 , wherein correlation values that exceed the threshold value indicate rates of activity in the digitized cardiac signal.  
   
   
       11 . The method as set forth in  claim 10 , and further comprising generating a frequency domain representation of the digitized cardiac signal and of the correlation values.  
   
   
       12 . The method as set forth in  claim 11 , wherein the frequency domain representation of the digitized cardiac signal comprises a plot of frequency versus power.  
   
   
       13 . The method as set forth in  claim 1 , and wherein: 
 the digitized signal is a digitized cardiac signal generated from a plurality of leads; and    the correlation values are plotted, with each plot comprising a representation of correlation values of two leads from the plurality of leads, wherein for each plot the correlation values of one of the two leads is plotted against the correlation values of the other of the two leads.    
   
   
       14 . The method as set forth in  claim 13 , wherein the plurality of leads is used to calculate a rate of activity in the digitized cardiac signal in one or more of the plurality of leads.  
   
   
       15 . The method as set forth in  claim 13 , wherein the plurality of leads is used to calculate one or more features of a rate of the digitized cardiac signal.  
   
   
       16 . The method as set forth in  claim 15 , wherein the one or more features comprise a highest rate of activity of the digitized cardiac signal.  
   
   
       17 . The method as set forth in  claim 15 , wherein the one or more features comprise a lowest rate of activity of the digitized cardiac signal.  
   
   
       18 . The method as set forth in  claim 15 , wherein the one or more features comprise a range of rates of the digitized cardiac signal.  
   
   
       19 . The method as set forth in  claim 15 , wherein the one or more features comprise peak frequencies of the digitized cardiac signal.  
   
   
       20 . The method as set forth in  claim 15 , wherein the one or more features comprise a width of the frequency peaks of the digitized cardiac signal.  
   
   
       21 . The method as set forth in  claim 1 , and whereinat least a part of the amplitudes represent tracings corresponding to electrical activity from organs other than the heart.  
   
   
       22 . The method as set forth in  claim 1 , wherein the digitized signal is a digitized cardiac signal and the providing is preceded by: 
 a. placing a medical instrument into proximity of a heart;    b. moving the medical instrument in one or more of a direction toward a lead indicating a highest rate of the digitized cardiac signal, a direction toward a lead indicating a lowest rate of the digitized cardiac signal, a direction toward a lead indicating the highest frequency of the digitized cardiac signal, a direction toward a lead indicating the lowest frequency of the digitized cardiac signal, a direction toward a lead indicating the widest frequency peak of the digitized cardiac signal, and a direction toward a lead indicating the narrowest frequency peak of the digitized cardiac signal; and    c. using the medical instrument to cause at least one modification to tissue of the heart.    
   
   
       23 . The method as set forth in  claim 22 , wherein the modification comprises a reduction of heart function.  
   
   
       24 . The method as set forth in  claim 22 , wherein the modification comprises a destruction of heart function.  
   
   
       25 . The method as set forth in  claim 22 , wherein the modification comprises a stimulation of heart function.  
   
   
       26 . The method as set forth in  claim 22 , wherein the modification comprises a pacing of the heart.  
   
   
       27 . The method as set forth in  claim 22 , wherein the modification is caused by electromagnetic energy.  
   
   
       28 . The method as set forth in  claim 22 , wherein the modification is caused by cooling.  
   
   
       29 . The method as set forth in  claim 22 , wherein the modification is caused by ultrasound energy.  
   
   
       30 . The method as set forth in  claim 22 , wherein the modification is caused by biochemical alterations.  
   
   
       31 . The method as set forth in  claim 22 , wherein the modification is caused by gene therapy.  
   
   
       32 . The method as set forth in  claim 1 , wherein the digitized signal is a biopotential of a cardiac arrhythmia.  
   
   
       33 . The method as set forth in  claim 32 , wherein the distinct components of activity include atrial and ventricular activity.  
   
   
       34 . The method as set forth in  claim 32 , wherein the distinct components of activity include activation and repolarization.  
   
   
       35 . The method as set forth in  claim 1 , wherein the amplitudes represent tracings corresponding to non-electrical activity.