Vcg vector loop bifurcation

Abstract

An apparatus for analyzing a patient's cardiac activity to detect cardiac events includes a plurality of ECG electrodes configured to be attached to the patient. The plurality of ECG electrodes are configured to generate two or more ECG leads. The apparatus also includes a processor in communication with the plurality of ECG electrodes. The processor is configured to generate a control vectorcardiogram loop trajectory, receive an ECG signal, generate, based on the ECG signal, a plurality of ECG vectors, and generate, from the plurality of ECG vectors, a test vectorcardiogram loop trajectory. The processor is also configured to determine at least one T wave measure by comparing the test vectorcardiogram loop trajectory to the control vectorcardiogram loop trajectory, identify, based at least partially on the at least one T wave measure, a trajectory bifurcation, and determine, based on the trajectory bifurcation, an indicator of a cardiac event.

1 - 27 . (canceled) 
     
     
         28 . An apparatus for analyzing a patient's cardiac activity to detect cardiac events, the apparatus comprising:
 a plurality of ECG electrodes configured to be attached to the patient, the plurality of ECG electrodes configured to generate two or more ECG leads; and   a processor in communication with the plurality of ECG electrodes, the processor configured to:
 generate a control vectorcardiogram loop trajectory, 
 receive, from the plurality of ECG electrodes, an ECG signal, 
 generate, based on the ECG signal, a plurality of ECG vectors, 
 generate, from the plurality of ECG vectors, a test vectorcardiogram loop trajectory, 
 determine at least one T wave measure by comparing the test vectorcardiogram loop trajectory to the control vectorcardiogram loop trajectory, 
 identify, based at least partially on the at least one T wave measure, a trajectory bifurcation, and 
 determine, based on the trajectory bifurcation, an indicator of a cardiac event. 
   
     
     
         29 . The apparatus of  claim 28 , wherein the processor is configured to generate the control vectorcardiogram loop trajectory using either odd beats or even beats of a time period, and wherein the processor is configured to generate the test vectorcardiogram loop trajectory using the other of the odd beats or the even beats of the time period. 
     
     
         30 . The apparatus of  claim 28 , wherein the processor is configured to generate the control vectorcardiogram loop trajectory using every third beat of a time period, and wherein the processor is configured to generate the test vectorcardiogram loop trajectory using every beat of the time period following the third beat used for the control vectorcardiogram loop trajectory. 
     
     
         31 . The apparatus of  claim 28 , wherein the processor is configured to generate the control vectorcardiogram loop trajectory using every k beat of a time period, and wherein the processor is configured to generate the test vectorcardiogram loop trajectory using every k+1 beat of the time period. 
     
     
         32 . The apparatus of  claim 28 , wherein the at least one T wave measure comprises T wave alternans. 
     
     
         33 . The apparatus of  claim 28 , wherein the processor is configured to generate the control vectorcardiogram loop trajectory by
 creating a plurality of control subgroups of potential control vectorcardiogram loop trajectories;   analyzing statistical variance of shapes of the plurality control subgroups; and   selecting the subgroup with a lowest variation in shape as the control vectorcardiogram loop trajectory.   
     
     
         34 . The apparatus of  claim 28 , wherein the processor is configured to generate the test vectorcardiogram loop trajectory by detecting an onset of a portion of the ECG signal and an end of the portion of the ECG signal;
 isolating the portion of the ECG signal based on detecting the onset of the portion of the ECG signal and the end of the portion of the ECG signal; and   filtering the isolated portion of the ECG signal.   
     
     
         35 . The apparatus of  claim 28 , wherein the indicator of the cardiac event indicates one or more of an impeding acute degeneration of the patient's medical condition, a cardiac arrest, or a traumatic arrest. 
     
     
         36 . The apparatus of  claim 28 , wherein the apparatus comprises a wearable defibrillator. 
     
     
         37 . The apparatus of  claim 36 , wherein the wearable defibrillator is configured to deliver a treatment to the patient based on the indicator of the cardiac event. 
     
     
         38 . The apparatus of  claim 28 , wherein the apparatus comprises a portable ECG monitor. 
     
     
         39 . The apparatus of  claim 28 , wherein the apparatus comprises a back-end data server, wherein the back-end data server comprises the processor in communication with the plurality of ECG electrodes. 
     
     
         40 . The apparatus of  claim 28 , further comprising a display, wherein the processor is further configured to output the indicator of the cardiac event to the display. 
     
     
         41 . The apparatus of  claim 28 , wherein the processor is further configured to output the indicator of the cardiac event to a remote display device. 
     
     
         42 . The apparatus of  claim 28 , wherein the processor is configured to identify the trajectory bifurcation by further measuring a degree of the trajectory bifurcation. 
     
     
         43 . The apparatus of  claim 42 , wherein the processor is configured to measure the degree of the trajectory bifurcation based on a non-Gaussian statistical analysis. 
     
     
         44 . The apparatus of  claim 28 , wherein the processor is configured to identify the trajectory bifurcation by further identifying landmarks in the control vectorcardiogram loop trajectory and in the test vectorcardiogram loop trajectory. 
     
     
         45 . The apparatus of  claim 28 , wherein the processor is further configured to identify the trajectory bifurcation by further determining a measure of a shape uncertainty of the control vectorcardiogram loop trajectory and of the test vectorcardiogram loop trajectory. 
     
     
         46 . The apparatus of  claim 45 , wherein the processor is configured to determine the measure of shape uncertainty based on a statistical analysis of an uncertainty boundary of the control vectorcardiogram loop trajectory and of the test vectorcardiogram loop trajectory. 
     
     
         47 . The apparatus of  claim 28 , wherein the processor is further configured to
 repeat identifying the trajectory bifurcation for at least three cardiac cycles to determine a trend of the trajectory bifurcation; and   define an episodic trajectory bifurcation based on the trend.