Method and apparatus for quantitative assessment of cardiac electrical events
View Patent ↗Method and apparatus for computer enabled analysis of ECG (electro cardiographic) data by exploiting computerized three-dimensional spatial presentation of the measured data using vectors. A three-dimensional presentation of the human heart may be correlated with waveforms specific for standard ECG or derived ECG signals based on the dipole approximation of the heart electrical activity. Additional tools for analyzing ECG data are also provided which may be used to determine the time of cardiac electrical events, to select specific beats for automated cardiac interval determination, and to flag ECGs that have been evaluated by automated means but may benefit by human reading.
1. A computer-assisted method for selecting ECG complexes for further evaluation, the method comprising:
receiving a recorded patient ECG signal comprising a plurality of m ECG complexes; and
using a processor to evaluate ECG complexes of the plurality of m ECG complexes, and to identify a subset of n ECG complexes of the plurality for further evaluation, where n is greater than two and less than m, and wherein the n ECG complexes of the identified subset have a highest degree of similarity to one another relative to any other possible subset of n ECG complexes of the plurality of m ECG complexes.
2. The method of claim 1 , wherein the identified subset of n ECG complexes is identified by applying an autocorrelation function to the m ECG complexes of the plurality of ECG complexes.
3. The method of 2 , wherein the autocorrelation function is
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where τ is an increment of time t, f is a function and f is the complex conjugate of function f.
4. The method of claim 1 , wherein the identified subset of ECG complexes is identified from virtual ECG data derived from the recorded ECG signal.
5. The method of claim 4 , wherein the virtual ECG data is vector magnitude data or normalized vector magnitude data.
6. The method of claim 1 , wherein the identified subset of n ECG complexes is a first identified subset of n ECG complexes, the method further comprising:
determining a first value of a complex dissimilarity factor for the first identified subset of n ECG complexes;
identifying from the plurality of m ECG complexes a second subset of n ECG complexes, wherein the second identified subset has at least one ECG complex that than is not part of the first identified subset;
determining a second value of a complex dissimilarity factor for the second identified subset; and
if the second value is less than the first value, selecting the second identified subset for further evaluation instead of the first identified subset.
7. A computer-assisted method for selecting ECG complexes for further evaluation, the method comprising:
receiving a recorded patient ECG signal comprising a plurality of m ECG complexes, each ECG complex of the plurality having a duration; and
using a processor to evaluate ECG complexes of the plurality of m ECG complexes, and to identify a subset of n ECG complexes for further evaluation, where n is greater than two and less than m, and wherein the n ECG complexes of the identified subset have a lowest standard deviation in duration out of all possible subsets of n ECG complexes of the plurality of m ECG complexes.
8. A computer-assisted method for selecting ECG complexes upon which to evaluate cardiac events, the method comprising:
receiving a recorded patient ECG signal comprising a plurality of m ECG complexes;
using a processor to evaluate a respective same electrical event in each ECG complex of the plurality of m ECG complexes; and
using a processor to identify a subset of n ECG complexes of the plurality of m ECG complexes, where n is greater than two and less than m, wherein the ECG complexes of the identified subset have a lowest standard deviation in the evaluated electrical event out of all possible subsets of n ECG complexes of the plurality of m ECG complexes.
9. The method of claim 8 , wherein the electrical event is a time interval selected from the group consisting of:
duration of the ECG complex,
PR interval,
RR interval,
QT interval,
rate-corrected QT interval,
time interval between Tpeak and Tend,
time interval between QRSonset and J point,
time interval between Ponset and Pend, and
time interval between peak voltage for R wave and peak voltage for T wave.
10. The method of claim 8 , wherein the electrical event is a voltage selected from the group consisting of:
peak voltage for T wave,
peak voltage for R wave,
peak voltage for P wave.
11. The method of claim 8 , wherein the identified subset of n ECG complexes is a first identified subset of n ECG complexes, the method further comprising:
determining a first value of a complex dissimilarity factor for the first identified subset of n ECG complexes;
identifying from the plurality of m ECG complexes a second subset of n ECG complexes, wherein the second identified subset has at least one ECG complex that is not part of the first identified subset;
determining a second value of a complex dissimilarity factor for the second identified subset; and
if the second value is less than the first value, selecting the second identified subset for further evaluation.