Electrocardiogram (“ECG”) signal analysis and S-T segment measurement

1 . A method of processing of electrocardiogram (“ECG”) signals from a plurality of ECG leads connected to a patient, comprising:

selecting at least one lead to provide an ECG signal from the patient; and

for each of the at least one selected leads:

computing an average beat from a plurality of beats occurring during a predetermined averaging interval;

determining an onset point and a J-point of the average beat;

computing an interval complex measurement reflecting an S-T segment of the average beat based on the determined onset point and J-point;

computing an isoelectric point of the average beat relative to the computed onset point;

computing an S-T segment separately for each beat during the averaging interval using the isoelectric point and J-point of the average beat;

sorting the computed S-T segments of each beat and discarding upper and lower marginal values;

computing an each beat averaged measurement comprising an average of undiscarded S-T segments;

computing an average of the interval complex measurement and the each beat averaged measurement; and

reporting the computed average of the interval complex measurement and the each beat averaged measurement to a clinician.

2 . The method of claim 1 , further comprising removing baseline noise from each of the ECG signals from the at least one selected lead.

3 . The method of claim 1 , wherein the averaging interval is 15 seconds.

4 . The method of claim 1 , wherein determining the onset point and J-point of the average beat comprises generating an arc-length curve function for the average beats.

5 . The method of claim 4 , wherein the arc-length curve function comprises:

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where i is a time index, C is a constant related to sample interval in mSec, w is time window approximately equal to the width of the widest QRS complex during the predetermined period of time.

6 . The method of claim 1 , wherein computing an average beat from a plurality of beats occurring during a predetermined averaging interval comprises updating the average beat on each incoming new beat such that each beat contributes a fractional weighting to the average beat.

7 . The method of claim 1 , further comprising performing low-frequency and high-frequency noise measurements of the ECG signal on each selected lead and excluding beats with low or high frequency noise exceeding a predetermined threshold.

8 . A physiological monitoring system for processing electrocardiogram (“ECG”) signals from a plurality of ECG leads connected to a patient, comprising:

at least one lead for providing an ECG signal from the patient;

signal processing circuitry coupled to each of the at least one selected leads, the signal processing circuitry configured to:

compute an average beat from a plurality of beats occurring during a predetermined averaging interval;

determine an onset point and a J-point of the average beat;

computing an isoelectric point of the average beat relative to the onset point;

compute an interval complex measurement reflecting an S-T segment of the average beat based on the determined isoelectric point and J-point;

compute an S-T segment separately for each beat during the averaging interval using the onset point and the J-point of the average beat;

sort the computed S-T segments of each beat and discarding upper and lower marginal values;

compute an each beat averaged measurement comprising an average of undiscarded S-T segments;

compute an average of the interval complex measurement and the each beat averaged measurement; and

report the computed average of the interval complex measurement and the each beat averaged measurement to a clinician.

9 . The system of claim 8 , wherein the signal processing circuitry removes baseline noise from the ECG signals from the at least one selected lead.

10 . The system of claim 8 , wherein the averaging interval is 15 seconds.

11 . The system of claim 8 , wherein the signal processing circuitry determines the onset point and J-point of the average beat by generating an arc-length curve function for the average beats.

12 . The system of claim 11 , wherein the arc-length curve function comprises:

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where i is a time index, C is a constant related to sample interval in mSec, w is time window approximately equal to the width of the widest QRS complex during the predetermined period of time.

13 . The system of claim 8 , wherein the signal processing circuitry computes an average beat from a plurality of beats occurring during a predetermined averaging interval by updating the average beat on each incoming new beat such that each beat contributes a fractional weighting to the average beat.

14 . The system of claim 8 , wherein the signal processing circuitry performs low-frequency and high-frequency noise measurements of the ECG signal on each selected lead and excludes beats with low or high frequency noise exceeding a predetermined threshold from the computed average beat.

15 . A computer-readable medium tangibly embodying instructions that, when executed by a processor, performs a method of processing of electrocardiogram (“ECG”) signals from a plurality of ECG leads connected to a patient, comprising:

selecting at least one lead to provide an ECG signal from the patient;

for each of the at least one selected leads:

computing an average beat from a plurality of beats occurring during a predetermined averaging interval;

determining an onset point and a J-point of the average beat;

computing an isoelectric point of the average beat relative to the onset point;

computing an interval complex measurement reflecting an S-T segment of the average beat based on the determined isoelectric point and J-point;

computing an S-T segment separately for each beat during the averaging interval using the onset point and J-point of the average beat;

sorting the computed S-T segments of each beat and discarding upper and lower marginal values;

computing an each beat averaged measurement comprising an average of undiscarded S-T segments;

computing an average of the interval complex measurement and the each beat averaged measurement; and

reporting the computed average of the interval complex measurement and the each beat averaged measurement to a clinician.

16 . The computer-readable medium of claim 15 , wherein the method further comprises removing baseline noise from the ECG signals from the at least one selected lead.

17 . The computer-readable medium of claim 15 , wherein the averaging interval is 15 seconds.

18 . The computer-readable medium of claim 15 , wherein determining the onset point and J-point of the average beat comprises generating an arc-length curve function for the average beats.

19 . The computer-readable medium of claim 18 , wherein the arc-length curve function comprises:

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where i is a time index, C is a constant related to sample interval in mSec, w is time window approximately equal to the width of the widest QRS complex during the predetermined period of time.

20 . The computer-readable medium of claim 15 , wherein computing an average beat from a plurality of beats occurring during a predetermined averaging interval comprises updating the average beat on each incoming new beat such that each beat contributes a fractional weighting to the average beat.