System for Cardiac Condition Characterization Using Electrophysiological Signal Data

• US 20120123285A1
• Filed: 06/15/2011
• Published: 05/17/2012
• Est. Priority Date: 11/11/2010
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: Siemens Medical Solutions USA Incorporated (Siemens AG)
• Inventors: Zhang, Hongxuan
• Granted Patent: US 8,868,168 B2
• Time in Patent Office: Days
• US Class Current: 600/516
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/35 by template matching

Abstract

A system for heart performance characterization and abnormality detection includes an interface for receiving signal data representing an electrical signal indicating electrical activity of a patient heart over multiple heart beat cycles. A signal processor uses the received signal data in calculating at least one of, (a) a first signal characteristic value substantially comprising a ratio of a time interval from S wave to T wave, to a time interval from Q wave to S wave and (b) a second signal characteristic value substantially comprising a ratio of a T wave base voltage from a peak of a T wave to a zero base reference voltage, to an R wave base voltage from a peak of an R wave to a zero base reference voltage. A comparator compares at least one of the first and second characteristic values with a threshold value to provide a comparison indicator. A patient monitor in response to the comparison indicator indicating a calculated signal characteristic value exceeds the threshold value, generates an alert message associated with the threshold.

Claims

1. A system for heart performance characterization and abnormality detection, comprising:

an interface for receiving signal data representing an electrical signal indicating electrical activity of a patient heart over a plurality of heart beat cycles;

a signal processor for using the received signal data in calculating at least one of,

(a) a first signal characteristic value substantially comprising a ratio of a time interval from S wave to T wave, to a time interval from Q wave to S wave and

(b) a second signal characteristic value substantially comprising a ratio of a T wave base voltage from a peak of a T wave to a zero base reference voltage, to an R wave base voltage from a peak of an R wave to a zero base reference voltage;

a comparator for comparing at least one of the first and second characteristic values with a threshold value to provide a comparison indicator; and

a patient monitor for in response to said comparison indicator indicating a calculated signal characteristic value exceeds the threshold value, generating an alert message associated with the threshold.

2. A system according to claim 1, wherein

said time interval occurs within a single heart cycle.

3. A system according to claim 1, wherein

said signal data is digitally sampled data.

4. A system according to claim 1, wherein

said signal processor processes the received signal data to calculate at least one of,

(i) a third signal characteristic value substantially comprising a ratio of a maximum magnitude (peak to peak) voltage value for a T wave, to a maximum magnitude (peak to peak) voltage value for an R wave and

(ii) a fourth signal characteristic value substantially comprising a ratio of a time interval from a Q wave to an R wave, to a time interval from an R wave to and S wave and

said comparator compares at least one of the third and fourth characteristic values with a threshold value to provide a comparison indicator.

5. A system according to claim 1, wherein

said signal processor processes the received signal data to calculate a third signal characteristic value substantially comprising,

6. A system according to claim 1, wherein

said signal processor processes the received signal data to calculate a weighted sum of different calculated ratios of parameters derived from the received signal.

7. A system according to claim 6, wherein

individual weights of said weighted sum are at least one of,

(a) adaptively controlled by a processor and

(b) time varying.

8. A system according to claim 6, wherein

said weighted sum of different calculated ratios of parameters is of the form,

9. A system according to claim 1, wherein

said threshold value is derived from recorded electrical signal data for said patient.

10. A system according to claim 1, wherein

said threshold value is derived from recorded electrical signal data for a population of patients.

11. A system according to claim 10, wherein

said population of patients has similar demographic characteristics including at least two of, (a) age, (b) weight, (c) gender and (d) height, to those of said patient.

12. A system according to claim 1, wherein

said signal processor dynamically adjusts said threshold value in response to a determined sensitivity of arrhythmia detection.

13. A system according to claim 1, wherein

said signal processor calculates a standard deviation of said first or second signal characteristic value ratio over a plurality of heart cycles and

said patient monitor, in response to a comparison indicator indicating a calculated standard deviation value exceeds a predetermined threshold value, generates an alert message.

14. A system according to claim 1, wherein

said signal processor calculates a signal variability of said time intervals determined over a plurality of heart cycles and

said patient monitor, in response to a comparison indicator indicating a calculated signal variability value exceeds a predetermined threshold value, generates an alert message.

15. A system according to claim 14, wherein

said signal variability is calculated over a plurality of heart cycles and is of the form,

16. A system according to claim 1, including

a repository of predetermined mapping information, associating ranges of the first or second characteristic values with corresponding medical conditions and

said comparator compares the first or second characteristic values with said ranges to provide a comparison indicator identifying a medical condition and

said patient monitor generates an alert message identifying said medical condition.

17. A system according to claim 16, wherein

said predetermined mapping information associates ranges of the first or second characteristic values with particular patient demographic characteristics and with corresponding medical conditions and said system uses patient demographic data including at least one of age weight, gender and height in comparing the ratio with said ranges and generating an alert message indicating a potential medical condition.

18. A method for heart performance characterization and abnormality detection, comprising the activities of:

receiving signal data representing an electrical signal indicating electrical activity of a patient heart over a plurality of heart beat cycles;

using the received signal data in calculating at least one of,

(a) a first signal characteristic value substantially comprising a ratio of a time interval from S wave to T wave, to a time interval from Q wave to S wave and

(b) a second signal characteristic value substantially comprising a ratio of a T wave base voltage from a peak of a T wave to a zero base reference voltage, to an R wave base voltage from a peak of an R wave to a zero base reference voltage;

comparing at least one of the first and second characteristic values with a threshold value to provide a comparison indicator; and

in response to said comparison indicator indicating a calculated signal characteristic value exceeds the threshold value, generating an alert message associated with the threshold.

19. A system for heart performance characterization and abnormality detection, comprising:

an interface for receiving signal data representing an electrical signal indicating electrical activity of a patient heart over a plurality of heart beat cycles; and

a signal processor for using the received signal data in calculating at least one of,

(a) a first signal characteristic value substantially comprising a ratio of a time interval from S wave to T wave, to a time interval from Q wave to S wave and

(b) a second signal characteristic value substantially comprising a ratio of a T wave base voltage from a peak of a T wave to a zero base reference voltage, to an R wave base voltage from a peak of an R wave to a zero base reference voltage, and

in response to comparing at least one of the first and second characteristic values with a threshold value, generating an alert message associated with the threshold.