SYSTEMS AND METHODS FOR DETERMINING SYSTOLIC TIME INTERVALS

• US 20080167566A1
• Filed: 01/04/2008
• Published: 07/10/2008
• Est. Priority Date: 08/08/2006
• Status: Abandoned Application

• Current Assignee: Arvind Thiagarajan, Damon J. Coffman, Kamil Unver, Tat-Jin Teo
• Original Assignee: Arvind Thiagarajan, Damon J. Coffman, Kamil Unver, Tat-Jin Teo
• Inventors: Coffman, Damon J., Teo, Tat-Jin, Unver, Kamil, Thiagarajan, Arvind
• Application Number:
  US11/969,750
• Publication Number:
  US 20080167566A1
• Time in Patent Office: Days
• US Class Current: 600/513
• CPC Class Codes: A61B 2562/0204 Acoustic sensors
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/25 Bioelectric electrodes therefor
• CPC Class Codes: A61B 7/00 Instruments for auscultation
• CPC Class Codes: A61B 8/4472 Wireless probes
• CPC Class Codes: A61B 8/488 involving Doppler signals

Abstract

A method and system for determining systolic time intervals, by analysis of radio frequency (RF) scatter patterns in conjunction with Electrocardiogram (ECG) data, is provided. An RF emitter is placed on the cardiac patient. The emitter includes two or more transmitting antennas which emit RF radiation into the cardiac patient, resulting in an RF scatter pattern. An RF sensor receives the scattered RF signals. The RF emitted from the antennas will differ spatially with regard to the RF sensor, causing the RF scatter patterns to differ from one another. A signal processor analyzes these differences to identify inhomogeneous structures, and to identify aortic valve motion, including aortic valve opening and closure. An electrocardiogram identifies the onset of the cardiac cycle. Systolic intervals are determined using the onset of the cardiac cycle and the aortic valve motion. Cardiac contractility also is determined by correlation to systolic intervals. An acoustic sensor is used to verify the aortic valve closure.

Claims

1. A method for cardiac contractility analysis, useful in association with a cardiac patient, and a systolic interval determination device having a radio frequency emitter, an acoustic sensor, a radio frequency sensor, and an electrocardiogram sensor and a signal processor, the method comprising:

orienting the acoustic sensor on the cardiac patient, wherein the acoustic sensor includes a pressure sensor, and wherein the acoustic sensor includes a transducer;

measuring pressure of the acoustic sensor on the cardiac patient;

generating an audio pulse on the cardiac patient by utilizing the transducer;

receiving an echo audio signal resulting from the generated audio pulse, wherein the echo audio signal is received by the acoustic sensor;

generating a bright line image along the echo audio signal;

receiving a heart sound signal of the cardiac patient by the acoustic sensor, wherein the heart sound signal includes a first acoustic peak and a second acoustic peak;

calibrating the heart sound utilizing the measured pressure of the acoustic sensor on the cardiac patient;

orienting the radio frequency emitter on the cardiac patient;

emitting radio frequency energy from at least two transmitting antennas, wherein the radio frequency emitter includes at least two transmitting antennas, and wherein the radio frequency energy scatters in the cardiac patient;

orienting the radio frequency sensor on the cardiac patient;

receiving the scattered radio frequency energy using the radio frequency sensor;

analyze differences in radio frequency energy scattering to identify internal inhomogeneous structures in the cardiac patient;

orienting the electrocardiogram sensor on the cardiac patient;

receiving electrical signals from the cardiac patient using the electrocardiogram sensor;

identifying onset of the cardiac cycle from the received electrical signals;

identifying opening of aortic valve of the cardiac patient utilizing the bright line image and the identified internal inhomogeneous structures;

identifying closing of aortic valve of the cardiac patient utilizing the bright line image, the second heart sound, and the identified internal inhomogeneous structures;

calculating a pre-ejection period by subtracting the onset of the cardiac cycle from the opening of the aortic valve;

calculating a left ventricular ejection time by subtracting the opening of the aortic valve from the closing of the aortic valve; and

computing the cardiac contractility by correlation to the pre-ejection period divided by the left ventricular ejection time.

2. A method for determining systolic intervals, useful in association with a cardiac patient, and a systolic interval determination device having a radio frequency emitter, a radio frequency sensor, and an electrocardiogram sensor and a signal processor, the method comprising:

orienting the radio frequency emitter on the cardiac patient;

emitting radio frequency energy from at least two transmitting antennas, wherein the radio frequency emitter includes at least two transmitting antennas, and wherein the radio frequency energy scatters in the cardiac patient;

orienting the radio frequency sensor on the cardiac patient;

receiving the scattered radio frequency energy using the radio frequency sensor;

analyze differences in radio frequency energy scattering to identify internal inhomogeneous structures in the cardiac patient;

orienting the electrocardiogram sensor on the cardiac patient;

receiving electrical signals from the cardiac patient using the electrocardiogram sensor;

identifying onset of the cardiac cycle from the received electrical signals;

identifying aortic valve motion of the cardiac patient utilizing the identified internal inhomogeneous structures, wherein the aortic valve motion includes aortic valve opening and aortic valve closure; and

determining the systolic intervals using the onset of the cardiac cycle and the aortic valve motion.

3. The method of claim 2, wherein determining the systolic intervals includes calculating a pre-ejection period and calculating a left ventricular ejection time.

4. The method of claim 3, wherein calculating the pre-ejection period includes subtracting the onset of the cardiac cycle from the opening of the aortic valve.

5. The method of claim 4, wherein calculating the left ventricular ejection time includes subtracting the opening of the aortic valve from the closing of the aortic valve.

6. The method of claim 2, further comprising computing cardiac contractility by correlation to the pre-ejection period divided by the left ventricular ejection time.

7. The method of claim 6, wherein computing cardiac contractility includes determining ejection fraction and rate of change in pressure in the heart.

8. The method of claim 2, further comprising:

orienting an acoustic sensor on the cardiac patient;

receiving a heart sound signal of the cardiac patient by the acoustic sensor, wherein the heart sound signal includes a first acoustic peak and a second acoustic peak; and

verifying the aortic valve closure using the second acoustic peak.

9. The method of claim 8, further comprising:

wherein the acoustic sensor includes a transducer;

generating an audio pulse on the cardiac patient by utilizing the transducer;

receiving an echo audio signal resulting from the generated audio pulse, wherein the echo audio signal is received by the acoustic sensor;

generating a bright line image along the echo audio signal; and

verifying the aortic valve motion using the generated bright line image.

10. The method of claim 8, further comprising:

wherein the acoustic sensor includes a pressure sensor;

measuring pressure of the acoustic sensor on the cardiac patient; and

calibrating the heart sound utilizing the measured pressure of the acoustic sensor on the cardiac patient.

11. A system for determining systolic intervals, useful in association with a cardiac patient, the system comprising:

a radio frequency emitter configured to emit radio frequency energy from at least two transmitting antennas, wherein the radio frequency emitter includes at least two transmitting antennas, and wherein the radio frequency energy scatters in the cardiac patient;

a radio frequency sensor configured to receive the scattered radio frequency energy;

an electrocardiogram sensor configured to receive electrical signals from the cardiac patient; and

a signal processor configured to analyze differences in radio frequency energy scattering to identify internal inhomogeneous structures in the cardiac patient, identify onset of the cardiac cycle from the received electrical signals, identify aortic valve motion of the cardiac patient utilizing the identified internal inhomogeneous structures, wherein the aortic valve motion includes aortic valve opening and aortic valve closure, and determine the systolic intervals using the onset of the cardiac cycle and the aortic valve motion.

12. The system of claim 11, wherein the signal processor is configured to determine the systolic intervals includes calculating a pre-ejection period and calculating a left ventricular ejection time.

13. The system of claim 12, wherein the signal processor is configured to calculate the pre-ejection period includes subtracting the onset of the cardiac cycle from the opening of the aortic valve.

14. The system of claim 13, wherein the signal processor is configured to calculate the left ventricular ejection time includes subtracting the opening of the aortic valve from the closing of the aortic valve.

15. The system of claim 11, further comprising the signal processor configured to compute cardiac contractility by correlation to the pre-ejection period divided by the left ventricular ejection time.

16. The system of claim 15, wherein computing cardiac contractility includes determining ejection fraction and rate of change in pressure in the heart.

17. The system of claim 11, further comprising:

an acoustic sensor configured to receive a heart sound signal of the cardiac patient, wherein the heart sound signal includes a first acoustic peak and a second acoustic peak; and

the signal processor configured to verify the aortic valve closure using the second acoustic peak.

18. The system of claim 17, further comprising:

a transducer configured to generate an audio pulse on the cardiac patient;

the acoustic sensor configured to receive an echo audio signal resulting from the generated audio pulse; and

the signal processor configured to generate a bright line image along the echo audio signal, and verify the aortic valve motion using the generated bright line image.

19. The system of claim 17, further comprising:

a pressure sensor configured to measure pressure of the acoustic sensor on the cardiac patient; and

the signal processor configured to calibrate the heart sound utilizing the measured pressure of the acoustic sensor on the cardiac patient.