Intrinsic Frequency Hemodynamic Waveform Analysis

• US 20130184573A1
• Filed: 12/21/2012
• Published: 07/18/2013
• Est. Priority Date: 12/22/2011
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Pahlevan, Niema, Gharib, Morteza, Tavallali, Peyman, Hou, Thomas Yizhao
• Granted Patent: US 9,026,193 B2
• Time in Patent Office: Days
• US Class Current: 600/430
• CPC Class Codes: A61B 5/0004 characterised by the type of physiological signal transmitted
• CPC Class Codes: A61B 5/0013 Medical image data A61B1/00011, A61B6/56, A61B8/56 take precedence
• CPC Class Codes: A61B 5/0077 Devices for viewing the surface of the body, e.g. camera, magnifying lens
• 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 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/0507 using microwaves or terahertz waves
• CPC Class Codes: A61B 5/7235 Details of waveform analysis A61B5/349 takes precedence
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61B 8/02 Measuring pulse or heart rate
• CPC Class Codes: A61B 8/06 Measuring blood flow measuring volume flow in general G01F, e.g. G01F1/66, G01F1/72; measuring speed of fluids in general G01P5/00
• CPC Class Codes: A61B 8/5223 for extracting a diagnostic or physiological parameter from medical diagnostic data for algorithms to analyse biomedical images G06T7/0012
• CPC Class Codes: A61B 8/565 involving data transmission via a network

Abstract

Hardware and software methodology are described for cardiac health measurement. Hemodynamic waveforms variously acquired for a subject are analyzed to calculate or approximate intrinsic frequencies in two domains in two domains across the Dicrotic Notch. The intrinsic frequencies provide metrics/measures that correlate to the cardiac health of the subject. The systems may be used for monitoring a condition and/or is diagnosis. Exemplary uses include identifying (diagnosing) the presence of arrhythmia, heat failure, atrial fibrillation, aneurysms, vessel stenosis or aortic valve dysfunction and the necessity for valve replacement and/or monitoring congestive heart failure progression, together with identifying the acute need for hospitalization in connection with daily testing for any such condition.

Claims

1. A system for acquiring and analyzing a hemodynamic waveform of a subject, the system comprising:

an optical scanner, the scanner adapted to capture a signal corresponding to a hemodynamic waveform; and

at least one computer processor connected to the scanner by a wired or wireless connection, wherein the computer processor is adapted to receive the signal for the hemodynamic waveform, determine a Dicrotic Notch using the signal, calculate first and second intrinsic frequencies (ω

₁, ω

₂) on each side of the Dicrotic Notch for the waveform, and output a signal corresponding to intrinsic frequencies results.

5. The system of any of claims 1-4, wherein the processor is further adapted to calculate an instantaneous frequency curve for the hemodynamic waveform, and wherein the Dicrotic Notch is determined from the instantaneous frequency curve.

6. The system of any of claims 1-4, wherein the processor is further adapted to calculate a second derivative waveform for the hemodynamic waveform, and determine the Dicrotic Notch is from the second derivative waveform.

7. The system of any of claims 1-4 wherein the result comprises ω

₁, ω

₂ and Δ

ω

.

8. The system of any of claims 1-4, wherein the result comprises an indication of health status of the subject.

9. The system of any of claims 8, wherein the indication is an alert for hospitalization.

2. A system for acquiring and analyzing a hemodynamic waveform of a subject, the system comprising:

an ultrasound scanner, the scanner adapted to capture a signal corresponding to a hemodynamic waveform; and

at least one computer processor connected to the scanner by a wired or wireless connection, wherein the computer processor is adapted to receive the signal for the hemodynamic waveform, determine a Dicrotic Notch using the signal, calculate first and second intrinsic frequencies (ω

₁, ω

₂) on each side of the Dicrotic Notch for the waveform, and output a signal corresponding to intrinsic frequencies results.

3. A system for acquiring and analyzing a hemodynamic waveform of a subject, the system comprising:

a tonomeric scanner, the scanner adapted to capture a signal corresponding to a hemodynamic waveform; and

at least one computer processor connected to the scanner by a wired or wireless connection, wherein the computer processor is adapted to receive the signal for the hemodynamic waveform, determine a Dicrotic Notch using the signal, calculate first and second intrinsic frequencies (ω

₁, ω

₂) on each side of the Dicrotic Notch for the waveform, and output a signal corresponding to intrinsic frequencies results.

4. A system for acquiring and analyzing a hemodynamic waveform of a subject, the system comprising:

a microwave scanner, the scanner adapted to capture a signal corresponding to a hemodynamic waveform; and

at least one computer processor connected to the scanner by a wired or wireless connection, wherein the computer processor is adapted to receive the signal for the hemodynamic waveform, determine a Dicrotic Notch using the signal, calculate first and second intrinsic frequencies (ω

₁, ω

₂) on each side of the Dicrotic Notch for the waveform, and output a signal corresponding to intrinsic frequencies results.

10. A computer readable medium having stored thereon instructions, which when executed cause one or more processors to:

receive an input signal corresponding to a hemodynamic waveform;

determine a Dicrotic Notch using the input signal,

calculate first and second intrinsic frequencies on each side of the Dicrotic Notch for the waveform; and

output a signal corresponding to the intrinsic frequencies.

11. A computer-implemented method of analyzing a signal, comprising:

inputting a hemodynamic waveform data for a subject, the waveform including a Dicrotic Notch;

determining a position of the Dicrotic Notch in the waveform for dividing the signal into first and second sections for analysis;

analyzing each of the first and second sections of the waves by to determine first and second intrinsic frequencies (ω

₁, ω

₂) where each intrinsic frequency is at or about a frequency that carries the highest energy for all frequencies of an instantaneous frequency curve; and

outputting a result of the analyzing.

12. The computer-implemented method of claim 11, wherein the result comprises ω

₁, ω

₂ and Δ

ω

.

13. The computer-implemented method of claim 11, wherein the result comprises an indication of health status of the subject.

14. The computer-implemented method of claim 13, wherein the subject is a human subject.

15. The computer-implemented method of claim 14, wherein the indication is a diagnosis of atrial fibrillation.

16. The computer-implemented method of claim 14, wherein the indication is a diagnosis of heart failure.

17. The computer-implemented method of claim 14, wherein the indication is a diagnosis of aortic valve dysfunction.

18. The computer-implemented method of claim 14, wherein the indication is a diagnosis of arterial disease.

19. The computer-implemented method of claim 18, wherein the arterial disease is selected from aneurysm, stenosis and hypertension.

20. The computer-implemented method of claim 14, wherein the indication is a diagnosis of arrhythmia

21. The computer-implemented method of claim 14, wherein the indication is an alert for hospitalization.

22. The computer-implemented method of claim 11, wherein the waveform is selected from an arterial pressure wave, a wall displacement wave and a flow or velocity wave.

23. The computer-implemented method of claim 11, repeated in a periodic fashion for monitoring the subject.

24. The computer-implemented method of claim 23, further comprising comparing at least one of ω

₁, ω

₂ and Δ

ω

for the subject with historical results of at least one of ω

₁, ω

₂ and Δ

ω

for the subject.

25. The computer-implemented method of claim 11, further comprising comparing at least one of ω

₁, ω

₂ and Δ

ω

for the subject with non-subject values of ω

₁, ω

₂ and Δ

ω

.

26. The computer-implemented method of claim 11, wherein the results for the subject are logged.

27. The computer-implemented method of claim 11, wherein the waveform data is input from a sensor and the method comprises scanning the subject.

28. The computer-implemented method of claim 26, wherein the sensor is of a type selected from ultrasound, microwave, optical and tonomeric sensors.

29. The computer-implemented method of claim 11, further comprising calculating an instantaneous frequency curve for the hemodynamic waveform, and wherein the Dicrotic Notch is determined from the instantaneous frequency curve.

30. The computer-implemented method of claim 11, further comprising calculating a second derivative waveform for the hemodynamic waveform, and wherein the Dicrotic Notch is determined from the second derivative waveform.