DEVICE FOR MEASUREMENT AND EVALUATION OF CARDIAC FUNCTION ON THE BASIS OF THORACIC IMPEDANCE

• US 20170143225A1
• Filed: 12/16/2016
• Published: 05/25/2017
• Est. Priority Date: 06/25/2014
• Status: Active Grant

• Current Assignee: Medical Corporation Ushiroda Internal Medicine Clinic
• Original Assignee: Medical Corporation Ushiroda Internal Medicine Clinic
• Inventors: Ushiroda, Shinichi
• Granted Patent: US 10,244,958 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/0535 Impedance plethysmography for measuring blood flow A61B5/0295
• CPC Class Codes: A61B 5/303 Patient cord assembly, e.g. cable harness
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/333 Recording apparatus specially adapted therefor
• CPC Class Codes: A61B 5/339 Displays specially adapted therefor
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/361 Detecting fibrillation
• CPC Class Codes: A61B 5/364 Detecting abnormal ECG interval, e.g. extrasystoles, ectopic heartbeats
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

A cardiac function measurement and evaluation device is provided to measure and evaluate cardiac function in patients with atrial fibrillation, sinus arrhythmia, and the like, using thoracic impedance data and electrocardiogram data. By creating a two-dimensional scatter plot in which (dZ/dt)min values and preceding RR intervals (RR1) corresponding thereto, and the like obtained by thoracic impedance measurement, are plotted, it is possible to visually and easily evaluate the state of cardiac function in patients with atrial fibrillation and sinus arrhythmia. Using the measurement and evaluation device of the present invention makes it possible to perform examinations easily and repeatedly with less burden on patients. Therefore, it is possible to provide very useful information for diagnosing heart disease, selecting drugs, and the like.

Claims

1. A cardiac function measurement and evaluation device that is a device for measuring and evaluating cardiac function in a subject, the device comprising:

thoracic impedance measuring unit;

electrocardiogram measuring unit;

arithmetic unit;

storage unit; and

display unit, wherein

the thoracic impedance measuring unit includes drive electrodes for applying an electrical current, and receive electrodes for extracting an impedance signal, and measures a plurality of continuous sets of thoracic impedances,

the electrocardiogram measuring unit includes a signal detection module that detects electrocardiogram signals from electrodes applied to the subject, and measures a plurality of continuous sets of electrocardiogram signals,

the arithmetic unit calculates (dZ/dt)min values of the plurality of continuous sets of thoracic impedances measured by the thoracic impedance measuring unit, and preceding RR intervals (RR1) of continuous sets of electrocardiogram data from R waves of the electrocardiogram signal obtained by the electrocardiogram measuring unit,

the storage unit stores, as a data set;

a (dZ/dt)min value of each of the sets of thoracic impedance data corresponding to an RR1 value of each of the calculated plurality of continuous sets of electrocardiogram data, and

the display unit displays each of the (dZ/dt)min values corresponding to each of the RR1 values.

2. The cardiac function measurement and evaluation device according to claim 1, wherein

the display unit displays respective (dZ/dt)min values of the thoracic impedance data corresponding to the respective RR1 values of the obtained plurality of sets of electrocardiogram data as a scatter plot.

3. The cardiac function measurement and evaluation device according to claim 2, wherein

an approximate curve is obtained from the scatter plot of the (dZ/dt)min values of the thoracic impedance data corresponding to the respective RR1 values, and is displayed.

4. The cardiac function measurement and evaluation device according to claim 1, wherein

from the plurality of continuous sets of electrocardiogram data obtained by the electrocardiogram measuring unit, pre-preceding RR intervals (RR2) and RR1/RR2 values are calculated by the arithmetic unit, and corresponding (dZ/dt)min values are displayed.

5. The cardiac function measurement and evaluation device according to claim 4, wherein

(dZ/dt)min values where RR1/RR2≦

1 are extracted as (dZ/dt)min values (FSM+MR) in which PESP is not involved,

(dZ/dt)min values where RR1/RR2>

1 are extracted as (dZ/dt)min values (PESP+FSM+MR) in which PESP is involved, and

the respective (dZ/dt)min values corresponding to the RR1 values are displayed distinguishably as a scatter plot.

6. The cardiac function measurement and evaluation device according to claim 5, wherein

from the scatter plot of the respective (dZ/dt)min values of the thoracic impedance data extracted as the FSM+MR and the PESP+FSM+MR, respective approximate curves are obtained and are displayed.

7. The cardiac function measurement and evaluation device according to claim 4, wherein

(dZ/dt)min values where RR1/RR2≦

1 are extracted as (dZ/dt)min values (FSM+MR) in which PESP is not involved,

(dZ/dt)min values where RR1/RR2>

1 are extracted as (dZ/dt)min values (PESP+FSM+MR) in which PESP is involved, and

a total of the respective (dZ/dt)min values are calculated.

8. The cardiac function measurement and evaluation device according to claim 4, wherein

(dZ/dt)min values where RR1/RR2≦

1 are extracted as (dZ/dt)min values (FSM+MR) in which PESP is not involved,

(dZ/dt)min value where RR1/RR2>

1 are extracted as (dZ/dt)min value (PESP+FSM+MR) in which PESP is involved, and

RR1, RR1/RR2, and (dZ/dt)min values are displayed as a three-dimensional scatter plot.

9. The cardiac function measurement and evaluation device according to claim 4, wherein

(dZ/dt)min values where RR1/RR2>

1 are extracted as (dZ/dt)min values (PESP+FSM+MR) in which PESP is involved, and

the (dZ/dt)min values corresponding to the respective RR1/RR2 values are displayed as a scatter plot.

10. The cardiac function measurement and evaluation device according to claim 9, wherein

from the scatter plot of the respective (dZ/dt)min values of the thoracic impedance data extracted as the PESP+FSM+MR, an approximate straight line is obtained and is displayed.

11. The cardiac function measurement and evaluation device according to any one of claim 1, wherein

the storage unit is allowed to store standard data, and

the arithmetic unit includes a determination module that compares obtained data of the subject with the standard data and determines cardiac function.

12. The cardiac function measurement and evaluation device according to any one of claim 2, wherein

the storage unit is allowed to store standard data, and

the arithmetic unit includes a determination module that compares obtained data of the subject with the standard data and determines cardiac function.

13. The cardiac function measurement and evaluation device according to any one of claim 4, wherein

the storage unit is allowed to store standard data, and

the arithmetic unit includes a determination module that compares obtained data of the subject with the standard data and determines cardiac function.

14. The cardiac function measurement and evaluation device according to any one of claim 5, wherein

the storage unit is allowed to store standard data, and

the arithmetic unit includes a determination module that compares obtained data of the subject with the standard data and determines cardiac function.

15. The cardiac function measurement and evaluation device according to any one of claim 7, wherein

the storage unit is allowed to store standard data, and

the arithmetic unit includes a determination module that compares obtained data of the subject with the standard data and determines cardiac function.

16. The cardiac function measurement and evaluation device according to claim 11, wherein

the determination module further performs comparison with past data of same subject stored in the storage unit, and determines the course of cardiac function.

17. The cardiac function measurement and evaluation device according to claim 12, wherein

the determination module further performs comparison with past data of same subject stored in the storage unit, and determines the course of cardiac function.

18. The cardiac function measurement and evaluation device according to claim 13, wherein

the determination module further performs comparison with past data of same subject stored in the storage unit, and determines the course of cardiac function.

19. The cardiac function measurement and evaluation device according to claim 14, wherein

the determination module further performs comparison with past data of same subject stored in the storage unit, and determines the course of cardiac function.

20. The cardiac function measurement and evaluation device according to claim 15, wherein

the determination module further performs comparison with past data of same subject stored in the storage unit, and determines the course of cardiac function.