Method and device for deriving and evaluating cardiovascular information from curves of the cardiac current, in particular for applications in telemedicine

• US 20100331711A1
• Filed: 09/04/2007
• Published: 12/30/2010
• Est. Priority Date: 09/07/2006
• Status: Active Grant

• Current Assignee: Telozo GmbH
• Original Assignee: Teloza GmbH
• Inventors: Schubert, Jörg, Hartmann, Olaf, Krauss, Manfred, Schlund, Joachim
• Granted Patent: US 8,467,859 B2
• Time in Patent Office: Days
• US Class Current: 600/509
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: G16H 15/00 ICT specially adapted for medical reports, e.g. generation or transmission thereof
• CPC Class Codes: G16H 40/67 for remote operation
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

The invention relates to a method and a device for deriving and evaluating cardiovascular information from curves of the cardiac current, in particular for applications in telemedicine. According to the invention, for data reduction purposes, a mean value and a standard deviation across the whole recording time are initially determined from a recorded ECG from the high-resolution signal, after which the RR intervals are assessed by means of an identification algorithm and only the results obtained are transmitted and/or recorded, for the purpose of data reduction.

Claims

1. Method for deriving and evaluating cardiovascular information from electrocardiograms, especially for telemedical applications,

characterized in that

for the reduction of data, a mean value and a standard deviation are initially determined from the high-resolution signal of a recorded ECG over the total recording time and the R-R intervals are subsequently evaluated by means of a detection algorithm, and only the received results are transmitted and/or recorded for the purpose of the data reduction.

2. Method according to claim 1,

characterized in that

from an FFT spectrum of the determined heart period durations area integrals F are determined for the defined LF and HF frequency ranges of 0.04 to 0.15 Hz and 0.15 to 0.4 Hz and are related to the mean area-normal-values, so that spectral indexes for the evaluation are obtained as follows:

3. Method according to claim 1,

characterized in that

a weighting of the square s_TH² of the standard deviation, the absolute heart rate variability, with the square of the mean heart rate f_H is performed

4. Method according to claim 3,

characterized in that

by weightings of the indexes M_LF and M_HF with the square of the mean heart rate f_H it is determined how the sympatho-vagal balance B varies, so that the sympathetic activity components occurring in the LF frequency range become quantifiable as compared to the parasympathetic activity components.

5. Method according to claim 4,

characterized in that

a quantification is performed with the weighted indexes as follows:

normalized dimension for sympathetic activity, stress and strain;

6. Method according to claim 1,

characterized in that

beside the R-R determination it is determined by a frequency analysis of the derived ECG total time function in the range of 0 to about 2 Hz whether two dominant frequency lines f_1;

2 in the form of a frequency doubling occur at a same amplitude A<sub>f1;

2</sub>, so as to define a (stability) criterion K_μ

for the actually non-linear cardiovascular system, derived from the ECG time function, as follows;

11. Method according to claim 2,

characterized in that

a weighting of the square s_TH² of the standard deviation, the absolute heart rate variability, with the square of the mean heart rate f_H is performed

12. Method according to claim 11,

characterized in that

by weightings of the indexes M_LF and M_HF with the square of the mean heart rate f_H it is determined how the sympatho-vagal balance B varies, so that the sympathetic activity components occurring in the LF frequency range become quantifiable as compared to the parasympathetic activity components.

7. Device for deriving and evaluating cardiovascular information from electrocardiograms, especially for telemedical applications, comprising a sensor unit for ECG recording, wherein the sensor unit includes at least two fixed electrodes and an evaluation device, wherein the fixed electrodes can be brought into contact with the skin surface of the subject,

characterized in that

for determining a sufficient contact pressure, the contact resistance fixed electrode/skin of the subject is determined, wherein a high frequency test signal with a constant amplitude is added to the measured signal, wherein further the sum signal is attenuated by the subject connected in parallel to the input voltage divider and the resulting amplitude value of the higher-frequency test signal is proportional to the impedance of the fixed electrode-skin transition.

8. Device according to claim 7,

characterized in that

the sensor unit comprises operating means according to the 1-key principle, wherein an internal logic circuit is provided, which realizes a self-holding function, and the device provides an operating voltage with the first keystroke until, by a repeated operation, a switching off takes place or a predetermined time is exceeded.

9. Device according to claim 7,

characterized in that

it comprises a display with surfaces of a tachometer-like design, which include cardiovascular characteristics and data about standard values and wherein a visual relative motion takes place between scale components and pointer to display the tendency.

10. Device according to claim 7,

characterized in that

it comprises a data and monitoring device which is permanently installed in an automobile or aircraft, wherein, for the exchange of data, the sensor unit is connected to the data box via a preferably wireless interface so as to allow a continuous recording of vital data, wherein further the data and monitoring device comprises means, or is connected to such a means, allowing the localization of an automobile or aircraft.

13. Device according to claim 8,

characterized in that

it comprises a display with surfaces of a tachometer-like design, which include cardiovascular characteristics and data about standard values and wherein a visual relative motion takes place between scale components and pointer to display the tendency.

14. Device according to claim 8,

characterized in that

it comprises a data and monitoring device which is permanently installed in an automobile or aircraft, wherein, for the exchange of data, the sensor unit is connected to the data box via a preferably wireless interface so as to allow a continuous recording of vital data, wherein further the data and monitoring device comprises means, or is connected to such a means, allowing the localization of an automobile or aircraft.

15. Device according to claim 9,

characterized in that

it comprises a data and monitoring device which is permanently installed in an automobile or aircraft, wherein, for the exchange of data, the sensor unit is connected to the data box via a preferably wireless interface so as to allow a continuous recording of vital data, wherein further the data and monitoring device comprises means, or is connected to such a means, allowing the localization of an automobile or aircraft.

16. Device according to claim 13,

characterized in that

it comprises a data and monitoring device which is permanently installed in an automobile or aircraft, wherein, for the exchange of data, the sensor unit is connected to the data box via a preferably wireless interface so as to allow a continuous recording of vital data, wherein further the data and monitoring device comprises means, or is connected to such a means, allowing the localization of an automobile or aircraft.