System and apparatus for determining the left-ventricular ejection time TLVE of a heart of a subject

• US 20060167363A1
• Filed: 03/22/2006
• Published: 07/27/2006
• Est. Priority Date: 10/11/2001
• Status: Active Grant

• Current Assignee: Osypka Medical GmbH
• Original Assignee: Osypka Medical GmbH
• Inventors: Bernstein, Donald P., Osypka, Markus J.
• Granted Patent: US 7,904,141 B2
• Time in Patent Office: Days
• US Class Current: 600/508
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• 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 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives

Abstract

In order to reliably determine the left-ventricular ejection time T_LVE of a heart of a subject, at least two different measuring methods are employed. This includes in any case the derivation of a first waveform related to thoracic electrical bioimpedance or bioadmittance. A second waveform can be determined by using pulse oximetry, Doppler velocimetry, measurement of arterial blood pressure and measurement of peripheral electrical bioimpedance or bioadmittance. Depending on signal quality, the results obtained by each method are weighted and then averaged. The weighted average for left-ventricular ejection time is used as an input variable for cardiovascular monitoring methods, which determine objective measurements of cardiovascular function and performance. Such measurements include, but are not limited to, left ventricular ejection fraction, stroke volume, cardiac output, systolic time ratio, and indices of ventricular contractility.

Claims

1. A system for determining the left-ventricular ejection time T_LVE of a heart of a subject, comprising:

a first apparatus for measuring a value selected from the group comprising thoracic electrical bioimpedance and thoracic electrical bioadmittance over time; and

at least one second apparatus selected from the group comprising;

an apparatus for deriving plethysmogram data,

an apparatus for deriving signal data representing the velocity of blood in an artery in the vicinity of the esophagus of the subject,

an apparatus for deriving signal data representing the velocity of blood in radial artery of the subject,

a first apparatus for measuring data representing the blood pressure in an artery of the subject, said first apparatus for measuring data comprising a pressure sensor adapted to be non-invasively attached to the subject,

a second apparatus for measuring data representing the blood pressure in an artery of the subject, said second apparatus for measuring data comprising a pressure sensor adapted to be inserted into an artery of the subject,

an apparatus for measuring peripheral electrical bioimpedance, and

an apparatus for measuring peripheral electrical bioadmittance.

2. The system according to claim 1, further comprising:

a device coupled to said first apparatus for determining a value of T_LVE from the values measured by said first apparatus,

for each of said second apparatus selected from the group;

a device coupled to the respective second apparatus for determining a value of T_LVE from the data obtained by said apparatus, and

a device for averaging all determined values of T_LVE according to predetermined weights.

3. The system according to claim 1, further comprising:

a device coupled to said first apparatus for defining the opening and the closure time of the aortic valve of the subject on the basis of the values measured by said first apparatus, and

for each of said second apparatus selected from the group;

a device coupled to the respective second apparatus for determining the opening and the closure time of the aortic valve of the subject on the basis of the data obtained by said second apparatus,

a device for deriving an averaged opening time of the aortic valve on the basis of all opening times defined by respective devices,

a device for deriving an averaged closure time of the aortic valve on the basis of all closure times defined by respective devices,

a device for calculating a time from said averaged opening time to said average closure time.

4. The system according to claim 1, further comprising at least one of the devices selected from the group of a display for displaying the value of T_LVE determined by said system, an output line for electronically outputting the value of T_LVE determined by said system, and a printer for printing out the value of T_LVE determined by said system.

5. The system according to claim 1, wherein said first apparatus comprises:

at least two electrodes;

an alternating current (AC) source;

a voltmeter; and

a processing unit for calculating said value.

6. The system according to claim 5, wherein said electrodes are adapted to attach to the thorax of the subject.

7. The system according to claim 5, wherein said electrodes are placed on a catheter adapted to be inserted in the esophagus of the subject.

8. The system according to claim 5, wherein

said second apparatus is an apparatus for deriving signal data representing the velocity of blood in an artery in the vicinity of the esophagus of the subject, said second apparatus comprising a transducer attached to a catheter, and wherein

said at least two electrodes of said first apparatus are also placed on said catheter.

9. A system for determining the left-ventricular ejection time T_LVE of a heart of a subject, comprising:

a) at least two electrodes,

an alternating current (AC) source, and

a voltmeter;

b) an emitter and a sensor for electromagnetic radiation, both being adapted to be attached to at least one of a fingertip and a toe of the subject; and

c) a processing apparatus comprising;

i) one of the group selected from an electrical bioimpedance analyzer and an electrical bioadmittance analyzer,

ii) a pulse oximetry processor, and

iii) a processing unit coupled to said analyzer and said processor.

10. A system for determining the left-ventricular ejection time T_LVE of a heart of a subject, comprising:

a) at least two electrodes,

an alternating current (AC) source, and

an voltmeter;

b) an ultrasound emitter, and

an ultrasound detector; and

c) a processing apparatus comprising;

i) one of the group selected from an electrical bioimpedance analyzer and an electrical bioadmittance analyzer,

ii) a Doppler velocimeter for controlling said ultrasound emitter and for obtaining signals from said ultrasound detector, and

iii) a processing unit coupled to said analyzer and said Doppler velocimeter.

11. The system according to claim 10, wherein said electrodes, said ultrasound emitter and said ultrasound detector are placed on a catheter.

12. The system according to claim 10, further comprising:

d) an emitter and a sensor for electromagnetic radiation, both being adapted to attach to at least one of a fingertip and a toe of said subject, and wherein said processing apparatus further comprises;

iv) a pulse oximetry processor, said processing unit being coupled to said processor.

13. The system according to claim 11, further comprising:

d) an emitter and a sensor for electromagnetic radiation, both being adapted to attach to at least one of a fingertip and a toe of said subject, and wherein said processing apparatus further comprises;

iv) a pulse oximetry processor, said processing unit being coupled to said processor.

14. A system for determining the left-ventricular ejection time T_LVE of a heart of a subject, comprising:

a) at least two electrodes,

an alternating current (AC) source, and

an voltmeter;

b) an emitter and a sensor for electromagnetic radiation including infrared;

c) a device applicable to a limb of said subject for obtaining data representing physical entities which are changing during the stroke of said heart; and

d) a processing apparatus comprising;

i) one of the group selected from an electrical bioimpedance analyzer and an electrical bioadmittance analyzer,

ii) a pulse oximetry processor,

iii) a processor for processing the data obtained by said device, and

iv) a processing unit coupled to said analyzers and said processors.

15. The system according to claim 14, wherein said device is selected from the group comprising:

an ultrasound transducer adapted to be attached to a wrist of said subject,

a pressure sensor adapted to be attached to a wrist of said subject, and

a pressure sensor adapted to be inserted in a peripheral artery of said subject.

16. An apparatus adapted to be inserted into the esophagus of a subject, comprising:

a catheter;

at least two electrodes placed onto said catheter, and

an ultrasound emitter and an ultrasound receiver placed onto said catheter.

17. The catheter according to claim 16, wherein a single transducer is used as said ultrasound emitter and receiver.