System for Determining the Left-Ventricular Ejection Time TLVE of a Heart of a Subject

• US 20110190601A1
• Filed: 03/07/2011
• Published: 08/04/2011
• 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 8,562,538 B2
• Time in Patent Office: Days
• US Class Current: 600/301
• 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) 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.

2. 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.

3. The system according to claim 2, wherein said electrodes, said ultrasound emitter and said ultrasound detector are placed on a catheter.

4. The system according to claim 2, 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.

5. The system according to claim 3, 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.

6. 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.

7. The system according to claim 6, 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.

8. 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.

9. The catheter according to claim 8, wherein a single transducer is used as said ultrasound emitter and receiver.

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

a first apparatus for measuring data representing one of thoracic electrical bioimpedance and thoracic electrical bioadmittance over time;

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

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

an apparatus for measuring data representing peripheral electrical bioimpedance, and

an apparatus for measuring data representing peripheral electrical bioadmittance; and

a device adapted to calculate a value for T_LVE from an averaged opening time of the aortic valve determined from the data obtained by said first apparatus and said at least one second apparatus and an averaged closure time of the aortic valve determined from the data obtained by said first apparatus and said at least one second apparatus.

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

a device communicating with said first apparatus for determining the opening and the closure time of the aortic valve of the subject based on the data obtained by said first apparatus, and

for each of said at least one second apparatus selected from the group, a device communicating with said at least one second apparatus for determining the opening and the closure time of the aortic valve of the subject based on the data obtained by said at least one second apparatus.

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

a device for deriving the averaged opening time of the aortic valve based on all opening times defined by said devices communicating with said first apparatus and said at least one second apparatus; and

a device for deriving the averaged closure time of the aortic valve based on all opening times defined by said devices communicating with said first apparatus and said at least one second apparatus.