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

• US 7,904,141 B2
• Filed: 03/22/2006
• Issued: 03/08/2011
• 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.
• Primary Examiner(s): Patel; Niketa I
• Assistant Examiner(s): ALTER, ALYSSA MARGO
• Application Number:
  US11/386,422
• Publication Number:
  US 20060167363A1
• Time in Patent Office: 1,812 Days
• Field of Search: 600/513
• US Class Current: 600/513
• 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, 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 input a first value for T_LVE determined from the data obtained by said first apparatus and at least a second value for T_LVE determined from the data obtained by said at least one second apparatus, and to average all derived values of T_LVE according to predetermined weights to determine T_LVE.

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

a device communicating with said first apparatus for determining the first value of T_LVE from the data obtained by said first apparatus, and

for each of said second apparatus selected from the group, a device communicating with said second apparatus for determining the second value of T_LVE from the data obtained by said second apparatus.

3. The system according to claim 1, further comprising at least one 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.

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

at least two electrodes attached to the subject;

an alternating current (AC) source connected to said at least two electrodes and applied to the subject;

a voltmeter adapted to measure a voltage drop across the subject; and

a processing unit for calculating the first value for T_LVE from the measured voltage drop.

5. The system according to claim 4, wherein said electrodes are adapted to attach to the thorax of the subject.

6. The system according to claim 4, further comprising a catheter adapted to be inserted in the esophagus of the subject, wherein said electrodes are placed on said catheter.

7. The system according to claim 4, 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 catheter, and wherein

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

8. A system according to claim 2, wherein said device adapted to input and to average, said device communicating with said first apparatus for determining the first value of T_LVE, and said device communicating with said second apparatus for determining the second value of T_LVE are formed as a unit.