Cardiac monitoring system
First Claim
1. A method of determining a measure of cardiac function in a subject, the method comprising:
- (a) determining a characteristic frequency for the subject, wherein the characteristic frequency is the most negative reactance within an applied frequency range;
(b) determining the impedance phase angle at the characteristic frequency; and
(c) determining a measure of cardiac function using the impedance phase angle determined solely at the characteristic frequency and displaying, storing, or transmitting the measure of cardiac function.
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Accused Products
Abstract
A method of analyzing cardiac functions in a subject using a processing system is described. The method may include applying one or more electrical signals having a plurality of frequencies to the subject and detecting a response to the applied one or more signals from the subject. A characteristic frequency can then be determined from the applied and received signals, and at least one component of the impedance (e.g., reactance, phase shift) can be measured at the characteristic frequency. Thus, the impedance or a component of impedance at a characteristic frequency can be determined for a number of sequential time instances. A new characteristic frequency may be determined within a cardiac cycle (e.g., with each sequential time instant) or the same characteristic frequency may be used throughout the cardiac cycle during which instantaneous values of impedance (or a component of impedance) are determined. These instantaneous values may be used to determine one or more indicia of cardiac function.
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Citations
24 Claims
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1. A method of determining a measure of cardiac function in a subject, the method comprising:
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(a) determining a characteristic frequency for the subject, wherein the characteristic frequency is the most negative reactance within an applied frequency range; (b) determining the impedance phase angle at the characteristic frequency; and (c) determining a measure of cardiac function using the impedance phase angle determined solely at the characteristic frequency and displaying, storing, or transmitting the measure of cardiac function. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of determining a measure of cardiac function in a subject, the method comprising:
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(a) applying an electrical signal having a plurality of frequencies to the subject; (b) receiving an electrical signal from the subject in response to the applied signal; (d) determining a characteristic frequency for the subject by comparing the applied and received electrical signals, wherein the characteristic frequency is the most negative reactance within an applied frequency range; (c) determining the impedance phase angle at substantially the characteristic frequency; and (d) determining a measure of cardiac function using the impedance phase angle determined solely at the characteristic frequency and displaying, storing, or transmitting the measure of cardiac function. - View Dependent Claims (17, 18, 19)
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20. A system for analyzing cardiac function in a subject, the device comprising:
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a plurality of electrodes configured to be attached to a subject; and a processor connected to the plurality of electrodes, the processor configured to execute processing logic, the processing logic configured to; (a) control the application of an electrical signal having a plurality of frequencies to the subject; (b) receive an electrical signal from the subject in response to the applied signal; (c) determine a characteristic frequency by comparing the applied and received electrical signals, wherein the characteristic frequency is the most negative reactance within an applied frequency range; (d) determine the impedance phase angle at the characteristic frequency; and (e) determine a measure of cardiac function using the impedance phase angle determined solely at the characteristic frequency. - View Dependent Claims (21, 22, 23, 24)
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Specification