Impedance cardiometer
First Claim
1. A heart monitoring system for assessing a patient'"'"'s cardiac condition comprising:
- bioimpedance means for inducing an electric current through the thorax of a patient'"'"'s body and obtaining a first signal representing amplitude of transthoracic impedance as a function of time;
electrocardiograph means for obtaining an electrocardiograph signal from the patient simultaneously with obtaining the first signal;
first processing means connected to said bioimpedance means for processing the first signal and producing therefrom a second signal representing cardiovascular hemodynamic changes as a function of time;
second processing means connected to said electrocardiograph means for measuring changes in the electrocardiograph signal;
analysis means connected to said first and second processing means for producing an output indicating changes in a portion of the second signal over a period of time relative to changes in the electrocardiograph signal over the same period of time; and
presentation means connected to said analysis means for visually presenting the output of said analysis means for use in providing an assessment of cardiac condition.
1 Assignment
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Accused Products
Abstract
A heart monitoring system for assessing a patient'"'"'s cardiac condition. Bioimpedance components induce an electric current through the thorax of a patient'"'"'s body and a first signal representing amplitude of transthoracic impedance as a function of time is obtained. Electrocardiograph components obtain an electrocardiograph signal from the patient simultaneously with the first signal. First processing circuitry is connected to the bioimpedance components for processing the first signal and producing therefrom a second signal representing cardiovascular hemodynamic changes as a function of time. Second processing circuitry is connected to the electrocardiograph components for measuring changes in the electrocardiograph signal. An analyzer is connected to the first and second processing circuits for producing an output indicating changes in a portion of the second signal over a period of time relative to changes in the electrocardiograph signal over the same period of time. A presentation device presents a visualization of the output of the analyzer for use in providing an assessment of cardiac condition.
79 Citations
18 Claims
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1. A heart monitoring system for assessing a patient'"'"'s cardiac condition comprising:
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bioimpedance means for inducing an electric current through the thorax of a patient'"'"'s body and obtaining a first signal representing amplitude of transthoracic impedance as a function of time; electrocardiograph means for obtaining an electrocardiograph signal from the patient simultaneously with obtaining the first signal; first processing means connected to said bioimpedance means for processing the first signal and producing therefrom a second signal representing cardiovascular hemodynamic changes as a function of time; second processing means connected to said electrocardiograph means for measuring changes in the electrocardiograph signal; analysis means connected to said first and second processing means for producing an output indicating changes in a portion of the second signal over a period of time relative to changes in the electrocardiograph signal over the same period of time; and presentation means connected to said analysis means for visually presenting the output of said analysis means for use in providing an assessment of cardiac condition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for diagnosing coronary artery disease in a patient comprising:
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measuring transthoracic impedance amplitude as a function of time while a patient is at rest and during exercise; obtaining an electrocardiograph of the patient simultaneously with said measuring step; processing the transthoracic impedance amplitude as a function of time to obtain a signal representing changes in cardiovascular hemodynamics as a function of time; deriving a value for a predetermined parameter obtained from a selected portion of the signal during a cardiac cycle at rest and from a corresponding selected portion of the signal during a cardiac cycle while exercising; forming the difference between the parameter values at rest and during exercise; determining a change in a predetermined aspect of the electrocardiograph between respective ones of the cardiac cycles at rest and during exercise used in said deriving step; and combining the difference in parameter values and the change in the predetermined aspect of the electrocardiograph to form a hybrid indicator for providing an assessment of cardiac condition. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification