Hemodynamic status assessment
First Claim
1. A system for determining a hemodynamic status model and providing therapy based on the hemodynamic status model, the system comprising:
- a lead connector electrically connectable to at least two electrodes of at least one electric lead;
a signal generator connected to the lead connector and configured to generate, during a period of normal hemodynamic status of a subject and in connection with a period of abnormal hemodynamic status of the subject, electric signals applicable over two electrodes of the at least two electrodes;
a signal sensing unit connected to the lead connector and configured to sense, during the period of normal hemodynamic status of the subject and in connection with the period of abnormal hemodynamic status of the subject, resulting electric signals over two electrodes of the at least two electrodes;
an impedance processor configured to determine a first impedance signal based on the electric signals applied and the resulting electric signals sensed during the period of normal hemodynamic status of the subject and determine a second impedance signal based on the electric signals applied and the resulting electric signals sensed in connection with the period of abnormal hemodynamic status of the subject;
a parameter processor configured to calculate first parameter values of a set of N different impedance-derivable parameters based on the first impedance signal and calculate second parameter values of the set of N different impedance-derivable parameters based on the second impedance signal, N is a positive integer equal to or larger than two;
a model processor configured to estimate based on the first parameter values and the second parameter values, N+1 coefficients of a linear parametric status model
1 Assignment
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Accused Products
Abstract
A patient-specific hemodyanmic status model is determined from impedance data collected during periods of normal and abnormal hemodynamic status by deriving parameter values of a set of multiple impedance-derivable parameters from impedance signals collected during periods of normal hemodynamic status and in connection with periods of abnormal hemodynamic status. The parameter values are employed to estimate coefficients of a linear parametric status model. These coefficients can then be used together with parameter values determined from impedance signals determined during status assessment periods in order to determine a current hemdoynamic status of the patient.
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Citations
7 Claims
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1. A system for determining a hemodynamic status model and providing therapy based on the hemodynamic status model, the system comprising:
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a lead connector electrically connectable to at least two electrodes of at least one electric lead; a signal generator connected to the lead connector and configured to generate, during a period of normal hemodynamic status of a subject and in connection with a period of abnormal hemodynamic status of the subject, electric signals applicable over two electrodes of the at least two electrodes; a signal sensing unit connected to the lead connector and configured to sense, during the period of normal hemodynamic status of the subject and in connection with the period of abnormal hemodynamic status of the subject, resulting electric signals over two electrodes of the at least two electrodes; an impedance processor configured to determine a first impedance signal based on the electric signals applied and the resulting electric signals sensed during the period of normal hemodynamic status of the subject and determine a second impedance signal based on the electric signals applied and the resulting electric signals sensed in connection with the period of abnormal hemodynamic status of the subject; a parameter processor configured to calculate first parameter values of a set of N different impedance-derivable parameters based on the first impedance signal and calculate second parameter values of the set of N different impedance-derivable parameters based on the second impedance signal, N is a positive integer equal to or larger than two; a model processor configured to estimate based on the first parameter values and the second parameter values, N+1 coefficients of a linear parametric status model - View Dependent Claims (2)
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3. A system for determining a hemodynamic status model and providing therapy based on the hemodynamic status model, the system comprising:
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a lead connector electrically connectable to at least two electrodes of at least one electric lead; a signal generator connected to the lead connector and configured to generate, during a period of normal hemodynamic status of a subject and in connection with a period of abnormal hemodynamic status of the subject, electric signals applicable over two electrodes of the at least two electrodes; a signal sensing unit connected to the lead connector and configured to sense, during the period of normal hemodynamic status of the subject and in connection with the period of abnormal hemodynamic status of the subject, resulting electric signals over two electrodes of the at least two electrodes; an impedance processor configured to determine a first impedance signals based on the electric signals applied and the resulting electric signals sensed during the period of normal hemodynamic status of the subject and determine a second impedance signal based on the electric signals applied and the resulting electric signals sensed in connection with the period of abnormal hemodynamic status of the subject; a parameter processor configured to calculate first parameter values of a set of N different impedance-derivable parameters based on the first impedance signal and calculate second parameter values of the set of N different impedance-derivable parameters based on the second impedance signal, N is a positive integer equal to or larger than two; a model processor configured to estimate, based on the first parameter values and the second parameter values, N+1 coefficients of a linear parametric status model
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4. An implantable medical device comprising:
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a lead connector electrically connectable to at least two electrodes of the at least one electric lead; a signal generator connected to the lead connector and configured to generate, during a status assessment period, electric signals applicable over two electrodes of the at least two electrodes; a signal sensing unit connected to the lead connector and configured to sense, during the status assessment period, resulting electric signals over two electrodes of the at least two electrodes; an impedance processor configured to determine an impedance signal based on the electric signals applied and the resulting electric signals sensed during the status assessment period; a parameter processor configured to calculate parameter values of a set of N different impedance-derivable parameters based on the impedance signal; a status processor configured to a calculate an index representative of a current hemodynamic status of a subject based on the parameter values calculated by the parameter processor and N+1 coefficients of a linear parametric status model
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5. A method of determining a hemodynamic status model, and providing therapy based on the hemodynamic status model, the method comprising:
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generating, during a period of normal hemodynamic status of a subject and in connection with a period of abnormal hemodynamic status of the subject, electric signals applicable over two electrodes of at least one electric lead; sensing, during the period of normal hemodynamic status of the subject and in connection with the period of abnormal hemodynamic status of the subject, resulting electric signals over two electrodes of the at least one electric lead; determining a first impedance signal based on the electric signals applied and the resulting electric signals sensed during the period of normal hemodynamic status of the subject; determining a second impedance signal based on the electric signals applied and the resulting electric signals sensed in connection with the period of abnormal hemodynamic status of the subject; calculating first parameter values of a set of N different impedance-derivable parameters based on the first impedance signal; calculating second parameter values of the set of N different impedance-derivable parameters based on the second impedance signal, N is a positive integer equal to or larger than two; estimating, based on the first parameter values and the second parameter values, N+1 coefficients of a linear parametric status model
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6. A method of determining a hemodynamic status model and providing therapy based on the hemodynamic status model, the method comprising:
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generating, during a period of normal hemodynamic status of a subject and in connection with a period of abnormal hemodynamic status of the subject, electric signals applicable over two electrodes of at least one electric lead; sensing, during the period of normal hemodynamic status of the subject and in connection wit the period of abnormal hemodynamic status of the subject, resulting electric signals over two electrodes of the at least one electric lead; determining a first impedance signal based on the electric signals applied and the resulting electric signals sensed during the period of normal hemodynamic status of the subject; determining a second impedance signal based on the electric signals applied and the resulting electric signals sensed in connection with the period of abnormal hemodynamic status of the subject; calculating first parameter values of a set of N different impedance-derivable parameters based on the first impedance signal; calculating second parameter values of the set of N different impedance-derivable parameters based on the second impedance signal, N is a positive integer equal to or larger than two; estimation, based on the first parameter values and the second parameter values, N+1 coefficients of a linear parametric status model
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7. A method of assessing a hemodynamic status of a subject and providing therapy based on the hemodynamic status, the method comprising:
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generating, during a status assessment period, electric signals applicable over two electrodes of at least one electric lead; sensing, during the status assessment period, resulting electric signals over two electrodes of the at least one electric lead; determining an impedance signal based on the electric signals applied and the resulting electric signals sensed during the status assessment period; calculating parameter values of a set of N different impedance-derivable parameters based on the impedance signal; calculating an index representative of a current hemodynamic status of the subject based on the parameter values and N+1 coefficients of a linear parametric status model
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Specification