Thoracic or intracardiac impedance detection with automatic vector selection
First Claim
1. An ambulatory medical device comprising:
- an impedance module including inputs configured to receive impedance signals from respective different electrode configurations associated with a subject'"'"'s thorax;
a cardiac stroke module coupled to the impedance module, the cardiac stroke module configured to;
extract corresponding cardiac stroke signals from the impedance signals; and
extract corresponding cardiac stroke amplitudes from the cardiac stroke signals;
a respiration module coupled to the impedance module, the respiration module configured to;
extract corresponding respiration signals from the impedance signals; and
extract corresponding respiration amplitudes from the respiration signals; and
a processor configured to;
compute a comparative measurement between each cardiac stroke amplitude and each corresponding respiration amplitude from the same electrode configuration; and
select, based on relative values of the comparative measurement associated with each electrode configuration, a particular electrode configuration for use in obtaining at least one of a cardiac stroke signal or a respiration signal for use in a diagnostic or therapeutic algorithm.
0 Assignments
0 Petitions
Accused Products
Abstract
Vector selection is automatically achieved via a thoracic or intracardiac impedance signal collected in a cardiac function management device or other implantable medical device that includes a test mode and a diagnostic mode. During a test mode, the device cycles through various electrode configurations for collecting thoracic impedance data. At least one figure of merit is calculated from the impedance data for each such electrode configuration. In one example, only non-arrhythmic beats are used for computing the figure of merit. A particular electrode configuration is automatically selected using the figure of merit. During a diagnostic mode, the device collects impedance data using the selected electrode configuration. In one example, the figure of merit includes a ratio of a cardiac stroke amplitude and a respiration amplitude. Other examples of the figure of merit are also described.
83 Citations
20 Claims
-
1. An ambulatory medical device comprising:
-
an impedance module including inputs configured to receive impedance signals from respective different electrode configurations associated with a subject'"'"'s thorax; a cardiac stroke module coupled to the impedance module, the cardiac stroke module configured to; extract corresponding cardiac stroke signals from the impedance signals; and extract corresponding cardiac stroke amplitudes from the cardiac stroke signals; a respiration module coupled to the impedance module, the respiration module configured to; extract corresponding respiration signals from the impedance signals; and extract corresponding respiration amplitudes from the respiration signals; and a processor configured to; compute a comparative measurement between each cardiac stroke amplitude and each corresponding respiration amplitude from the same electrode configuration; and select, based on relative values of the comparative measurement associated with each electrode configuration, a particular electrode configuration for use in obtaining at least one of a cardiac stroke signal or a respiration signal for use in a diagnostic or therapeutic algorithm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. An ambulatory medical device comprising:
-
an impedance detector configured to; measure a first impedance signal between at least first and second electrodes, which define a first electrode configuration, associated with a subject'"'"'s thorax; and measure a second impedance signal between at least third and fourth electrodes, which define a second electrode configuration, associated with a subject'"'"'s thorax, wherein at least one of the third and fourth electrodes is a different electrode from at least one of the first and second electrodes; a processor coupled to the impedance detector, the processor configured to; calculate a first figure of merit using the first impedance signal; calculate a second figure of merit using the second impedance signal; and use values of the first and second figures of merit as a basis for automatically selecting one of the first and second electrode configurations for subsequent diagnostic extraction of one of the first and second impedance signals; and an arrhythmia detector configured to; detect an arrhythmic heartbeat; and exclude an impedance signal corresponding to the arrhythmic heartbeat from consideration in calculating the first figure of merit or the second figure of merit. - View Dependent Claims (12, 13, 14)
-
-
15. An ambulatory medical device comprising:
-
an impedance detector including inputs configured to receive impedance signals from respective different electrode configurations associated with a subject'"'"'s thorax; a cardiac stroke module coupled to the impedance detector, the cardiac stroke module configured to; extract corresponding cardiac stroke signals from the impedance signals; and extract corresponding cardiac stroke amplitudes from the cardiac stroke signals; a respiration module coupled to the impedance detector, the respiration module configured to; extract corresponding respiration signals from the impedance signals; and extract corresponding respiration amplitudes from the respiration signals; a processor configured to; compute a ratio between each cardiac stroke amplitude and each corresponding respiration amplitude from the same electrode configuration; and select, based on relative values of the ratio associated with each electrode configuration, a particular electrode configuration for use in obtaining at least one of a cardiac stroke signal or a respiration signal for use in a diagnostic or therapeutic algorithm; and an arrhythmia detector configured to; detect an arrhythmic heartbeat; and exclude at least one of a cardiac stroke amplitude or a respiration amplitude corresponding to the arrhythmic heartbeat from consideration in computing the ratio. - View Dependent Claims (16, 17, 18, 19, 20)
-
Specification