Closed-loop adaptive adjustment of pacing therapy based on cardiogenic impedance signals detected by an implantable medical device
First Claim
1. A method for controlling therapy provided by an implantable cardiac stimulation device to reduce mechanical dyssynchrony, the method comprising:
- detecting an interventricular cardiogenic impedance signal (ZC) associated with individual heartbeats with the interventricular cardiogenic impedance signal having an interventricular waveform morphology, the interventricular cardiogenic impedance signal having sufficient resolution to detect a notch within an individual heartbeat occurring even in the absence of mechanical dyssynchrony, the interventricular waveform morphology of individual heartbeats having additional features corresponding to periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony;
deriving a measure of interventricular fractionation from the interventricular waveform morphology, wherein interventricular fractionation quantifies the features of the interventricular waveform morphology of individual heartbeats corresponding to periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; and
adjusting therapy provided by the device based on the interventricular cardiogenic impedance signal (ZC) to improve the measure of interventricular fractionation and reduce periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony;
wherein the features of the interventricular waveform morphology corresponding to periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony include a plurality of additional notches within an individual heartbeat arising due to mechanical dyssynchrony and wherein therapy is adjusted to reduce at least one of the plurality of additional notches within the individual heartbeat to reduce interventricular fractionation and reduce mechanical dyssynchrony.
1 Assignment
0 Petitions
Accused Products
Abstract
Techniques are provided for controlling therapy provided by the implantable cardiac stimulation device based on cardiogenic impedance. A cardiogenic impedance signal (or intracardiac impedance signal) is an impedance signal representative of the beating of the heart of the patient in which the device is implanted. The cardiogenic impedance signal is sensed along a sensing vector passing through at least a portion of the heart so that the sensed impedance is affected by the mechanical beating of the heart along that sensing vector. Pacing therapy is automatically and adaptively adjusted based on the cardiogenic impedance signal. For example, pacing timing parameters such as the atrioventricular delay and the inter-ventricular delay may be adjusted. Preferably, the adjustments are adaptive, i.e. the adjustments are performed in a closed-loop so as to adapt the adjustments to changes in the cardiogenic impedance signal so as to optimize therapy. In one particular example, the adjustments are performed so as to reduce a degree of fractionation within a cardiogenic impedance waveform.
-
Citations
50 Claims
-
1. A method for controlling therapy provided by an implantable cardiac stimulation device to reduce mechanical dyssynchrony, the method comprising:
-
detecting an interventricular cardiogenic impedance signal (ZC) associated with individual heartbeats with the interventricular cardiogenic impedance signal having an interventricular waveform morphology, the interventricular cardiogenic impedance signal having sufficient resolution to detect a notch within an individual heartbeat occurring even in the absence of mechanical dyssynchrony, the interventricular waveform morphology of individual heartbeats having additional features corresponding to periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; deriving a measure of interventricular fractionation from the interventricular waveform morphology, wherein interventricular fractionation quantifies the features of the interventricular waveform morphology of individual heartbeats corresponding to periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; and adjusting therapy provided by the device based on the interventricular cardiogenic impedance signal (ZC) to improve the measure of interventricular fractionation and reduce periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; wherein the features of the interventricular waveform morphology corresponding to periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony include a plurality of additional notches within an individual heartbeat arising due to mechanical dyssynchrony and wherein therapy is adjusted to reduce at least one of the plurality of additional notches within the individual heartbeat to reduce interventricular fractionation and reduce mechanical dyssynchrony. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
-
-
36. A system for controlling therapy provided by an implantable cardiac stimulation device to reduce the system comprising:
-
a cardiogenic impedance (ZC) detector operative to detect an interventricular cardiogenic impedance signal (ZC) associated with individual heartbeats, the interventricular cardiogenic impedance signal having an interventricular waveform morphology, the interventricular cardiogenic impedance signal having sufficient resolution to detect a notch within an individual heartbeat occurring even in the absence of mechanical dyssynchrony, the interventricular waveform morphology of individual heartbeats having additional features corresponding to periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; a cardiac function evaluation system operative to derive a measure of interventricular fractionation from the interventricular waveform morphology, wherein interventricular fractionation quantifies the features of the interventricular waveform morphology of individual heartbeats corresponding to the periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; and a cardiogenic impedance-based therapy adjustment system operative to adjust therapy provided by the device based on the interventricular cardiogenic impedance signal (ZC) to improve the measure of interventricular fractionation and reduce periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; wherein the features of the interventricular waveform morphology corresponding to periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony include a plurality of additional notches within an individual heartbeat arising due to mechanical dyssynchrony and wherein the therapy adjustment system operates to adjust therapy to reduce at least one of the plurality of additional notches within the individual heartbeat to reduce interventricular fractionation and reduce mechanical dyssynchrony. - View Dependent Claims (37, 38, 39)
-
-
40. A system for controlling therapy provided by an implantable cardiac stimulation device to reduce mechanical dyssynchrony, the system comprising:
-
means for detecting an interventricular cardiogenic impedance signal (ZC) associated with individual heartbeats, the interventricular cardiogenic impedance signal having an interventricular waveform morphology, the interventricular cardiogenic impedance signal having sufficient resolution to detect a notch within an individual heartbeat occurring even in the absence of mechanical dyssynchrony, the interventricular waveform morphology of individual heartbeats having additional features corresponding to periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; means for deriving a measure of interventricular fractionation from the interventricular waveform morphology, wherein interventricular fractionation quantifies the features of the interventricular waveform morphology of individual heartbeats corresponding to periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; and means for adjusting therapy provided by the device based on the interventricular cardiogenic impedance signal (ZC) so as to improve the measure of interventricular fractionation and reduce periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; wherein the features of the interventricular waveform morphology corresponding to periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony include a plurality of additional notches within an individual heartbeat arising due to mechanical dyssynchrony and wherein the means for adjusting therapy operates to adjust therapy to reduce at least one of the plurality of additional notches within the individual heartbeat to reduce interventricular fractionation and reduce mechanical dyssynchrony.
-
-
41. A method for controlling therapy provided by an implantable cardiac stimulation device, the method comprising:
-
detecting an interventricular cardiogenic impedance signal (ZC) associated with individual heartbeats with the interventricular cardiogenic impedance signal having an interventricular waveform morphology, the interventricular waveform morphology of individual heartbeats having features corresponding to periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; deriving a measure of interventricular fractionation from the interventricular waveform morphology, wherein interventricular fractionation quantifies the features of the interventricular waveform morphology of individual heartbeats corresponding to the periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; adjusting therapy provided by the device based on the interventricular cardiogenic impedance signal (ZC) to improve the measure of interventricular fractionation and reduce periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; and wherein the features of the interventricular waveform morphology corresponding to periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony include higher spectral frequencies compared to spectral frequencies associated with periods of time when chambers of the heart are beating uniformly and wherein therapy is adjusted to reduce at least some of the higher spectral frequencies to reduce interventricular fractionation. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49)
-
-
50. A system for controlling therapy provided by an implantable cardiac stimulation device, the system comprising:
-
a cardiogenic impedance (ZC) detector operative to detect an interventricular cardiogenic impedance signal (ZC) associated with individual heartbeats, the interventricular cardiogenic impedance signal having an interventricular waveform morphology, the interventricular waveform morphology of individual heartbeats having features corresponding to periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; a cardiac function evaluation system operative to derive a measure of interventricular fractionation from the interventricular waveform morphology, wherein interventricular fractionation quantifies the features of the interventricular waveform morphology of individual heartbeats corresponding to the periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; and a cardiogenic impedance-based therapy adjustment system operative to adjust therapy provided by the device based on the interventricular cardiogenic impedance signal (ZC) to improve the measure of interventricular fractionation and reduce periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony; wherein the features of the interventricular waveform morphology corresponding to periods of time when chambers of the heart are not beating uniformly due to mechanical dyssynchrony include higher spectral frequencies compared to spectral frequencies associated with periods of time when chambers of the heart are beating uniformly and wherein the therapy adjustment system operates to adjust therapy to reduce at least some of the higher spectral frequencies to reduce interventricular fractionation.
-
Specification