Ischemia detection during non-standard cardiac excitation patterns
AssigneeMedtronic, Inc.
InventorsRobert Stadler, Shannon Nelson
Life of this patent
Estimating the term…
Abstract
In using electrogram signals to determine physiologic conditions like ischemia, the bad cardiac cycle information due to noise, axis shifts in the cardiac electrical axis, and the like must be removed if the electrogram signal can be made to be a good indicator. If this is accomplished through the adaptive filtering techniques shown here, the signal can be used to drive a closed loop therapy system responsive to those physiologic conditions discernible from good cardiac cycle electrocardiogram signals.
Claims28
A method of determining ischemic condition during a ventricular paced rhythm comprising;
- a.) pacing at a rate above an intrinsic or a sensor indicated rate,
- b.) deriving data from electrical signals of the heart during said pacing above an intrinsic or sensor indicated rate,
- c.) processing data derived from electrical signals,
- d.) making a determination of ischemia based on said processing.
A method of determining cardiac ischemia that is applied in the presence of pacing and in the presence of intrinsic beats, comprising:
- when in the presence of pacing,
- b.) deriving data from electrical signals of the heart during said pacing,
- c.) processing data drived from electrical signals,
- d.) making a determination of ischemia based on said processing, and
- when in the presence of intrinsic beats,
- e.) deriving data from electrical signals of a heart surrounding Ventricular sense events,
- f.) processing data derived from step (e), and
- g.) making a determination of ischemia based on said processing in step (f).
An implantable medical device for making a determination of cardiac ischemia comprising:
- an implantable housing having electrodes sufficient for receiving an electrocardiogram signal,
- an electrocardiogram receiving circuit for receiving said electrocardiogram signal,
- a sampling circuit for sampling said electrocardiogram signal and providing a sample value for each sample sampled,
- a fiducial point determining circuit for determining a fiducial point from among said samples,
- a processor circuit and memory circuit operative therewith for running a program in said memory by said processor circuit to review said sample values and upon such review and employing said fiducial pint, to determine whether there is an indication of cardiac ischemia,
- and wherein, and electrode connected is connected to a pacing circuit in said housing, and said pacing circuit provides pacing pulses for causing depolarizations in a ventricle of a heart,
- and wherein a second program for initiating pacing pulse delivery initiates pacing pulse delivery,
- and wherein said fiducial point determining circuit employs a time of pacing pulse delivery signal as a fiducial point to determine which from among said samples is the fiducial point.
An implantable medical device for making a determination of cardiac ischemia comprising:
- an implantable housing having electrodes sufficient for receiving an electrocardiogram signal,
- an electrocardiogram receiving circuit for receiving said electrocardiogram signal,
- a sampling circuit for sampling said electrocardiogram signal and providing a sample value for each sample sampled,
- a fiducial point determining circuit for determining a fiducial point from among said samples,
- a processor circuit and memory circuit operative therewith for running a program in said memory by said processor circuit to review said sample values and upon such review and employing said fiducial pint, to determine whether there is an indication of cardiac ischemia,
- and wherein, an electrode connected is connected to a pacing circuit in said housing, and said pacing circuit provides pacing pulses for causing cardiac depolarizations in a ventricle of a heart,
- and wherein a second program for initiating pacing pulse delivery initiates pacing pulse delivery,
- and wherein said fiducial point determining circuit employs an occurrence of a pacing pulse delivery signal and a determination feature of a following paced waveform for determining said fiducial point from among said samples.
An implantable medical device for making a determination of cardiac ischemia comprising:
- an implantable housing having electrodes sufficient for receiving an electrocardiogram signal,
- an electrocardiogram receiving circuit for receiving said electrocardiogram signal,
- a sampling circuit for sampling said electrocardiogram signal and providing a sample value for each sample sampled,
- a fiducial point determining circuit for determining a fiducial point from among said samples,
- a processor circuit and memory circuit operative therewith for running a first program in said memory by said processor circuit to review said sample values and upon such review and employing said fiducial pint, to determine whether there is an indication of cardiac ischemia,
- and wherein an electrode is connected to a pacing circuit in said housing, and said pacing circuit provides pacing pulses for causing cardiac depolarizations in a ventricle of a heart,
- and further comprising a second program for initiating pacing pulse delivery initiates pacing pulse delivery,
- and wherein said first program comprises a paced algorithm and an intrinsic algorithm and wherein samples taken during a heart beat that is intrinsic are employed by said intrinsic algorithm to determine ischemia and wherein samples taken during a heart beat that is paced are employed by said paced algorithm to determine ischemia.
A process for determining the temporal location for sampling ST segments for measurement leading to a determination of ischemic condition of a heart from intracardiac electrogram signals comprising;
- finding the sample at which said intracardiac electrogram has a QRS peak in a paced beat electrogram waveform,
- selecting ST segment samples at a predetermined time delay from said QRS peak for said sampling ST segments.
Dependencies are inferred from the claim text.