Method and devices for performing cardiac waveform appraisal

• US 8,346,357 B2
• Filed: 05/21/2012
• Issued: 01/01/2013
• Est. Priority Date: 06/02/2003
• Status: Expired due to Fees

• Current Assignee: Cameron Incorporated (Schlumberger NV)
• Original Assignee: Cameron Incorporated (Schlumberger NV)
• Inventors: Palreddy, Surekha, Warren, Jay A., Phillips, James W.
• Primary Examiner(s): Manuel, George
• Assistant Examiner(s): Wieland, Robert N
• Application Number:
  US13/476,313
• Publication Number:
  US 20120232415A1
• Time in Patent Office: 225 Days
• Field of Search: 607/5, 600/515, 600/518
• US Class Current: 607/5
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/35 by template matching
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence

Abstract

Implementations of various technologies described herein are directed toward a sensing architecture for use in cardiac rhythm management devices. The sensing architecture may provide a method and means for certifying detected events by the cardiac rhythm management device. Moreover, by exploiting the enhanced capability to accurately identifying only those sensed events that are desirable, and preventing the use of events marked as suspect, the sensing architecture can better discriminate between rhythms appropriate for device therapy and those that are not.

Claims

1. A method of identifying treatable cardiac conditions in an implantable cardiac stimulus device (ICSD), the ICSD comprising a plurality of electrodes for implantation in a patient and operational circuitry electrically coupled to the electrodes and configured to perform analysis of cardiac signals to identify malignant conditions, the method comprising:

the ICSD monitoring a signal captured between the electrodes;

the ICSD detecting an event in the monitored signal;

the ICSD capturing a set of data associated with the detected event;

the ICSD dividing the captured set of data into a number of data subgroups;

the ICSD assessing the shape of the signal in each of the data subgroups;

the ICSD characterizing the signal in each of the data subgroups as either suggesting noise or not suggesting noise;

the ICSD determining, for the captured set of data, how many of the data subgroups suggest noise to generate a factor, N;

the ICSD comparing N to a threshold for noise indications associated with a detected event;

if N exceeds the threshold for noise, the ICSD treating the detected event as caused by noise;

or

else the ICSD treating the detected event as a cardiac event.

2. The method of claim 1 wherein:

the set of data comprises a series of A data samples;

the step dividing the captured set of data into a number of data subgroups comprises dividing into sets of B data samples;

the step of assessing the shape of the signal in each of the data subgroups includes determining whether the each set of B data samples is monophasic; and

the step of characterizing the signal in each of the data subgroups is performed such that any data subgroup which is monophasic is found as not suggesting noise, and any data subgroup which is not monophasic is found as suggesting noise.

3. The method of claim 2 wherein A is 32, B is 4, and the threshold for noise is 5.

4. An implantable cardiac stimulus device (ICSD), the ICSD comprising a plurality of electrodes for implantation in a patient and operational circuitry electrically coupled to the electrodes and configured to perform analysis of cardiac signals to identify malignant conditions, the operational circuitry being configured to perform a method of identifying cardiac event detections comprising:

monitoring a signal captured between the electrodes;

detecting an event in the monitored signal;

capturing a set of data associated with the detected event;

dividing the captured set of data into a number of data subgroups;

assessing the shape of the signal in each of the data subgroups;

characterizing the signal in each of the data subgroups as either suggesting noise or not suggesting noise;

determining, for the captured set of data, how many of the data subgroups suggest noise to generate a factor, N;

comparing N to a threshold for noise indications associated with a detected event;

if N exceeds the threshold for noise, treating the detected event as caused by noise;

or

else treating the detected event as a cardiac event.

5. An ICSD as in claim 4 wherein the operational circuitry is configured such that:

the set of data comprises a series of A data samples;

the step dividing the captured set of data into a number of data subgroups comprises dividing into sets of B data samples;

the step of assessing the shape of the signal in each of the data subgroups includes determining whether the each set of B data samples is monophasic; and

the step of characterizing the signal in each of the data subgroups is performed such that any data subgroup which is monophasic is found as not suggesting noise, and any data subgroup which is not monophasic is found as suggesting noise.

6. The ICSD of claim 5 wherein A is 32, B is 4, and the threshold for noise is 5.