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Method and system for noise measurement in an implantable cardiac device

  • US 6,917,830 B2
  • Filed: 08/19/2003
  • Issued: 07/12/2005
  • Est. Priority Date: 10/29/2001
  • Status: Expired due to Fees
First Claim
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1. A method for operating a cardiac rhythm management device, comprising:

  • sampling an electrogram signal from a sensing channel of the device to obtain a series of samples, where each sample can be designated by X[n] with n an integer;

    determining whether each sample represents a local peak or not, wherein a sample X[n] is a local peak if its amplitude is either;

         1) greater than the amplitude of the preceding sample X[n−

    1] by a specified threshold value δ

    1 and also greater than the amplitude of the subsequent sample X[n+1] by the specified threshold δ

    2, or

         2) less than the amplitude of the preceding sample X[n−

    1] by a specified threshold δ

    3 and also less than the amplitude of the subsequent sample X[n+1] by the specified threshold δ

    4;

    computing a local peak density in a predetermined number of consecutive samples;

    computing a noise flag as either set or cleared in accordance with the computed local peak density, wherein the noise flag is set if the local peak density exceeds a first threshold value; and

    , estimating a noise level in the electrogram signal by computing a noise statistic from a series of samples when the noise flag is set.

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