Medtronic, Inc.

Harry W M De Bruyn

Peter W Wohlgemuth

Henk Westendorp

Jacob Dave Munneke

Anton L Huijnen

J Dave Munneke

A cardiac pacing system and method incorporate DSP processing and software algorithms for collecting signal amplitude data and noise data, and organizing the data for automatic checking of signal channel gain and signal detection sensitivity. Unfiltered signals are used to obtain values representative of maximum amplitude, which values are stored in a gain histogram, from which determination of the percentage of clipped signals can be made. Gain is adjusted by limiting clipping to a predetermined range of allowed clipping, to optimize use of the DSP range. The signals, both P waves and R waves for a dual chamber system, are also processed by DSP and parameters representing maximum amplitudes are stored in amplitude histograms. At the same time, noise is analyzed for respective windows of time following each ventricular event, and noise amplitude data is stored in noise histograms. After a predetermined waiting period, the signal amplitude and noise histograms are analyzed and compared, and for each channel the sensitivity is adjusted to fall between a calculated noise floor and the lowest bin of the amplitude histogram that contains valid data.

Implantable medical device with autosensitivity algorithm for controlling sensing of cardiac signals

A method for determining a representative noise floor in a cardiac pacing system from which future events are measured is provided. An event amplitude is determined. Pluralities of noise levels are recorded, when each of the plurality of noise levels is less than a predetermined percentage of the event amplitude. The noise floor is determined as an absolute maximum value of the plurality of recorded noise levels.

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Arnhem, Netherlands

Harry W M De Bruyn