Patent ID: 6745076
Filing Date: 2004-06-01
Classification: A61N

Abstract:
A cardiac pacing system having a pacing device and a lead for connecting patient cardiac signals to said pacing device, said device having at least one DSP channel having DSP means for amplifying and processing said cardiac signals, said DSP means further having sensitivity means for setting the sensitivity level for use in detection of a said cardiac signal, gain control means for adjusting the gain used in said amplifying, and event means for determining when a said cardiac signal is determined to be a valid cardiac event, further comprising:amplitude sample means for enabling said DSP means to amplify and process cardiac signals periodically at a first sampling interval in the range of 1 minute to 60 minutes; amplitude means for obtaining and storing signal amplitude data representative of the amplitude of sampled cardiac signals that have been amplified by said DSP means; noise sample means for enabling said DSP means to sample noise in said DSP channel following each sampled cardiac signal; noise means for obtaining and storing noise amplitude data representative of sampled noise in said DSP channel; and check means for comparing said stored signal amplitude data with said stored noise amplitude data periodically at a predetermined check interval greater than at least one hour and for adjusting said sensitivity level in accord with each said comparison.