| 摘要 |
An implantable medical device (IMD) coupled with leads extending to body tissue providing storage of lead related data, monitoring of lead functional status, and indication of lead integrity to the clinician. A lead status monitor (LSM) processes lead related data in a system self test mode and provides a lead status report that identifies and declares conductor/connector issues, insulation issues, and electrode/tissue interface issues indicative of suspected lead related condition mechanisms for each lead employed in the IMD. The LSM operates employing a set of LSM rules that process measured lead impedance values and loss of capture (LOC) values. In a pacing system, particular LSM rules are defined that process periodically determined, pacing pulse characteristic at LOC and bipolar and unipolar lead impedance values that are measured periodically. The lead impedance values are compared to upper and lower limits or trip points of a normal impedance range. Simultaneously, significant changes in lead impedance are detected, and the unipolar impedance value is compared to the bipolar lead impedance value of each lead. Counts of deviations in lead impedances satisfying each LSM rule are maintained. Certain of the lead related condition mechanisms are declared if a count of lead impedance deviations meets a programmed threshold number of such lead impedance deviations within a further programmed number of sequential impedance measurements. Preferably, the pacing pulse strength or voltage at LOC (characterized as LOC_RHEOBASE herein) is periodically determined and compared to a reference LOC_RHEOBASE.
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