Medtronic, Inc.

Medtronic, Ind.

Ross O Starkson

John D Wahlstrand

Rick D McVenes

Bradley C Peck

David J Jorgenson

Charles D Trautmann

H Toby Markowitz

Craig L Schmidt

Michael B Shelton

Michael W Heinks

Michael T Hemming

Kent E Samuelson

Denise Dirnberger

Lori Durose-Schrimpf

A system for monitoring trends in lead impedance includes collecting data from various sources in an implantable medical device system. Lead impedance, non-physiologic sensed events percentage of time in mode switch, results of capture management operation, sensed events, adversion pace counts, refractory sense counts and similar data are used to determine the status of a lead. A set of weighted sum rules are implemented by a software system to process the data and provide displayable information to health care professionals via a programmer. The lead monitoring system includes a patient alert system for patients to seek help in the event a serious lead condition is identified.

Implantable lead functional status monitor and method

An implantable medical device (IMD) includes a lead status monitoring system. The lead status monitoring system employs a method including the steps of: collecting data sets from a lead impedance source, a stimulation threshold source, and at least one additional source included in the IMD; and processing the data sets to determine if a lead status event has occurred.

A system and method for acquiring and processing an EGM signal during a pacing event, wherein a unique converter code is generated upon digitizing of the EGM signal and encrypted in the EGM signal to demarcate a transient event. The system further provides dynamic filtering of the EGM signal and subsequent detection of an intrinsic event signal during the pacing event, from which rhythm events may be diagnosed and classified.

EGM signal acquisition and processing system

A software system implemented in a medical device includes an allocation scheme for allocating storage of cardiac data. The software system enables storing cardiac data in a plurality of addressable locations. When all available locations within the plurality of addressable locations are full, a scratch location is assigned based on predetermined episode type priorities and characteristics. The priorities represent a graduated order based on the clinical significance of the cardiac episode under consideration. The characteristics provide classifications based on fastest rate, longest duration and last to occur care for each of the priorities.

Prioritized dynamic memory allocation of arrhythmia episode detail collection

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.

A pacemaker having a fault-tolerant elective replacement indicator (ERI) triggering scheme in which transient excursions of parameters used as criteria for triggering ERI are rejected as triggering events. Periodic assessments of certain indicia of battery depletion are made, and subjected to a long-term low-pass filtering operation in order to reduce the effects of transient excursions of the indicia which result from non-ERI conditions. Over a long period of time (e.g., a day) predetermined threshold values of the indicia of interest must be exceeded a predetermined number of times in order for the device to issue an ERI. In one disclosed embodiment of the invention, the battery's loaded terminal voltage and internal impedance are used as indicators of the battery's depletion level. Periodically, these values are measured and converted to digital values. The digital values are subjected to a low-pass filtering operation to prevent temporary or transient excursions of the impedance and voltage curves from causing ERI to be triggered. In another disclosed embodiment of the invention, a long term fading average of periodically measured values is maintained. When the measured values are found to fulfill the ERI criteria, assessment of the parameters of interest is performed at an increased rate. While assessments are performed at the increased rate, the continuously updated fading average value must fulfill the ERI triggering criteria at least a predetermined number of times before ERI is triggered. If the fading average fails to fulfill the ERI triggering criteria the required number of times, assessments are resumed at the first, slower periodic rate.

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Minneapolis, MN, United States of America

Ross O Starkson