Medtronic, Inc.

Physio-control, Inc.

David J Jorgenson

John D Wahlstrand

Rick D McVenes

Bradley C Peck

Ross O Starkson

Charles D Trautmann

Robert Michael Ecker

Lawrence C McClure

Christopher M Manrodt

Charles H Malmskog

In general, the invention is directed to techniques for using an external defibrillator to detect a presence of an implantable medical device (IMD) implanted within a patient, and providing therapy to the patient through communication between the external defibrillator and the IMD. An external defibrillator provides prompts to a user of the external defibrillator to determine the presence of an IMD implanted within the patient. For example, the external defibrillator may prompt the user to visually inspect the patient's chest for signs that an IMD was implanted, such as a scar or raised portion of skin near the patient's clavicles. As another example, the external defibrillator may prompt the user to place a detection device on the patient's chest. The detection device may be coupled to the external defibrillator, and may employ a magnet to initiate telemetry by the IMD to detect the presence of the IMD.

Defibrillator with implantable medical device detection

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.

In an implantable medical device having an electrical lead coupled to tissue of a user and a circuit for measuring the impedance of the lead, a method and apparatus for responding to impedance variations in the lead which includes measuring the impedance of the lead while monitoring physiologic parameters of the user, detecting the presence or absence of electromagnetic interference, and if the impedance of the lead is out-of-range, determining whether the electromagnetic interference exceeds a predetermined value, and if the electromagnetic interference exceeds a predetermined value, administering a therapy to the tissue of the user.

Impedance measurement in implanted device

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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Bloomington, MN, United States of America

David J Jorgenson