Cordis Corporation

Baxter Travenol Laboratories, Inc.

James P Martucci

Alan A Figler

Michael E Leckrone

Francisco J Barreras

Daniel J Grimm

Leonard F Goloski, Sr

A process is provided for detecting if a temperature sensor (18) is correctly located in a heating conduit at a point that is remote from the heater (28). Power is applied to the heater (28) in a predetermined manner. The change in the temperature sensed by the temperature sensor (18) is observed. If the temperature sensed by the temperature sensor (18) has changed in a certain manner, a signal is provided indicating that the temperature sensor (18) is located correctly. If, during observation, the temperature sensed has not changed in the certain manner, an alarm signal is provided.

Safety system for heating conduit

An implantable cardiac pacer having atrial and ventricular electrodes includes an input/output circuit which can be programmed for use with either unipolar or bipolar pacer leads. The circuit can be reprogrammed by the physician after implant to accommodate physiological changes in the patient or chronic changes in pacer lead characteristics, and can be utilized with single channel or dual channel cardiac pacers.

Cardiac pacer having input/output circuit programmable for use with

Atrial refractory and ventricular inhibit functions are independently implemented in an atrial-synchronized pacer. Spontaneous signals on the ventricular lead inhibit ventricular stimulation for a predetermined interval independent of the atria, except when there is noise on the ventricular lead. The atrial-based pacing logic establishes the usual refractory period following spontaneous P-waves, and when noise is detected on the atrial lead, the pacing logic reverts to a fixed atrial rate. The ventricular-inhibited logic includes a retriggerable noise timing circuit and a non-retriggerable inhibit timing circuit both triggered by the output of the ventricular sense amplifier. The output of the inhibit circuit disables the ventricular stimulation output circuit. However, if the output of the noise circuit stays high for an interval indicative of electromagnetic interference, the trigger input to the inhibit timing circuit is disabled to permit ventricular stimulation. Meanwhile, the pacing logic institutes fixed rate pacing due to atrial noise. In AV synchronous and atrial-synchronized AV sequential pacer embodiments, the digital pacing logic uses existing circuitry while the ventricular-inhibited logic is implemented by an add-on RC-timed circuit. In the AV sequential pacer, the AV delay circuit is separate from the pacing logic, and its input is provided by the atrial sense amplifier normally and by the output of the pacing logic during ventricular noise.

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Palatine, IL, United States of America

James P Martucci