Telectronics Pacing Systems, Inc.

Robert A Morris

Bruce M Steinhaus

James A Nolan

Tibor A Nappholz

Ken Koestner

Kent E Samuelson

A time domain reflectometry (TDR) impedance sensor is provided for measuring body impedance along a lead or catheter implanted in a patient's cardiovascular system. The TDR sensor applies an electrical stimulus to the lead and measures reflections echoed from impedance variations along and distal to the lead, which are superimposed on the applied stimulus. The measured signals may be analyzed with respect to time-of-flight and distance along the lead to detect a plurality of physiologically meaningful signals.

Time domain reflectometer impedance sensor method of use and implantable

A rate-responsive pacemaker employing a rate control parameter of respiratory minute volume, derived over a unipolar lead. The pacemaker performs the minute volume measurement by periodically applying a measuring current between the lead and a reference point on the pacemaker case. This measuring current has frequency components in a range from approximately 10 kilohertz to 1000 megahertz. Application of this measuring current allows the pacemaker to detect the voltage which arises from the applied current and, from the detected voltage, to measure the patient's spatial impedance. Spatial impedance and minute volume vary as a function of the patient's pleural pressure. The pacemaker derives minute volume and rate-responsive pacing rate from the spatial impedance measurement.

Minute volume rate-responsive pacemaker employing impedance sensing on a

A metabolic demand rate-responsive cardiac stimulation apparatus and method are disclosed which employ multiple physiological rate control parameters, such as respiratory minute volume, patient motion and cardiac stroke volume. The parameters are derived using a single standard pacing lead or transducer. The apparatus and method perform each physiological measurement by periodically applying a measuring current between two points within the apparatus. This measuring current has frequency components in a range of from approximately 10 kilohertz to 1000 megahertz. Application of this measuring current allows the apparatus to detect the voltage which arises from the applied current and, from the detected voltage, to measure the patient's spatial impedance. For a particular measurement, the apparatus controls which physiological parameter is sensed by regulating the frequency content of the measuring current. The apparatus analyzes the physiological parameters to determine the best pacing rate in terms of characteristics such as response time and stability.

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Palmer Lake, CO, United States of America

Robert A Morris