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A R Livingston

Publications and source records attributed to A R Livingston.

3 recordsLinked to original sources
PubMed1988

Atrial capture detection with endocardial electrodes.

A new method of evoked response detection, previously demonstrated in the ventricle, has been studied in the atrium at the time of routine pacemaker implant in 16 patients. The atrial evoked response was readily detectable in all patients due to excellent recovery from poststimulus polarization. In six patients, as experimental threshold-tracking pacemaker was used to automatically verify atrial capture and to generate strength-duration curves. It is concluded that this pacing technique is both simple and reliable, and that automatic atrial threshold tracking is feasible.

Atrial Function↗
PubMed1987

Functional mechanisms of polymer-based in vivo reference electrodes.

We describe a reference electrode catheter based upon a haemocompatible porous liquid junction of poly(2-hydroxyethyl methacrylate) (pHEMA). The diffusion properties of pHEMA rapidly reach a steady state in a variety of physiological environments. To elucidate the functional mechanisms, the transport of ions through pHEMA membranes was studied in electrolyte solutions, plasma solutions and whole blood. Plasma was shown to enhance ion transport by approximately 10% whereas blood decreased transport rates by 40%. The stability of the reference electrode catheter remained within 1 mV over an 8 h period. The mechanisms of stability lie in those material properties of pHEMA which control diffusion, limit protein adsorption and respond to changes in pH, properties which may result in micromechanical fluctuations and subsequent renewal of the polymer/blood interface.

Biocompatible Materials↗