Author
   Guardo R. Trudelle S. Adler A. Boulay C. Savard P.
Institution
   Dept. de Genie Biomed., Ecole Polytech. de Montreal, Que., Canada.
Title
   Contactless recording of cardiac related thoracic conductivity changes.
Source
   1995 IEEE Engineering in Medicine and Biology 17th Annual Conference and
   21 Canadian Medical and Biological Engineering Conference (Cat.
   No.95CH35746). IEEE. Part vol.2, 1997, pp.1581-2 vol.2. New York, NY, USA.
Conference Information
   Proceedings of 17th International Conference of the Engineering in
   Medicine and Biology Society. Montreal, Que., Canada. 20-23 Sept. 1995.
Abstract
   Cardiac related changes in the electrical conductivity distribution of the
   thorax were recorded in real-time with an electromagnetic sensor
   consisting of a 3.5 cm radius coil, a 4 MHz oscillator and an active RF
   voltmeter. Operation of the sensor is based on measuring changes in the
   amplitude of a marginal RF oscillator, caused by eddy current losses in
   the heart region. Signals recorded from 6 normal subjects in multiple
   sessions (1 hour to 1 month) showed good repeatability. The average SNR
   for signals recorded with the coil placed over the sternum was 34 dB. A
   possible application of this type of sensor is for non-invasive continuous
   assessment of left ventricular ejection fraction.