This document describes, among other things, systems, devices, and methods that use frequency domain analysis of a thoracic signal. One example uses frequency domain analysis for discriminating between different pulmonary physiological states. Examples of breathing states include normal breathing, periodic...http://www.google.de/patents/US20050004609?utm_source=gb-gplus-sharePatent US20050004609 - Implantable devices and methods using frequency-domain analysis of thoracic signal
