A method including sensing local accelerations or changes in sensor position, including orientation and displacement, with a local acceleration sensor mounted on a chest or abdomen of a patient, and calculating energy of polyphasic motions, based on sensed information of the local acceleration sensor and classifying severity of cardiac decompensation by calculating an excessive energy index (EEi) that compares excessive energy that appears in the polyphasic motions to energy required for inspiration at a basic respiratory rate.
