A system to monitor heart sounds, such as to detect a worsening condition of heart failure decompensation. The system comprises a medical device that includes an implantable multi-axis heart sound sensor, operable to produce, for each of at least two nonparallel axes, an electrical signal representative...http://www.google.ca/patents/US20060270939?utm_source=gb-gplus-sharePatent US20060270939 - Systems and methods for multi-axis cardiac vibration measurements
