Patent ID: 8140158

Claim:
An implantable heart monitoring system comprising: a housing configured for implantation in a subject; a vibrator configured for implantation in the subject and operable to emit a vibration signal from a first in vivo site into cardiac tissue exhibiting a tissue transfer function representing physical properties of the cardiac tissue in the subject; a vibration sensor configured for implantation at a second in vivo site in the subject, said vibration sensor configured to detect said vibration signal after said vibration signal has propagated through said tissue between said first in vivo site and said second in vivo site and is further configured to emit a detection signal that represents the detected vibrations; and a control circuit in said housing in communication with said vibrator and said vibration sensor, said control circuit being configured to execute a procedure comprising actuating said vibrator to emit said vibration signal and receiving said detection signal from said vibration sensor, and to derive based on the detected vibrations in relation to the vibration signal said tissue transfer function, and to derive from said tissue transfer function, information describing at least one medical property of the heart of the subject, selected from the group consisting of stiffness of a heart portion of the heart and a thickness of a portion of the heart.