Patent ID: 7963926
Filing Date: 2011-06-21
Classification: A61B,A61N

Abstract:
1. An implantable cardiac device, comprising: a pressure sensor adapted for disposition so as to sense the acoustic vibrations produced by a systolic murmur and produce a pressure signal reflective thereof; circuitry for measuring the intensity of the systolic murmur from the pressure signal produced by the pressure sensor; an impedance sensor configured to measure transthoracic impedance reflective of cardiac volume; a controller programmed to record a baseline murmur intensity; and, wherein the controller is further programmed to measure a current murmur intensity as an average of intensity measurements taken over some period of time, compare the current murmur intensity to the baseline murmur intensity, and detect a change indicative of worsening cardiac status if the current murmur intensity exceeds the baseline murmur intensity by a first specified threshold amount and if the transthoracic impedance measurement indicates an increase in cardiac volume above a second specified threshold amount.