Trending of systolic murmur intensity and cardiac volume

摘要

Described is an implantable cardiac device, comprising:a pressure sensor (100) adapted for disposition so as to sense the acoustic vibrations produced by a systolic murmur and produce a pressure signal reflective thereof;circuitry (103) for measuring the intensity of the systolic murmur from the pressure signal produced by the pressure sensor (100);an impedance sensor (95) configured to measure transthoracic impedance reflective of cardiac volume;a controller (10) programmed to record a baseline murmur intensity; and,wherein the controller (10) 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.