Patent ID: 8211034

Claim:
A system comprising: an implantable heart sound sensor circuit configured to produce an electrical heart sound signal representative of a heart sound of a subject; a second implantable sensor circuit configured to produce a second electrical sensor signal related to one or more physiologic cardiovascular events in the subject; a processor circuit coupled to the heart sound sensor circuit and the second sensor circuit, wherein the processor circuit includes: a heart sound feature circuit configured to identify a heart sound feature in the electrical heart sound signal in an absence of a physiologic perturbation; a detection circuit configured to detect the physiologic perturbation using the second electrical sensor signal, wherein the heart sound feature circuit is configured to identify the heart sound feature in the electrical heart sound signal in relation to the presence of the detected physiologic perturbation; and a trending circuit configured to trend a change in a difference between the heart sound feature in the presence of the physiologic perturbation and in the absence of the physiologic perturbation, and wherein the processor circuit is configured to declare a change in a physiologic condition of the patient according to the trend and provide an indication of the change to a user or process.