Fluid status detection from a cardiac electrical signal and impedance signal

A method performed by an implantable medical device, the method comprising:

• determining a plurality of impedance metrics from an impedance signal resulting from a drive signal applied to electrodes coupled to the medical device;
• determining a first plurality of amplitudes from a cardiac electrical signal received by a sensing circuit via electrodes coupled to the medical device;
• determining a first calibration relationship between the plurality of impedance metrics and the first plurality of amplitudes;
• determining a second plurality of amplitudes from the cardiac electrical signal;
• generating fluid status signal data by adjusting the second plurality of amplitudes according to the determined first calibration relationship;
• and
• transmitting the fluid status signal data to another medical device for generating a display of the fluid status signal data.

A non-transitory computer-readable medium storing a set of instructions which when executed by a control circuit of a medical device, cause the medical device to:

• determine a plurality of impedance metrics from an impedance signal resulting from a drive signal applied to electrodes coupled to the medical device;
• determine a first plurality of amplitudes from a cardiac electrical signal received by a sensing circuit via electrodes coupled to the medical device;
• determine a calibration relationship between the plurality of impedance metrics and the first plurality of amplitudes;
• determine a second plurality of amplitudes from the cardiac electrical signal;
• generate fluid status signal data by adjusting the second plurality of amplitudes according to the determined first calibration relationship;
• and
• transmit the fluid status signal data to another medical device for displaying the fluid status signal data.

A medical device, comprising:

• a telemetry circuit configured to receive fluid status data from another medical device, the fluid status data comprising a plurality of cardiac electrical signal amplitudes and a plurality of impedance metrics;
• and
• a control circuit coupled to the telemetry circuit and configured to:
• determine a calibration relationship between the plurality of impedance metrics and the plurality of cardiac signal amplitudes;
• adjust the plurality of cardiac electrical signal amplitudes according to the determined calibration relationship;
• and
• generate a fluid status signal comprising the adjusted cardiac electrical signal amplitudes;
• compare the fluid status signal to at least one threshold;
• determining a therapy adjustment command based on the comparison;
• and
• transmitting the therapy adjustment command to a therapy delivery device for delivering a therapy to a patient according to the therapy adjustment command.