Multi-channel blind system identification for cardiovascular monitoring

A method for evaluating cardiac performance in a body of a subject having a circulatory system, the method comprising:

• (a) measuring outputs of a plurality of sensors, each sensor deployed at a site of the circulatory system of the subject and providing a signal constituting a channel, each channel having an output;
• (b) collecting a plurality of channel outputs from the plurality of channels at specified instants of time;
• (c) identifying distinct dynamics from an impulse response and transfer function for each channel based at least in part upon the plurality of channel outputs;
• (d) identifying an intermediate input by deconvolution based on the plurality of channel outputs and the distinct dynamics of the impulse response and transfer function for each channel;
• (e) identifying common dynamics of the plurality of channels based at least in part upon the intermediate input;
• and
• (f) identifying a system input by deconvolution based on the common dynamics.

A computer program product for use on a computer system for estimating a system input from a plurality of system outputs, the computer readable program code including:

• (a) module for collecting signals from a plurality of sensors at specified instants of time, the signals corresponding to a measured set of system outputs, each signal constituting a channel;
• (b) program code for expressing the signals in terms of a finite set of auto-regression parameters by recursive solution of an estimation model for auto-correlation functions, and thereby estimating an impulse response and transfer function for each channel;
• (c) program code for estimating an input by deconvolution based on the estimated impulse response and the signals from the plurality of sensors;
• and
• (d) a routine for updating the input by continued collection of signals from the plurality of sensors and continued execution of the program code in steps (b) and (c) that utilize new signals and disregard earlier signals.

A computer program product for use on a computer system for identifying a system input from a plurality of system outputs, the computer readable program code including:

• (a) module for collecting signals from a plurality of sensors at specified instants of time, the signals corresponding to a measured set of system outputs, each signal constituting a channel;
• (b) program code for identifying distinct dynamics from an impulse response and transfer function for each channel based at least in part upon the signals from the plurality of sensors;
• (c) program code for identifying an intermediate input by deconvolution based on the identified distinct dynamics and the signals from the plurality of sensors;
• (d) program code for identifying common dynamics of the plurality of channels based at least in part upon the identified intermediate input;
• and
• (e) program code for identifying a system input by deconvolution using the identified common dynamics.