Patent ID: 8821404

Claim:
A medical device comprising: a processor, including: a first data input, configured to receive time-varying sensed first physiological data x(t) from a first physiological sensor, the first physiological data x(t) corresponding to multiple instances over a first time window; and a second data input, configured to receive time-varying sensed second physiological data y(t) from a second physiological sensor, the second physiological data y(t) corresponding to multiple instances over the first time window; and a non-transitory processor-readable medium, including instructions that, when performed by the processor, configure the medical device to: form an at least two-dimensional function f(x, y) of the time-varying sensed first physiological data x(t) against the time-varying sensed second physiological data y(t), the function f(x, y) having a multivalued output; identify an at least two-dimensional boundary b(x, y) in the multivalued output of the function f(x, y), the boundary b(x, y) dividing the multivalued output into respective multiple data clusters including a first at least two-dimensional data cluster g(x, y) and a second at least two-dimensional data cluster h(x, y), the first and second data clusters separated by the boundary b(x, y); determine a quantitative attribute of at least one of the multiple data clusters; and use the quantitative attribute to provide a heart failure decompensation indicator.