A system for heart performance characterization receives an electrical signal indicating heart electrical activity of a patient over a heart beat cycle. The electrical signal is acquired at a particular anatomical location. A gating signal generator generates a gating signal for use in identifying a particular portion of the heart beat cycle. An acquisition device, responsive to the gating signal, derives first and second voltage potentials from the received electrical signal. The first voltage potential comprises a voltage potential derived over a time period comprising a heart beat cycle and the second voltage potential comprises a voltage potential derived over a time period comprising a particular portion of the heart beat cycle. A computation processor derives a dynamic impedance representative value by adjusting a baseline impedance value by a ratio of the first and second voltage potentials. The dynamic impedance represents an average impedance at the particular anatomical location over a time period comprising the particular portion of the heart beat cycle.
