A system for use with an implantable medical device for implant within a patient, the system comprising: a ventricular cardiogenic impedance measurement system operative to measure values representative of ventricular cardiogenic impedance; an E-wave parameter derivation system (707, 852) operative to generate an E-wave impedance template representative of passive filling of the ventricles based on ventricular cardiogenic impedance values measured during an initial period of non-demand pacing; measure additional values representative of ventricular impedance during a subsequent cardiac cycle to be examined; and determine a convolution of the E-wave impedance template with the additional ventricular impedance values to derive E-wave parameters representative of passive filling contributions to diastolic function within the subsequent cardiac cycle; an atrial cardiogenic impedance measurement system operative to measure values representative of atrial cardiogenic impedance; an A-wave parameter derivation system (709, 852) operative to generate an A-wave impedance template representative of active filling of the ventricles based on atrial cardiogenic impedance values measured during an initial period of non-demand pacing; measure additional values representative of atrial impedance during a subsequent cardiac cycle; and determine a convolution of the A-wave impedance template with the additional atrial impedance values to derive A-wave parameters representative of active filling contributions to diastolic function within the subsequent cardiac cycle; and a diastolic function assessment system (715, 850) operative to track passive filling contributions to diastolic function based on the E-wave parameters and track active filling contributions to diastolic function based on the A-wave parameters. a ventricular cardiogenic impedance measurement system operative to measure values representative of ventricular cardiogenic impedance; an E-wave parameter derivation system (707, 852) operative to generate an E-wave impedance template representative of passive filling of the ventricles based on ventricular cardiogenic impedance values measured during an initial period of non-demand pacing; measure additional values representative of ventricular impedance during a subsequent cardiac cycle to be examined; and determine a convolution of the E-wave impedance template with the additional ventricular impedance values to derive E-wave parameters representative of passive filling contributions to diastolic function within the subsequent cardiac cycle; an atrial cardiogenic impedance measurement system operative to measure values representative of atrial cardiogenic impedance; an A-wave parameter derivation system (709, 852) operative to generate an A-wave impedance template representative of active filling of the ventricles based on atrial cardiogenic impedance values measured during an initial period of non-demand pacing; measure additional values representative of atrial impedance during a subsequent cardiac cycle; and determine a convolution of the A-wave impedance template with the additional atrial impedance values to derive A-wave parameters representative of active filling contributions to diastolic function within the subsequent cardiac cycle; and a diastolic function assessment system (715, 850) operative to track passive filling contributions to diastolic function based on the E-wave parameters and track active filling contributions to diastolic function based on the A-wave parameters.