1. An implantable heart stimulator, comprising: at least one electrode or at least one connector for electrodes; at least one stimulation pulse generator connected to said at least one electrode or said at least one connector for intracardiac placement and configured to selectively generate a stimulation pulse for delivery to at least one ventricle of a heart; at least one sensing unit connected to said at least one electrode or said at least one connector for intracardiac placement and configured to process electric potentials that can be picked up by an intracardiac electrode in said at least one ventricle of said heart to thus acquire an intracardiac electrocardiogram or IEGM; at least one impedance measuring unit connected to said at least one electrode or said at least one connector for intracardiac placement and configured to determine a unipolar ventricular impedance or conductance signal having a magnitude corresponding to intracardiac impedance of conductivity of said at least one ventricle of said heart; a hemodynamic sensor configured to generate an output signal reflecting physical activity or hemodynamic need of a patient; a memory unit configured to store data; a telemetry unit configured for wireless transmission of data; a control unit connected to said at least one stimulation pulse generator, said at least one sensing unit, said at least one impedance measuring unit and said hemodynamic sensor, and configured to determine on a regular basis primary signals including ventricular unipolar intracardiac impedance values and physical activity values as represented by an output signal of said hemodynamic sensor; and, determine from said regular basis primary signals one or more values of systemic dynamics indices that include: Peak Systolic Dynamics, Resting Systolic Dynamics, Systolic Reserves, Systemic Control Power, Systemic Control Reserves, Cardiac Demand Balance; wherein said indices are determined from filtering said regular basis primary signals using a calculation which combines data from said regular basis primary signals and isolates a cardiac centric performance from systemic specific performance; and wherein said indices are configured to remove interfering and confounding factors using one or more of data selection, arithmetic correction, data filtering and normalization.