Patent ID: 7330759

Claim:
A cardiac pacemaker comprising a stimulation pulse generator (RVP; LVP) adapted for biventricular stimulation of a heart, which is to be connected to at least one right-ventricular electrode adapted for the stimulation of a right ventricle of the heart and to at least one left-ventricular electrode adapted for the stimulation of a left ventricle of the heart and is connected to a control unit and is adapted to trigger right-ventricular and left-ventricular stimulation pulses with an interventricular delay time which is adjustable by means of the control unit, wherein the control unit is connected to an impedance detection unit which is adapted to be connected to a plurality of intercardiac electrodes and is adapted to form from an input signal formed by the impedance detection unit and dependent on an intracardiac impedance, an output signal indicating an optimum biventricular stimulation mode, wherein the control unit is adapted to adjust the interventricular delay time at which a second derivative of the pattern of the intracardiac impedance during a cardiac cycle is at the greatest.