Patent ID: 7640058

Claim:
A heart stimulator comprising: a. at least one stimulation pulse generator being connected to or being connectable to a right ventricular stimulation electrode lead and a left ventricular electrode lead and being adapted to generate right ventricular stimulation pulses and left ventricular stimulation pulses, b. a control unit connected to the stimulation pulse generator and being adapted to trigger right ventricular stimulation pulses and left ventricular stimulation pulses, wherein: (1) a left ventricular stimulation pulse follows a right ventricular stimulation pulse after expiration of a positive interventricular delay interval (VVD) that is started with triggering of a right ventricular stimulation pulse, or (2) a right ventricular stimulation pulse following a left ventricular stimulation pulse after expiration of a negative interventricular delay interval (VVD) that is started with triggering of a left ventricular stimulation pulse, the interventricular delay interval being adjustable, c. an intracardiac impedance or conductivity measuring stage being connected to the control unit and being adapted to put out a time varying signal corresponding to the intracardiac impedance or conductivity, wherein the intracardiac impedance or conductivity measuring stage is adapted to generate a right ventricular impedance signal representing the right ventricular impedance or conductivity and a left ventricular impedance signal representing the left ventricular impedance or conductivity, wherein the control unit is adapted to (1) vary the interventricular delay interval, (2) determine a difference area between the right ventricular impedance signal and the left ventricular impedance signal for each interventricular delay interval duration, and (3) determine an optimized interventricular delay interval duration leading to a minimum of the difference area.