Arrangement for controlling a pacemaker

Abstract

An arrangement is provided for controlling a stimulation frequency of a pacemaker. The arrangement includes an atrial bipolar electrode system and a ventricular bipolar electrode system. A first electrode pair comprises an electrode from each of the atrial and ventricular bipolar electrode systems, with the electrodes of the first electrode pair being disposed intracardially in the atrium and ventricle, respectively. A pacemaker control unit generates stimulation pulses for stimulating the heart. A constant current source impresses a constant current to a second electrode pair, comprising at least one electrode from one of the atrial and ventricular bipolar electrode systems being disposed intracardially in one of the atrium and ventricle, for developing an electrical potential between the electrodes of the first electrode pair during predetermined cardiac phases. An impedance measuring unit measures impedance between the electrodes of the first electrode pair based upon the electrical potential and constant current and generates a control signal representing relative cardiac volume as a function of the measured impedance. The control signal is fed to the pacemaker control unit for influencing a stimulation frequency of the stimulation pulses.

Dependencies are inferred from the claim text.