Abstract: An implantable arrangement for operating a body-assist device, the body-assist device including circuitry for generating electrical signals and also being implanted in a patient, includes circuitry for controlling the generation of the electric signals, a measuring probe in the patient for obtaining signals to be used by the control circuitry, a single current conductor electrically connecting the control circuitry and the measuring probe and forming a first current path therebetween, and spaced electrodes connected to the measuring probe and the control circuitry disposed in the patient with body tissue therebetween such that a second current path is formed in the body tissue.

Abstract: A measuring instrument for the intracardial acquistion of the blood oxygen saturation of a patient for use in controlling a heart pacemaker implanted in the patient has a measuring probe with a measuring current path which includes a light transmitter and a light receiver which receives light emitted by the light transmitter and reflected by the blood. The measuring probe is connected to an evaluation circuit via two lines. A useful signal measurement and a reference measurement, independent of the blood reflection, are made and the blood oxygen saturation is identified by comparing the two signals. A separate evaluation of the useful signal measurement and the reference signal measurement is enabled by making the useful signal measurement chronologically offset with respect to the reference measurement in one embodiment, or by using the amplitude of the current from the light receiver to make one measurement, and using the voltage amplitude to make the other measurement in another embodiment.

Abstract: A process and a device for regulating the stimulation frequency of heart pacemakers are disclosed. The process comprises generating with the aid of light emitted by a light-emitting element, reflected by the blood of a patient, and received by a light-receiving element, a current flow which causes, in a measuring probe, an increasing of the current flow at a constant probe voltage or a damping of the probe voltage at constant current flow. Thereafter, one of the possible changing values is measured and the change, with time, is evaluated as a measured quantity proportional to the change, with time, of the blood oxygen saturation, and, as a function of the measured quantity, the stimulation frequency of the heart pacemaker is regulated in such a manner that the greatest possible blood oxygen saturation is always achieved with the lowest stimulation frequency.