RATE ADAPTIVE PACEMAKER

A rate-adaptive pacemaker includes an impedance measuring device for measuring a waveform over time of the intracardial impedance over at least a predetermined portion of one cardiac cycle. An impedance processing device obtains an impedance value from the waveform. A rate determining device is connected downstream of the impedance processing device, and controlled by a sequence controller, determines the adaptive stimulation rate (HR) using the impedance value. The impedance processing device has an integrator stage for determining the time integral of the impedance waveform over the predetermined portion of the cardiac cycle as the primary impedance value.