Patent ID: 6263243
Filing Date: 2001-07-17
Classification: A61N

Abstract:
A rate-adaptive pacemaker comprising:an impedance measuring device for measuring a waveform over time of an intracardial impedance over at least a predetermined portion of one cardiac cycle;an impedance processing device for obtaining an impedance value from the waveform over time, the impedance processing device including:an integrator stage for determining a time integral of the impedance waveform over the predetermined portion of the cardiac cycle as a primary impedance value;an integral value memory coupled to the integrator stage for storing one reference integral value at a time, ascertained in at least one preceding cardiac cycle; andan arithmetic unit having inputs connected to outputs of the integrator stage and the integral value memory for calculating a secondary impedance value from the respective primary impedance value and from the reference integral value in accordance with a predetermined arithmetical equation; anda rate determining device, downstream of the impedance processing device and controlled by a sequence controller, for determining an adaptive stimulation rate on the basis of the secondary impedance value.