Patent ID: 6052622
Filing Date: 2000-04-18
Classification: A61N

Abstract:
A heart stimulator comprising:a pulse generator which emits a series of stimulation pulses each having a pulse width and an amplitude, the respective pulse widths and amplitudes of said stimulation pulses being variable from stimulation pulse-to-stimulation pulse, and each stimulation pulse having a charge associated therewith;an electrode system connected to said pulse generator for delivering said stimulation pulses in vivo to a heart and for picking up a combined signal comprising a polarization signal and, if present, an evoked response following each of said stimulation pulses;measuring and memory means for measuring the charge associated with a stimulation pulse as said stimulation pulse is emitted and for storing, as a reference voltage, a charge voltage value related to said charge;monitoring means, connected to said electrode system, for deriving a monitoring voltage value from said combined signal;a comparator supplied with said monitoring voltage value and said charge voltage value for comparing said monitoring voltage value and said charge voltage value and for producing a comparison result indicating whether an evoked response is present in said combined signal; andcontrol means for controlling said pulse generator to vary at least one of said pulse width and said pulse amplitude dependent on said comparison result.