Patent ID: 6658295
Filing Date: 2003-12-02
Classification: A61N

Abstract:
An implantable cardiac stimulation device for stimulating a patient's heart through a first electrode adapted for electrical contact with an atrium of the patient's heart, the implantable cardiac stimulation device comprising:a pulse generator adapted to be electrically coupled to the first electrode and configured to generate atrial stimulation pulses at a programmed amplitude level and rate for stimulating the patient's heart; an atrial detection circuit, adapted to be electrically coupled to the first electrode, configured to detect a presence or an absence of an evoked response to a stimulation pulse from the pulse generator, wherein the detected absence of an evoked response indicates a potential occurrence of a fusion beat; and a controller, coupled to the pulse generator and the atrial detection circuit, configured to determine a capture threshold level in response to the absence of an evoked response, wherein the controller causes the pulse generator to deliver a first atrial stimulation pulse at a first amplitude level and a second atrial stimulation pulse at a second amplitude level an atrial delay time after the first atrial stimulation pulse, whereby the second atrial stimulation pulse minimizes a potential occurrence of subsequent fusion beats by prolonging atrial refractoriness.