Patent ID: 7308310
Filing Date: 2007-12-11
Classification: A61N

Abstract:
1. An implantable cardiac device that provides autocapture and lead impedance assessment comprising: a pulse generator that provides pacing stimulation pulses; a sensing circuit that senses cardiac activity; a lead system that provides a bipolar electrode configuration and a unipolar electrode configuration associated with a chamber of a heart; wherein the pulse generator and sensing circuit are operative to provide pacing therapy with the bipolar electrode configuration; a capture threshold assessment circuit that measures capture threshold and that couples the pulse generator and sensing circuit to the bipolar electrode configuration to provide bipolar pacing pulses and bipolar evoked response sensing; an impedance measuring circuit that measures impedance of the bipolar electrode configuration responsive to the assessment circuit measuring a capture threshold above a preset threshold value; a comparison circuit that determines if the impedance of the bipolar electrode configuration is within a given range; and an electrode configuration control that causes the pacing therapy provided by the pulse generator and the sensing circuit to be switched to the unipolar electrode configuration responsive to the impedance being outside the given range; wherein the capture threshold assessment circuit couples the pulse generator and sensing circuit to the unipolar electrode configuration to provide unipolar primary pulses, unipolar backup pulses, and unipolar evoked response sensing during pacing therapy.