Patent ID: 6498950
Filing Date: 2002-12-24
Classification: A61N

Abstract:
An implantable cardiac stimulation device configured for sensing an atrial event through a first electrode to receive electrical signals from atrial tissue of a patient's heart and for stimulating the ventricle of a patient's heart through a second electrode implanted in electrical contact with ventricular tissue of the patient's heart, the stimulation device comprising:a first detection circuit coupled to the first electrode and configured to receive cardiac signals for determining the presence or absence of an atrial event; a ventricular pulse generator electrically coupled to the second electrode and configured to generate ventricular stimulation pulses at a controlled energy level to thereby stimulate the ventricle of the patient's heart; a second detection circuit electrically coupled to the second electrode and configured to receive cardiac signals for determining the presence or absence of a ventricular event wherein the ventricular event alternatively includes an evoked response to each of the stimulation pulses or an intrinsic ventricular depolarization; a controller coupled to the pulse generator for increasing the ventricular stimulation pulse energy level in response to the absence of at least one evoked response to a ventricular stimulation pulse; and whereby the controller periodically causes the ventricular pulse generator to generate ventricular stimulation pulses a threshold detection delay period after an atrial event and whereby the threshold detection delay period is determined based upon a measured time between an atrial event and an intrinsic ventricular depolarization.