Patent ID: 7130690

Claim:
In a pacing system adapted to be implanted in a patient's body to provide atrial pacing at an atrial pacing rate exceeding a slow intrinsic atrial heart rate insufficient to provide adequate cardiac output comprising an implantable pulse generator, an atrial lead extending from the implantable pulse generator having at least one active atrial pace/sense electrode adapted to be disposed in operative relation to an atrial heart chamber, and an indifferent atrial pace/sense electrode adapted to be implanted in the patient's body, the implantable pulse generator further comprising: atrial pace pulse generator means coupled to the active and indifferent atrial pace sense electrodes for delivering an atrial pace (A-PACE) pulse having an A-PACE pulse width and an A-PACE pulse amplitude to the atrial heart chamber; atrial sensing means coupled to the active and indifferent atrial pace/sense electrodes for sensing intrinsic atrial depolarizations and declaring an A-EVENT; A-A escape interval timing means for timing out an A-A escape interval following generation of an A-PACE pulse by said atrial pulse generator means and following an A-EVENT declared by the atrial sensing means; and means for triggering said atrial pulse generator means to generate an A-PACE pulse at the expiration of the A-A escape interval whereby the atrial heart chamber is paced in the absence of an A-EVENT declared during the A-A escape interval, an atrial capture management (ACM) method for periodically determining an A-PACE pulse energy sufficient to reliably capture the atrium without being wasteful of battery energy from a test A-PACE pulse energy at atrial loss of capture (ALOC) further comprising: defining an ACM test window exceeding a prevailing A-A escape interval and correlated to the slow intrinsic atrial heart rate; setting the A-PACE pulse energy of a test A-PACE pulse; triggering the atrial pace pulse generator means to deliver at least one test A-PACE pulse at the test A-PACE pulse energy during the ACM test window; timing out the ACM test window; declaring ALOC by the delivered test A-PACE pulse at the test A-PACE pulse energy if an A-EVENT is declared during the time-out of an ACM test window; declaring atrial capture by the delivered test A-PACE pulse at the test A-PACE pulse energy in the absence of an A-EVENT declared during the ACM test window; and setting the prevailing A-PACE pulse energy as a function of the test A-PACE pulse energy at ALOC.