In an implantable cardioverter-defibrillator and/or pacemaker, each having
DDD pacing capabilities, an improved method of operation is described
which dramatically increases the longevity of the implanted device by
conserving battery power. The method comprises deactivating at least one
unnecessary, power-consuming feature of the device until such feature is
needed and then reactivating said feature only for so long as it is
required by the patient. In a particular embodiment, the atrial sense
amplifier is deactivated during normal operation of the implantable
device, resulting in single-chamber sensing and pacing. Upon the
occurrence of a predefined event, indicative of a need for dual-chamber
sensing and pacing, the atrial sense amplifier is reactivated, the need
for DDD pacing confirmed, and if appropriate, DDD pacing is begun. Once
the patient's heart rate has returned to an acceptable level, the atrial
sense amplifier is again deactivated and single-chamber sensing/pacing
continued. In addition, the atrial sense amplifier of an ICD/pacemaker is
deactivated during normal operation of the device and reactivated
immediately following the detection of ventricular tachycardia. In this
embodiment, DDD sensing/pacing is preferably automatically begun following
this detection. Also contemplated herein, are improved devices employing
the improved methods.
