| 摘要 |
A dual chamber, rate-responsive pacemaker for pacing a patient's heart novel ly allows tracking of the patient's sinus rate when the sinus rate is slightly less than the sensor rate; i.e., within a predetermined "Sinus Preference Window Maximum Rate Drop". Pacing at the sensor rate occurs when the sensor rate exceeds the sinus rate by more than the Sinus Preference Window Maximum Rate Drop. In the preferred embodiment a Sinus Preference Window, which occu rs at the end of the ventricle-to-atrium interval, is decremented with successi ve heart beats by a programmable delta to increase the pacing rate until the Sinus Preference Window reaches zero, in which case the pacemaker paces at t he sensor rate. The Sinus Preference Window is reset to its maximum value upon either the detection of an atrial sensed event, or upon the expiration of a programmable Sinus Check Interval. The pacemaker paces at the sinus rate or the maximum rate drop rate, whichever is faster, for a number of recovery beats, and then increments the pacing rate up to the sensor rate.
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