| 摘要 |
A system for determining P-wave and R-wave capture in response to pacemaker supplied electrical stimuli. One embodiment includes a conventional bipolar atrial lead having a tip electrode, connected to a P-wave pace/sense amplifier and pulse output circuits within an implantable pacemaker, and a ring electrode, spaced apart from the tip electrode, connected to a P-wave sensing EGM amplifier within the pacemaker. The bandpass characteristics of the P-wave pace/sense amplifier allow detection of P-wave frequencies in the absence of atrial stimulation pulses. The bandpass characteristics of the P-wave sensing EGM amplifier allow detection of all electrical frequencies in the atrium within the bandpass chosen. Output signals from these two amplifiers are selectively telemetered to an external receiver, where the occurrence of atrial stimulation pulses and P-waves can be monitored. In operation, if constant time intervals between the monitored atrial stimulation pulses and P-wave occurrences are present, P-wave capture has occurred. In the event of variable time intervals, capture has not occurred and the magnitude of the atrial stimulation pulses can be increased until P-wave capture does occur. An alternative embodiment measures this time differential and makes the stimulation pulse adjustment automatically. Other embodiments use the same manual or automatic systems to determine R-wave capture.
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