摘要 |
A rate responsive pacemaker is provided having the capability of automatically adjusting the lower rate limit (LRL) for sleep, or nighttime. The pacemaker has a temperature sensor for determining patient blood temperature, and processes patient blood temperature data to obtain an average daily low value of nighttime blood temperature. The pacemaker monitors blood temperature to determine a drop below a threshold which is coupled to the average daily low value, as well as when the rate of temperature change exceeds a predetermined limit, these two coincident conditions suggesting onset of nighttime and/or sleep. Lower rate limit is decremented, preferably by a predetermined amount at onset of nighttime, and is automatically incremented when patient blood temperature and/or time of day indicate the end of nighttime.
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