摘要 |
An implantable, rate responsive pacemaker, sensitive to impedance changes in the heart, wherein the cardiac pacing rate and maximum cardiac pacing rate, or either of them, are adjusted as a function of an interval between either the administration of a pacing pulse or the detection of the R-wave and the occurrence of a maximum detected impedance, called the intercept interval. Because an intercept point in derivative of the impedance curve is detected, the apparatus and method are insensitive to electrode characteristics, electrode movement, body posture or other factors which could affect the magnitude of the detected impedance. The information contained in the intercept interval can also be combined with other sensed or calculated information to set the desired rates.
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