Apparatus for controlling pacing of a heart in response to changes in stroke volume

摘要

The apparatus is used for sensing opening and closing of a tricuspid valve in a heart, for using those sensings to determine stroke volume, and for controlling pacing of a heart relative to changes in stroke volume. The apparatus comprises a pacer, a pacing lead coupled to the pacer and having a lead body, a pressure sensor mounted in the lead body and a pacing electrode, circuit means in the pacer coupled to the sensor for sensing the opening of the tricuspid valve during each heart cycle and for sensing the closing of the tricuspid valve during each heart cycle; means for calculating ejection time from the openings and closings of the tricuspid valve; means for calculating the change in ejection time, &Dgr;ET, from calculations of ejection time; means for calculating changes in stroke volume, &Dgr;SV, means for determining the required change in heart rate, &Dgr;R, relative to the change in stroke volume, . DELTA.SV; and means for adjusting the pacing rate of said pacer relative to the required change in heart rate, &Dgr;R.