| 摘要 |
PCT No. PCT/DE93/00888 Sec. 371 Date Mar. 17, 1995 Sec. 102(e) Date Mar. 17, 1995 PCT Filed Sep. 16, 1993 PCT Pub. No. WO94/06512 PCT Pub. Date Mar. 31, 1994A circuit for determining the impedance in a heart having a pacemaker electrode to which voltages are applied disposed in the ventricle chamber thereof. The circuit uses the pacemaker electrode. The circuit includes a current source operatively connected to the pacemaker electrode to apply current thereto, the current source having a current direction which can be switched. Switching circuitry is provided for switching the current direction of the current source. The voltage applied to the pacemaker electrode at different measuring times is measured with measuring circuitry. A value representative of the impedance in the heart is determined from a difference between the voltages applied to the pacemaker electrode at two of the different measuring times measured by the measuring circuitry. Currents having an identical magnitude but having opposite directions are applied to the pacemaker electrode by the current source which is switched by the switching circuitry at the two respective measuring times.
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