Pacemaker system with porous electrode and residual charge or after-potential reduction

摘要

PCT No. PCT/DE93/00887 Sec. 371 Date Mar. 17, 1995 Sec. 102(e) Date Mar. 17, 1995 PCT Filed Sep. 16, 1993 PCT Pub. No. WO94/06508 PCT Pub. Date Mar. 31, 1994A cardiac pacemaker system is provided which includes a stimulation electrode adapted for being anchored in the heart. An output capacitor is coupled to the stimulation electrode. A first circuit coupled to the output capacitor generates stimulation pulses. A second circuit coupled to the output capacitor generates an autoshort pulse following each stimulation pulse to reduce a residual charge of the output capacitor for eliminating an after potential following a stimulation pulse by the stimulation electrode. A third circuit coupled to the output capacitor acquires an evoked pulse of the heart from an electrical signal picked up by the stimulation electrode. The stimulation electrode includes a porous surface coating made of an inert material and has an active surface that is substantially larger than a surface of the basic geometric form of the stimulation electrode. The second circuit includes circuit means for changing the time duration of the autoshort pulses as a function of the acquisition of the evoked pulses, with the time duration of the autoshort pulses being limited to 70 ms.