Automatic electrode configuration of an implantable pacemaker

In an implantable pacemaker, a system for ensuring operation of the implantable pacemaker despite incorrect programming or broken conductors, the implantable pacemaker being capable of programing an electrode configuration for delivery of stimulation pulses and for sensing intracardiac signals, the system comprising:

• a first and second pair of electrode terminals;
• a pair of electrodes adapted for contact with body tissue, the pair of electrodes being coupled to at least one pair of electrode terminals;
• measuring means for providing an impedance measurement between the first pair of electrodes terminals;
• means for determining whether the impedance measurement is within a preselected range;
• a first switching means, responsive to the determining means, for switching the measuring means to the second pair of electrode terminals when the impedance measurement of the first pair of electrode terminals is determined to be outside of the preselected range;
• means for initiating the impedance measuring means to provide an impedance measurement between the second pair of electrode terminals;
• and
• programming means for changing a programmed electrode configuration of the pacemaker to the pair of electrode terminals which is determined to have an impedance measurement within the preselected range.

An implantable pacemaker system having the capability of programmably operating in single chamber or dual chamber modes and in a unipolar or bipolar electrode configuration, the implantable pacemaker system including an implantable pacemaker coupled to implantable pacemaker leads, the system comprising:

• a stimulation and sense stage for generating stimulating signals and for sensing heart activity;
• a configuration switch for coupling the stimulation and sense stage to the implantable pacemaker leads in accordance with a selected electrode configuration;
• a microprocessor for controlling the stimulation and sense stage and the configuration switch;
• means for programming the microprocessor to operate in a selected mode and electrode configuration of the pacemaker;
• lead impedance measurement means for measuring a lead impedance of the implantable pacemaker leads in the selected electrode configuration;
• and
• means for triggering the programming means to change the selected electrode configuration when the measured lead impedance of the implantable pacemaker leads is above a selected reference.

A system for ensuring operation of the implantable pacemaker despite incorrect programming or broken conductors, the system comprising:

• an implantable lead having a selected one of a tip electrode or a tip and a ring electrode, the tip electrode or the ring electrode being adapted for contact with body tissue, each electrode having a conductor with an impedance associated therewith;
• a pulse generator, coupled to the implantable lead, for generating stimulation pulses;
• sensing means, coupled to the implantable lead, for sensing intracardiac signals;
• a pacemaker case for housing the pulse generator and the sensing means, the pacemaker case acting as a case electrode;
• means for programming an electrode configuration for the pulse generator means and for the sensing means;
• switching means, responsive to the programming means, for switchably connecting a pair of electrodes to the pulse generator and the sensing means;
• means for detecting an operative electrode configuration by detecting a stimulation impedance within a prescribed range, the stimulation impedance being the combined impedance of the pair of electrodes with the corresponding conductors and the body tissue impedance which results from a stimulation pulse delivered to body tissue;
• and
• means for automatically reprogramming the pacemaker's electrode configuration to the operative electrode configuration detected by the detection means.

A system for ensuring operation of the implantable pacemaker despite incorrect programming or broken conductors, the system comprising:

• an implantable lead having a selected one of a tip electrode or a tip and a ring electrode, the tip electrode or the ring electrode being adapted for contact with body tissue, each electrode having a conductor with an impedance associated therewith;
• a pulse generator, coupled to the implantable lead, for generating stimulation pulses;
• sensing means, coupled to the implantable lead, for sensing intracardiac signals;
• a pacemaker case for housing the pulse generator and the sensing means, the pacemaker case acting as a case electrode;
• means for programming an electrode configuration for the pulse generator means and for the sensing means;
• switching means, responsive to the programming means, for switchably connecting a pair of electrodes to the pulse generator and the sensing means, the selected from the group of pairs of electrodes comprising a tip and ring electrode, a tip and case electrode, and a ring and case electrode;
• means for detecting an operative electrode configuration by detecting an impedance within a prescribed range;
• and
• means for automatically reprogramming the pacemaker's electrode configuration to the operative electrode configuration detected by the detection means.