Cardiac pacer connector system

Claim 1

A cardiac pacer incorporating a connector system usable with either a unipolar lead having a single distal electrode or a bipolar lead having both a distal electrode and a reference electrode, both types of lead incorporating at the proximal end thereof a generally cylindrical plug having an extending pin portion to which the distal electrode is electrically connected, the plug of the bipolar lead having an annular ring to which the reference electrode is electrically connected; said pacer comprising: pulse generator means including an output circuit having a first side and a second side; batteries for powering said pulse generator means; a casing for said batteries and said pulse generator means including at least one conductive case wall; a first clamping means for establishing an electrical connection to said pin extending from said plug, said first clamping means being connected to one side of said output circuit; a second clamping means for establishing an electrical connection to said annular ring on said plug; and selectively operable electrical bridging means having a first part connected to the other side of said output circuit, a second part connected to said case wall, and a third part connected to said clamping means whereby, in the absence of a reference electrode on said lead, said bridging means may be operated to connect said first part and said second part so that said case wall is employed as a reference potential for the distal electrode; and whereby, in the presence of a reference electrode on said lead, said bridging means may be operated to connect said first part and said third part so that said reference electrode is electrically connected to the other side of said output circuit.