Patent ID: 7203550

Claim:
A cardiac stimulating device comprising: a pulse generator for generating a stimulation pulse adapted to stimulate the heart of a subject; detection circuitry for determining a refractory period following stimulation of the heart; a housing, adapted for implantation in the subject, said housing containing said pulse generator circuitry and said detection circuitry, and having an exterior surface that is entirely electrically conductive; an electrode lead connected to said housing and carrying an electrode adapted for implantation in the heart and having a proximal portion with an electrically conductive surface thereon, said electrically conductive surface extending substantially from said housing to a location, after implantation, situated after entry of the electrode lead into the venous system and before entry of the electrode lead into the superior vena cava, said proximal portion having an exterior with an electrically conductive surface thereon; said pulse generator comprising current generating circuitry electrically connected to said electrode; a normally open switch in said housing connected between said current generating circuitry and said exterior surface of said housing; and a controller in said housing connected to said detection circuitry and to said switch for closing said switch only at a time encompassed by said refractory period to complete a circuit including said current generating circuitry, said exterior surface of said housing, said electrode and said electrically conductive surface at the exterior of said proximal portion of said electrode lead, for an infection control current generated by said current generating circuitry to counteract bacterial growth at least at said exterior surface of said housing.