Cardiac pacing device with mechanical mode switching

An implantable medical device (IMD) comprising:

• a subassembly comprising:
• a first housing, the first housing being elongated, substantially sealed, and electrically conductive;
• a feedthrough that extends through a distal end of the first housing, the feedthrough being electrically conductive;
• and
• electronic circuitry within the first housing, the electronic circuitry electrically coupled to the first housing and the feedthrough, wherein the electronic circuitry is configured to at least one of sense electrical signals of a patient or deliver electrical stimulation therapy to the patient via the first housing and the feedthrough;
• a device electrode that comprises at least a portion of the first housing or is electrically coupled to the first housing;
• and
• a second housing enclosing the subassembly and the device electrode, the second housing comprising a removable portion and a lead connector configured to connect to a proximal end of an implantable medical lead, the lead connector comprising first and second connector contacts,
• wherein the removable portion is configured to insulate the device electrode from at least one of a fluid or tissue at a target site in a patient by covering the device electrode when the removable portion is present, and
• wherein the removable portion is configured to enable conduction between the device electrode and the at least one of the fluid or the tissue at the target site in the patient by exposing the device electrode when the removable portion is removed.

An implantable medical device kit, comprising:

• an implantable medical device comprising:
• a subassembly comprising:
• a first housing, the first housing being elongated, substantially sealed, and electrically conductive;
• a feedthrough electrically coupled to the electronic circuitry and extending through a distal end of the first housing;
• electronic circuitry enclosed within and electrically coupled to the first housing, the electronic circuitry configured to at least one of generate an electrical stimulation therapy for delivery to a patient and monitor a physiological parameter of the patient;
• and
• a device electrode electrically coupled to the electronic circuitry;
• and
• a second housing enclosing the subassembly and the device electrode, the second housing comprising an opening adjacent the device electrode and comprising a lead connector configured to connect to a proximal end of an implantable medical lead, the lead connector comprising a first connector contact electrically coupled to the feedthrough and a second connector contact electrically coupled to the electronic circuitry;
• and
• a removable plug configured to be inserted into the opening of the second housing;
• wherein the removable plug is configured to insulate the device electrode from at least one of a fluid and tissue at a target site in a patient by covering the device electrode when the removable plug is inserted into the opening of the second housing, and
• wherein the removable plug is configured to enable conduction between the device electrode and the at least one of the fluid or tissue at the target site in the patient by exposing the device electrode when the removable plug is removed from the opening of the second housing.

A method for configuring an implantable medical device prior to implantation in a patient, comprising:

• making a pacing determination to provide one of bipolar pacing and unipolar pacing with an implantable medical device comprising:
• electronic circuitry configured to provide a bipolar pacing mode and a unipolar pacing mode;
• a first housing, the first housing being electrically conductive and electrically coupled to the electronic circuitry;
• a feedthrough electrically coupled to the electronic circuitry and extending through the first housing;
• a device electrode electrically coupled to the electronic circuitry;
• and
• a second housing enclosing the first housing, the feedthrough, and the device electrode, the second housing comprising:
• a first portion comprising an opening adjacent the device electrode;
• a removable portion;
• and
• a lead connector comprising a first connector contact electrically coupled to the feedthrough and a second connector contact electrically coupled to the electronic circuitry;
• selecting one of a bipolar implantable medical lead or a unipolar implantable medical lead based on the pacing determination;
• inserting a proximal end of the selected implantable medical lead into the lead connector;
• and
• configuring the removable portion of the second housing based on the pacing determination.