Implanting a lead in the internal thoracic vasculature

A method of implanting a lead for a cardiac rhythm management device in a patient, the method comprising:

• screening the patient for at least one screening criteria including rib spacing, internal thoracic vein (ITV) location, and ITV diameter at one or more of the right or left second or third intercostal spaces, wherein screening includes at least measuring a diameter of the ITV;
• determining the patient meets at least a predetermined parameter for the screening criteria of the measured ITV diameter, wherein the predetermined parameter is a measurement of the patient's ITV diameter of at least 2 mm;
• marking at least one of rib margin or sternum margin on skin of the patient at the right or left second or third intercostal spaces to identify an ITV access location;
• making at least one incision at the ITV access location and dissecting to the ITV;
• inserting a micropuncture wire into the ITV;
• swapping the micropuncture wire for a guidewire having a diameter greater than a diameter of the micropuncture wire, and inserting a sheath into the ITV;
• forming a tunnel by subcutaneously or submuscularly tunneling between a pulse generator pocket location and the ITV access location;
• passing a first end of a lead into the tunnel and a second end of the lead into the sheath;
• removing the sheath to leave at least the second end of the lead in the ITV;
• and
• securing the first end of the lead to a pulse generator disposed within the pulse generator pocket.