System and method for positioning implantable medical devices within coronary veins

A sheath apparatus for receiving a steerable catheter to position implantable medical devices within the coronary sinus or a branch vein thereof, wherein the sheath apparatus comprises a substantially straight slittable sheath extending from a proximal end to a distal end defining an inner lumen, wherein the slittable sheath comprises:

• a shaft section;
• a distal section distal to the shaft section at the distal end of the sheath, wherein the distal section comprises a soft tip extending from a transition location along the distal section to the distal end of the sheath;
• a slittable braid extending along the shaft section and at least a portion of the distal section, the slittable braid terminating at a distal end thereof approximately at the transition location, wherein the braid is formed of stainless steel, wherein the braid has an ultimate tensile strength of between approximately 200 and 250 kilo-pounds per square inch (ksi), and further wherein the braid has a pic count of between 35 and 55 pics per inch;
• an internal liner adjacent at least a portion of the inner lumen and extending along the shaft section and terminating within the distal section of the sheath beyond the distal end of the slittable braid.