Bilumen catheters and methods of using same for facilitating implantation of cardiac leads for applying electrical stimulation to and/or sensing electrical activity of the heart through one or more electrode positioned at an implantation site within a heart chamber or cardiac vessel adjacent a heart chamber, and more particularly to a method and apparatus for introducing such a cardiac lead having low torqueability and pushability through a tortuous pathway to enable attachment of the cardiac lead at the implantation site employing a bilumen guide catheter are disclosed. The bilumen catheter body includes a relatively large diameter delivery lumen to introduce a small diameter cardiac lead and a small diameter guide lumen to receive a stylet or guidewire to locate the guide catheter body distal end at the implantation site. The small diameter lumen within a small diameter guide tube extends distally from the delivery exit port of the delivery lumen.