A rapid exchange catheter comprises a guide wire lumen including a substantially sealed portion in which a lumen wall extends around an entire periphery thereof and a channel portion including a channel opening the lumen to an exterior of the catheter, wherein a width of the channel is less than a maximum width of the channel portion. A guide wire ramp extends into the channel portion, with the ramp extending further into the lumen of the channel portion as a distal end of the ramp is approached.