Abstract: A steerable three dimensional catheter to engage the ostium of a right coronary artery in a patient includes: a torque-transmitting proximal shaft that receives manipulation by a user outside a patient in whom the catheter is used; and a distal shaft that is responsive to torque transmitted by the proximal shaft. The distal shaft includes a preformed support section having at least a segment that abuts a posterior or left lateral interior surface of the ascending aorta of the patient. The distal shaft also includes a preformed ostium entry section extending from the support section. In one implementation, the ostium entry section transitions from the support segment abutting the aortic wall to a distal tip end by way of at least two differently directed angles.