Percutaneous transluminal coronary angioplasty (PTCA) of lesions in a right coronary artery with a "shepherd's crook" configuration may pose procedural difficulties due to inadequate guiding catheter back-up support. We evaluated the utility of a new shape of guiding catheter, previously evaluated for PTCA of lesions in the left coronary artery, in five cases with this particular right coronary artery anatomy. Factors responsible for success in these cases relate to the catheter's shape and construction.