A catheter is provided having a catheter body whose distal end has an anchoring device and a stabilizing device that are adapted to respectively sit in and sit outside of an opening of a tubular region, such as an ostium of a pulmonary vein. A sheath covering the catheter body forms the anchoring device and the stabilizing device. In particular, the anchoring device and/or the stabilizing device comprises a plurality of slits cut into the sheath where the slits create spines. In one embodiment, the sheath is fixed at its distal end to the distal end of the catheter body. The spines of the anchoring device and the stabilizing device are deployed into radial expansion by distal movement of the sheath relative to the catheter body. Upon radial expansion of the anchoring device, the spines of the anchoring device exert pressure against the walls of the tubular region thereby generally anchoring the distal end of the catheter body inside the tubular region against proximal and/or radial movement relative to the tubular region. Upon radial expansion of the spines of the stabilizing assembly, the spines of the stabilizing device exert pressure against the ostium of the tubular region thereby generally stabilizing the distal end of the catheter body against distal and/or radial movement relative to the tubular region. Accordingly, the pressure exerted on the walls of the tubular region by the anchoring device and on the ostium by the stabilizing device minimizes, if not prevents, the distal end of the catheter body against both translational and rotational movement. In particular, the pressure exerted on the ostium of the tubular region by the stabilizing device stabilizes the catheter within the heart for delivery of ablation energy to treat the desired area of the heart. Other embodiments of the catheter are also contemplated, such as those having a telescoping portion extending distally from the distal end of the catheter. As such, the anchoring and stabilizing devices a
