Methods, devices, and systems for accessing and penetrating an anatomical structure using suction force and energy ablation or mechanical penetration. In one aspect, a catheter is stabilized on the occlusion, a longitudinal member is advanced to penetrate the occlusion and recanalize the body vessel. In another aspect, a catheter is stabilized on the pericardium, ablation energy is delivered through a longitudinal member to create an opening on the pericardium.
