An elongated catheter includes a tissue-engaging device configured to be urged to move and contact a first surface of the first biological wall. The tissue-engaging device extends from the distal catheter section. The tissue-engaging device is configured to be urged to puncture through the first biological wall. The tissue-engaging device is also configured to be urged to contact the first biological wall without impinging the second biological wall, after the tissue-engaging device has punctured through the first biological wall.