Abstract: Various methods and devices are provided for cutting an opening through tissue. In one embodiment, a tissue-penetrating device is provided and includes a flexible elongate needle shaft that has a distal end with a circumferentially extending tissue-cutting edge formed thereon. A proximal end of the elongate needle shaft interfaces with a rotary control member for selectively applying a rotary motion to the elongate needle shaft. When the rotating tissue-cutting edge is brought into contact with target tissue, the tissue-cutting edge cuts an opening through the tissue. The device may have a stylet that has a blunt end that can be adjusted to protrude out of the distal end of the elongate needle shaft out beyond the tissue-cutting edge and is biased inward into the elongate needle shaft when the blunt end is brought into contact with the tissue to expose the tissue-cutting edge to the tissue. The stylet may be used as a guide wire after the hole has been cut through the tissue.