Transseptal needle
Methods and apparatus are disclosed for a needle comprising a distal shaft and a proximal shaft joined at a junction, the needle having a distal tip which includes an electrode for delivering energy to puncture a tissue, wherein the distal shaft is comprised of a superelastic material. In typical embodiments, the needle includes a lumen for delivering and withdrawing fluids from a treatment site. In some embodiments the junction is comprised of a superelastic material.
1. A needle comprising a tubular distal shaft and a tubular proximal shaft joined at a junction to prevent movement of the tubular distal shaft and the tubular proximal shaft relative to each other, the tubular distal shaft and the tubular proximal shaft defining a lumen, the tubular distal shaft having an open distal end, the tubular distal shaft of the needle having a distal tip which includes an electrode for delivering energy to puncture a tissue, the electrode occluding the open distal end of the tubular distal shaft, wherein the tubular distal shaft is comprised of a superelastic material and the tubular proximal shaft is comprised of a non-superelastic material for providing columnar strength for pushability to enable advancement of the needle through a puncture in the tissue, wherein the junction comprises a proximal end portion of the tubular distal shaft overlapping with and being inside of a distal portion of the tubular proximal shaft to form an overlap.
2. The needle of claim 1 , wherein the tubular proximal shaft is comprised of stainless steel or titanium.
3. The needle of claim 1 , wherein the tubular distal shaft is comprised of a nickel-titanium alloy or a titanium-niobium-tin (TiNbSn) alloy.
4. The needle of claim 1 , wherein the tubular proximal shaft is comprised of stainless steel having a modulus of elasticity of about 180 to 200 GPa, and the tubular distal shaft is comprised of a nickel-titanium alloy having a modulus of elasticity of about 40 to 75 GPa.
5. The needle of claim 1 , further including an electrical insulator on an external surface of the tubular proximal shaft and the tubular distal shaft, leaving the electrode electrically exposed.
6. The needle of claim 1 , wherein the tubular distal shaft defines a side-port in fluid communication with the lumen, whereby the needle is operable for delivering fluid, withdrawing fluid, and monitoring pressure.
7. The needle of claim 1 , wherein the electrode comprises an external component which is operatively coupled to the distal tip of the tubular distal shaft.
8. The needle of claim 1 , wherein the electrode comprises a metal plug which is located in the open distal end of the tubular distal shaft.
9. The needle of claim 1 , wherein the junction comprises an interlocking joint.
10. The needle of claim 1 , further comprising a spiral cut in the tubular distal shaft for increasing a flexibility of the tubular distal shaft.
11. The needle of claim 10 , further comprising a support wire extending proximally from a distal end of the needle to at least within the lumen of the tubular distal shaft.
12. The needle of claim 1 , wherein the tubular proximal shaft and the tubular distal shaft have an end-to-end tube configuration.
13. The needle of claim 1 , wherein the tubular distal shaft is comprised of both the superelastic material and the non-superelastic material.
14. The needle of claim 13 , wherein the tubular distal shaft is comprised of an inner layer and an outer layer, wherein one of the inner layer or the outer layer is comprised of the superelastic material and the other of the inner layer or the outer layer is comprised of the non-superelastic material.
15. The needle of claim 1 , wherein the electrode is comprised of a superelastic material.
16. The needle of claim 1 , wherein the electrode is comprised of a non-superelastic material and is mechanically coupled to the tubular distal shaft.
17. The needle of claim 1 , wherein the tubular proximal shaft and the tubular distal shaft are joined by at least one of welding, soldering, friction fitting and a use of adhesives.
18. A needle comprising a tubular distal shaft and a tubular proximal shaft joined at a junction to prevent movement of the tubular distal shaft and the tubular proximal shaft relative to each other, the tubular distal shaft and the tubular proximal shaft defining a lumen, the tubular distal shaft of the needle having a distal tip which includes an electrode for delivering energy to puncture a tissue, the tubular distal shaft comprising a closed-ended tube having a closed distal end, the closed distal end is operable to function as an electrode, wherein the tubular distal shaft is comprised of a superelastic material and the tubular proximal shaft is comprised of a non-superelastic material for providing columnar strength for pushability to enable advancement of the needle through a puncture in the tissue, wherein the junction comprises a proximal end portion of the tubular distal shaft overlapping with and being inside of a distal portion of the tubular proximal shaft to form an overlap.
19. The needle of claim 18 , wherein the tubular distal shaft is a closed-ended hypotube.