The workflow of angioplasty guidewire-assisted transseptal puncture. (A) The puncture assembly (Swartz sheath, dilator, BRK needle, and stiff tail of the angioplasty guidewire) is placed in the SVC. (B) The BRK needle hub is rotated to the 5- to 6-o’clock position, and the whole assembly is slowly pulled back. (C) The centre of the FO (the ideal puncture site) is identified when two small jumps have been felt as the tip drops over the SVC into the RA. (D) The stiff tail of the angioplasty guidewire (0.014″ Runthrough) is advanced through the needle to pierce the inter-atrial septum multiple times, thus creating a sieve mesh structure at the puncture point. The puncture needle is then delivered to the LA along the stiff tail of the angioplasty guidewire through the sieve mesh structure with little breakthrough resistance. (E) The septum is crossed by the needle, the Runthrough guidewire is retracted, and the other end of the guidewire (floppy tip) is advanced into the LA and LSPV through the needle. (F) The dilator is advanced into the LA along the Runthrough guidewire, which is then exchanged for a 0.035″ J-tipped guidewire (Amplatz Super Stiff). (G) The sheath is introduced into the LSPV along the 0.035″ J-tipped guidewire. (H) All toolkits are withdrawn except for the sheath. BRK, Brockenbrough; FO, fossa ovalis; LA, left atrium; LSPV, left superior pulmonary vein; RA, right atrium; SVC, superior vena cava.