Method for single pass large bore transseptal crossing

A method of accessing a left atrium, the method comprising the steps of:

• providing a single pass, large bore transseptal crossing system having:
• a tubular access cannula at least a portion of the tubular access cannula being electrically conductive;
• an energy delivery wire comprising an electrically conductive portion, the energy delivery wire configured to be movable through the tubular access cannula, and be independently energized relative to the tubular access cannula;
• a first tubular insulation layer surrounding a sidewall of the tubular access cannula that leaves a distal tip of the tubular cannula exposed, the distal tip comprising at least one distal projection;
• and
• a second insulation layer in between the energy delivery wire and the sidewall;
• positioning the at least one distal projection of the tubular access cannula in contact with a fossa ovalis;
• energizing the energy delivery wire to deliver energy from the energy delivery wire and to the fossa ovalis and to enable passage into the left atrium;
• after energizing the energy delivery wire, advancing the energy delivery wire through the fossa ovalis;
• after advancing the energy delivery wire, energizing the at least one distal projection of the tubular access cannula to deliver energy from the tubular access cannula to the fossa ovalis to enlarge a passage into the left atrium created by the energy delivery wire and to enable the tubular access cannula to advance into the left atrium;
• and
• after energizing the tubular access cannula, advancing a large bore sheath directly over the tubular access cannula and into the left atrium.