Apparatus and method for transseptal puncture based on impedance

A method of transseptal puncture, comprising:

• positioning a guiding instrument near a septum with an atraumatic needle instrument slidably disposed in a lumen of the guiding instrument, the atraumatic needle instrument including a distal electrode and a proximal electrode;
• deploying the atraumatic needle instrument from the lumen with distal advancement relative to the guiding instrument;
• measuring a first distal impedance at the distal electrode to detect a first distal decrease indicative of the distal electrode being in contact with blood;
• measuring a second distal impedance at the distal electrode to detect a first distal increase indicative of the distal electrode being in contact with the septum;
• energizing the distal electrode to ablate the septum;
• measuring a third distal impedance at the distal electrode when the energization of the distal electrode begins;
• measuring a first proximal impedance at the proximal electrode to detect a first proximal increase indicative of the proximal electrode being in contact with the septum;
• after detecting the first proximal increase, measuring a second proximal impedance at the proximal electrode to detect a first proximal decrease indicative of the proximal electrode being in contact with blood;
• and
• suspending energization of the distal electrode upon detection of the first proximal decrease.

A method of transseptal puncture, comprising:

• positioning a guiding instrument near a septum with an atraumatic needle instrument slidably disposed in a lumen of the guiding instrument, the atraumatic needle instrument including a distal electrode and a proximal electrode;
• providing a predetermined threshold impedance;
• deploying the atraumatic needle instrument from the lumen with distal advancement relative to the guiding instrument;
• measuring a first distal impedance at the distal electrode to detect a first distal decrease relative to the predetermined threshold impedance indicative of the distal electrode being in contact with blood;
• measuring a second distal impedance at the distal electrode to detect a first distal increase relative to the predetermined threshold impedance indicative of the distal electrode being in contact with the septum;
• energizing the distal electrode to ablate the septum;
• measuring a third distal impedance at the distal electrode when the energization of the distal electrode begins and comparing the third distal impedance to the predetermined threshold impedance;
• measuring a first proximal impedance at the proximal electrode to detect a first proximal increase relative to the predetermined threshold impedance indicative of the proximal electrode being in contact with the septum;
• after detecting the first proximal increase, measuring a second proximal impedance at the proximal electrode to detect a first proximal decrease relative to the predetermined threshold impedance indicative of the proximal electrode being in contact with blood;
• and
• suspending energization of the distal electrode upon detection of the first proximal decrease.