Electrosurgical device with sensing

A system for accessing a left atrium of the heart through a septum during a tissue puncture procedure, comprising:

• a guidewire comprising a conductive core wire and a distal portion having an atraumatic distal tip;
• a generator configured to deliver to an electrode at the distal tip of the guidewire energy sufficient to aid in the puncture of the septum;
• and
• a sensor system configured to:
• detect electrical properties of a material in contact with the electrode during the tissue puncture procedure;
• and
• measure a change in the detected electrical properties;
• wherein the generator is configured to automatically stop the energy delivery based on the measured change in the electrical properties.

A system for accessing a left atrium of the heart through a septum, comprising:

• a generator configured to provide energy for puncturing tissue during a tissue puncture procedure, wherein the generator is configured to provide a voltage;
• a guidewire comprising a distal portion having an electrode at a distal tip, the electrode configured to deliver the energy to aid in puncturing the septum during the tissue puncture procedure;
• and
• a sensor system configured to:
• measure a value of impedance of material in contact with the electrode or electrical current delivered by the electrode during the tissue puncture procedure;
• compute dielectric properties of the material in contact with the electrode during the tissue puncture procedure using the measured value of impedance or electrical current;
• and
• compute a change in the computed dielectric properties indicative of a transition of the electrode from contact with tissue to contact with blood;
• and
• a generator switch configured to automatically stop the energy delivery based on the computed change in the dielectric properties.

A method for controlling energy delivery of a system for accessing a left atrium of the heart through a septum during a tissue puncture procedure, comprising:

• delivering energy to aid in puncturing tissue to an electrode at a distal tip of a guidewire during a tissue puncture procedure;
• measuring a value of impedance of material in contact with the electrode or electrical current delivered by the electrode during the tissue puncture procedure;
• computing dielectric properties of a material in contact with the electrode during the tissue puncture procedure;
• computing a change in the computed dielectric properties indicative of a transition of the electrode from contact with tissue to contact with blood indicative of entry by the distal tip into the left atrium;
• and
• automatically stopping energy delivery by the system based on the computed change in the computed dielectric properties.