Figure 2. Technology used for LI measurement
IntellaNav MiFi OITM catheter (A; Boston Scientific) and an image of an electric field generated by the catheter (B). An electric field was created by altering the current (5.0 micro-A at 14.5 KHz) between each tip of the three miniature electrodes and the proximal ring of the ablation catheter. Voltage is measured between the miniature electrode and the distal ring. Impedance was calculated by dividing the voltage by the stimulatory current. Among three impedance measurements from the three miniature electrodes, the highest impedance was used as the LI. Illustrations were provided by Boston Scientific.
A representative graph showing the impedance change with a large impedance drop during RFA (C), and that with a small impedance drop (D).
LI indicates local impedance; RFA, radiofrequency application.