A method and system for assessing proximity between an electrode and tissue is provided. The system includes an electronic control unit (ECU). The ECU is configured to acquire values for first and second components of a complex impedance between the electrode and the tissue, and to calculate an electrical coupling index (ECI) responsive to the first and second values. The ECU is further configured to process the ECI to determine the proximity of the electrode to the tissue. The ECU may be configured to calculate an electrical coupling index rate (ECIR) based on the calculated ECI and information relating to the change in location of the electrode, and to assess proximity based on the ECIR. Alternatively, the ECU may be configured to assess the proximity using the calculated ECI, as opposed to the ECIR.