A medical system for determining when an electrode (20,22a-n) of a catheter has exited from a catheter guiding introducer, wherein a sheath of the catheter guiding introducer is guided to an internal tissue location of interest, the medical system comprising: the catheter; and an impedance measurement module adapted to: measure a first impedance of the electrode (20, 22a-n) in response to a first electrical signal received on the electrode (20, 22a-n) at a first position of the electrode (20, 22a-n) at least partially disposed within an interior of the catheter guiding introducer; and measure a second impedance of the electrode (20, 22a-n) at a second position of the electrode disposed relative to an end of the catheter guiding introducer; a memory configured to store predetermined impedance threshold information associated with the catheter and the catheter guiding introducer; and a processor configured to: identify an impedance change between the first impedance and the second impedance; compare the impedance change to the predetermined impedance threshold information stored in the memory; and generate an output indicating the electrode (20, 22a-n) has at least partly passed out of the introducer if a predetermined change in the impedance is detected. the catheter; and an impedance measurement module adapted to: measure a first impedance of the electrode (20, 22a-n) in response to a first electrical signal received on the electrode (20, 22a-n) at a first position of the electrode (20, 22a-n) at least partially disposed within an interior of the catheter guiding introducer; and measure a second impedance of the electrode (20, 22a-n) at a second position of the electrode disposed relative to an end of the catheter guiding introducer; a memory configured to store predetermined impedance threshold information associated with the catheter and the catheter guiding introducer; and a processor configured to: identify an impedance change between the first impedance and the second impedance; compare the impedance change to the predetermined impedance threshold information stored in the memory; and generate an output indicating the electrode (20, 22a-n) has at least partly passed out of the introducer if a predetermined change in the impedance is detected. measure a first impedance of the electrode (20, 22a-n) in response to a first electrical signal received on the electrode (20, 22a-n) at a first position of the electrode (20, 22a-n) at least partially disposed within an interior of the catheter guiding introducer; and measure a second impedance of the electrode (20, 22a-n) at a second position of the electrode disposed relative to an end of the catheter guiding introducer; a memory configured to store predetermined impedance threshold information associated with the catheter and the catheter guiding introducer; and a processor configured to: identify an impedance change between the first impedance and the second impedance; compare the impedance change to the predetermined impedance threshold information stored in the memory; and generate an output indicating the electrode (20, 22a-n) has at least partly passed out of the introducer if a predetermined change in the impedance is detected. identify an impedance change between the first impedance and the second impedance; compare the impedance change to the predetermined impedance threshold information stored in the memory; and generate an output indicating the electrode (20, 22a-n) has at least partly passed out of the introducer if a predetermined change in the impedance is detected.