Figure 1. Unipolar signal modification and impedance changes
Example of a change in unipolar electrogram with dynamic changes in
generator impedance. S-wave of unipolar signal disappeared three seconds
after the radiofrequency application (RFA) according to significant
impedance decrease, and R-pattern was achieved five seconds after the
RFA. After that, impedance gradually decreased from 133 ohm, and finally
reached 120 ohm while a notch in positive unipolar electrogram
completely disappeared.