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.