Unipolar and bipolar electrogram characteristics of recurrent cases of idiopathic ventricular arrhythmias undergoing repeat catheter ablation

Activation mapping guided catheter ablation (CA) of ventricular arrhythmias (VAs) is limited in some cases when it is only relied on bipolar electrogram (EGM). We hypothesized that activation mapping with use of combined bipolar and unipolar EGM facilitates to identify the focal origin of VAs and results in reduction of recurrence rate of CA of VAs. We analyzed the data of patients undergoing repeat ablations for idiopathic out-flow tract VAs. The EGM of the 1 st and 2 nd ablations were compared for earliest local activation time (LAT), presence of discrete potentials, and polarity reversal, unipolar potential morphology (QS or non-QS), potential amplitude and activation slope. Thirty-seven patients were included. The Local activation time was significantly earlier in the 2nd ablation as compared to the 1st procedure (36.90 msec vs 31.85 msec, P