High‐Amplitude Pace Mapping Increases Safety of Radiofrequency Catheter Ablation of Parahisian Ectopic Foci

Background: The objective of the study is to assess the efficacy of high‐amplitude pace mapping in terms of the atrioventricular (AV) block risk after radiofrequency catheter ablation (RCA) of parahisian ectopic foci. Methods: Twenty patients aged 38 ± 14 years with no structural heart disease underwent RCA of parahisian ectopic foci. All the patients were randomized into two groups: Group I (n = 11) had RCA performed in the region defined as ectopic focus by electrophysiology study and Group II (n = 9) had high‐amplitude pacing performed in the region of “perfect” mapping. RCA was done only at the sites where high‐amplitude pacing revealed the absence of His bundle capture. Results: In group I, the efficacy of RCA was 54.5% and it was 100% in group II (P = 0.0195). Group II had no complications; in group I there were 27% of AV blocks (P = 0.0893). The late recurrence of ectopic activity was comparable in both groups: 3 (27%) and 2 (22%), respectively (P = 0.7953). In all the cases of recurrent ectopic activity and in all the cases of ineffective primary procedure, group I had effective reablation procedures performed using high‐amplitude pace mapping. The overall efficacy in terms of repeated procedures was 90%. Conclusion: High‐amplitude pace mapping increases primary and secondary efficacy of parahisian ectopic foci RCA and decreases the risk of AV block development. (PACE 2012;35:1458–1463)