• radiofrequency catheter ablation;
  • parahisian ectopic foci;
  • ventricular ectopy

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)