Ablation of Antero-Septal and Intermediate Septal Accessory Pathways: How Safe Is It? How Can One Minimize the Risk of AV Block?
The current goal of radiofrequency catheter ablation of supraventricular tachycardias is to cure a large cohort of patients with a primary success rate close to 100% and a complication and recurrence rate close to 0%. In this setting, the ablation of the atrioventricular (A-V) accessory pathway in the triangle of Koch may still represent a grey area, since the strict anatomical relationship between the bypass tract and the A-V node-His bundle may affect the feasibility and safety of the procedure. Consequently, the only rationale for successful ablation with no complication in this area relies on the assumption that the accessory pathway is more sensitive to radiofrequency energy delivery than the normal A-V conduction system . The risk of damaging the normal A-V conduction pathway and of inducing a complete A-V block requiring a permanent pacemaker has been pointed out by both early [2, 3] and recent [4–6] reports, although successful and safe ablation has been described in limited series of cases [7, 8], even with “para-hissian” accessory pathways . Moreover, in the risk/benefit ratio of ablation of by-pass tracts in the Koch’s triangle one must consider not only failure and the risk of permanent complete A-V block, but also the theoretical possibility of creating an incessant reentrant circuit by partially damaging both the accessory pathway and the A-V node conduction.
KeywordsCatheter Ablation Accessory Pathway Right Bundle Branch Block Successful Ablation Radiofrequency Catheter Ablation
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- 6.Lin JL, Huang SK, Lai LP, Cheng TF, Tseng YZ, Lien WP (1998) Radiofrequency catheter ablation of septal accessory pathways within the triangle of Koch: importance of energy titration testing other than local electrogram characteristics for identifying the successful target site. Pacing Clin Electrophysiol 21:1909–1917PubMedCrossRefGoogle Scholar
- 9.Storti C, Salerno JA, Stanke A, De Ponti R, Ferrari A, Longobardi M (1994) Junctional area mapping for radiofrequency catheter ablation of the fast pathway in patients with AV nodal reentrant tachycardia. Pacing Clin Electrophysiol 17:846Google Scholar
- 10.Ho SY, Anderson RH (1998) Anatomy of the accessory pathways: are there lessons relevant to radiofrequency catheter ablation? In: Farrè J, Moro C (eds) Ten years of radiofrequency catheter ablation. Futura, Armonk, NY, pp 149–163Google Scholar
- 13.Salerno JA, De Ponti R, Storti C, Zardini M, Tritto M, Longobardi M (1999) Focal atrial tachycardia originating from the apex of the Koch’s triangle: a weak arrhythmogenic substrate in a risky site? Pacing Clin Electrophysiol 22:845Google Scholar
- 15.Calkins H, Prystowsky E, Berger RD, Saul JP, Klein LS, Liem LB, Huang SK, Gillette P, Yong P, Carlson M (1996) Recurrence of conduction following radiofrequency catheter ablation procedures: relationship to ablation target and electrode temperature. The Atakr Multicenter Investigators Group. J Cardiovasc Electrophysiol 7:704–712PubMedCrossRefGoogle Scholar