Study design
This retrospective study was performed reviewing the procedural reports
patients undergoing a repeat ablation. Data collection included
patients’ characteristics at initial and redo procedures, number and
characteristics of previous ablations, type and location of accessory
pathway, type of access, type of catheter and energy used, type of
imaging to guide the procedure and procedure duration. The most probable
reason for recurrence was determined by the operator based on the prior
reports and on the findings during the redo procedure. The initial
reasons for failure and /or recurrence were classified as 1, inaccurate
mapping or diagnosis, 2, inadequate lesion formation due to poor
contact, deep/epicardial location or inadequate energy delivery, 3,
inadequate long-term lesion consolidation due to the use of cryoenergy
as source of energy, or 4, unknown (in the case the cause remained
unclear). The differences between the initial procedure and the final
procedure were compared. Recurrence was defined as reappearance of
anterograde accessory pathway conduction or documented supraventricular
tachycardia. Long-term success was defined as no recurrence of accessory
pathway conduction, no documented supraventricular tachycardia, or
palpitations during at least 6 months of follow-up after the redo
procedure.