2. Methods:
This study was approved by the Institutional Review Board (IRB) of Mayo
Clinic hospital.
Study cohort: This study is a retrospective analysis of
patients that underwent AAFL ablation in the past 5 years (2017-2022) at
different sites of Mayo Clinic. High-density activation sequence mapping
and small-diameter multipolar catheter usage have become more prevalent
in the past 5 years. Therefore, we wanted to study the impact of our
contemporary practice on the overall outcome of AAFL.
Ablation and Follow-up: All included patients had Intra Cardiac
Echo (ICE), a multipolar small diameter catheter used for mapping, and
irrigated Radiofrequency (RF) catheter for ablation. Successful ablation
was defined as the termination of AAFL during RF energy application
(either without cycle length change or lengthening) and the inability to
reinduce the index AAFL. The termination was not considered successful
if the index arrhythmia terminated due to a premature beat or cycle
length shortening. All included patients were routinely followed up for
any clinically relevant atrial arrhythmia recurrence according to the
clinical standards of care. If prompted by symptoms, they were seen at
the outpatient clinic or via virtual appointment. Routinely scheduled
appointments were at 1, 3, and 12 months. Besides symptomatic
recurrences, routine electrocardiograms and Holter monitoring were
utilized to confirm recurrent events, even if unaccompanied by symptoms.
The primary outcome of interest was one-year recurrence-free survival in
all symptomatic event-based recordings or opportunistic, incidental
routine monitoring. Early recurrent symptoms during the 90-day blanking
period were excluded.
Statistical analysis: Continuous variables were summarized
using median and interquartile range (IQR), and categorical variables
were summarized using frequency and percentage. A Kaplan Meier curve
with log-rank analysis examined the primary outcome, recurrence-free
survival. Patients were censored as of the date of the last follow-up,
and a p-value of <0.05 was considered significant. Statistical
software R 4.1.2 was used for analysis.