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.