Effect of outcome measures on the apparent efficacy of ablation for
atrial fibrillation: Why “success” is an inappropriate term
Abstract
INTRODUCTION: Different endpoint criteria, different durations of follow
up and the completeness of follow up can dramatically affect the
perceived benefits of Atrial Fibrillation (AF) ablation. METHODS: We
defined three endpoints for recurrence of AF post ablation in a cohort
of 200 patients with symptomatic AF, refractory to antiarrhythmic drugs
(AADs). A “Strict Endpoint” where patients were considered to have a
recurrence with any symptomatic or documented recurrence for ≥30 seconds
with no blanking period, and off their AADs, a “Liberal Endpoint”
where only documented recurrences after the blanking period, either on
or off AADs were counted, and “Liberal Endpoint + Redo” which was the
same as the Liberal endpoint but allowing for 1 redo ablation or 1
cardioversion (DCCV) during follow up. We also surveyed 50 patients on
the waiting list for an AF ablation and asked them key questions
regarding what they would consider to be a successful result for them.
RESULTS: Freedom from recurrence of atrial tachyarrhythmias (AT) at 5
years was 62% for the strict endpoint, 73% for the liberal endpoint,
and 80% for the liberal endpoint + redo group (p<0.001). Of
the 50 patients surveyed awaiting AF ablation, 70% said they would
still consider the procedure a success if it required one repeat
ablation or one DCCV (p=0.004), and 76% would be accepting of one or
two recurrences during follow-up (p<0.001). CONCLUSION: In
this study the most important predictor of AT recurrence following AF
ablation was the criteria used to define recurrence.