Ablation of Perimitral Flutter Following Catheter Ablation of Atrial Fibrillation: Impact on Outcomes

Background: In recent years, catheter ablation has been accepted as the treatment-of-choice
for drug-refractory atrial fibrillation (AF). It is centered around isolating pulmonary
veins (PVs) and its success rate in curing AF is very high (56%-85%) (1). However, despite
isolation of this dominant source of triggers, recurrent tachyarrhythmia is the major
complication of this procedure with peri-mitral atrial flutter (PMFL) being the most common
macro-reentrant arrhythmia in context of AF ablation (2). These often drug-refractory
arrhythmias are frequently associated with more severe symptoms than the original AF (3) and
warrant the necessity for redo-ablation.

This study aims to compare the impact of two different redo-ablation strategies on the
procedure outcome; (1) ablation of the perimitral flutter only and (2) cardioversion and
repeat isolation of pulmonary veins (PV) with ablation of additional triggers.

Study method: A total number of 65 AF patients presenting for redo-ablation and PMFL will be
randomized to perimitral flutter ablation only or cardioversion and re-isolation (PVI) plus
ablation of additional triggers. Additional triggers will be identified with the help of
post-ablation drug provocation with isoproterenol. Patients will enter a follow-up period of
12 months after the ablation procedure, when they will be monitored for recurrence of
arrhythmia detected either by in-clinic or remote device interrogation at 1, 3, 6 and 12
month post-procedure.