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.

Inclusion criteria

• Patients with previous AF ablation presenting with PMFL and recurrent AF
• Age: 18- 75 years
• Willingness and ability to give written informed consent
• Therapeutic INR for at least 4 weeks prior to the procedure

Exclusion criteria

• Reversible causes of AF such as pericarditis and hyperthyroidism
• Documented intra-atrial thrombus, tumor or any other abnormality which prevents easy catheter manipulation
• Enrollment in another clinical study
• Any other terminal illness