Flutter ablation may unmask AF

MUNCIE, INDIANA. Common atrial flutter (AFL) originates in the right atrium between the tricuspid valve and the crista terminalis. Because the location of the AFL-associated macroreentrant circuit is so well defined a catheter ablation to interrupt it is usually successful. However, as many as half of all patients ablated for AFL may later develop atrial fibrillation (AF) thought to be unmasked by eliminating the flutter. An obvious question is would it be desirable to combine the standard AFL ablation (cavotricuspid isthmus or CTI) ablation with a pulmonary vein isolation (PVI) procedure at the time of the initial flutter ablation?

A group of doctors from the Ball Memorial Hospital provides a preliminary answer to this question. Their clinical trial involved 48 patients with lone right atrial flutter. NOTE: In this case, lone means that no other cardiac arrhythmia was present. The average age of the patients was 55 years, very few (number not specified) had heart disease, but 60% had hypertension. Patients were randomly assigned to receive only a CTI ablation (25 patients) or a CTI ablation combined with a PVI procedure with additional lesions as required (23 patients). Total average procedure time for the CTI ablation was 84 minutes as compared to 239 minutes for the combined procedure. Fluoroscopy time was 8.2 minutes and 20.1 minutes respectively. All patients were anticoagulated for one month prior to the procedure and for two months following. All received a Class 1C antiarrhythmic drug (flecainide or propafenone) for two months following their procedure and underwent 48-hour Holter monitoring every two months. Only four minor adverse events were observed – hematoma and mild pericardial effusion.

After a 16-month follow-up, 87% of the group that had undergone both CTI and PVI ablation were free of any arrhythmia without the use of medication. However, in the CTI ablation group only 44% were so lucky – 10 patients (36%) developed paroxysmal AF and 5 (20%) developed persistent AF during follow-up. The researchers conclude that adding PVI ablation to CTI ablation for lone atrial flutter provides better long-term freedom from arrhythmias than just performing the CTI ablation on its own.

Navarrete, A, et al. Ablation of atrial fibrillation at the time of cavotricuspid isthmus ablation in patients with atrial flutter without documented atrial fibrillation derives a better long-term benefit. Journal of Cardiovascular Electrophysiology, July 19, 2010 [Epub ahead of print]

Editor’s comment: It is well established that undergoing just a CTI ablation in an attempt to cure afib, or afib coexisting with atrial flutter, is usually fruitless with a success rate somewhere between 5 and 10%. This study provides convincing evidence that even if a patient has only been diagnosed with atrial flutter, it would be better to combine the CTI ablation with a PVI procedure “right off the bat” rather than wait to see if the flutter ablation “unmasks” coexisting afib.