Linear lesions needed for successful AF ablation

MedWire News: Left atrial (LA) linear lesions are nearly always necessary for successful catheter ablation of atrial fibrillation (AF), French researchers have demonstrated.

Their study found that although persistent AF could be terminated without LA linear lesions, most patients require such lesions to prevent the later development of macro re-entrant atrial tachycardia.

A team led by Sébastien Knecht (Université Victor Segalen Bordeaux II) retrospectively studied 180 patients with persistent AF who had undergone catheter ablation.
AF was successfully terminated in 154 patients, report Knecht et al in the European Heart Journal. Of these, 69 had required both LA linear lesions (ie, the roofline and the mitral isthmus line) to terminate AF whereas 85 had not.

Patients who required linear lesions had a longer duration of AF (9 vs 12 months), but otherwise the two groups were similar with regard to clinical and echocardiographic characteristics.

After 28 months of follow-up, however, the incidence of LA macro re-entrant atrial tachycardia was significantly higher among patients who had not required LA lesions than those who had, at 78% versus 33% (p=0.002).

And the vast majority of patients ultimately required a roof line and/or a mitral line in order to remain in sinus rhythm.

“This study highlights that although pulmonary vein isolation and electrogram-based ablation without linear lesions are effective for terminating persistent AF in a significant number of patients, macro re-entrant AT requiring LA linear ablation is very likely to occur during the overall follow-up period,” Knecht and co-authors conclude.

In a related editorial, Thomas Rostock and Stephan Willems from University Hospital Eppendorf in Germany said it remains unclear whether the atrial tachycardias are a cause or a consequence of AF; nevertheless they added: “It has become clearer that LA linear ablation remains an imperative step on the road to sinus rhythm in patients with chronic AF.”

Eur Heart J 2008; 29: 2359–2366