In the decade after catheter ablation for atrial fibrillation, late recurrences arise from triggers outside the pulmonary vein, a study showed.
After 12 years of follow-up at least every 9 months, 58.7% of patients remained free from arrhythmia with just the initial extended-pulmonary vein isolation (PVI) ablation procedure, Andrea Natale, MD, of the Texas Cardiac Arrhythmia Institute in Austin, and colleagues found.
With the repeat procedures done in 74% of patients, 12-year freedom from recurrent atrial fibrillation or tachycardia was achieved in 87%, they reported online in Circulation: Arrhythmia and Electrophysiology.
Pulmonary vein reconnection was found on the first repeat procedure for 31% of patients but in none of the third or fourth procedures done in the prospective cohort of 513 patients initially treated from 2000-2002 at several centers.
Nonpulmonary vein triggers found in all the the multiple repeat cases were almost exclusively new sites (92% for third procedures, 100% for fourth procedures).
"Occurrence of recurrent atrial fibrillation after being arrhythmia-free for several years suggested that the evolution of the cardiac substrate facilitating origin of the non-pulmonary vein triggers can happen even after establishment of sinus rhythm by earlier procedures, especially in elderly patients, females and subjects with genetic predisposition," the researchers noted.
"Thus, patients should be educated about the need for long-term close rhythm surveillance because of the possibility of atrial fibrillation recurrence consequent upon cardiac substrate changes as they age."
As the first large study of its kind with more than a decade of follow-up, the findings were on par with the modest, roughly 50% single-procedure efficacy reported form other studies at 3 to 6 years after PVI, Saurabh Kumar, MBBS, PhD, and Gregory F. Michaud, MD, both of Brigham and Women's Hospital in Boston, noted in an accompanying editorial.
"The high rate of non-pulmonary vein triggers seems to align with those of more recent studies, suggesting that non-pulmonary vein foci may contribute to atrial fibrillation initiation identifiable at the index ablation," they wrote. "It is plausible that trigger ablation at the index procedure may have improved outcomes even further, as suggested recently." However, "because the majority emerged beyond 3 years after the index procedure, and it is thus theoretically possible that even further de novo triggers may evolve beyond the follow up of this study," the editorialists added. "Identification of factors that lead to a progressive atrial myopathy may thus be of greater importance in preventing atrial fibrillation progression."
Factors independently associated with recurrence in the study included age 64 or older, left atrial diameter, female sex, and obesity (body mass index ≥30 kg/m2).
The study "provides impetus that much further work is needed if we are to get beyond a 50% chance of success from a single procedure," Kumar and Michaud concluded. "For PVI, which is in its infancy compared with other established medical procedures, attempting decennial follow-up is invariably challenging and will incorporate heterogeneities that are both necessary and critical to the future refinement of the procedure."