Ablation for Atrial Flutter: Treats the Arrhythmia but Not the Stroke Risk

The reentrant mechanism characteristic of atrial flutter (AFL) makes pharmacologic rate control of the arrhythmia notoriously more difficult than it is with atrial fibrillation (AF). Conversely, because the electrical circuit seen in AFL is so well defined, the condition is also associated with higher rates of procedural success after catheter-based ablation therapy.  Referral of AFL patients for ablation therapy is steadily increasing. In fact, it is a Class I recommendation in the 2012 Heart Rhythm Society Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation to refer AFL patients for ablation therapy if the arrhythmia is refractory to medical management.

A recent retrospective observational analysis published recently in PLoSOne by Dewland and colleagues from University of California San Francisco, however, reported results that suggest that ablation may be appropriate even earlier in AFL patients because of the positive impact it has on use of healthcare resources. 

This large study used the California Healthcare Cost and Utilization Project database. Among 33,004 patients with a diagnosis of AFL, 2,733 (8%) underwent ablation between 2005 and 2009 and were followed for a median of 2.1 years. AFL ablation was associated with a 12% lower adjusted risk of inpatient hospitalization; a 40% lower risk of emergency department visits; and 6% lower overall hospital-based healthcare utilization. There also was a lower hazard for development of AF (HR 0.89, 95% CI 0.81-0.97). Interestingly, despite the success of the procedure, there was no difference in the incidence of acute stroke between those who underwent ablation and those who did not (HR 1.09, 95% CI 0.81-1.45, p-0.57).

AFL ablation has been previously associated with decreased recurrence of the arrhythmia, fewer symptoms, and overall improved quality of life. But, as one of the few outcomes studies that exist in the literature, this observational report of a real-world population shows that it is also associated with reduced healthcare utilization and decreased progression to AF.  An important take-home point, however, is that despite its ability to treat the arrhythmia and improve the symptom complex, catheter ablation for AFL does not decrease the risk of incident stroke. Therefore, even after ablation and restoration of sinus rhythm, anticoagulation therapy should be continued if clinically indicated by the CHADS₂-VASc score.  Based on this constellation of findings, the study authors urge revision of the guidelines to recommend referral for ablation as first-line therapy. However, as of now, it is a recommendation only for those who have failed medical management or who have recurrent arrhythmia.

References:

1. Calkins H, Kuck KH, Capputo R, et al. 2012 HRS/EHRA/ECAS Expert Consensus Statement on Catheter and Surgical Ablation of Atrial Fibrillation: Recommendations for Patient Selection, Procedural Techniques, Patient Management and Follow-up, Definitions, Endpoints, and Research Trial Design. Heart Rhythm. 2012;9:632-696.

2. Dewland T, Glidden DV, Marcus GM. Healthcare utilization and clinical outcomes after catheter ablation of atrial flutter. PLoS One. 2014;9:e100509. Published online Jul 1, 2014.  doi:  10.1371/journal.pone.0100509