Atrial Fibrillation After Atrial Flutter Ablation

Study Questions:

What is the incidence of atrial fibrillation (AF) after successful ablation of the cavotricuspid isthmus for typical atrial flutter (AFL)?

Methods:

The meta-analysis consisted of 48 studies (1996-2015), which described the outcome of patients undergoing catheter ablation for typical AFL. The study population was made up of 8,257 patients (mean age, 63 years; 79% male). The acute procedural endpoint was demonstration of bidirectional conduction block (as opposed to only termination of AFL).

Results:

Over a mean follow-up of about 2.5 years, the incidence of AF post AFL ablation was 23% and 52% in patients without and with a prior history of AF, respectively. Studies with longer follow-up found that the incidence of de novo AF was significantly higher (14% or 26%, when follow-up was <2 or >2 years). The incidence of de novo AF also varied depending on the intensity of rhythm assessment: 12% (electrocardiography, symptoms), 19% (up to 7 days of monitoring per year, irrespective of symptoms), and 45% (>7 days of monitoring period per year, including implantable devices).

Conclusions:

The authors concluded that the incidence of AF after catheter ablation of AF is high, and that AF detection increases with more intense monitoring methods.

Perspective:

In most cases, AFL is triggered by episodes of AF, commonly from the pulmonary veins. Catheter ablation of the cavotricuspid isthmus for typical AFL is highly efficacious, durable, and associated with a low risk of complications. However, elimination of AFL cannot be expected to reduce the incidence of AF. It follows that patients with pre-existing AF are likely to develop AF over follow-up. It also should not be surprising that a significant number of patients without clinical AF before AFL ablation develop AF over long-term follow-up. The authors also raise an important issue regarding anticoagulation in patients who have undergone successful AFL ablation, but have not developed AF. Since the incidence approaches 50%, the authors advocate utilization of the current risk stratification schemes even in the absence of documentation of AF. This important question should be addressed by randomized trials.

Keywords: Arrhythmias, Cardiac, Atrial Fibrillation, Atrial Flutter, Catheter Ablation, Electrocardiography, Heart Block, Incidence, Pulmonary Veins


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