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Ip S, Terasawa T, Balk EM, et al. Comparative Effectiveness of Radiofrequency Catheter Ablation for Atrial Fibrillation [Internet]. Rockville (MD): Agency for Healthcare Research and Quality (US); 2009 Jul. (Comparative Effectiveness Reviews, No. 15.)
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Comparative Effectiveness of Radiofrequency Catheter Ablation for Atrial Fibrillation [Internet].
Show detailsA summary of the studies reviewed for this report is given in Table 22.
Table 22
Summary of reviewed studies: radiofrequency catheter ablation for atrial fibrillation.
Key Question 1: Medical Treatment Versus Radiofrequency Ablation (RFA)
There is a moderate level of evidence to show that patients who received RFA as a second-line therapy (i.e., in patients who did not respond to medical therapy) had a higher chance of maintaining sinus rhythm compared to those treated with medical therapy alone (relative risk (RR) 3.46, 95% CI 1.97–6.09) at 12 months postprocedure. This finding is in general agreement with a previously published metaanalysis.142 We did not find a statistically significant difference in the risk of cerebrovascular events in patients who were treated with RFA compared to those treated with medical therapy. However, clinically meaningful differences could not be excluded because the event rates were small and studies were not powered to detect such small differences.
There were insufficient data to draw meaningful conclusions concerning RFA use as a first-line therapy for rhythm control (i.e., in patients who have never been treated with antiarrhythmic drugs (AADs)).
Key Question 2: Patient- and Intervention-Level Characteristics Associated with Rhythm Control
There is low level of evidence to show that atrial fibrillation (AF) type, namely nonparoxysmal AF, is predictive of a higher rate of AF recurrence. Although metaanalyses of univariable analyses support an association (RR about 1.6 suggesting more recurrence with nonparoxysmal AF), the studies were clinically and statistically heterogeneous, and more importantly, only six of 17 multivariable analyses bear this out, with hazard ratios ranging from 1.1 to 22 (favoring paroxysmal AF).
There is a moderate level of evidence to show that among patients with approximately normal ejection fraction (EF) or left atrial diameter (LAD), these parameters are not independent predictors of AF recurrence; however, there is insufficient evidence to estimate the predictive value of abnormal EF or LAD on recurrence rates. There is a high level of evidence to show that sex, AF duration, and the presence of structural heart disease are not associated with AF recurrence. Among patients between approximately 40 and 70 years of age, there is a high level of evidence to show that age is not associated with AF recurrence; however, the evidence is insufficient to estimate the predictive value of young or very old age. There is insufficient evidence for other potential predictors of AF recurrence.
Key Question 3: Approaches and Technical Issues Concerning RFA
Approaches to RFA
There is a moderate level of evidence to show that wide-area circumferential ablation (WACA) resulted in a higher rate of freedom from AF recurrence compared to ostial pulmonary vein isolation (PVI) (absolute difference: ~20%) in patients with either paroxysmal AF or persistent AF.
It is unclear whether the addition of left sided ablation lines to PVI increases the freedom from AF recurrence compared to PVI alone. Three studies found that the addition of left sided lines in RFA increased the freedom from AF recurrence compared to RFA alone, and two studies did not find significant differences. The heterogeneity of the different types of additional left sided ablation lines may have precluded meaningful comparisons among the studies.
One study found that adding a cavotricuspid isthmus ablation line to PVI in patients with persistent or permanent AF and a history of atrial flutter did not result in a significantly lower recurrence of AF. The limited evidence does not allow us to draw definitive conclusions.
Retrospective studies have limitations in the comparability among groups. The majority of the studies used historical (non-concurrent) controls. The proportions of patients with different types of AF were different between groups in many comparisons. None of the studies adjusted for potential confounders. It is not possible to draw conclusions from this group of studies.
Technical Issues Related to RFA
There is a moderate level of evidence suggesting no differences in using the 8 mm tip catheter or an irrigated tip catheter for RFA in long-term rhythm control in patients with AF. Furthermore, there is a low level of evidence suggesting no differences in rhythm control in patients with drug refractory AF comparing different imaging modalities used during RFA.
There were insufficient data to draw conclusions regarding the outcomes of PVI for AF comparing different energy outputs, mapping techniques, or ablation times.
Key Question 4: Adverse Events Associated with RFA
There is a low level of evidence suggesting major adverse events associated with RFA are relatively uncommon. The level of evidence was rated low because the studies reviewed employed nonuniform definitions and assessments of adverse events, with sample sizes generally less than 100, and incomplete reporting. While there is no doubt that certain adverse events are uniquely associated with the use of RFA (e.g., atrioesophageal fistula), the limitations cited precluded accurate estimates of those adverse event rates. Asymptomatic PV stenosis, cardiac tamponade, and cerebrovascular events were reported at rates of 4% or less in the majority of the studies. Symptomatic PV stenosis was reported at rates of 1% or less. Four studies reported rates of atrioesophageal fistula ranging from 0.1% to 0.9%. A total of five deaths were reported in all the studies reviewed (one patient died from a pulmonary infection, one died from anaphylaxis after the procedure, and three died from atrioesophageal fistulas (three publications from the same group of investigators each reported one death from atrioesophageal fistula). However, it is difficult to compare the rates of adverse events across studies as the descriptions of the various adverse events were not always comparable. For example, even though the presence of PV stenosis was generally evaluated at around 3 months post-RFA, severe and moderate PV stenoses were defined differently across studies. Some clearly reported stroke as periprocedural, and some reported stroke without stating a time of occurrence. Also, it was not always made clear whether the lack of information on a particular adverse event meant zero events (i.e., the researchers systematically ascertained for it and found none) or it was simply not spontaneously reported. In addition, the sample sizes in most RCTs and comparative studies were generally small, precluding reliable risk estimates of the adverse events. Furthermore, many of the studies had a mean followup of no more than 12 months, any long term events like late AF recurrence or mortality or delayed adverse effects from radiation exposure could not be properly assessed from this group of studies.
- Discussion - Comparative Effectiveness of Radiofrequency Catheter Ablation for A...Discussion - Comparative Effectiveness of Radiofrequency Catheter Ablation for Atrial Fibrillation
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