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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.)

  • This publication is provided for historical reference only and the information may be out of date.

This publication is provided for historical reference only and the information may be out of date.

Cover of Comparative Effectiveness of Radiofrequency Catheter Ablation for Atrial Fibrillation

Comparative Effectiveness of Radiofrequency Catheter Ablation for Atrial Fibrillation [Internet].

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4Conclusions

Key Question 1. What is the effect of RFA on short- (6 to 12 months) and long- (>12 months) term rhythm control, rates of congestive heart failure, left atrial and ventricular size changes, rates of stroke, quality of life, avoiding anticoagulation, and readmissions for persistent, paroxysmal and long-standing persistent (chronic) atrial fibrillation?

Our literature search identified six RCTs and two retrospective cohort studies of patients with AF that compared RFA with medical treatment. Studies included mainly patients with PAF who had failed AADs. The patients underwent various ablation approaches and medical treatments across studies, and clinical outcomes were assessed in nonuniform ways. The methodological quality of five RCTs was rated fair, and one RCT was rated poor.

Rhythm Control

There is a moderate level of evidence to show that patients with AF 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% confidence interval (CI)1.97–6.09) at 12 months postprocedure. The summary estimate was derived from metaanalysis of three RCTs that assessed the rhythm control of patients exclusively after single procedure.

There is insufficient evidence to compare freedom from AF recurrence in patients who had RFA as first-line therapy versus medically treated patients. One fair quality RCT of 67 patients (96% PAF) reported an increased freedom from AF recurrence at 12 months for RFA as first-line therapy compared to medical treatment (88% vs. 37%, P<0.001).

It should be noted that the majority (70%) of the patients enrolled in RCTs of RFA versus medical therapy had paroxysmal AF. Therefore, a reliable estimate of the efficacy of RFA for maintenance of sinus rhythm in patients with non-paroxysmal AF (i.e., persistent and longstanding persistent AF) will require further study.

Rates of Congestive Heart Failure

There is insufficient evidence comparing the rate of congestive heart failure between RFA and medical treatment. Only one observational study reported that patients who underwent RFA had a lower risk of developing congestive heart failure compared to those treated with medical therapy (5% vs. 10%, P value not reported) at a mean followup of 30 months.

Left Atrial and Ventricular Size Changes

There is a low level of evidence showing no statistically significant difference in the improvement of left atrial diameter (LAD), left ventricular end diastolic diameter (LVED), or ejection fraction (EF) at 12 months in patients who underwent RFA compared to those treated with medical therapy

Rates of Stroke

There is a low level of evidence showing no statistically significant difference in the risk of cerebrovascular events at 12 months in patients who underwent RFA compared to those treated with medical therapy (risk difference 0.6%, 95% CI -1.1 to 2.3%; favoring AAD)). The summary estimate was derived from a metaanalysis of six RCTs.

Quality of Life

There is a low level of evidence to suggest that RFA improves QoL compared to medical treatment. Three RCTs and one observational study reported more improvement in general or physical functioning score of the SF-36 health survey in patients who underwent RFA compared to patients who had medical treatment alone (net difference between two treatments: +1 to +25; favoring RFA). However, these studies assessed the results at nonuniform time points and therefore the findings may be difficult to interpret.

Avoiding Anticoagulation

There is a low level of evidence suggesting that patients treated with RFA have a better chance of avoiding anticoagulation than those treated with AADs. Only one RCT found a higher proportion of patients reported freedom from anticoagulation at 12 months, comparing RFA with medical therapy (60% vs. 34%, P=0.02).

Readmissions

There is a low level of evidence on differences in readmission rates between patients treated with RFA and those treated with AADs. Two RCTs compared the rates or number of readmissions between RFA and medical treatment. One RCT reported a lower readmission rate in patients treated with RFA than medical treatment (9% vs. 54%, P<0.001), while the other RCT reported that there was no statistically significant difference in the median number of readmissions between RFA and medical treatment (one readmission vs. two readmissions, P=0.34). The findings on the rates of readmissions are inconsistent. This may be because readmission rates depend on many other factors besides the recurrence of disease (e.g., the particular health care system, bed availability, severity of illness).

Key Question 2. What are the patient-level and intervention-level characteristics associated with RFA effect on short- and long-term rhythm control?

There is a low level of evidence to show that AF type, namely nonparoxysmal AF, is predictive of a higher rate of AF recurrence. Univariable analyses within 31 studies that reported recurrence rates for PAF versus other types of AF were clinically and statistically heterogeneous, but metaanalysis found statistically significant higher rates of recurrence in patients with nonparoxysmal AF, with RRs of about 1.6. However, only a minority of multivariable analyses bear this out. Overall, 25 studies reported multivariable analyses of the association between patient-level characteristics and AF recurrence. Among these, 17 evaluated AF type, only 6 found statistically significant independent associations between AF type and recurrence rates. In the eight (of 25) studies that reported hazard ratios, these ranged from 1.1 to 22, suggesting lower recurrence rates in patients with PAF; 16 of the remaining 17 studies reported only that no significant association was found (one reported only that there was a significant association). Among 11 comparisons that reported both univariable and multivariable analyses, six found statistically significant crude and adjusted higher recurrence rates in patients with nonparoxysmal AF, three found significant crude but nonsignificant adjusted associations, and two found nonsignificant crude and adjusted associations. In both the studies that reported univariable or multivariable analyses, no study or population factors were found to explain the heterogeneity among the studies.

There is a moderate level of evidence to show that among patients with approximately normal EF or LAD, these parameters are not independent predictors of AF recurrence. In multivariable analyses, five of 17 studies found an association between lower EF and AF recurrence, and four of 20 found an association between larger LAD and AF recurrence. However, the reported data suggest that only a few percent of patients included in the analyses had EFs below about 40% or LADs above about 60 mm. The evidence is insufficient to estimate the predictive value of abnormal EF or LAD on recurrence rates.

There is a high level of evidence to show that sex, the presence of structural heart disease, and duration of AF are not associated with AF recurrence. All of 23 studies found no independent association of sex with AF recurrence. Only one of 21 studies found a consistent association between structural heart disease and AF recurrence. Only three of 16 studies found a statistically significant association between duration and recurrence of AF, with hazard ratios of 1.03 and 1.08 for longer duration.

There is a high level of evidence to show that age, within the approximate range of 40 to 70 years, is not independently associated with AF recurrence. Only one of 24 studies found an association (that higher age was associated with lower rates of AF recurrence). However, the reported data suggest that only a few percent of patients included in the analyses were younger than about 40 years or older than about 70 years. 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 as other predictors were only rarely evaluated.

There is insufficient evidence to show that intervention-level characteristics, such as operator experience or setting are predictors of AF recurrence as no study addressed this question.

Key Question 3. How does the effect of RFA on short- and long-term rhythm control differ among the various techniques or approaches used?

Different Approaches

Sixteen RCTs, two nonrandomized comparative trials, two prospective cohort studies, and 17 retrospective cohort studies met eligibility criteria and reported outcomes of AF after RFA using different approaches. Approaches used in these studies included pulmonary vein isolation (PVI) within and around PV ostia, a wide-area circumferential ablation (WACA), or additional ablation lines. The majority of the studies included a mixture of patients with either PAF or persistent/permanent AF.

PVI versus WACA. There is a moderate level of evidence to show that WACA may result in lower rates of AF recurrence than ostial PVI in patients with either PAF or persistent AF, with followup ranging from 6 to 15 months. Five RCTs of ostial PVI versus WACA with or without additional ablation lines compared the efficacy to maintain sinus rhythm. Only two studies reported results after a single procedure and off AADs. Both studies found that patients who had WACA had a higher rate of success (freedom from AF recurrence) than patients who had ostial PVI (67% vs. 49%, P≤0.05; 88% vs. 67%, P=0.02). Of the three studies that included patients who had reablation during followup, two reported similar findings.

RFA with or without additional left sided ablation lines. There is insufficient evidence to make definitive conclusions concerning the effects of the addition of left sided ablation lines to RFA. The substantive heterogeneity of the different types of additional left sided ablation lines that were used by the studies preclude meaningful comparisons among the studies as to the value of the addition of left-sided ablation lines during RFA. Six RCTs compared the efficacy of one RFA technique with versus without the addition of left-sided ablation lines (e.g., mitral-isthmus line (MIL), roof or posterior left atrial lines). The majority of the studies reported AF recurrence rates including patients who had reablation or were continued on AADs. Three of five studies on patients with PAF or nonparoxysmal AF found that patients who had additional left sided ablation lines had less AF or atrial arrhythmia recurrence at followup than patients who did not (MIL 71% vs. 53%, P=0.01; roof line 87% vs. 69%, P=0.04; MIL 74% vs. 83%, no P value reported). Two studies did not find a significant difference in AF recurrence with the addition of left-sided ablation lines.

PVI versus PVI with right sided lines. There is insufficient evidence concerning the effects on AF recurrence by adding right sided lines in RFA. One RCT examined the incremental benefit of adding a cavotricuspid isthmus ablation line in patients undergoing RFA for AF. This study, which included patients with AF and at least one episode of atrial flutter, found no significant difference in AF recurrence between the group that had ostial-antral PVI and the group that had ostial-antral PVI with cavotricuspid isthmus ablation at 12 months followup. Another RCT compared WACA with versus without superior vena cava ablation. This study of patients with PAF found no significant difference at 12 months followup in the recurrence of atrial tachyarrhythmia between the patients who had WACA with superior vena cava ablation and the patients who only had WACA.

Different approaches in retrospective studies. There is insufficient evidence to draw meaningful conclusions from this group of retrospective studies. These observational studies compared many different approaches to RFA. They have limitations in the comparability among groups. Historical controls were used in the majority of the studies. In some instances, the proportions of patients with different types of AF differed between groups, and followup results from different time points were compared between groups. None of the studies adjusted for potential confounders.

Technical Issues

There is a moderate level of evidence to suggest that there was no difference 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 is insufficient evidence to draw conclusions in the rest of the studies as they were all poor quality individual studies that addressed separate technical issues. These studies analyzed the outcomes of PVI for AF comparing different energy outputs, postprocedure durations of observation in the EP laboratory, various mapping techniques (e.g., circular mapping alone versus circular mapping enhanced with intracardiac echocardiogram with or without monitoring of microbubbles) or different ablation time.

Key Question 4. What are the short- and long-term complications and harms associated with RFA?

There is a low level of evidence that 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. There were 84 studies that reported at least one adverse event associated with RFA. Most of the studies did not report the time of occurrence of the adverse events. Based on the study description, we surmised that most of the adverse events either took place in a peri-procedural time frame or shortly after being discharged home postprocedure. The only exception was the diagnosis of PV stenosis which was routinely screened for at around 3 months. Major adverse events included PV stenosis, cardiac tamponade, stroke and/or TIA, peripheral vascular complications such as bleeding/hematoma, pseudoaneurysm, femoral vein thrombosis, or arteriovenous fistula. There were 78 studies that assessed the rates of asymptomatic or symptomatic PV stenosis. These studies reported asymptomatic PV stenosis rates that ranged from 0% to 19% (median 0.3%); 36 studies did not identify a single case of PV stenosis. Symptomatic PV stenosis requiring interventions occurred in less than 1% of patients in six studies. Cardiac tamponade occurred between 0% and 5% (median 1%) in the 70 studies that evaluated this adverse event. Rates of cerebrovascular events ranged from 0% to 7% (median 0.9%) in the 72 studies that evaluated stroke and/or TIA. Twenty-six studies assessed for atrioesophageal fistula. Among these, four studies reported one case each with an event rate ranged from 0.1 to 0.9%; the rest of the studies did not identify any cases. Among 16 studies, five deaths were reported within 30 days postprocedure; 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; it is unclear whether these are three separate incidents or a single incident reported multiple times).

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