Comparison of high‐power short‐duration and low‐power long‐duration radiofrequency ablation for treating atrial fibrillation: Systematic review and meta‐analysis

Abstract Background High power shorter duration (HPSD) ablation seen to increase efficacy and safety treating of atrial fibrillation (AF); however, comparative data between HPSD and low power longer duration (LPLD) ablation are limited. Hypothesis We thought that HPSD might bring more clinical benefits. The aim of this meta‐analysis was to evaluate the clinical benefits of HPSD in patients with AF. Methods The Medline, PubMed, Embase, and the Cochrane Library databases were searched for studies comparing HPSD and LPLD ablation. Results Ten trials with 2467 patients were included in the analysis. Pooled analyses demonstrated that HPSD showed a benefit of first‐pass pulmonary vein isolation (PVI) (risk ratio [RR]: 1.20; 95% confidence interval [CI]: 1.10‐1.31, P < .001) and recurrence of atrial arrhythmias (RR: 0.73; 95% CI: 0.58‐0.91, P = .005). Additionally, HPSD could reduce procedural time (weighted mean difference [WMD]: −42.93; 95% CI, −58.10 to −27.75, P < .001), ablation time (WMD: −21.01; 95% CI: −24.55 to −17.47, P < .001), and fluoroscopy time (WMD: −4.11; 95% CI: −6.78 to −1.45, P < .001). Moreover, major complications and esophageal thermal injury (ETI) were similar between two groups (RR: 0.75; 95% CI: 0.44‐1.30, P = .31) and (RR: 0.57; 95% CI: 0.21‐1.51, P = .26). Conclusions HPSD was safe and efficient for treating AF. Compared with LPLD, HPSD was associated with advantages of procedural features, higher first‐pass PVI and reducing recurrence of atrial arrhythmias. Moreover, major complications and ETI were similar between two groups.


| Quality assessment and data extraction
The study quality was evaluated by two investigators (Mei-jun Liu and Chao-lun Jin) using the Newcastle-Ottawa Scale (NOS) for observational studies and the Delphi consensus criteria for randomized controlled studies (RCTs). The NOS system consisted of eight questions with nine possible points. A star system was used to judge the data according to the selected populations, comparability of the groups, and exposure/outcome of interest. A study with NOS ≥7 was judged to be a study of good quality. 9 The Preferred Reporting Items for Systematic Reviews and Meta-analyses Amendment to the Quality of Reporting of Meta-analyses Statement and recommendations from the Cochrane Collaboration in epidemiology were followed. Data extraction was conducted by mutual agreement, and all potential disagreements were resolved by consensus. 10 First-pass PVI: Rate of complete PVI after first-pass circumferential RF delivery. LGE involving more than 5 mm of tissue or in more than one location; endoscopy shows an ulcer).

| Assessment of heterogeneity reported bias and statistical analysis
All statistical analyses were performed using RevMan version 5.3 (Nordic Cochrane Center; The Cochrane Collaboration, 2014). The statistical analysis was completed by an independent statistician (Chao-feng Chen). Odds ratios (ORs) or risk ratios (RRs) with 95% confidence intervals (CIs) were used as risk estimates and were pooled by the software. Continuous variables were analyzed using weighted mean differences (WMD). Random-effect or fixed-effect models used weightings based on an inverse variance, which were calculated according to the method by DerSimonian and Laird. 12 The heterogeneity of studies was evaluated by Cochran's Q and the I 2 statistic. An I 2 value >50% was defined as significant heterogeneity.
If there have significant heterogeneity, the random-effects model was used. 13 3 | RESULTS

| Eligible studies
A flowchart of the detailed search process is illustrated in Figure 1.
Initially, 447 potentially studies were identified, of which 78 were duplicates and 248 were excluded after reviewing the titles and abstracts. Of the remaining 121 studies, 18 review articles, 3 editorial/letters, 11 case reports or case series stidies, and 23 abstracts were excluded. Next, 56 studies were excluded after a detailed evaluation of the full text for the following reasons: 19 were uncontrolled studies, 6 were clinical studies design, 18 lacked study endpoints, and 11 reported duplicate data. And then, two trails by Berte B et al 14

| Study characteristics
The characteristics of the included trials and ablation settings are shown in Table 1 and Table S1 (Supplementary file). A total of 2467 patients were enrolled in these trials (1466 in the HPSD group and 1001 in the LPLD group). The mean ages of the study participants ranged from 58.7 ± 11.1 to 69 ± 11.8 years, and the mean follow-up duration was from 10 months to 36 months. Some trails included other characteristics like as left atrial size, left atrial volume, rate of hypertension, diabetes mellitus, coronary artery disease, heart failure and transient ischemic attack/stroke. Six of ten were prospective studies [17][18][19][20][21]23 , and one was RCT. 21 The meta-regression analysis    revealed that no baseline characteristics could affect the correlation between two groups. A visual inspection of the funnel plot including all studies showed symmetry, indicating a low risk of publication bias (Appendix S1 Supplementary file). Moreover, in the most of studies consecutive patients receiving HPSD were compared with patients who were age and sex matched but treated with LPLD. Additionally, all patients received PVI, and additional linear ablations were performed in select patients at the operator's discretion in some trials. 8,16,18,21,24 All studies had good methodological qualities. The grouping results ensured the feasibility of this meta-analysis.

| Clinical outcomes
In all included studies, HPSD was found to be associated with a high rate of first-pass PVI (RR: 1.20; 95% CI: 1.10-1.31, P < .001 This study showed a higher first-pass PVI in the HPSD group than in the LPLD group. The main reasons may be the larger sizes, better uniformities, and better consistencies of the lesions created by HPSD than those by LPLD. Catheter-tissue contact stability is an important factor contributing to lesion creation, and catheter instability in a constantly moving heart may account for the difficulty in transmitting heat to the tissue. 20 The shortening of HPSD may mitigate the negative effects of catheter instability and likely optimize lesion creation by increasing the likelihood of keeping the catheter stable throughout the application. 28 In the LPLD group, catheter stability was an issue when longer single-lesion ablation was required, leading to unevenness of lesions, tissue edema, and a lower rate of first-pass PVI.
HPSD may reduce the rate of long-term recurrence of atrial arrhythmias. Complete PVI with transmural injury is most important for the freedom from AF during long-term follow-up. 29

| CONCLUSIONS
This analysis demonstrated that HPSD was a feasible, efficient, safe, and effective approach for AF ablation. The approach had some significant advantages over LPLD, including reduced procedure, ablation, and fluoroscopy time. Simultaneously, HPSD was associated with a higher first-pass PVI than that of LPLD and could reduce the recurrence of atrial arrhythmias than in LPLD cases. Moreover, HPSD was as safe as LPLD with a low rate of complications and ETI. However, there was no consensus about the power and duration settings for HPSD. Therefore, more clinical trials should be conducted to optimize dwell times, power settings, and even catheter selection to consistently create optimal lesions in the atrium.

CONFLICT OF INTEREST
The authors declare no potential conflict of interest.

AUTHOR CONTRIBUTIONS
Chao-feng Chen and Jing Wu: contributed to write the manuscript; Chao-feng Chen contributed to design of this work, statistical analysis, and wrote the article; Mei-jun Liu: contributed to evaluate quality and retrieved the required data, Chao-lun Jin: contributed to review the literature, performed the selection of the studies, and helped gather references for the manuscript. Dr Yi-zhou Xu: contributed to design of this work, revised, and approved the final version of the manuscript.

DATA AVAILABILITY STATEMENT
The data that support the findings of this study are available from the corresponding author upon reasonable request.

ETHICS STATEMENT
There were not any ethics problems in our paper.

SUPPORTING INFORMATION
Additional supporting information may be found online in the Supporting Information section at the end of this article.
How to cite this article: Chen C, Wu J, Jin C, Liu M, Xu Y.
Comparison of high-power short-duration and low-power long-duration radiofrequency ablation for treating atrial fibrillation: Systematic review and meta-analysis. Clin Cardiol.