Comparison of high-power and conventional-power radiofrequency energy deliveries in pulmonary vein isolation using unipolar signal modification as a local endpoint

Characteristics of tissue temperature during ablation with THERMOCOOL SMARTTOUCH SF versus TactiCath versus QDOT MICRO catheters (Qmode and Qmode+): An in vivo porcine study

INTRODUCTION

High-power short-duration (HPSD) ablation at 50 W, guided by ablation index (AI) or lesion size index (LSI), and a 90 W/4 s very HSPD (vHPSD) setting are available for atrial fibrillation (AF) treatment. Yet, tissue temperatures during ablation with different catheters around venoatrial junction and collateral tissues remain unclear.

METHODS

In this porcine study, we surgically implanted thermocouples on the epicardium near the superior vena cava (SVC), right pulmonary vein, and esophagus close to the inferior vena cava. We then compared tissue temperatures during 50W-HPSD guided by AI 400 or LSI 5.0, and 90 W/4 s-vHPSD ablation using THERMOCOOL SMARTTOUCH SF (STSF), TactiCath ablation catheter, sensor enabled (TacthCath), and QDOT MICRO (Qmode and Qmode+ settings) catheters.

RESULTS

STSF produced the highest maximum tissue temperature (Tmax ), followed by TactiCath, and QDOT MICRO in Qmode and Qmode+ (62.7 ± 12.5°C, 58.0 ± 10.1°C, 50.0 ± 12.1°C, and 49.2 ± 8.4°C, respectively; p = .005), achieving effective transmural lesions. Time to lethal tissue temperature ≥50°C (t-T ≥ 50°C) was fastest in Qmode+, followed by TacthCath, STSF, and Qmode (4.3 ± 2.5, 6.4 ± 1.9, 7.1 ± 2.8, and 7.7 ± 3.1 s, respectively; p < .001). The catheter tip-to-thermocouple distance for lethal temperature (indicating lesion depth) from receiver operating characteristic curve analysis was deepest in STSF at 5.2 mm, followed by Qmode at 4.3 mm, Qmode+ at 3.1 mm, and TactiCath at 2.8 mm. Ablation at the SVC near the phrenic nerve led to sudden injury at t-T ≥ 50°C in all four settings. The esophageal adventitia injury was least deep with Qmode+ ablation (0.4 ± 0.1 vs. 0.8 ± 0.4 mm for Qmode, 0.9 ± 0.3 mm for TactiCath, and 1.1 ± 0.5 mm for STSF, respectively; p = .005), correlating with Tmax .

CONCLUSION

This study revealed distinct tissue temperature patterns during HSPD and vHPSD ablations with the three catheters, affecting lesion effectiveness and collateral damage based on Tmax and/or t-T ≥ 50°C. These findings provide key insights into the safety and efficacy of AF ablation with these four settings.

Comparison of very high-power short-duration, high-power short-duration, and low-power long-duration radiofrequency ablation for atrial fibrillation: A systematic review and network meta-analysis

BACKGROUND

The optimal power and duration settings for radiofrequency (RF) atrial fibrillation (AF) ablation to improve efficacy and safety is unclear. We compared low-power long-duration (LPLD), high-power short-duration (HPSD), and very HPSD (vHPSD) RF settings for AF ablation.

METHODS

This network meta-analysis (NMA) was structured according to the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. Medline, Scopus and Cochrane Central Register of Controlled Trials were systematically searched to identify relevant studies. Observational and randomized studies were included. Eligible studies compared outcomes in AF patients who underwent first-time RF ablation with the following settings: vHPSD (70-90 W, 3-10 s), HPSD (45-60 W, 5-10 s), or LPLD (20-40 W, 20-60 s).

RESULTS

Thirty-six studies comprising 10,375 patients were included (33% female). Frequentist NMA showed LPLD tended toward a lower odds of freedom from arrhythmia (FFA) versus HPSD (OR 0.93, 95% CI 0.86-1.00). There was no difference in FFA between vHPSD versus HPSD. Splitwise interval estimates showed a lower odds of FFA in LPLD versus vHPSD on direct (OR 0.78, 95% CI 0.65-0.93) and network estimates (OR 0.85, 95% CI 0.73-0.98). Frequentist NMA showed less total procedural (TP) time with HPSD versus LPLD (generic variance 1.06, 95% CI 0.83 to 1.29) and no difference between HPSD versus vHPSD.

CONCLUSION

This NMA shows improved procedural times in HPSD and vHPSD versus LPLD. Although HPSD tended toward improved odds of FFA compared to LPLD, the overall result was not statistically significant. The odds of FFA in LPLD was lower versus vHPSD on direct and network estimates on splitwise interval analysis. Large prospective head-to-head randomized trials are needed to validate HPSD and vHPSD settings.

Multicenter prospective comparison of conventional and high-power short duration radiofrequency application for pulmonary vein isolation: the high-power short-duration radiofrequency application for faster and safer pulmonary vein ablation (POWER FAST III) trial

BACKGROUND

Electrical isolation of pulmonary veins (PV) with high-power short-duration (HPSD) radiofrequency application (RFa) may reduce the duration of atrial fibrillation (AF) ablation, without compromising the procedural efficacy and safety in comparison with the conventional approach. This hypothesis has been generated in several observational studies; the POWER FAST III will test it in a randomized multicenter clinical trial.

METHODS

It is a multicenter randomized, open-label and non-inferiority clinical trial with two parallel groups. AF ablation using 70 W and 9-10 s RFa is compared with the conventional technique using 25-40 W RFa guided by numerical lesion indexes. The main efficacy objective is the incidence of atrial arrhythmia recurrences electrocardiographically documented during 1-year follow-up. The main safety objective is the incidence of endoscopically detected esophageal thermal lesions (EDEL). This trial includes a substudy of incidence of asymptomatic cerebral lesions detected by magnetic resonance imaging (MRI) after ablation.

RESULTS

A randomized clinical trial compares for the first time high-power short-duration and conventional ablation in order to obtain data about the efficacy and safety of the high-power technique in an adequate methodological context.

CONCLUSIONS

The results of the POWER FAST III could support the use of the high-power short-duration ablation in clinical practice.

REGISTRATION

ClinicalTrials.gov: NTC04153747.

Comparative Efficacy and Safety Profiles of High-power, Short-duration and Low-power, Long-duration Radiofrequency Ablation in Atrial Fibrillation: A Systematic Review and Meta-analysis

High-power, short-duration (HPSD) radiofrequency (RF) ablation is expected to be more effective and safer than low-power, long-duration (LPLD) RF ablation in treating atrial fibrillation (AF). Given the limited data available, the findings are controversial. This meta-analysis evaluated whether the clinical effects of HPSD outweigh those of LPLD. A systematic search of PubMed, Embase, and Google Scholar databases identified studies comparing HPSD to LPLD ablation. All the analyses used the random-effects model. This analysis included 21 studies with a total of 4,169 patients. Pooled analyses revealed that HPSD was associated with a lower recurrence of atrial tachyarrhythmias (ATAs) at 1 year (relative risk [RR], 0.62; 95% confidence interval [CI], 0.50-0.78; P = .00001; I² = 0%). Furthermore, the HPSD approach reduced the risk of AF recurrence (RR, 0.64; 95% CI, 0.40-1.01; P = .06; I² = 86%). The HPSD approach was associated with a lower risk of esophageal thermal injury (ETI) (RR, 0.78; 95% CI, 0.58-1.04; P = .09; I² = 73%). The HPSD strategy increased first-pass pulmonary vein (PV) isolation (PVI) and decreased acute PV reconnection (PVR), both of which were predominantly manifested in bilateral and left PVs. HPSD facilitated a reduction in procedural time, number of lesions created during PVI, and fluoroscopy time. The HPSD method reduces ETI, PVR, and recurrent AF. The HPSD approach also reduced the procedural time, number of lesions created during PVI, fluoroscopy time, and post-ablation AF relapse in 1 year, improving patient outcomes and safety.

Network meta-analysis and systematic review comparing efficacy and safety between very high power short duration, high power short duration, and conventional radiofrequency ablation of atrial fibrillation

BACKGROUND

High-power short-duration (HPSD) atrial fibrillation (AF) ablation with a power of 40-50 W was proved to be safe and effective. Very high-power short-duration (vHPSD) AF ablation is a novel method using >50 W to obtain more durable AF ablation. This study aimed to evaluate the efficacy and safety of vHPSD ablation compared with HPSD ablation and conventional power ablation.

METHODS

A literature search for studies that reported AF ablation outcomes, including short-term freedom from atrial arrhythmia, first-pass isolation (FPI) rate, procedure time, and major complications, was conducted utilizing MEDLINE, EMBASE, and Cochrane databases. All relevant studies were included in this analysis. A random-effects model of network meta-analysis and surface under cumulative ranking curve (SUCRA) were used to rank the treatment for all outcomes.

RESULTS

A total of 29 studies with 9721 patients were included in the analysis. According to the SUCRA analysis, HPSD ablation had the highest probability of maintaining sinus rhythm. Point estimation showed an odds ratio of 1.5 (95% confidence interval [CI]: 1.2-1.9) between HPSD ablation and conventional power ablation and an odds ratio of 1.3 (95% CI: 0.78-2.2) between vHPSD ablation and conventional power ablation. While the odds ratio of FPI between HPSD ablation and conventional power ablation was 3.6 (95% CI: 1.5-8.9), the odds ratio between vHPSD ablation and conventional power ablation was 2.2 (95% CI: 0.61-8.6). The procedure times of vHPSD and HPSD ablations were comparable and, therefore, shorter than that of conventional power ablation. Major complications were low in all techniques.

CONCLUSION

vHPSD ablation did not yield higher efficacy than HPSD ablation and conventional power ablation. With the safety concern, vHPSD ablation outcomes were comparable with those of other techniques.

Correlation of unipolar electrogram modification with ablation index during pulmonary vein isolation: A pilot study

BACKGROUND

Pulmonary vein isolation (PVI) using radiofrequency catheter ablation is a widely accepted therapy for drug-refractory atrial fibrillation patients. Elimination of the negative component of the local unipolar electrogram (UEGM) during PVI is a marker of transmural lesion formation. The ablation index (AI) can predict the quality of ablation lesion. Combining these two parameters could make PVI safer and efficient. The purpose of this pilot study was to examine the correlation between UEGM modification characteristics of the different target areas of left atrium and the associated AI values during PVI.

METHODS

We analyzed 10 patients who underwent PVI using radiofrequency energy. The local electrophysiological properties and ablation parameters of 15 designated areas of interest in the left atria targeted by radiofrequency catheter ablation were collected.

RESULTS

Out of the 10 patients, six were men (mean age 66 years) and 80% had paroxysmal AF. The mean time to achieve the UEGM modification in the posterior wall was shorter than that of the anterior wall (8.9 seconds vs. 11.1 s, respectively). The UEGM modification for every lesion was achieved at significantly lower AI values than conventional AIs (p < .001).

CONCLUSION

During PVI, the AIs deduced according to the local UEGM modification are markedly shorter than those generally recommended AIs in contemporary practice. This indicates that conventionally recommended AIs could be safely reduced while ensuring the efficacy and quality of radiofrequency ablation during PVI. This approach would probably reduce to risk of collateral thermal injuries.

High-Power, Short-Duration Ablation under the Guidance of Relatively Low Ablation Index Values for Paroxysmal Atrial Fibrillation: Long-Term Outcomes and Characteristics of Recurrent Atrial Arrhythmias

OBJECTIVE

The purpose of this study was to evaluate the difference in effectiveness and safety of high-power, short-duration (HPSD) radiofrequency catheter ablation (RFA) guided by relatively low ablation index (AI) values and conventional RFA in paroxysmal atrial fibrillation (PAF) patients.

METHODS

The HPSD RFA strategy (40-50 W, AI 350-400 for anterior, 320-350 for posterior wall; n = 547) was compared with the conventional RFA strategy (25-40 W, without AI; n = 396) in PAF patients who underwent their first ablation. Propensity-score matching analyses were used to compare the outcomes of the two groups while controlling for confounders.

RESULTS

After using propensity-score matching analysis, the HPSD group showed a higher early recurrence rate (22.727% vs. 13.636%, p = 0.003), similar late recurrence rate, and comparable safety (p = 0.604) compared with the conventional group. For late recurrent atrial arrhythmia types, the rate of regular atrial tachycardia was significantly higher in the HPSD group (p = 0.013). Additionally, the rate of chronic pulmonary vein reconnection and non-pulmonary vein triggers during repeat procedures was similar in both groups.

CONCLUSIONS

For PAF patients, compared with the conventional RFA strategy, the HPSD RFA strategy at relatively low AI settings had a higher early recurrence rate, similar long-term success rate, and comparable safety.

Ablation index-guided high-power ablation for superior vena cava isolation in patients with atrial fibrillation

Background

The strategy of ablation index (AI)-guided high-power ablation seems to be a novel strategy for performing pulmonary vein isolation (PVI). An AI-guided high-power ablation strategy was used in this study to determine whether superior vena cava isolation (SVCI) after PVI was feasible and safe for patients with AF.

Methods

Data from 53 patients with AF were collected. Mapping and ablation of SVC were performed. The applied power was set at 45 W and the procedure was guided by AI. The SVC was divided into six segments in a cranial view. The RF applications and AI values in different segments were compared and analyzed. Using receiver operating characteristic (ROC) analysis, the diagnostic accuracy of AI value for predicting segment block was evaluated.

Results

Electrical SVCIs were successfully achieved in all patients. SVCI was performed by segment ablation in most cases, with RF applications in different segments. The mean AI value in non-lateral walls was higher than that of the lateral wall (392 ± 28 vs. 371 ± 37, P < 0.001). Acutely blocked sites had significantly larger AI values compared with no-blocked sites (390 ± 30 vs. 343 ± 23, P < 0.001). The optimal AI cut-off value for non-lateral segments was 379 (sensitivity: 75.9%, specificity: 100%) and for lateral segments was 345 (sensitivity: 82.3%, specificity: 100%).

Conclusion

The AI values were predictive of the acute conduction block of SVCI. With AI values of 345 and 379, respectively, conduction block was achieved in the lateral walls at a lower level than in the non-lateral walls.

Comparison of Effectiveness and Safety between High-Power Short-Duration Ablation and Conventional Ablation for Atrial Fibrillation: A Systematic Review and Meta-Analysis

Aim. We aimed to evaluate the effectiveness and safety between high-power short-duration (HPSD) radiofrequency ablation (RFA) and conventional RFA in patients with atrial fibrillation (AF). Methods. Studies comparing HPSD and traditional applications in patients undergoing initial catheter ablation for atrial fibrillation from inception through December 2021 were searched on Pubmed, Medline, Cochrane, and Clinicaltrials.gov. Results. The meta-analysis included seventeen studies with a total of 4934 patients. HPSD group decreased procedure duration (mean difference (MD) −38.28 min, $P<0.001$ ), RF duration (MD −20.51 min, $P<0.001$ ), fluoroscopy duration (MD −5.19 min, $P<0.001$ ), and acute pulmonary vein reconnection (Odds ratio (OR) 0.40, $P<0.001$ ), while improving the freedom from atrial arrhythmia at one year (OR 1.48, 95% confidence interval (CI) 1.12–1.94, $P=0.005$ ) and rates of first-pass isolation (OR 8.92, $P=0.001$ ). Compared with the conventional group, freedom from atrial arrhythmia at one-year follow-up was higher in the HPSD group without the guidance of AI/LSI (OR 1.66, $P=0.01$ ) and studies with a power setting of 40–50 W (OR 1.93, $P=0.002$ ). Nevertheless, the two groups had similar effectiveness with a power setting of 50 W in the HPSD RFA (OR 1.10, $P=0.52$ ). There was no difference in complications between the two groups ( $P=0.71$ ). Conclusion. HPSD RFA was associated with shorter procedure duration, higher freedom from atrial arrhythmia, and comparable safety compared to conventional RFA.

Comparison between High-Power Short-Duration and Conventional Ablation Strategy in Atrial Fibrillation: An Updated Meta-Analysis

High-power short-duration (HPSD) setting during radiofrequency ablation has become an attempt to improve atrial fibrillation (AF) treatment outcomes. This study ought to compare the efficacy, safety, and effectiveness between HPSD and conventional settings. PubMed, Embase, and Cochrane Library were searched. Studies that compared HPSD and conventional radiofrequency ablation settings in AF patients were included while studies performed additional ablations on nonpulmonary vein targets without clear recording were excluded. Data were pooled with random-effect model. Efficacy endpoints include first-pass pulmonary vein isolation (PVI), acute pulmonary vein (PV) reconnection, free from AF, and free from atrial tachycardia (AT) during follow-up. Safety endpoints include esophagus injury rate and major complication rate. Effectiveness endpoints include complete PVI rate, total procedure time, PVI time, and PVI radiofrequency ablation (PVI RF) time. We included 22 studies with 3867 atrial fibrillation patients in total (2393 patients received HPSD radiofrequency ablation). Perioperatively, the HPSD group showed a higher first-pass PVI rate (risk ratio, $\text{RR}=1.10$ , $P=0.0001$ ) and less acute PV reconnection rate ( $\text{RR}=0.56$ , $P=0.0004$ ) than the conventional group. During follow-up, free from AF ( $\text{RR}=1.11$ , $P=0.16$ ) or AT ( $\text{RR}=1.06$ , $P=0.24$ ) rate did not differ between HPSD and conventional groups 6-month postsurgery. However, the HPSD group showed both higher free from AF ( $\text{RR}=1.17$ , $P=0.0003$ ) and AT ( $\text{RR}=1.11$ , $P<0.0001$ ) rate than the conventional group 12-month postsurgery. The esophagus injury ( $\text{RR}=0.99$ , $P=0.98$ ) and major complications ( $\text{RR}=0.76$ , $P=0.70$ ) rates did not differ between the two groups. The HPSD group took shorter total procedure time ( $\text{MD}=-33.71$ 95% CI: -43.10 to -24.33, $P<0.00001$ ), PVI time ( $\text{MD}=-21.60$ 95% CI: -25.00 to -18.21, $P<0.00001$ ), and PVI RF time ( $\text{MD}=-13.72$ , 95% CI: -14.45 to -13.00, $P<0.00001$ ) than conventional groups while complete procedure rate did not differ between two groups ( $\text{RR}=1.00$ , $P=0.93$ ). HPSD setting during AF radiofrequency ablation has better effectiveness, efficacy, and similar safety compared with the conventional setting.

Response to Letter to the Editor

I appreciate Dr. Koichiro Ejima and collegues pointing out my oversight in not including their second excellent article comparing high-power short duration with low power long duration ablation This article is protected by copyright. All rights reserved.

Meta-analysis of high power short duration in atrial fibrillation ablation - a superior efficient ablation strategy

BACKGROUND

The high power short duration (HPSD) approach was hoped to further improve the efficacy and safety in radiofrequency ablation of atrial fibrillation (AF), compared with Low power long duration (LPLD). However, the conclusion was controversial based on the previous limited data. The aim of this meta-analysis was to evaluate whether the clinical benefits of HPSD are superior to that of LPLD.

METHODS

The PubMed, OVID, the Cochrane Library, and Elsevier's ScienceDirect databases were searched for clinical studies to compare HPSD and LPLD approach by simple search strings benefiting to a wider screened scope.

RESULTS

Fifteen trials with 3255 patients were included in this analysis. Pooled analyses suggested that HPSD was associated with a lower recurrence of atrial tachyarrhythmias (ATAs) at 1-year follow-up (OR: 0.49; 95% CI: 0.35 to 0.67, p < .0001), benefitted from AF recurrence reduced (OR: 0.46; 95% CI: 0.31 to 0.67, p < .0001), rather than atrial tachycardia/atrial flutter (AT/AFL), but similar at 6 months follow-up, with a decreased oesophageal thermal injury (ETI) (OR: 0.48; 95% CI: 0.30 to 0.77, p = .002). Meanwhile, the HPSD approach benefitted to increase first-pass pulmonary vein isolation (FPI) (OR: 0.47; 95% CI: 0.34 to 0.64, p < .00001) and decrease acute pulmonary vein re-isolation (PVR) (OR: 0.45; 95% CI: 0.35 to 0.58, p < .00001), both mainly embodied in left pulmonary veins (PVs). HPSD showed a decreased procedural time (SMD: -0.95; 95% CI: -1.06 to -0.85, p < .00001), ablation number for pulmonary vein isolation (PVI) (SMD: -0.41; 95% CI: -0.58 to -0.24, p < .00001) and fluoroscopy time (SMD: -0.22; 95% CI: -0.32 to -0.12, p < .0001), which benefits from PVI + additional ablation strategy (SMD: -0.33; 95% CI: -0.46 to -0.21, p < .0001).

CONCLUSIONS

The HPSD approach was associated with decreasing post-ablation AF recurrence in the 1-year follow-up, ETI, acute PVR (increasing FPI correspondingly), procedural time, ablation number for PVI and fluoroscopy time, benefitted to improve clinical outcomes and procedural process with improved safety.

Meta-analysis comparing outcomes of high-power short-duration and low-power long-duration radiofrequency ablation for atrial fibrillation

OBJECTIVE

High power short duration (HPSD) ablation strategy is proposed to be more effective than low power long duration (LPLD) for radiofrequency ablation of atrial fibrillation. Although small trials abound, data from a large cohort are lacking. This meta-analysis compares all the existing studies comparing these two approaches to evaluate perceived advantages of one over the other.

METHODS

A systematic search of PubMed, EMBASE, and Cochrane databases identified studies comparing HPSD to LPLD ablation. All the analyses used the random-effects model.

RESULTS

Ablation settings varied widely across 20 studies comprising 2,136 patients who underwent HPSD and 1,753 patients who underwent LPLD. The pooled incidence of atrial arrhythmia recurrence after HPSD ablation was 20% [95% confidence interval (CI): 0.16-0.25; I2=88%]. Atrial arrhythmia recurrences were significantly less frequent with HPSD ablation (incidence risk ratio=0.66; 95% CI: 0.49-0.88; I2=72%; p=0.004). Procedural, fluoroscopy, and ablation times were significantly shorter with HPSD ablation. First-pass pulmonary vein isolations (PVIs) were significantly more [odds ratio (OR)=2.94; 95% CI: 1.50-5.77; I2=89%; p=0.002), and acute pulmonary vein reconnections (PVRs) were significantly lesser (OR=0.41; 95% CI: 0.28-0.62; I2=62%; p<0.001) in the HPSD group. Although radiofrequency energy was significantly higher, esophageal thermal injuries (ETI) were lower with HPSD ablation. Acute complications, including steam-pops, were rare and statistically similar in both the groups.

CONCLUSION

HPSD ablation enables faster first-pass PVI with fewer PVRs, similar ETI rates, rare collateral damage, and lower recurrence of atrial arrhythmia in the long term than LPLD. Randomized controlled studies with a larger cohort are indicated both to confirm the benefit of HPSD ablation and standardize the ablation protocol.

Assessment of High-Power Catheter Ablation in Patients With Atrial Fibrillation: A Meta-Analysis

Background: High-power radiofrequency (RF) catheter ablation was considered as a promising alternative strategy to conventional-power ablation in the treatment of patients with atrial fibrillation (AF). This study sought to compare the efficacy and safety of high-power energy delivery to that of conventional-power setting in AF catheter ablation. Methods: We performed a systematic review of relevant literature in Pubmed, Embase, Cochrane library, and Google Scholar database. Sixteen eligible studies totaling 3,307 patients (1,929 for high-power ablation; 1,378 for conventional-power ablation) met inclusion criteria. Results: During a median 12 month follow-up, high-power ablation showed a significantly higher AF/atrial tachycardia-free survival rate in comparison with conventional-power ablation (risk ratio [RR] 1.09, 95% CI 1.02 to 1.15, p = 0.008). Notably, a high-power strategy convincingly decreased the procedure time (weighted mean difference [WMD] -46.11 min, 95% CI -59.15 to -33.07, p < 0.001) and RF ablation time (WMD -19.19 min, 95% CI -24.47 to -13.90, p < 0.001), along with reduced fluoroscopy time (WMD -7.82 min, 95% CI -15.13 to -0.68, p = 0.036). In addition, there was no perceptible difference in the potential risk of procedure-related complications between these two approaches (RR 0.81, 95% CI 0.48 to 1.37, p = 0.428). Conclusions: High-power RF catheter ablation was associated with an improvement in long-term sinus rhythm maintenance for treatment of AF, without exacerbating the risk of adverse events during the procedure. Impressively, high-power pulmonary vein isolation had the potential to shorten the application duration and minimize fluoroscopic exposure.

Regional differences in the predictors of acute electrical reconnection following high-power pulmonary vein isolation for paroxysmal atrial fibrillation

BACKGROUND

Acute pulmonary vein reconnection (PVR) is associated with long procedure times and large radiofrequency (RF) energy delivery during pulmonary vein isolation (PVI). Although the efficacy of high-power PVI (HP-PVI) has been recently established, the determinants of acute PVR following HP-PVI remain unclear.

METHODS

We evaluated data on 62 patients with paroxysmal atrial fibrillation undergoing unipolar signal modification (USM)-guided HP-PVI. A 50-W RF wave was applied for 3-5 seconds after USM. In the segments adjacent to the esophagus (SAEs), the RF time was limited to 5 seconds. Each circle was subdivided into six regions (segments), and the possible predictors of acute PVR, including minimum contact force (CFmin), minimum force-time integral (FTImin), minimum ablation index (AImin), minimum impedance drop (Imp-min), and maximum inter-lesion distance (ILDmax), were assessed in each segment.

RESULTS

We investigated 1162 ablations in 744 segments (including 124 SAEs). Acute PVR was observed in 21 (17%) SAEs and 43 (7%) other segments (P = .001). The acute PVR segments were characterized by significantly lower CFmin, FTImin, AImin, and Imp-min values in the segments other than the SAEs and larger ILDmax values in the SAEs. Furthermore, lower Imp-min and larger ILDmax values independently predicted acute PVR in the segments other than the SAEs and SAEs (odds ratios 0.90 and 1.39 respectively). Acute PVR was not significantly associated with late atrial fibrillation recurrence.

CONCLUSIONS

Avoiding PVR remains a challenge in HP-PVI cases, but it might be resolved by setting the optimal target impedance drop and lesion distance values.

High-power short duration vs. conventional radiofrequency ablation of atrial fibrillation: a systematic review and meta-analysis

AIMS

We sought to compare the effectiveness and safety of high-power short-duration (HPSD) radiofrequency ablation (RFA) with conventional RFA in patients with atrial fibrillation (AF).

METHODS AND RESULTS

MEDLINE, Cochrane, and ClinicalTrials.gov databases were searched until 15 May 2020 for relevant studies comparing HPSD vs. conventional RFA in patients undergoing initial catheter ablation for AF. A total of 15 studies involving 3718 adult patients were included in our meta-analysis (2357 in HPSD RFA and 1361 in conventional RFA). Freedom from atrial arrhythmia was higher in HPSD RFA when compared with conventional RFA [odds ratio (OR) 1.44, 95% confidence interval (CI) 1.10-1.90; P = 0.009]. Acute PV reconnection was lower (OR 0.56, P = 0.005) and first-pass isolation was higher (OR 3.58, P < 0.001) with HPSD RFA. There was no difference in total complications between the two groups (P = 0.19). Total procedure duration [mean difference (MD) -37.35 min, P < 0.001], fluoroscopy duration (MD -5.23 min, P = 0.001), and RF ablation time (MD -16.26 min, P < 0.001) were all significantly lower in HPSD RFA. High-power short-duration RFA also demonstrated higher freedom from atrial arrhythmia in the subgroup analysis of patients with paroxysmal AF (OR 1.80, 95% CI 1.29-2.50; P < 0.001), studies with ≥50 W protocol in the HPSD RFA group (OR 1.53, 95% CI 1.08-2.18; P = 0.02] and studies with contact force sensing catheter use (OR 1.65, 95% CI 1.21-2.25; P = 0.002).

CONCLUSION

High-power short-duration RFA was associated with better procedural effectiveness when compared with conventional RFA with comparable safety and shorter procedural duration.

The superiority of high-power short-duration radiofrequency catheter ablation strategy for atrial fibrillation treatment: A systematic review and meta-analysis study

BACKGROUND

Radiofrequency catheter ablation (RFCA) using the high-power short duration (HPSD) results in better ablation lesion formation in the swine model. This systematic review and meta-analysis purposed to investigate the safety and efficacy profile between HPSD and low-power long-duration (LPLD) ablation strategies to treat atrial fibrillation (AF) patients.

METHODS

We completed the literature review after identifying the relevant articles comparing HPSD and LPLD ablation methods for AF recorded in ClinicalTrials.com, CENTRAL, PubMed, and ScienceDirect until February 2021. The overall effects were calculated using pooled risk ratio (RR) and mean difference (MD) for categorical and continuous data, respectively. We also estimated the 95% confidence interval (CI).

RESULTS

The HPSD strategy took shorter procedure time (MD = -33.75 min; 95% CI = -44.54 to -22.97; P < .01), fluoroscopy time (MD = -5.73 min; 95% CI = -8.77 to -2.70; P < .001), and ablation time (MD = -17.71; 95% CI = -21.02 to -14.41) than LPLD strategy. The HPSD RFCA was correlated with lower risk of esophageal thermal injury (RR = 0.75; 95% CI = 0.59 to 0.94; P = .02). The HPSD method resulted in higher first-pass pulmonary vein isolation (PVI) (RR = 1.36; 95% CI = 1.13 to 1.64; P < .01), lower PV reconnection (RR = 0.47; 95% CI = 0.34 to 0.64; P < .01), and lower recurrent AF (RR = 0.72; 95% CI = 0.54 to 0.96; P = .02) than LPLD strategy.

CONCLUSION

HPSD RFCA was superior to the conventional LPLD RFCA in terms of safety and efficacy in treating AF patients.

Comparison of higher-power and conventional power ablation of atrial fibrillation using contact force-sensing catheters: a systematic review and meta-analysis

BACKGROUND

Contact force-sensing catheters have been widely used in catheter ablation. During the past few decades, more attention has been paid on the technique of high-power ablation. The purpose of this meta-analysis is to compare the efficacy and safety of conventional power and high power on atrial fibrillation radiofrequency ablation by contact force-sensing catheters.

METHODS

We identified studies through searching MEDLINE, Embase, the Web of Science, Scopus, and the Cochrane Library from inception up until July 2020. The primary outcomes were defined as recurrence of atrial tachyarrhythmia and complications. The secondary outcomes were acute reconnections of pulmonary veins (PVs), ablation time, and the total procedural time.

RESULTS

Four nonrandomized, observational studies (nROS) were selected involving 231 patients with high-power ablation and 239 patients with conventional power ablation. There were insignificant differences in the recurrence rate of atrial tachyarrhythmia (14.2% versus 20.5%, OR: 0.64, 95%CI: 0.39 to 1.04, Z = 1.82, P = 0.07) and clinical complications (1.7% versus 2.5%, OR: 0.72, 95%CI: 0.21 to 2.47, Z = 0.51, P = 0.61) between high-power and conventional power ablation. However, compared with conventional power group, the high-power group had fewer acute PVs reconnections (P = 0.0001), shorter in ablation time (P < 0.0001), and the total procedural time (P < 0.0001).

CONCLUSIONS

High-power ablation could not only ablate safely and efficiently but also reduce focal ablation time and total procedural time significantly.

Efficiency, Safety, and Efficacy of High-Power Short-Duration Radiofrequency Ablation in Patients with Atrial Fibrillation

Pulmonary vein isolation (PVI) is the cornerstone therapy of atrial fibrillation (AF). Radiofrequency catheter ablation (RFCA) is performed using a point-by-point method to achieve durable PVI. However, this procedure remains complex and time-consuming, and the long-term clinical outcomes are still not satisfactory. Recently, there has been increasing interest in the clinical application of high-power short-duration (HPSD) approaches in the field of RFCA. HPSD ablation, distinguishing it from the conventional ablation strategy, delivers RF energy at a high power and saves the dwell time at each site. It is unknown whether the HPSD approach can bring some gratifying changes in the field of RF energy ablation. A number of experimental studies and clinical studies have been conducted regarding this topic. The review aimed to summarize the research findings and evaluate the procedural efficiency, safety, and clinical outcomes of the HPSD approach based on the evidence available to date.

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

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.

Comparison of high-power and conventional-power radiofrequency energy deliveries in pulmonary vein isolation using unipolar signal modification as a local endpoint

Introduction

Negative component abolition of the unipolar signal (unipolar signal modification [USM]) reflects the lesion transmurality. The purpose of this study was to compare the procedural safety and outcome between high‐power and conventional‐power atrial radiofrequency applications during a pulmonary vein isolation (PVI) using USM as a local endpoint.

Methods and Results

High‐power (50 W) and conventional‐power (25‐40 W) applications were compared among 120 consecutive patients with paroxysmal atrial fibrillation who underwent a USM‐guided PVI. The first 60 patients were treated with conventional‐power (CP) group and last 60 with high‐power (HP) group. The atrial radiofrequency applications lasted for 5 to 10 seconds (CP group) or 3 to 5 seconds (HP group) after the USM. All procedures were performed using 3D mapping systems with image integration and esophageal temperature monitoring. The baseline characteristics were similar between the two groups. The HP group had fewer acute PV reconnections (62% vs 78%; P = .046) and a reduced procedure time (119.3 ± 28.1 vs 140.1 ± 51.2 minutes; P = .04). Freedom from recurrence after a single ablation procedure without any antiarrhythmic drugs was higher in the HP group than CP group (88.3% vs 73.3% at 12‐months after the procedure, log‐rank; P = .0423). There were no major complications that required any intervention.

Conclusions

The high‐power PVI guided by USM decreased the procedural time and may improve the procedural outcomes without compromising the safety.