Efficacy of high-power and short-duration ablation in patients with atrial fibrillation: a prospective randomized controlled trial

Comparison of high-power single-ring isolation and box isolation in elderly patients with persistent atrial fibrillation

BACKGROUND

This study evaluated the superiority of single-ring isolation (SRI) over box isolation using high power in elderly patients with persistent atrial fibrillation (PeAF).

METHODS

We retrospectively studied elderly patients with PeAF who underwent primary catheter ablation. The patients were divided into the SRI group and the posterior box isolation (BOXI) group. Basic characteristics, procedural variables, complications and atrial arrhythmia recurrence rates were collected.

RESULTS

Forty-five pairs of patients in the two groups were matched by 1:1 PSM. Compared with that in the BOXI group, the total procedure time in the SRI group was not significantly different (P = 0.340). However, there were significant reductions in the total ablation time, ring ablation lesions and number of lesions on the posterior wall in patients who underwent SRI compared to those who underwent BOXI (all P < 0.001). The cardiac troponin level in the SRI group was significantly lower (P = 0.023). There were significantly fewer mismatched three-dimensional mapping models and mismatched models per patient due to pain-induced movement in the SRI group (all P < 0.05). The questionnaires revealed that the pain score was significantly lower in the SRI group than in the BOXI group (P < 0.001). In addition, significantly fewer patients with SRI than with BOXI experienced gastrointestinal symptoms after the procedure (15.56% vs. 37.78%, P = 0.017). K‒M analysis revealed no significant difference in atrial arrhythmia-free survival at 12 months between the SRI and BOXI patients (P > 0.05).

CONCLUSIONS

High-power SRI is safe and feasible and may be superior to the BOXI for experience of elderly patients with PeAF.

Association of a Left Atrial Diverticulum with Adverse Events During Catheter Ablation for Atrial Fibrillation

Background/Objectives: Left atrial diverticula (LADs) have been reported to potentially be associated with arrhythmic substrates, thromboembolic events, and complications during catheter ablation for atrial fibrillation (AF), but their clinical significance remains unclear. This study aimed to assess the prevalence, location, and potential relationship with complications during AF catheter ablation using preoperative CT. Methods: This study included 595 consecutive patients undergoing AF catheter ablation at Keio University Hospital from April 2021 to February 2024. Preoperative ECG-gated cardiac MDCT scans were analyzed to assess the presence and location of the LAD. Intraoperative adverse events were documented, and the association between the LAD and mechanical complications, such as a cardiac perforation and tamponade, was evaluated. Results: A total of 595 patients undergoing catheter ablation for AF or atrial tachycardia (AT) were included, with 210 (35.3%) found to have an LAD. No significant differences in age, sex, body mass index, or arrhythmia type were observed between patients with or without an LAD. LADs were most commonly located in the anterior region of the right superior pulmonary vein (53.4% of cases), followed by the anterior region of the left superior pulmonary vein (15% of cases). Perioperative complications occurred in 12 cases (2.0%), with 7 in the LAD group and 5 in the non-LAD group. Mechanical complications were observed exclusively in the LAD group (n = 4), with three of the cases associated with LADs. In all cases, LADs were present in the anterior region of the right superior pulmonary vein and were caused by the accidental insertion of an angiographic catheter into the LAD during pulmonary venography before insertion of the ablation catheter into the left atrium. However, all cases were hemodynamically stable, and the procedures were completed as planned. Conclusions: LADs are a more common anatomical structure than generally recognized and may be associated with mechanical complications during AF catheter ablation. Identifying the presence of an LAD on preoperative CT is crucial for predicting potential risks.

Safety and efficacy of lesion size index guided 50 W radiofrequency ablation in patients with paroxysmal atrial fibrillation

BACKGROUND

Pulmonary vein isolation (PVI) using conventional power (30-35 W) radiofrequency ablation (RFA) has been an effective treatment strategy for paroxysmal atrial fibrillation (PAF), but its longer duration may cause collateral damage to peripheral tissue including esophageal and phrenic nerve. High-power (HP) RFA, due to better transmural performance and shorter duration, may reduce the damage to adjacent tissue and is expected to be a safe and efficient ablation strategy.

METHODS

In this retrospective cohort study, we included 259 patients with PAF who underwent lesion size index (LSI)-guided radiofrequency ablation. All patients underwent PVI-based ablation, and some underwent additional ablation, including superior vena cava isolation, tricuspid isthmus block, or left anterior atrial matrix modification. A total of 119 PAF patients underwent 50 W ablation. Complications and twelve-month arrhythmia-free outcomes of the procedure were compared with those of 140 patients who underwent 30-35 W ablation.

RESULTS

PVI was successfully achieved in all patients. The procedural duration (140.3 ± 34.4 vs. 151.3 ± 40.6 min, P = 0.022) and overall radiation (112.0 ± 67.2 vs. 188.2 ± 119.2 mGy·cm2, P < 0.001) were significantly lower in the 50 W group. No major complications occurred in the high-power short-duration (HPSD) group, whereas in the conventional power group, five participants developed complications. Among them, three cases were related to venipuncture, one had pericardial tamponade, and one had slight pericardial effusion. The recurrence of arrhythmia at the twelve-month follow-up was not significantly different between the two groups [11 (9.2%) vs. 19 (13.6%), P = 0.278].

CONCLUSION

LSI-guided HPSD-RFA was demonstrated to be comparably safe and efficacious compared to conventional ablation and resulted in reduced procedure time and radiation exposure.

High-Power Short-Duration Radiofrequency Application for Faster and Safer Pulmonary Vein Isolation: The POWER-FAST III Trial

BACKGROUND

The optimal radiofrequency application (RFa) parameters for safe and durable pulmonary vein isolation (PVI) are debated. High-power short-duration (HPSD) has been used as an alternative to conventional power delivery (CPD).

OBJECTIVES

This study sought to compare HPSD 70 W/9-10 s (HPSD-70) with CPD 25-40 W in patients undergoing PVI.

METHODS

Patients were randomized to HPSD-70 or CPD (25-40). The primary outcomes were freedom from atrial arrhythmia recurrences and the incidence of esophageal thermal lesions (EDELs) after ablation.

RESULTS

Among 304 patients randomized, 301 remained in the study (median age: 61 years; Q1-Q3: 53-69 years; 72% men): 294 patients (97.7%) underwent ablation, 285 (94.7%) underwent endoscopy, and 290 (98.6%) completed the follow-up. At 12 months, 100 patients (73.5%) in the CPD (25-40) group and 87 patients (67%) in the HPSD-70 group were free from recurrences off antiarrhythmic drugs (HR: 1.28; 95% CI: 0.82-1.99; P = 0.28). The incidences of EDELs were 2.7% in the CPD (25-40) group and 3.6% in the HPSD-70 group (P = 0.94). Median left atrial dwell (153 vs 137 min; P = 0.03) and total RF times for definitive PVI (31 vs 11.2 min; P < 0.001) were shorter with HPSD-70 ablation. Four symptomatic embolic events (2 strokes, 1 transient ischemic attack, and 1 splenic infarct) occurred with HPSD-70 and none with CPD (25-40) RFa (P = 0.056).

CONCLUSIONS

HPSD-70 RFa was noninferior to prevent arrhythmia recurrences, and the incidence of EDELs was similar compared with CPD (25-40) RFa. The embolic events were numerically higher in the HPSD-70 group. (High Radiofrequency Power for Faster and Safer Pulmonary Vein Ablation Trial [POWER FAST III]; NCT04153747).

Safety and efficacy of intracardiac echocardiography-guided zero-fluoroscopy ablation in atrial fibrillation patients: a comparative study of high-power short-duration and low-power long-duration strategies

Introduction

In atrial fibrillation (AF) ablation, fluoroscopy has been a standard tool for catheter guidance. However, the combination of electroanatomic mapping systems (EAMs) and intracardiac echocardiography (ICE) now allows for minimal or zero-fluoroscopy procedures. Concurrently, high-power short-duration (HPSD) ablation has emerged as a promising technique, offering enhanced resistive heating while reducing conductive heating. This approach potentially improves both safety and efficacy. Despite these advancements, there is a lack of comprehensive clinical data on the safety and effectiveness of HPSD ablation when used in conjunction with ICE-guided zero-fluoroscopy procedures.

Objective

To compare two different ablation strategies-high-power short-duration (HPSD) and low-power long-duration (LPLD)-both utilizing intracardiac echocardiography (ICE)-guided zero-fluoroscopy in the context of atrial fibrillation (AF) ablation.

Methods

This retrospective study included 173 consecutive patients with AF who underwent ICE-guided zero-fluoroscopy ablation. Patients were divided into two groups: HPSD and LPLD. All procedures were conducted using an EAM system with ICE guidance. Both groups underwent routine pulmonary vein isolation (PVI), with additional linear ablations performed for persistent AF when necessary. We compared treatment outcomes and the incidence of complications between the two groups.

Results

All procedures were successfully completed under ICE-guided zero-fluoroscopy, establishing a feasible and reliable workflow. The procedure and ablation times were significantly shorter in the HPSD group compared to the LPLD group. At one-year follow-up, sinus rhythm was maintained in 77 patients in the HPSD group and 74 patients in the LPLD group, with no significant difference between the two group. Postoperative complications occurred in 5 patients in the HPSD group and 3 patients in the LPLD group. Importantly, there were no major adverse cardiac and cerebrovascular events (MACCE) in either group.

Conclusion

A zero-fluoroscopy workflow utilizing an EAM system combined with ICE appears to be both feasible and safe for ablation in AF patients. In patients undergoing ICE-guided zero-fluoroscopy ablation, the HPSD strategy is comparable to LPLD ablation in effectiveness while offering the benefit of shorter procedure and ablation times.

Efficacy of catheter ablation for atrial fibrillation in heart failure: a meta-analysis of randomized controlled trials

The study aims to evaluate whether rhythm control by catheter ablation is superior to medical therapy for the patients with atrial fibrillation (AF) and heart failure (HF). The literatures were searched by using PubMed, Cochrane Library, Embase, and Web of Science databases up to 12 October 2023. The randomized controlled trials (RCTs) comparing rhythm control using catheter ablation vs. medical therapy in AF patients with HF were pooled. The primary outcomes included all-cause mortality, HF re-hospitalization, and stroke, and the secondary outcomes included left ventricular ejection fraction (LVEF), atrial tachyarrythmia recurrence, quality of life (Minnesota Living with Heart Failure Questionnaire score, MLHFQ score), 6 min walking distance (6MWD), the level of N-terminal B-type natriuretic peptide precursor (NT-proBNP), and adverse events. Nine RCTs involving in 2293 patients met the inclusion criteria. Compared with medical therapy, catheter ablation reduced all-cause mortality [10.07% (121/1201) vs. 15.26% (175/1147), risk ratio (RR):0.60, 95% confidence interval (CI): 0.48-0.74, P < 0.00001, I2 = 0%] and the rate of HF re-hospitalization (RR: 0.65, P = 0.02, 95% CI: 0.45 to 0.94, I2 = 74%), but had no obvious difference in incidence of stroke (RR: 0.67, P = 0.27, 95% CI: 0.32 to 1.38, I2 = 0%). Catheter ablation enhanced LVEF [mean difference (MD), 6.26%, P < 0.00001, I2 = 89%], reduced AT recurrence (RR: 0.37, P < 0.00001, 95% CI: 0.26 to 0.52, I2 = 89%), improved the quality of life (MLHFQ score) (MD: -6.83, P = 0.003, I2 = 67%), elevated 6MWD (MD: 15.92, P = 0.006, I2 = 76%), and diminished the level NT-proBNP (MD: -44.19, P < 0.00001, I2 = 75%), but had no significant difference in adverse events [25.81% (310/1201) vs. 30.25% (347/1147), RR: 0.81, 95% CI: 0.65-1.01, P = 0.06, I2 = 55%]. Catheter ablation as rhythm control strategy substantially enhances the survival rate, reduces HF re-hospitalization, increases the rate of sinus rhythm maintenance, improves the left ventricular function and the quality of life for AF patients with HF, and has similar safety, compared with medical therapy. The rhythm control by catheter ablation may be a better strategy for the AF patients with HF.

Efficacy and safety of high-power short-duration ablation for atrial fibrillation: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

High-power short-duration (HPSD) ablation has emerged as an alternative to conventional standard-power long-duration (SPLD) ablation. We aim to assess the efficacy and safety of HPSD versus SPLD for atrial fibrillation (AF) ablation.

METHODS

A systematic review and meta-analysis of randomized controlled trials (RCTs) retrieved from PubMed, WOS, SCOPUS, EMBASE, and CENTRAL were performed through August 2023. We used RevMan V. 5.4 to pool dichotomous data using risk ratio (RR) and continuous data using mean difference (MD) with a 95% confidence interval (CI).

PROSPERO ID

CRD42023471797.

RESULTS

We included six RCTs with a total of 694 patients. HPSD was significantly associated with a decreased total procedure time (MD: -22.88 with 95% CI [-36.13, -9.63], P = 0.0007), pulmonary vein isolation (PVI) time (MD: -19.73 with 95% CI [-23.93, -15.53], P < 0.00001), radiofrequency time (MD: -10.53 with 95% CI [-12.87, -8.19], P < 0.00001). However, there was no significant difference between HPSD and SPLD ablation with respect to the fluoroscopy time (MD: -0.69 with 95% CI [-2.00, 0.62], P = 0.30), the incidence of esophageal lesions (RR: 1.15 with 95% CI [0.43, 3.07], P = 0.77), and the incidence of first pass isolation (RR: 0.98 with 95% CI [0.88, 1.08], P = 0.65).

CONCLUSION

HPSD ablation was significantly associated with decreased total procedure time, PVI time, and radiofrequency time compared with SPLD ablation. On the contrary, SPLD ablation was significantly associated with low maximum temperature.

2023 Cardiac Society of Australia and New Zealand Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation

Catheter ablation for atrial fibrillation (AF) has increased exponentially in many developed countries, including Australia and New Zealand. This Expert Position Statement on Catheter and Surgical Ablation for Atrial Fibrillation from the Cardiac Society of Australia and New Zealand (CSANZ) recognises healthcare factors, expertise and expenditure relevant to the Australian and New Zealand healthcare environments including considerations of potential implications for First Nations Peoples. The statement is cognisant of international advice but tailored to local conditions and populations, and is intended to be used by electrophysiologists, cardiologists and general physicians across all disciplines caring for patients with AF. They are also intended to provide guidance to healthcare facilities seeking to establish or maintain catheter ablation for AF.

Does the same lesion index mean the same efficacy and safety profile: influence of the differential power, time, and contact force on the lesion size and steam pops under the same lesion index

BACKGROUND

The lesion index (LSI) helps predict the lesion size and is widely used in ablation of various types of arrhythmias. However, the influence of the ablation settings on the lesion formation and incidence of steam pops under the same LSI value remains unclear.

METHODS

Using a contact force (CF) sensing catheter (TactiCath™) in an ex vivo swine left ventricle model, RF lesions were created with a combination of various power steps (30 W, 40 W, 50 W) and CFs (10 g, 20 g, 30 g, 40 g, 50 g) under the same LSI values (5.2 and 7.0). The correlation between the lesion formation and ablation parameters was evaluated.

RESULTS

Ninety RF lesions were created under a target LSI value of 5.2, and eighty-four were developed under a target LSI value of 7.0. In the LSI 5.2 group, the resultant lesion size widely varied according to the ablation power, and a multiple regression analysis indicated that the ablation energy delivered was the best predictor of the lesion formation. To create a lesion depth > 4 mm, an ablation energy of 393 J is the best cutoff value, suggesting a possibility that ablation energy may be used as a supplemental marker that better monitors the progress of the lesion formation in an LSI 5.2 ablation. In contrast, such inconsistency was not obvious in the LSI 7.0 group. Compared with 30 W, the 50-W ablation exhibited a higher incidence of steam pops in both the LSI 5.2 and 7.0 groups.

CONCLUSIONS

The LSI-lesion size relationship was not necessarily consistent, especially for an LSI of 5.2. To avoid any unintentional, weak ablation, the ablation energy may be a useful supportive parameter (393 J as a cutoff value for a 4-mm depth) during ablation with an LSI around 5.2. Thanks to a prolonged ablation time, the LSI-lesion size relationship is consistent for an LSI of 7.0. However, it is accompanied by a high incidence of steam pops. Care should be given to the ablation settings even when the same LSI value is used.

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.

Impact of high-power short-duration atrial fibrillation ablation technique on the incidence of silent cerebral embolism: a prospective randomized controlled study

BACKGROUND

High-power short-duration (HPSD) ablation strategy has emerged as a popular approach for treating atrial fibrillation (AF), with shorter ablation time. The utilized Smart Touch Surround Flow (STSF) catheter, with 56 holes around the electrode, lowers electrode-tissue temperature and thrombus risk. Thus, we conducted this prospective, randomized study to investigate if the HPSD strategy with STSF catheter in AF ablation procedures reduces the silent cerebral embolism (SCE) risk compared to the conventional approach with the Smart Touch (ST) catheter.

METHODS

From June 2020 to September 2021, 100 AF patients were randomized 1:1 to the HPSD group using the STSF catheter (power set at 50 W) or the conventional group using the ST catheter (power set at 30 to 35 W). Pulmonary vein isolation was performed in all patients, with additional lesions at operator's discretion. High-resolution cerebral diffusion-weighted magnetic resonance imaging (hDWI) with slice thickness of 1 mm was performed before and 24-72 h after ablation. The incidence of new periprocedural SCE was defined as the primary outcome. Cognitive performance was assessed using the Montreal Cognitive Assessment (MoCA) test.

RESULTS

All enrolled AF patients (median age 63, 60% male, 59% paroxysmal AF) underwent successful ablation. Post-procedural hDWI identified 106 lesions in 42 enrolled patients (42%), with 55 lesions in 22 patients (44%) in the HPSD group and 51 lesions in 20 patients (40%) in the conventional group (p = 0.685). No significant differences were observed between two groups regarding the average number of lesions (p = 0.751), maximum lesion diameter (p = 0.405), and total lesion volume per patient (p = 0.669). Persistent AF and CHA2DS2-VASc score were identified as SCE determinants during AF ablation procedure by multivariable regression analysis. No significant differences in MoCA scores were observed between patients with SCE and those without, both immediately post-procedure (p = 0.572) and at the 3-month follow-up (p = 0.743).

CONCLUSIONS

Involving a small sample size of 100 AF patients, this study reveals a similar incidence of SCE in AF ablation procedures, comparing the HPSD strategy using the STSF catheter to the conventional approach with the ST catheter.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT04408716. AF = Atrial fibrillation, DWI = Diffusion-weighted magnetic resonance imaging, HPSD = High-power short-duration, ST = Smart Touch, STSF = Smart Touch Surround Flow.

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.

High power short duration versus low power long duration ablation in patients with atrial fibrillation: A meta-analysis of randomized trials

BACKGROUND

High-power-short-duration (HPSD) radiofrequency (RF) ablation is a viable alternative to low-power-long-duration (LPLD) RF for pulmonary vein isolation (PVI). Nevertheless, trials showed conflicting results regarding atrial fibrillation (AF) recurrences and few data concerning complications. Therefore, we conducted a meta-analysis of randomized trials comparing HPSD versus LPLD.

METHODS

We systematically searched the electronic databases for studies published from inception to March 31, 2023 focusing on HPSD versus LPLD. The study endpoints were AF recurrence, procedural times and overall complications.

RESULTS

Five studies enrolling 424 patients met the inclusion criteria (mean age 61.1 years; 54.3% paroxysmal AF; mean LVEF 58.2%). Compared to LPLD, HPSD showed a significantly lower AF recurrence rate [16.3% vs. 30,1%; RR: 0.54 (95% CI: 0.38-0.79); p = 0.001] at a mean 10.9 months follow-up. Moreover, HPSD led to a significant reduction in total procedural time [MD: -26.25 min (95%CI: -42.89 to -9.61); p = 0.002], PVI time [MD: -26.44 min (95%CI: -38.32 to -14.55); p < 0.0001], RF application time [MD: -8.69 min (95%CI: -11.37 to -6.01); p < 0.00001] and RF lesion number [MD: -7.60 (95%CI: -10.15 to -5.05); p < 0.00001]. No difference was found in either right [80.4% vs. 78.2%; RR: 1.04 (95% CI: 0.81-1.32); p = 0.77] or left [92.3% vs. 90.2%; RR: 1.02 (95% CI: 0.94-1.11); p = 0.58] first-pass isolation and overall complications [6% vs. 3.7%; RR: 1.45 (95%CI: 0.53-3.99); p = 0.47] between groups.

CONCLUSION

In our metanalysis of randomized trials, HPSD ablation appeared to be associated to a significantly improved freedom from AF and shorter procedures, without increasing the risk of complications.

Optimization of superior vena cava isolation with aid of ablation index guidance

INTRODUCTION

To investigate the optimal range of quantitative ablation index (AI) value during superior vena cava (SVC) electrical isolation by radiofrequency catheter ablation (RFCA).

METHODS

First, in a development cohort of patients with atrial fibrillation (AF), the RFCA with 40 W was performed to complete SVC isolation guided by the conduction breakthrough point from the right atrium to SVC. Then, the range of AI value was calculated by offline analysis on different segments of SVC. Lastly, for the validation of AF patients, the safety and effectiveness of SVC isolation with the optimized target range of AI value were evaluated with an additional adenosine test.

RESULTS

A total of 101 patients with AF were included in the study (44 patients in the development cohort/57 in the validation cohort). The segmental ablation strategy was applied in 70% of the patients. According to the offline analysis of the AI values in the development cohort, the target AI value range was set as 350-400. The success rate of SVC isolation in the validation cohort was significantly higher than that in the exploration cohort (100% vs. 90.9%, p = .02), and no complications occurred in the exploration cohort. During the adenosine test, the recovery rate of electrical conduction in SVC was significantly lower than that in the pulmonary vein (3.5% vs. 17.5%).

CONCLUSION

The target AI value with a range from 350 to 400 is safe and effective for high-power RFCA to complete SVC isolation.

Higher power achieves greater local impedance drop, shorter ablation time, and more transmural lesion formation in comparison to lower power in local impedance guided radiofrequency ablation of atrial fibrillation

BACKGROUND

Since the local impedance (LI) of the ablation catheter reflects tissue characteristics, the efficacy of higher power (HP) compared to lower power (LP) in LI-guided ablation may differ from other index-guided ablations.

OBJECTIVE

This study aimed to assess the efficacy of HP ablation in LI-guided ablation of atrial fibrillation (AF).

METHODS

A prospective observational study was conducted, enrolling patients undergoing de novo ablation for AF. Pulmonary vein isolation was performed using point-by-point ablation with a RHYTHMIA HDxTM Mapping System and an open-irrigated ablation catheter with mini-electrodes (IntellaNav MIFI OI). Ablation was stopped when the LI drop reached 30 ohms, three seconds after the LI plateaued, or when ablation time reached 30 s. To balance the baseline differences, a unique method was used in which the power was changed between HP (45 W to anterior wall/40 W to posterior wall) and LP (35 W/30 W) alternately for each adjacent point.

RESULTS

A total of 551 ablations in 10 patients were analyzed (HP, n = 276; LP, n = 275). The maximum LI drop was significantly larger (HP: 28.3 ± 5.4 vs. LP: 24.8 ± 6.3 ohm), and the time to minimum LI was significantly shorter (HP: 15.0 ± 6.3 vs. LP: 19.3 ± 6.6 s) in the HP setting. The unipolar electrogram analysis of three patients revealed that the electrogram indicating transmural lesion formation was observed more frequently in the HP setting.

CONCLUSION

In LI-guided ablation, the HP could achieve a larger LI drop and shorter time to minimum LI, which may result in more transmural lesion formation compared to a LP setting.

Effects of Inflammatory Cell Death Caused by Catheter Ablation on Atrial Fibrillation

Atrial fibrillation (AF) poses a serious healthcare burden on society due to its high morbidity and the resulting serious complications such as thrombosis and heart failure. The principle of catheter ablation is to achieve electrical isolation by linear destruction of cardiac tissue, which makes AF a curable disease. Currently, catheter ablation does not have a high long-term success rate. The current academic consensus is that inflammation and fibrosis are central mechanisms in the progression of AF. However, artificially caused inflammatory cell death by catheter ablation may have a significant impact on structural and electrical remodeling, which may affect the long-term prognosis. This review first focused on the inflammatory response induced by apoptosis, necrosis, necroptosis, pyroptosis, ferroptosis and their interaction with arrhythmia. Then, we compared the differences in cell death induced by radiofrequency ablation, cryoballoon ablation and pulsed-field ablation. Finally, we discussed the structural and electrical remodeling caused by inflammation and the association between inflammation and the recurrence of AF after catheter ablation. Collectively, pulsed-field ablation will be a revolutionary innovation with faster, safer, better tissue selectivity and less inflammatory response induced by apoptosis-dominated cell death.

Progress in atrial fibrillation ablation during 25 years of Europace journal

The first edition of Europace journal in 1999 came right around the time of the landmark publication of the electrophysiologists from Bordeaux, establishing how elimination of ectopic activity from the pulmonary veins (PVs) resulted in a marked reduction of atrial fibrillation (AF). The past 25 years have seen an incredible surge in scientific interest to develop new catheters and energy sources to optimize durability and safety of ablation, as well as study the mechanisms for AF and devise ablation strategies. While ablation in the beginning was performed with classic 4 mm tip catheters that emitted radiofrequency (RF) energy to create tissue lesions, this evolved to using irrigation and contact force (CF) measurement while increasing power. Also, so-called single-shot devices were developed with balloons and arrays to create larger contiguous lesions, and energy sources changed from RF current to cryogenic ablation and more recently pulsed field ablation with electrical current. Although PV ablation has remained the basis for every AF ablation, it was soon recognized that this was not enough to cure all patients, especially those with non-paroxysmal AF. Standardized approaches for additional ablation targets have been used but have not been satisfactory in all patients so far. This led to highly technical mapping systems that are meant to unravel the drivers for the maintenance of AF. In the following sections, the development of energies, strategies, and tools is described with a focus on the contribution of Europace to publish the outcomes of studies that were done during the past 25 years.

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.

Clinical outcome of lesion size index-guided high-power radiofrequency catheter ablation for pulmonary vein isolation in patients with atrial fibrillation: 2-year follow-up

INTRODUCTION

The long-term efficacy of high-power (50 W) ablation guided by lesion size index (LSI-guided HP) for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF) remains undetermined. Our study sought to assess the clinical efficacy of LSI-guided HP ablation for PVI in patients with AF and explore the potential predictors associated with clinical outcomes.

METHODS

We consecutively included 186 patients with AF who underwent LSI-guided HP (50 W) ablation at Fuwai Hospital from June 2019 to October 2021. The target LSI values of 4.5-5.5 and 4.0-4.5 at the anterior and posterior walls, respectively, were used in our study. The baseline clinical characteristics, procedural and ablation data, and clinical outcomes were evaluated. The independent potential predictors associated with AF recurrence were further evaluated.

RESULTS

The incidence rate of first-pass PVI was 83.9% (156/186). A total of 11 883 lesions were analyzed, and compared with posterior walls of pulmonary veins, anterior walls had significantly lower mean contact force (8.2 ± 3.0 vs. 8.3 ± 2.3 g, p = .015), longer mean radiofrequency duration (16.9 ± 7.2 vs. 12.9 ± 4.5 s, p < .001) and higher mean LSI (4.8 ± 0.2 vs. 4.4 ± 0.2, p < .001). The overall incidence of periprocedural complications was 3.7%, and steam pops without pericardial effusion occurred in three patients (1.6%). During a mean follow-up of 24.0 ± 8.4 months, the overall AF recurrence-free survival was 87.1% after a single procedure. Patients with paroxysmal AF had a higher incidence of freedom from AF recurrence than those with persistent AF (91.2% vs. 80.8%, log-rank p = .034). Higher LSI (HR 0.50, p < .001) and paroxysmal AF (HR 0.39, p = .029) were significantly associated with decreased AF recurrence. By receiver operating characteristic analysis, the LSI of 4.7 and 4.3 for the anterior and posterior walls of the PVs had the highest predictive value for AF recurrence, respectively.

CONCLUSION

LSI-guided HP (50 W) ablation for PVI was an efficient and safe strategy and led to favorable single-procedure 2-year AF recurrence-free survival in patients with AF. Higher LSI and paroxysmal AF were independent predictors of decreased 2-year AF recurrence. The LSI of 4.7 for the anterior wall and 4.3 for the posterior wall of the PVs were the best cutoff values for predicting AF recurrence after LSI-guided HP ablation.

Higher power short duration vs. lower power longer duration posterior wall ablation for atrial fibrillation and oesophageal injury outcomes: a prospective multi-centre randomized controlled study (Hi-Lo HEAT trial)

AIMS

Radiofrequency (RF) ablation for pulmonary vein isolation (PVI) in atrial fibrillation (AF) is associated with the risk of oesophageal thermal injury (ETI). Higher power short duration (HPSD) ablation results in preferential local resistive heating over distal conductive heating. Although HPSD has become increasingly common, no randomized study has compared ETI risk with conventional lower power longer duration (LPLD) ablation. This study aims to compare HPSD vs. LPLD ablation on ETI risk.

METHODS AND RESULTS

Eighty-eight patients were randomized 1:1 to HPSD or LPLD posterior wall (PW) ablation. Posterior wall ablation was 40 W (HPSD group) or 25 W (LPLD group), with target AI (ablation index) 400/LSI (lesion size index) 4. Anterior wall ablation was 40-50 W, with a target AI 500-550/LSI 5-5.5. Endoscopy was performed on Day 1. The primary endpoint was ETI incidence. The mean age was 61 ± 9 years (31% females). The incidence of ETI (superficial ulcers n = 4) was 4.5%, with equal occurrence in HPSD and LPLD (P = 1.0). There was no difference in the median value of maximal oesophageal temperature (HPSD 38.6°C vs. LPLD 38.7°C, P = 0.43), or the median number of lesions per patient with temperature rise above 39°C (HPSD 1.5 vs. LPLD 2, P = 0.93). Radiofrequency ablation time (23.8 vs. 29.7 min, P < 0.01), PVI duration (46.5 vs. 59 min, P = 0.01), and procedure duration (133 vs. 150 min, P = 0.05) were reduced in HPSD. After a median follow-up of 12 months, AF recurrence was lower in HPSD (15.9% vs. LPLD 34.1%; hazard ratio 0.42, log-rank P = 0.04).

CONCLUSION

Higher power short duration ablation was associated with similarly low rates of ETI and shorter total/PVI RF ablation times when compared with LPLD ablation. Higher power short duration ablation is a safe and efficacious approach to PVI.

Prevalence, Predictors and Mechanisms of Steam Pops in Ablation Index-Guided High-Power Pulmonary Vein Isolation

Despite the good cooling effect of the contact-force porous catheter, the risk of steam pops (SP) remains one of the major concerns in high-power circumferential pulmonary vein isolation (CPVI). This study aimed to investigate the prevalence, predictors and possible mechanisms of SPs in CPVI. Patients experiencing SPs in de novo high-power CPVI were 1:3 matched by non-SP patients with gender, age (±5 years) and left atrial diameter (LAD) (±5 mm) to compare the ablation parameters of SP and non-SP lesions. Catheter tip displacement (Tipdisp) was compared between “edge-of-ridge” and “PV-side-of-ridge” placement at anterior and roof segments of the left pulmonary vein (PV). SPs occurred in 11 (1.57%) of 701 patients, including 6 at the antero-superior left PV, 2 at the roof, 1 at the postero-superior left PV, 1 at the bottom left PV and 1 at the antero-superior aspect of the right PV. There was significantly shorter RF delivery duration (13.9 ± 6.3 vs. 23.3 ± 6.0 s), greater Δimpedance (17.6 ± 6.7 vs. 6.7 ± 4.1 Ω) and lower ablation index (357.7 ± 68.8 vs. 430.2 ± 30.7) in SP patients than those in non-SP patients. Δimpedance >12 Ω during ablation could predict SP occurrence. Tipdisp was greater in “PV-side-of-ridge” than that in “edge-of -ridge” placement (3.2 ± 1.6 mm vs. 2.0 ± 0.8 mm) at antero-superior and roof segments of the left PV. The prevalence of SP was 1.57% in high-power CPVI procedures, with the most common site at the antero-superior segment of the left PV. Δimpedance was a significant predictor of SP occurrence. “PV-side-of-ridge” ablation at antero-superior and roof segments of left PV might predispose to SP occurrence due to excessive tissue coverage.

Radiofrequency ablation of atrial fibrillation-50 W or 90 W?

BACKGROUND

This study sought to evaluate the short and midterm efficacy and safety of the novel very high power very short duration (vHPvSD) 90 W approach compared to HPSD 50 W for atrial fibrillation (AF) ablation as well as reconnection patterns of 90 W ablations.

METHODS AND RESULTS

Consecutive patients undergoing first AF ablation with vHPvSD (90 W; predefined ablation time of 3 s for posterior wall ablation and 4 s for anterior wall ablation) were compared to patients using HPSD (50 W; ablation index-guided; AI 350 for posterior wall ablation, AI 450 for anterior wall ablation) retrospectively. A total of 84 patients (67.1 ± 9.8 years; 58% male; 47% paroxysmal AF) were included (42 with 90 W, 42 with 50 W) out of a propensity score-matched cohort. 90 W ablations revealed shorter ablation times (10.5 ± 6.7 min vs. 17.4 ± 9.9 min; p = .001). No major complication occurred. 90 W ablations revealed lower first pass PVI rates (40% vs. 62%; p = .049) and higher AF recurrences during blanking period (38% vs. 12%; p = .007). After 12 months, both ablation approaches revealed comparable midterm outcomes (62% vs. 70%; log-rank p = .452). In a multivariable Cox regression model, persistent AF (hazard ratio [HR]: 1.442, 95% confidence interval [CI]: 1.035-2.010, p = .031) and increased procedural duration (HR: 1.011, 95% CI: 1.005-1.017, p = .001) were identified as independent predictors of AF recurrence during follow-up.

CONCLUSIONS

AF ablation using 90 W vHPvSD reveals a similar safety profile compared to 50 W ablation with shorter ablation times. However, vHPvSD ablation was associated with lower rates of first-pass isolations and increased AF recurrences during the blanking period. After 12 months, 90 W revealed comparable efficacy results to 50 W ablations in a nonrandomized, propensity-matched comparison.

Percutaneous Treatment Approaches in Atrial Fibrillation: Current Landscape and Future Perspectives

Atrial fibrillation (AF), the most common sustained arrhythmia in clinical practice, represents a major cause of morbidity and mortality, with an increasing prevalence. Pharmacologic treatment remains the cornerstone of its management through rhythm and rate control, as well as the prevention of thromboembolism with the use of oral anticoagulants. Recent progress in percutaneous interventional approaches have provided additional options in the therapeutic arsenal, however. The use of the different catheter ablation techniques can now lead to long arrhythmia-free intervals and significantly lower AF burden, thus reducing the rate of its complications. Particularly encouraging evidence is now available for patients with persistent AF or concomitant heart failure, situations in which catheter ablation could even be a first-line option. In the field of stroke prevention, targeting the left atrial appendage with percutaneous device implantation may reduce the risk of thromboembolism to lower rates than that predicted with conventional ischemic risk scores. Left atrial appendage occlusion through the approved Watchman or Amplatzer devices is a well-established, efficacious, and safe method, especially in high-ischemic and bleeding risk patients with contraindications for oral anticoagulation.

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.

Atrial Fibrillation Ablation in a Patient with Cor Triatriatum Sinister and Left Common Pulmonary Vein: Impact of Left Atrium Anatomy on Ablation Approach

Atrial fibrillation is the most common presentation in adult patients with cor triatriatum sinister. The key to successful and safe catheter ablation in these patients is an accurate exploration and thorough understanding of the left atrial anatomy, both before and during the procedure. Catheter manipulation is highly dependable on left atrial anatomy, including the interatrial septum, insertion of pulmonary veins and cor triatriatum membrane. Anatomical variants such as the left common pulmonary trunk may influence the ablation approach and outcome. We report the case of a 52-year-old patient with cor triatriatum sinister and the left common pulmonary vein variant who underwent successful high-power, short-duration catheter ablation for paroxysmal atrial fibrillation.

Performance of the ablation index during pulmonary vein isolation: periprocedural data from a multicenter registry

PURPOSE

Our study aimed to assess the achievement of target ablation index (AI) values and their impact on first-pass pulmonary vein isolation (FPI) as well as to identify FPI predictors.

METHODS

Atrial fibrillation (AF) ablation was performed according to the local practice, and target AIs were evaluated. The actual AI was calculated as the median value of all ablation points for the anterior and posterior left atrial (LA) walls.

RESULTS

A total of 450 patients from nine centers were enrolled. Patients with first-time ablation (n = 408) were divided into the FPI and non-FPI groups. In the FPI group, a higher median target AI was reported for both the anterior and posterior LA walls than those in the non-FPI group. A higher actual AI was observed for the anterior LA wall in the FPI group. The actual AI was equal to or higher than the target AI for the posterior, anterior, and both LA walls in 54%, 47%, and 35% (n = 158) cases, respectively. Parameters such as hypertension, stroke, ablation power, actual AI value on the anterior wall, target AI values on both LA walls, AI achievement on the posterior wall, carina ablation, and operator experience were all associated with FPI in a univariate logistic regression model; only carina ablation was an independent predictor of FPI.

CONCLUSIONS

According to our multicenter study, FPI and a target AI were not achieved in a significant proportion of AF ablation procedures. Higher actual and target AI values were associated with FPI, but only carina ablation can independently predict FPI.

Optimal Lesion Size Index for Pulmonary Vein Isolation in High-Power Radiofrequency Catheter Ablation of Atrial Fibrillation

Background

Although both high-power (HP) ablation and lesion size index (LSI) are novel approaches to make effective lesions during pulmonary vein isolation (PVI) for atrial fibrillation (AF), the optimal LSI in HP ablation for PVI is still unclear. Our study sought to explore the association between LSI and acute conduction gap formation and investigate the optimal LSI in HP ablation for PVI.

Methods

A total of 105 consecutive patients with AF who underwent HP ablation guided by LSI (LSI-guided HP) for PVI in our institute between June 2019 and July 2020 were retrospectively enrolled. Each ipsilateral PV circle was subdivided into four segments, and ablation power was set to 50 W with target LSI values at 5.0 and 4.0 for anterior and posterior walls, respectively. We compared the LSI values with and without acute conduction gaps after the initial first-pass PVI.

Results

PVI was achieved in all patients, and the incidence of first-pass PVI was 78.1% (82/105). A total of 6,842 lesion sites were analyzed, and the acute conduction gaps were observed in 23 patients (21.9%) with 45 (0.7%) lesion points. The gap formation was significantly associated with lower LSI (3.9 ± 0.4 vs. 4.6 ± 0.4, p < 0.001), lower force-time integral (82.6 ± 24.6 vs. 120.9 ± 40.4 gs, p < 0.001), lower mean contact force (5.7 ± 2.4 vs. 8.5 ± 2.8 g, p < 0.001), shorter ablation duration (10.5 ± 3.6 vs. 15.4 ± 6.4 s, p < 0.001), lower mean temperature (34.4 ± 1.4 vs. 35.6 ± 2.6°C, p < 0.001), and longer interlesion distance (4.4 ± 0.3 vs. 4.3 ± 0.4 mm, p = 0.031). As per the receiver operating characteristic analysis, the LSI had the highest predictive value for gap formation in all PVs segments, with a cutoff of 4.35 for effective ablation (sensitivity 80.0%; specificity 75.4%, areas under the curve: 0.87). The LSI of 4.55 and 3.95 had the highest predictive value for gap formation for the anterior and posterior segments of PVs, respectively.

Conclusion

Using LSI-guided HP ablation for PVI, more than 4.35 of LSI for all PVs segments showed the best predictive value to avoid gap formation for achieving effective first-pass PVI. The LSI of 4.55 for the anterior wall and 3.95 for the posterior wall were the best cutoff values for predicting gap formation, respectively.

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.

Radiofrequency ablation to achieve durable pulmonary vein isolation

Pulmonary vein isolation (PVI) by radiofrequency (RF) ablation is an important alternative to antiarrhythmic drugs in the treatment of symptomatic atrial fibrillation. However, the inability to consistently achieve durable isolation of the pulmonary veins hampers the long-term efficacy of PVI procedures. The large number of factors involved in RF lesion formation and the complex interplay of these factors complicate reliable creation of durable and transmural ablation lesions. Various surrogate markers of ablation lesion formation have been proposed that may provide information on RF lesion completeness. Real-time assessment of these surrogates may aid in the creation of transmural ablation lesions, and therefore, holds potential to decrease the risk of PV reconnection and consequent post-PVI arrhythmia recurrence. Moreover, titration of energy delivery until lesions is transmural may prevent unnecessary ablation and subsequent adverse events. Whereas several surrogate markers of ablation lesion formation have been described over the past decades, a 'gold standard' is currently lacking. This review provides a state-of-the-art overview of ablation strategies that aim to enhance durability of RF-PVI, with special focus on real-time available surrogates of RF lesion formation in light of the biophysical basis of RF ablation.

High-power short-duration versus standard-power standard-duration settings for repeat atrial fibrillation ablation

INTRODUCTION

High-power short-duration (HPSD) ablation is a novel strategy using contact force-sensing catheters optimized for radiofrequency ablation for atrial fibrillation (AF). No study has directly compared HPSD versus standard-power standard-duration (SPSD) contact force-sensing settings in patients presenting for repeat ablation with AF recurrence after initial ablation.

METHODS

We studied consecutive cases of patients with AF undergoing repeat ablation with SPSD or HPSD settings after their initial pulmonary vein isolation (PVI) with temperature controlled non-contact force, SPSD or HPSD settings between 6/23/14 and 3/4/20. Procedural data collected included radiofrequency ablation delivery time (RADT). Clinical data collected include sinus rhythm maintenance post-procedure.

RESULTS

A total of 61 patients underwent repeat ablation (36 SPSD, 25 HPSD). A total of 51 patients (83.6%) were found to have pulmonary vein reconnections necessitating repeat isolation, 10 patients (16.4%) had durable PVI and ablation targeted non-PV sources. RADT was shorter when comparing repeat ablation using HPSD compared to SPSD (22 vs 35 min; p = 0.01). There was no difference in sinus rhythm maintenance by Kaplan-Meier survival analysis (log rank test p = 0.87), after 3 or 12-months between groups overall, and when stratified by AF type, left atrial volume index, CHA₂DS₂-VASc score, or left ventricular ejection fraction.

CONCLUSION

We demonstrated that repeat AF ablation with HPSD reduced procedure times with similar sinus rhythm maintenance compared to SPSD in those presenting for repeat ablation.

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.

Acute and long-term efficacy of ablation index-guided higher power shorter duration ablation in patients with atrial fibrillation: A prospective registry

BACKGROUND

Theoretically, targeting the same ablation index (AI) using higher power may achieve the same lesion size with a shorter ablation time. We evaluated the acute and long-term efficacy of higher-powered ablation guided by ablation index (HPAI) compared with conventional-powered ablation guided by AI (CPAI) for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF).

METHODS

Drug refractory symptomatic AF patients who had been ablated with 40 W on the anterior/roof segments and 30 W on the posterior/inferior/carina segments were enrolled (HPAI group). We compared the HPAI group with the CPAI group who were ablated with 30 W on the anterior/roof segments and 25 W on the posterior/inferior/carina segments. The same AI was targeted (≥450 on the anterior/roof segments and ≥350 on the posterior/inferior/carina segments). We compared ablation time, acute pulmonary vein reconnection (PVR) and 1-year AF recurrence between the two groups.

RESULTS

A total of 118 patients were included (86 in the HPAI group and 32 in the CPAI group, paroxysmal AF, 73%). There was no significant difference in the acute PVR rate between the HPAI and the CPAI groups (3.7% vs. 4.2%, P = .580) with a 41% reduction in ablation time for PVI (38.7 ± 8.3 vs. 65.8 ± 13.7 minutes, P < .001). The 1-year AF recurrence rate was not significantly different between HPAI and CPAI groups (12.8% vs. 21.9%, Log-rank P = .242). There were no major complications in either group.

CONCLUSIONS

Increased power during AF ablation, using the same AI targets, reduced the procedure and ablation times, and showed a comparable acute and long-term outcome without compromising safety.

CLINICAL TRIAL REGISTRATION

https://www.clinicaltrials.gov. Unique identifier: NCT04379557.

Higher than recommended lesion size index target values for pulmonary vein isolation result in better clinical outcomes in paroxysmal atrial fibrillation patients

PURPOSE

Catheter ablation is a cornerstone of the therapy for paroxysmal atrial fibrillation. The importance of effective lesion size formation during pulmonary vein isolation is gauged through conduction recovery and recurrence of arrhythmia. Therefore, the lesion size index (LSI) is designed to utilize traditional intraprocedural parameters and predict procedural success. The impact of the optimal LSI index and the respective segments of the pulmonary veins has not been commonly evaluated. We aimed to assess whether higher and targeted LSI on the different segments of pulmonary veins could actually lead to better clinical outcomes of paroxysmal atrial fibrillation ablation.

METHODS

Retrospective analyses of drug-refractory paroxysmal atrial fibrillation patients who underwent first catheter ablation were conducted. Targeted LSI of 6.5 at the anterior wall and 5.2 at the posterior wall, roof, and floor of the pulmonary vein was applied. The primary endpoint was defined as arrhythmias recurrence assessed by routine electrocardiograms and 24-h ambulatory electrocardiographic monitoring at 3, 6, and 12 months post-ablation.

RESULTS

Among the included 39 patients, the single-procedure 12-month freedom from arrhythmias was reached in 92.3% of patients. Interestingly, there was no tendency towards an increased number of adverse effects using a higher LSI index.

CONCLUSIONS

Atrial fibrillation ablation guided by targeted LSI value showed efficiency on the freedom from arrhythmias during 1-year follow-up period without harmful effects.

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.

Effect of intracardiac blood flow pulsatility during radiofrequency cardiac ablation: computer modeling study

PURPOSE

To assess the effect of intracardiac blood flow pulsatility on tissue and blood distributions during radiofrequency (RF) cardiac ablation (RFCA).

METHODS

A three-dimensional computer model was used to simulate constant power ablations with an irrigated-tip electrode and three possible catheter orientations (perpendicular, parallel and 45°). Continuous flow and three different pulsatile flow profiles were considered, with four average blood velocity values: 3, 5.5, 8.5 and 24.4 cm/s. The 50 °C contour was used to assess thermal lesion size.

RESULTS

The differences in lesion size between continuous flow and the different pulsatile flow profiles were always less than 1 mm. As regards maximum tissue temperature, the differences between continuous and pulsatile flow were always less than 1 °C, with slightly higher differences in maximum blood temperature, but never over 6 °C. While the progress of maximum tissue temperature was identical for continuous and pulsatile flow, maximum blood temperature with the pulsatile profile showed small amplitude oscillations associated with blood flow pulsatility.

CONCLUSIONS

The findings show that intracardiac blood pulsatility has a negligible effect on lesion size and a very limited impact on maximum tissue and blood temperatures, which suggests that future experimental studies based on ex vivo or in silico models can ignore pulsatility in intracardiac blood flow.

The Cutting Edge of Atrial Fibrillation Ablation

This article describes the advances in catheter ablation for AF that have allowed the creation of more durable and efficient lesions. It describes advances in high-power, short-duration radiofrequency ablation, radiofrequency balloon devices, ultra-low cryoablation and irreversible electroporation. It also considers the way these devices may change the way catheter ablation is performed for AF.

Safety and Efficacy of High Power Shorter Duration Ablation Guided by Ablation Index or Lesion Size Index in Atrial Fibrillation Ablation: A Systematic Review and Meta-Analysis

Background

High power shorter duration (HPSD) ablation may lead to safe and rapid lesion formation. However, the optimal radio frequency power to achieve the desired ablation index (AI) or lesion size index (LSI) is insubstantial. This analysis aimed to appraise the clinical safety and efficacy of HPSD guided by AI or LSI (HPSD-AI or LSI) in patients with atrial fibrillation (AF).

Methods

The Medline, PubMed, Embase, Web of Science, and the Cochrane Library databases from inception to November 2020 were searched for studies comparing HPSD-AI or LSI and low power longer duration (LPLD) ablation.

Results

Seven trials with 1013 patients were included in the analysis. The analyses verified that HPSD-AI or LSI revealed benefits of first-pass pulmonary vein isolation (PVI) (RR: 1.28; 95% CI: 1.05–1.56, P = 0.01) and acute pulmonary vein reconnection (PVR) (RR: 0.65; 95% CI: 0.48–0.88, P = 0.005) compared with LPLD. HPSD-AI or LSI showed higher freedom from atrial tachyarrhythmia (AT) (RR = 1.32, 95% CI: 1.14–1.53, P = 0.0002) in the subgroup analysis of studies with PVI ± (with or without additional ablation beyond PVI). HPSD-AI or LSI could short procedural time (WMD: −22.81; 95% CI, −35.03 to −10.60, P = 0.0003), ablation time (WMD: −10.80; 95% CI: −13.14 to −8.46, P < .00001), and fluoroscopy time (WMD: −7.71; 95% CI: −13.71 to −1.71, P = 0.01). Major complications and esophageal lesion in HPSD-AI or LSI group were no more than LDLP group (RR: 0.58; 95% CI: 0.20–1.69, P = 0.32) and (RR: 0.84; 95% CI: 0.43–1.61, P = 0.59).

Conclusions

HPSD-AI or LSI was efficient for treating AF with shorting procedural, ablation, and fluoroscopy time, higher first-pass PVI, and reducing acute PVR and may increase freedom from AT for patients with additional ablation beyond PVI compared with LPLD. Moreover, complications and esophageal lesion were low and no different between two groups.

The efficacy of high-power short-duration radiofrequency for atrial fibrillation ablation: A protocol for systematic review and meta-analysis

BACKGROUND

Studies comparing data between the high-power short-duration radiofrequency (HPSR) and low power longer duration therapy were limited and inconsistent. Therefore, we conduct a high-quality systematic review and meta-analysis to assess the efficacy and safety of HPSR on outcomes for patients with atrial fibrillation (AF).

METHODS

The online literature is searched using the following combination of medical subject heading terms: "high-power" OR "high power" AND "radiofrequency" AND "atrial fibrillation." MEDLINE (PubMed), EMBASE (OVID), Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science (ISI database) will be searched without any language restrictions. All clinical trials to assess the efficacy and safety of HPSR in the treatment of atrial fibrillation will be considered eligible for analysis. The present study will be performed by Review Manager Software (RevMan Version 5.3, The Cochrane Collaboration, Copenhagen, Denmark). Ethical approval and patient consent are not required because this study is a literature-based study.

RESULTS

This study expects to provide credible and scientific evidence for the efficacy and safety of HPSR on outcomes for patients with AF.

REGISTRATION NUMBER

10.17605/OSF.IO/WAEBN.

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.

HPSD ablation for AF high-power short-duration RF ablation for atrial fibrillation: A review

This manuscript reviews the literature for all in silico, ex vivo, in vitro, in vivo and clinical studies of high-power short-duration (HPSD) radiofrequency (RF) ablations. It reviews the biophysics of RF energy delivery applicable to HPSD and the use of surrogate endpoints to guide the duration of HPSD ablations. In silico modeling shows that a variety of settings in power, contact force and RF duration can result in the same surrogate endpoint value of ablation index and several HPSD combinations produce lesion volumes similar to a low-power long-duration (LPLD) RF application. HPSD lesions are broader with more endocardial effect and are slightly shallower but still transmural. The first 10 s of RF application is most important for lesion formation with diminishing effect beyond 20 s. The ideal contact force is 10-20 g with only a small effect beyond 30 g. In vitro and in vivo models confirm that HPSD makes transmural lesions that are often broader and shallower, and with proper settings, result in fewer steam pops than LPLD. One randomized trial shows better outcomes with HPSD and validates lesion size index as a surrogate endpoint. Clinical studies of HPSD using comparator groups of LPLD ablations uniformly show shorter procedure times and shorter total RF energy delivery for HPSD. HPSD generally has a higher first pass vein isolation rate and a lower acute vein reconnection rate than LPLD. Although not dramatically different from LPLD, long-term freedom from atrial fibrillation and complication rates seem slightly better with HPSD.

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.