Efficacy and safety of ablation index-guided catheter ablation for atrial fibrillation: an updated meta-analysis

[Initial ablation of atrial fibrillation-Is pulmonary vein isolation sufficient? : Pro and contra]

Pulmonary vein isolation (PVI) is currently the gold standard for the ablation of atrial fibrillation (AF). Although this procedure shows good success rates, the recurrence rates after PVI alone are significantly higher in advanced AF and in the presence of comorbidities. Therefore, it is important to consider additional arrhythmogenic mechanisms outside the pulmonary veins, depending on the individual case, in order to improve the patients' outcome.

Long-term outcome of high-power ablation guided by ablation index in the treatment of atrial fibrillation

Objective

High-power ablation has been widely used in atrial fibrillation (AF). However, there were many studies observed the outcomes of the short-term follow-up. This study aims to the long-term results of high-power ablation guided by ablation index (AI) in patients with AF.

Methods

Analysis of patients with AF, who first received high-power (40-50 W) ablation, to pulmonary vein isolation (PVI) in the Second Hospital of Shanxi Medical University from May 2020 to March 2022. All patients were managed perioperatively according to the routine treatment procedures. High-power ablation was conducted under the guidance of our conventional power AI and baseline data, first-pass PVI rate, ablation time, operative time, and long-term surgical success rate were analyzed.

Results

A total of 83 patients with atrial fibrillation were enrolled in the study, with an average age of 61.62 ± 9.04 years, 47 male patients, and 49 paroxysmal atrial fibrillation. All patients achieved PVI, and the rate of first pass was 82%. The ablation time of the left atrial was 28.54 ± 9.11 min. There were no serious complications related to ablation, and only a small amount of pericardial effusion was found in 4 patients. During the follow-up period of 26.36 ± 6.11 months, 8 patients were lost to follow-up and the overall success rate was 84%, including 91% for paroxysmal AF and 71% for persistent AF.

Conclusion

High-power ablation long-term results appear a high freedom atrial arrhythmia, but further expanded samples are needed for controlled studies.

Incidence and predictors of thermal oesophageal and vagus nerve injuries in Ablation Index-guided high-power-short-duration ablation of atrial fibrillation: a prospective study

AIMS

High-power-short-duration (HPSD) ablation is an effective treatment for atrial fibrillation but poses risks of thermal injuries to the oesophagus and vagus nerve. This study aims to investigate incidence and predictors of thermal injuries, employing machine learning.

METHODS AND RESULTS

A prospective observational study was conducted at Leipzig Heart Centre, Germany, excluding patients with multiple prior ablations. All patients received Ablation Index-guided HPSD ablation and subsequent oesophagogastroduodenoscopy. A machine learning algorithm categorized ablation points by atrial location and analysed ablation data, including Ablation Index, focusing on the posterior wall. The study is registered in clinicaltrials.gov (NCT05709756). Between February 2021 and August 2023, 238 patients were enrolled, of whom 18 (7.6%; nine oesophagus, eight vagus nerve, one both) developed thermal injuries, including eight oesophageal erythemata, two ulcers, and no fistula. Higher mean force (15.8 ± 3.9 g vs. 13.6 ± 3.9 g, P = 0.022), ablation point quantity (61.50 ± 20.45 vs. 48.16 ± 19.60, P = 0.007), and total and maximum Ablation Index (24 114 ± 8765 vs. 18 894 ± 7863, P = 0.008; 499 ± 95 vs. 473 ± 44, P = 0.04, respectively) at the posterior wall, but not oesophagus location, correlated significantly with thermal injury occurrence. Patients with thermal injuries had significantly lower distances between left atrium and oesophagus (3.0 ± 1.5 mm vs. 4.4 ± 2.1 mm, P = 0.012) and smaller atrial surface areas (24.9 ± 6.5 cm2 vs. 29.5 ± 7.5 cm2, P = 0.032).

CONCLUSION

The low thermal lesion's rate (7.6%) during Ablation Index-guided HPSD ablation for atrial fibrillation is noteworthy. Machine learning based ablation data analysis identified several potential predictors of thermal injuries. The correlation between machine learning output and injury development suggests the potential for a clinical tool to enhance procedural safety.

Durable pulmonary vein isolation with optimized high-power and very high-power short-duration temperature-controlled ablation: A step-by-step guide

INTRODUCTION

Through systematic scientific rigor, the CLOSE guided workflow was developed and has been shown to improve pulmonary vein isolation durability. However, this technique was developed at a time when using power-controlled ablation catheters with conventional power ranges was the norm. There has been increased adoption of a high-power and very high-power short-duration ablation practice propelled by the availability of the temperature-controlled radiofrequency QDOT MICRO catheter.

METHODS

There are fundamental differences in biophysics between very high-powered temperature guided ablation and conventional ablation strategy that may impact patient outcomes. The catheter's design and ablation modes offer flexibility in technique while accommodating the individual operator's clinical discretion and preference to deliver a durable, transmural, and contiguous lesion set.

RESULTS

Here, we provide recommendations for 3 different workflows using the QDOT MICRO catheter in a step-by-step manner for pulmonary vein isolation based on our cumulative experience as early adopters of the technology and the data available in the scientific literature.

CONCLUSIONS

With standardization, temperature-controlled ablation with the QDOT MICRO catheter provides operators the flexibility of implementing different ablation strategies to ensure durable contiguous pulmonary vein isolation depending on patient characteristics.

[Catheter ablation of atrial fibrillation : Evidence and current techniques]

Atrial fibrillation (AF) is the most frequent cardiac arrhythmia with increasing clinical and healthcare economic relevance. A timely treatment prevents or slows the remodelling process of the atrial and ventricular myocardium initiated by AF, emphasizing its relevance especially in heart failure patients. Catheter ablation for the treatment of AF is safe and effective. The three ablation techniques currently used are comparable in terms of success rates but differ in terms of risk profile and the type of lesion formation.

Radiofrequency lesion formation prediction with contact force versus local impedance

PURPOSE OF REVIEW

Safe and effective radiofrequency (RF) myocardial ablation requires real-time monitoring of lesion formation. Here, we review conventional and novel approaches proposed to guide titration of RF energy application.

RECENT FINDINGS

Conventional monitoring modalities, such as ablation electrode temperature, generator impedance, and tissue electrophysiological properties have been of limited value in predicting efficacy and safety of ablation. Therefore, several input-driven indices have been proposed to improve the quality and durability of RF ablation lesion while maintaining safety. These metrics predominantly incorporate RF power output, duration of RF application, and firmness and stability of electrode-tissue contact. More recently, novel catheters have enabled measuring local impedance at the catheter-tissue interface, which has been found valuable for real-time monitoring of RF lesion formation.

SUMMARY

It is likely that using the combination of multiple metrics would be required to improve the quality and safety of RF lesions, but further investigation is still required.

Efficacy and safety of the vein of Marshall ethanol infusion with radiofrequency catheter ablation for the treatment of persistent atrial fibrillation in elderly patients

Background

Increasing age is a significant risk factor for atrial fibrillation (AF) recurrence after catheter ablation (CA). We accomplished this study to evaluate the efficacy and safety of the vein of Marshall (VOM) ethanol infusion (VOM-EI) with CA in elderly patients with persistent AF (PsAF).

Methods

This retrospective observational study included 360 consecutive adult patients with PsAF, of which 141 were in the Elder group (age ≥65 years) and 219 were in the Younger group (age <65 years), who underwent the VOM-EI and radiofrequency CA (RFCA) between May 2020 and April 2022. The efficacy endpoint was no recurrence of AF within one year after CA.

Results

The VOM-EI was successfully performed in 90.8% of patients from the Elder and 88.6% from the Younger group. All patients achieved PVI; 97.9% of patients from the Elder and 98.6% from the Younger group reached LA roof block, and 93.6% of patients from the Elder and 95.9% from the Younger group achieved MI block. There was no significant difference in 1-year survival without recurrence of AF between the two groups (83.0% and 84.5%, respectively). The incidence of complications within 30 days after the procedure from the two groups was low and did not differ significantly.

Conclusion

The VOM-EI combined with RFCA proved to be an effective and safe strategy for treating PsAF in elderly and younger patients.

Superiority of the Combination of Input and Output Parameters to the Single Parameter for Lesion Size Estimation

BACKGROUND

For lesion size prediction, each input parameter, including ablation energy (AE), and output parameter, such as impedance, is individually used. We hypothesize that using both parameters simultaneously may be more optimal.

METHODS AND RESULTS

Radiofrequency applications at a range of power (30-50 W), contact force (10 g and 20 g), duration (10-60 s), and catheter orientation with normal saline (NS)- or half-normal saline (HNS)-irrigation were performed in excised porcine hearts. The correlations, with lesion size of AE, absolute impedance drop (∆Imp-drop), relative impedance drop (%Imp-drop), and AE*%Imp-drop were examined. Lesion size was analyzed in 283 of 288 lesions (NS-irrigation, n=142; HNS-irrigation, n=141) without steam pops. AE*%Imp-drop consistently showed the strongest correlations with lesion maximum depth (NS-irrigation, ρ=0.91; HNS-irrigation, ρ=0.94), surface area (NS-irrigation, ρ=0.87; HNS-irrigation, ρ=0.86), and volume (NS-irrigation, ρ=0.94; HNS-irrigation, ρ=0.94) compared with the other parameters. Moreover, compared with AE alone, AE*%Imp-drop significantly improved the strength of correlation with lesion maximum depth (AE vs. AE*%Imp-drop, ρ=0.83 vs. 0.91, P<0.01), surface area (ρ=0.73 vs. 0.87, P<0.01), and volume (ρ=0.84 vs. 0.94, P<0.01) with NS-irrigation. This tendency was also observed with HNS-irrigation. Parallel catheter orientation showed a better correlation with lesion depth and volume using ∆Imp-drop, %Imp-drop, and AE*%Imp-drop than perpendicular orientation.

CONCLUSIONS

The combination of input and output parameters is more optimal than each single parameter for lesion prediction.

Index-Guided High-Power Radiofrequency Catheter Ablation for Atrial Fibrillation: A Systematic Review and Meta-Analysis Study

PURPOSE OF REVIEW

Studies have suggested the superiority of high-power compared to standard-power radiofrequency ablation ablation (RFCA). This study aimed to assess the efficacy and safety of high-power compared to standard-power RFCA guided by ablation index (AI) or lesion index (LSI).

RECENT FINDINGS

A systematic review and meta-analysis study comparing IGHP and IGLP approaches for AF ablation was conducted. The relevant published studies comparing IGHP and IGSP methods for RFCA in AF patients until October 2022 were collected from Cochrane, ProQuest, PubMed, and ScienceDirect. A total of 2579 AF patients from 11 studies were included, 1682 received IGHP RFCA, and 897 received IGSP RFCA. To achieve successful pulmonary vein isolation (PVI), the IGHP RFCA group had a significantly shorter procedure time than the IGHP RFCA group (mean difference (MD) -19.91 min; 95% CI -25.23 to -14.59 min; p < 0.01), radiofrequency (RF) application time (MD -10.92 min; 95% CI -14.70 to -7.13 min; p < 0.01), and fewer number of lesions (MD -10.90; 95% CI -18.77 to -3.02; p < 0.01) than the IGSP RFCA. First-pass PVI was significantly greater in the IGHP RFCA group than in the IGSP RFCA group (risk ratio (RR) 1.17; 95% CI 1.07 to 1.28; p < 0.01). The IGHP RFCA is an effective and efficient strategy for AF ablation. The superiority of IGHP RFCA includes the shorter procedure time, shorter RF application time, fewer number of lesions for complete PVI, and more excellent first-pass PVI.

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.

Dielectric response as a novel marker for ablation lesion quality: Relation to conventional ablation parameters

Background

The tissue response viewer (TRV) is a novel marker for ablation lesion quality that aims to classify lesions into transmural or nontransmural lesions (high or low dielectric response, HDR or LDR) using dielectric-based tissue assessment. The objective of this study was to gain insight in the TRV by relating its outcomes to conventional ablation parameters.

Methods

Patients that had repeat ablation for atrial fibrillation with a dielectric imaging-based mapping system were enrolled. All ablation data were downloaded from the mapping system and analyzed to explore associations between TRV outcomes and other ablation parameters.

Results

The cohort included 24 patients, in which 58 pulmonary veins and 8 superior vena cavas were targeted. A total of 388 energy applications were applied, resulting in 639 ablation points. The system classified 36% of ablation points as HDR and 44% as LDR. The system did not provide a dielectric response in 20%. The system's ability to provide a dielectric response was related to longer ablation duration and absence of dragging ablation. HDR (versus LDR) was multivariably associated with longer energy applications, higher mean ablation power, and lower wall thickness. Greater impedance drop was univariably associated with HDR.

Conclusion

Outcomes of the TRV are associated with conventional ablation parameters (e.g., duration and power) but also local wall thickness. Catheter stability seems important for successful lesion assessment with the TRV. Further reduction of missing outcomes and validation of the tool are warranted before widespread use.

Acute and mid-term outcomes of ablation for atrial fibrillation with VISITAG SURPOINT: the Japan MIYABI registry

AIMS

The effectiveness of pulmonary vein isolation (PVI) guided by VISITAG SURPOINT (VS) has been demonstrated in Western populations. However, data for Asian populations are limited. VS settings may differ for Asians, given their smaller body size. This study aimed to describe outcomes of radiofrequency atrial fibrillation (AF) ablation guided by VS in a large Asian population.

METHODS AND RESULTS

The prospective, observational, multicentre MIYABI registry collected real-world data from patients undergoing VS-guided AF ablation using ThermoCool SmartTouch and ThermoCool SmartTouch SF catheters from 50 Japanese centres. All patients had paroxysmal AF or persistent AF for <6 months. Primary adverse events (PAEs) were evaluated for safety. The primary efficacy endpoint was the proportion of patients with PVI at the end of the procedure. Mid-term effectiveness (up to 12 months) was evaluated by freedom from documented atrial arrhythmias. Of the 1011 patients enrolled, 1002 completed AF ablation. The mean number of VS values per procedure was 428.8 on the anterior wall and 400.4 on the posterior wall. Nine patients (0.9%) experienced PAEs. Upon procedure completion, 99.7% of patients had PVI. Twelve-month freedom from atrial arrhythmia recurrence was 88.5%; 5.7% of patients were re-ablated. At repeat ablation, 54% of RSPV, 73% of RIPV, 70% of LSPV, and 86% of LIPV evaluated remained durably isolated.

CONCLUSION

Despite lower anterior wall VS values compared with the CLOSE protocol (≥550), the present study demonstrated comparable efficacy outcomes, indicating that a VS of ≥550 for the anterior wall may not be necessary for Asian patients.

Ostial vs. wide area circumferential ablation guided by the Ablation Index in paroxysmal atrial fibrillation

AIMS

Pulmonary vein isolation (PVI) guided by the Ablation Index (AI) has shown high acute and mid-term efficacy in the treatment of paroxysmal atrial fibrillation (AF). Previous data before the AI-era had suggested that wide-area circumferential ablation (WACA) was preferable to ostial ablation. However, with the use of AI, we hypothesize that ostial circumferential ablation is non-inferior to WACA and can improve outcomes in paroxysmal AF.

METHODS AND RESULTS

Prospective, multicentre, non-randomized, non-inferiority study of consecutive patients were referred for paroxysmal AF ablation from January 2020 to September 2021. All procedures were performed using the AI software, and patients were separated into two different groups: WACA vs. ostial circumferential ablation. Acute reconnection, procedural data, and 1-year arrhythmia recurrence were assessed. During the enrolment period, 162 patients (64% males, mean age of 60 ± 11 years) fulfilled the study inclusion criteria-81 patients [304 pulmonary vein (PV)] in the WACA group and 81 patients (301 PV) in the ostial group. Acute PV reconnection was identified in 7.9% [95% confidence interval (CI), 4.9-11.1%] of PVs in the WACA group compared with 3.3% (95% CI, 1.8-6.1%) of PVs in the ostial group [P < 0.001 for non-inferiority; adjusted odds ratio 0.51 (95% CI, 0.23-0.83), P = 0.05]. Patients in the WACA group had longer ablation (35 vs. 29 min, P = 0.001) and procedure (121 vs. 102 min, P < 0.001) times. No significant difference in arrhythmia recurrence was seen at 1-year of follow-up [11.1% in WACA vs. 9.9% in ostial, hazard ratio 1.13 (95% CI, 0.44-1.94), P = 0.80 for superiority].

CONCLUSION

In paroxysmal AF patients treated with tailored AI-guided PVI, ostial circumferential ablation is not inferior to WACA with regard to acute PV reconnection, while allowing quicker procedures with less ablation time.

Extensive Posterior Wall Isolation on Top of Pulmonary Vein Isolation Guided by Ablation Index in Persistent Atrial Fibrillation Ablation

Background: Durable pulmonary vein isolation (PVI) is recommended for symptomatic paroxysmal atrial fibrillation (AF) treatment, but it has been demonstrated that it may not be enough to treat persistent AF (Pe-AF). Therefore, posterior wall isolation (PWI) is among the strategies adopted on top of PVI to treat Pe-AF patients. However, PWI using contiguous and optimized radiofrequency lesions remains challenging, and few studies have evaluated the impact of the Ablation Index (AI) on the efficacy of PWI. Moreover, previous papers did not evaluate arrhythmia recurrences using continuous monitoring. Methods: This is a prospective, observational, single-center study on patients affected by Pe-AF undergoing treated PVI plus AI-guided PWI. Procedures were performed using the CARTO mapping system, SmartTouch SF ablation catheter, and PentaRay multipolar mapping catheter. The AI settings were 500–550 for the anterior PV aspect and roofline, while the settings were 450–500 for the posterior PV aspect, bottom line, and/or PW lesions. All patients received an implantable loop recorder (ILR). All patients underwent clinical evaluation in the outpatient clinic at 1, 3, 6, 12, 18, and 24 months. A standard 12-lead ECG was performed at each visit, and device data from the ILR were reviewed to assess for arrhythmia recurrence. Results: Between January 2021 and December 2021, forty-one consecutive patients underwent PVI plus PWI guided by AI at our center and were prospectively enrolled in the study. PVI was achieved in all patients, first-pass roofline block was obtained in 82.9% of the patients, and first-pass block of the bottom line was achieved in 36.5% of the patients. In 39% of the patients, PWI was not performed with a “box-only” lesion set, but with scattered lesions across the PW to achieve PWI. AI on the anterior aspect of the left PVs was 528 ± 22, while on the posterior aspect of the left PVs, it was 474 ± 18; on the anterior aspect of the right PVs, it was 532 ± 27, while on the posterior aspect of the right PVs, it was 477 ± 16; on the PW, AI was 468 ± 19. No acute complications occurred at the end of the procedure. After the blanking period, 70.7% of the patients reported no arrhythmia recurrence during the 12-month follow-up period. Conclusions: In patients with Pe-AF undergoing catheter ablation, PWI guided by AI seems to be an effective and feasible strategy in addition to standard PVI.

Atrial fibrillation: Primary prevention, secondary prevention, and prevention of thromboembolic complications: Part 2

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, once thought to be benign as long as the ventricular rate was controlled, is associated with significant cardiac morbidity and mortality. Increasing life expectancy driven by improved health care and decreased fertility rates has, in most of the world, resulted in the population aged ≥65 years growing more rapidly than the overall population. As the population ages, projections suggest that the burden of AF may increase more than 60% by 2050. Although considerable progress has been made in the treatment and management of AF, primary prevention, secondary prevention, and prevention of thromboembolic complications remain a work in progress. This narrative review was facilitated by a search of MEDLINE to identify peer-reviewed clinical trials, randomized controlled trials, meta-analyses, and other clinically relevant studies. The search was limited to English-language reports published between 1950 and 2021. Atrial fibrillation was searched using the terms primary prevention, hyperthyroidism, Wolff-Parkinson-White syndrome, catheter ablation, surgical ablation, hybrid ablation, stroke prevention, anticoagulation, left atrial occlusion and atrial excision. Google and Google scholar as well as bibliographies of identified articles were reviewed for additional references. In these two manuscripts, we discuss the current strategies available to prevent AF, then compare non-invasive and invasive treatment strategies to diminish AF recurrence. In addition, we examine the pharmacological, percutaneous device and surgical approaches to prevent stroke as well as other types of thromboembolic events.

Radiofrequency ablation using the second-generation temperature-controlled diamond tip system in paroxysmal and persistent atrial fibrillation: results from FASTR-AF

BACKGROUND

Catheter ablation (CA) technology development reflects the need to improve the effectiveness of atrial fibrillation (AF) treatment. Recently, the DiamondTemp Ablation (DTA) RF generator software was updated with a more responsive power ramp.

METHODS

DIAMOND FASTR-AF was a prospective, single-arm, multicenter trial. This study sought to characterize the performance of the updated DTA system for the treatment of patients with drug-refractory paroxysmal and persistent AF (PAF and PsAF). The primary effectiveness endpoint was freedom from atrial arrhythmia recurrence following a 90-day blanking period through 12 months, and the primary safety endpoint was a composite of serious adverse events.

RESULTS

In total, 60 subjects (34 PAF and 26 PsAF) underwent CA at three centers. Patients were 71.7% male, (age 63.9 ± 10.2 years, with an AF diagnosis duration 3.1 ± 3.9 years and left atrial size 4.4 ± 0.8 cm). Pulmonary vein isolation-only ablation strategy was performed in 34 (56.7%) subjects. The procedural characteristics show a procedure time 90.8 ± 31.6 min, total RF time 14.7 ± 7.7 min, ablation duration 10.7 ± 3.6 s, and fluid infusion 284.7 ± 111.5 ml. The serious adverse event rate was 8.3% (5/60), 3 pulmonary edema and 2 extended hospitalizations. Freedom from atrial arrhythmia recurrence was achieved in 67.6% of subjects by 12 months.

CONCLUSIONS

The updated DTA system demonstrated long-term safety and effectiveness through 12 months of post-ablation follow-up for patients with atrial fibrillation. Additionally, procedures were demonstrated to be highly efficient with short procedure times and low levels of fluid infusion.

TRIAL REGISTRATION

Sponsored by Medtronic, Inc.; FASTR-AF ClinicalTrials.gov; NCT03626649.

Cavotricuspid isthmus ablation for atrial flutter guided by contact force related parameters: A systematic review and meta-analysis

Background

Contact force (CF) and related parameters have been evaluated as an effective guide mark for pulmonary vein isolation, yet not for linear ablation of the cavotricuspid isthmus (CTI) dependent atrial flutter (AFL). We thus studied the efficacy and safety of CF related parameter-guided ablation for CTI-AFL.

Methods

Systematic search was performed on databases involving PubMed, EMbase, Cochrane Library and Web of Science (through June 2022). Original articles comparing CF related parameter-guided ablation and conventional parameter-guided ablation for CTI-AFL were included. One-by-one elimination, subgroup analysis and meta-regression were used for heterogeneity test between studies.

Results

Ten studies reporting on 761 patients were identified after screening with inclusion and exclusion criteria. Radiofrequency (RF) duration was significantly shorter in CF related parameter-guided group (p = 0.01), while procedural time (p = 0.13) and fluoroscopy time (p = 0.07) were no significant difference between two groups. CF related parameter-guided group had less RF lesions (p = 0.0003) and greater CF of catheter-tissue (p = 0.0002). Touch-up needed after first ablation line was less in CF related parameter-guided group (p = 0.004). In addition, there were no statistical significance between two groups on acute conduction recovery rates (p = 0.25), recurrence rates (p = 0.92), and complication rates (p = 0.80). Meta-regression analysis revealed no specific covariate as an influencing factor for above results (p > 0.10).

Conclusion

CF related parameters guidance improves the efficiency of CTI ablation, with the better catheter-tissue contact, the lower RF duration and the comparable safety as compared with conventional method, but does not improve the acute success rate and long-term outcome.

Predictive value of TRPV2 expression from peripheral blood mononuclear cells on the early recurrence of atrial fibrillation after radiofrequency catheter ablation

BACKGROUND

Recent study has shown that the transient receptor potential vanilloid 2 (TRPV2) channel was exclusively upregulated in patients with atrial fibrillation (AF), and that this overexpression might be detrimental for occurrence and maintenance of AF. We aimed to characterize the expression levels of TRPV2 mRNA in peripheral blood mononuclear cells (PBMCs) with/without early recurrence of atrial fibrillation (ERAF) after radiofrequency catheter ablation (RFCA), and to find a reliable predictor for ERAF.

METHODS

65 patients of AF, who underwent RFCA successfully, then divided into two groups according to ERAF during following 3 months. PBMCs were isolated from whole blood by Ficoll gradient centrifugation before and after RFCA. Gene set enrichment analysis was performed to evaluate TRPV channels expression levels and Kyoto Encyclopedia of Genes and Genomes (KEGG) mapping was used for pathway enrichment analysis.

RESULTS

There was no significant difference in the TRPV2 mRNA expression level between the two groups before RFCA, while without ERAF group of TRPV2 expression was markedly reduced compared to ERAF group after RFCA. Moreover, the number of TRPV2 expression was confirmed as an independent predictor for the first time through receiver operating characteristic and Kaplan-Meier survival curve analysis. It should be pointed out that the above results were only used to predict ERAF, and have no predictive significance for late recurrence of atrial fibrillation according to the current data. Additionally, ERAF was inversely correlated with P wave dispersion. KEGG mapping further clustered 41 pathways, revealing that ''cyclic guanosine monophosphate-protein kinase G signaling pathway'' was significantly enriched.

CONCLUSIONS

We firstly assume that downregulated expression of peripheral TRPV2 appear in patients without ERAF after RFCA. TRPV2 may thus represent a novel predictor of early phase after successful radiofrequency ablation.

The adjunctive effect for left pulmonary vein isolation of vein of Marshall ethanol infusion in persistent atrial fibrillation

OBJECTIVE

This study sought to assess the effect of ethanol infusion into the vein of Marshall (EIVOM) on the acute success of left pulmonary vein (LPV) isolation in persistent atrial fibrillation (PeAF).

METHODS AND RESULTS

A total of 313 patients with drug-resistant PeAF were enrolled (135 in Group 1 and 178 in Group 2). In Group 1, EIVOM was firstly performed, followed by radiofrequency ablation (RFA) including bilateral pulmonary vein isolation (PVI) and linear ablation at roofline, cavotricuspid isthmus, and mitral isthmus (MI). In Group 2, PVI and linear ablations were completed with RFA. First-pass isolation of the LPV was achieved in 119 (88.1%) and 132 (74.2%) patients in Groups 1 and 2, respectively (P = 0.002). The rate of acute pulmonary vein reconnection (PVR) was significantly lower in Group 1 (9.6% vs. 22.5%, P = 0.003). About half of acute PVR occurred in the carina with or without EIVOM.

CONCLUSION

EIVOM is effective in achieving a higher first-pass isolation and a lower acute PVR of LPV in PeAF.

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.

Radiofrequency Pulmonary Vein Isolation without Esophageal Temperature Monitoring: Contact-Force Characteristics and Incidence of Esophageal Thermal Damage

Esophageal thermal lesions following pulmonary vein isolation (PVI) for atrial fibrillation (AF) potentially harbor lethal complications. Radiofrequency (RF)-PVI using contact force-technology can reduce collateral damage. We evaluated the incidence of endoscopically detected esophageal lesions (EDEL) and the contribution of contact force to esophageal lesion formation without esophageal temperature monitoring. One hundred and thirty-one AF patients underwent contact force-guided RF-PVI. Contact force, energy, force-time-integral, and force-power-time-integral were adopted. During PVI at the posterior segment of the wide antral circumferential line, limits were set for energy (30 W), duration (30 s) and contact force (40 g). Ablations were analyzed postero-superior and -inferior around PVs. Endoscopy within 120 h identified EDEL in six patients (4.6%). In EDEL(+), obesity was less frequent (17% vs. 68%, p = 0.018), creatinine was higher (1.55 ± 1.18 vs. 1.07 ± 0.42 mg/dL, p = 0.016), and exclusively at the left postero-inferior site, force-time-integral and force-power-time-integral were greater (2973 ± 3267 vs. 1757 ± 1262 g·s, p = 0.042 and 83,547 ± 105,940 vs. 43,556 ± 35,255 g·J, p = 0.022, respectively) as compared to EDEL(-) patients. No major complications occurred. At 12 months, arrhythmia-free survival was 74%. The incidence of EDEL was low after contact force-guided RF-PVI. Implementing combined contact force-indices on the postero-inferior site of left-sided PVs may reduce EDEL.

Long-Term prognosis of radiofrequency catheter ablation for atrial fibrillation with different subtypes of heart failure in the era of ablation index guidance

Background

The long-term outcomes of ablation index (AI)-guided radiofrequency catheter ablation (RFCA) on atrial fibrillation (AF) and different subtypes of heart failure (HF) remain unknown. The aim of the study was to evaluate the long-term prognosis of AI-guided RFCA procedures in patients with AF and concomitant HF.

Methods

We retrospectively included consecutive patients with AF and HF who underwent the initial RFCA procedure with AI guidance from March 2018 to June 2021 in our institution. The patients were categorized into two groups: HF with preserved ejection fraction (HFpEF) group and HF with mid-range ejection fraction (HFmrEF) +HF with reduced ejection fraction (HFrEF) group.

Results

A total of 101 patients were included. HFpEF and HFmrEF + HFrEF groups consisted of 71 (70.3%) and 30 patients (29.7%), respectively. During a median follow-up of 32.0 (18.2, 37.6) months, no significant difference was detected in AF recurrence between groups (21.1 vs. 33.3%) after multiple procedures, whereas the incidence of the composite endpoint of all-cause death, thromboembolic events, and HF hospitalization was significantly lower in HFpEF group (9.9 vs. 25.0%, Log-rank p = 0.018). In multivariable analysis, a history of hypertension [hazard ratio (HR) 4.667, 95% confidence interval (CI) 1.433–15.203, p = 0.011], left ventricular ejection fraction (LVEF) < 50% (HR 5.390, 95% CI 1.911–15.203, p = 0.001) and recurrent AF after multiple procedures (HR 7.542, 95% CI 2.355–24.148, p = 0.001) were independently associated with the incidence of the composite endpoint.

Conclusion

Long-term success could be achieved in 75% of patients with AF and concomitant HF after AI-guided RFCA procedures, irrespective of different HF subtypes. Preserved LVEF was associated with a reduction in the composite endpoint compared with impaired LVEF. Patients with recurrent AF tend to have a poorer prognosis.

Effectiveness and Safety of High-Power Radiofrequency Ablation Guided by Ablation Index for the Treatment of Atrial Fibrillation

Background

To investigate the efficacy and safety of ablation index- (AI-) guided high-power radiofrequency ablation in the treatment of atrial fibrillation (AF).

Methods

Outcomes of radiofrequency (RF) applications were compared in a swine ventricular endocardial model (n = 10 each for 50 W, 40 W, and 30 W; AI = 500). And a total of 100 consecutive patients with paroxysmal AF undergoing pulmonary vein isolation (PVI) were included. The patients were divided into two groups (n = 50 for each) as follows: control group, treated with conventional power (30 W) ablation mode; and study group, treated with high power (40 W) radiofrequency ablation mode. All groups were treated with the same AI value guided the ablation (target AI = 400/500 on posterior/anterior wall, respectively). Acute pulmonary vein (PV) reconnection was assessed post adenosine administration 20 minutes after ablation. Subsequently, pathological observation of porcine heart lesions and necrotic tissue was performed. Additionally, statistical analyses were carried out on patients' baseline clinical characteristics, surgical data, and total RF energy.

Results

In swine ventricular endocardial RF applications, compared with 40 W and 30 W, the use of 50 W was associated with shallower tissue lesion depth (p < 0.001) and greater lesion maximum diameter (p < 0.001). Compared with 40 W and 30 W, tissue necrosis caused by 50 W was the deepest and largest (p < 0.001). In pulmonary vein isolation (PVI), there was no significant difference in baseline data between the study group and control group (p > 0.05). In patients with paroxysmal atrial fibrillation, the procedure time in the high-power group was significantly shortened (p < 0.001). The ablation time was significantly shorter (p < 0.001). Compared with control group, RF energy per point and acute pulmonary vein (PV) reconnection were lower (p < 0.001), and first-pass PVI was higher (p < 0.01) in study group. There were no significant differences in complications and sinus rhythm maintenance at 12 months between the two groups (p > 0.05).

Conclusions

Compared with conventional (30 W) PVI, AI-guided high-power (40 W) was safe and associated with shorter procedure time and reduced acute PV reconnection.

Tailored Target Ablation Index Guided Pulmonary Vein Isolation in Treating Paroxysmal Atrial Fibrillation: A Single Center Randomized Study in Asian Population (AI-Asian-I)

Objective

To evaluate the efficacy and safety of lower ablation indexes (AI) guided pulmonary vein isolation (PVI) in treating paroxysmal atrial fibrillation (AF).

Methods

Ninety patients with paroxysmal AF scheduled for radiofrequency ablation were randomly divided into three groups. The AI targets for PVI were as follows: In group A/B/C, 550/500/450 for roof and anterior wall, and 400/350/300 for posterior/inferior wall. The first-pass PVI rate, ablation time, complications and recurrence of atrial tachyarrhythmia (ATa) were compared.

Results

The mean age was 62.5 years (male: 63.0%), mean body mass index (BMI): 24.35 ± 3.66 kg/m². The baseline characteristics were comparable. There was no significant difference in the first-pass PVI rate among the three groups (left-sided-PV: 66.7% vs. 80% vs. 73.3%, P = 0.51; right-sided-PV: 70% vs. 83.3% vs. 73.3%, P = 0.64), also with similar gap rate during the procedural waiting time. At 1-year follow-up there was no significant difference in the recurrence rate of ATa among the three groups (10% vs. 13.3% vs. 13.3%, P = 1.00). The ablation time in the Group C was significantly less than that in the other two groups (47.8 min. vs. 47.0 min. vs. 36.6 min, P < 0.001). Higher AI seemed to link a non-significant trend toward higher rate of pericardial effusion (group A + B vs. group C:6.7% vs. 0%, P = 0.30), although the rate of overall complications was not different among the three groups.

Conclusion

This randomized study shows that, a relatively lower target AI guided ablation may be similarly effective to achieve PVI with significantly reduced ablation time and obtain similar clinical outcome in treating paroxysmal AF in Asian population.

Clinical Trial Registration

[www.ClinicalTrials.gov], identifier [NCT:04549714].

What we have learned: is pulmonary vein isolation still the cornerstone of atrial fibrillation ablation?

Ablation of atrial fibrillation (AF) is an established treatment option for symptomatic patients. The cornerstone of all ablation strategies is electrical isolation of the pulmonary veins (PVs). Ablation strategies going beyond PV isolation (PVI) might be considered in the setting of recurrent AF despite durably isolated PVs. The lack of persistent PVI, however, limits the opportunities to perceive the real impact of this endpoint on AF suppression and to fully understand the benefit of extended ablation strategies going beyond. To overcome this limitation, novel and innovative ablation systems have been developed to facilitate acute PVI and to increase its durability. These systems include balloon-based ablation devices incorporating different energy sources such as cryo energy, laser, or radiofrequency current, but also new energy sources such as pulsed field ablation as a non-thermal energy source. These technologies could advance catheter ablation of AF to an early stage of the disease and to the primary treatment tool. The current manuscript focuses on the past, the present, and the future value of PVI as the cornerstone for interventional treatment of AF and on how to achieve durable PVI during the first procedure and to further improve the clinical success rates of AF ablation. It also analyses extended ablation strategies going beyond PVI and their impact.

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.

Ablation Index Predicts Successful Ablation of Focal Atrial Tachycardia: Results of a Multicenter Study

A radiofrequency energy lesion transmurality marker incorporating power, contact force, and time (Ablation Index, AI) was shown to be associated with outcomes of catheter ablation (CA) of multiple arrhythmias, but was never systematically assessed in the CA of focal atrial tachycardias (AT). We aimed to evaluate the role of AI as a predictor of outcomes in focal AT CA, and therefore, retrospectively included 45 consecutive patients undergoing CA for focal AT in four referral electrophysiology laboratories. Clinical and procedural information were collected. For each patient, maximum and mean (by averaging maximum AI values for each radiofrequency ablation lesion) AI were measured. The primary outcome was focal AT-free survival, and was systematically assessed with periodical Holter monitors or cardiac implantable electronic devices. CA was acutely effective in each case; however, 20% (n = 9) of the study population experienced a focal AT recurrence over a median follow-up of 288 days. Both maximum and mean AI values were significantly higher among patients without AT recurrences (maximum AI = 568 ± 91, mean AI = 426 ± 105) than in patients with AT relapses (maximum AI = 447 ± 142, mean AI = 352 ± 76, p = 0.036, and p = 0.028, respectively). The optimal cutoffs associated with freedom from recurrences were 461 for maximum AI (sensitivity, 0.89; specificity, 0.56) and 301 for mean AI (sensitivity, 0.97; specificity, 0.44). In a time-to-event analysis, maximum AI was significantly associated with survival free from AT recurrence (p = 0.001), whereas mean AI was not (p = 0.08). In summary, maximum AI is the best procedural parameter associated with the outcomes of CA for focal AT, and may help standardize the procedural approach.

Ablation index-guided cavotricuspid isthmus ablation with contiguous lesions using fluoroscopy integrated 3D mapping in atrial flutter

PURPOSE

The feasibility and safety of cavotricuspid isthmus (CTI) ablation with contiguous lesions using ablation index (AI) under the guidance of fluoroscopy integrated 3D mapping (CARTO UNIVU/CU) in typical atrial flutter (AFL) remains uncertain. This study aimed to determine the efficacy of AI-guided CTI ablation with contiguous lesions in patients with AFL.

METHODS

In this single-center, prospective, non-randomized, single-arm, observational study, procedural outcomes were determined in 151 patients undergoing AI-guided CTI ablation (AI group) with a target AI value of 450 and an interlesion distance of ≤ 4 mm under CU guidance. These outcomes were compared with those of 30 patients undergoing non-AI-guided ablation (non-AI group).

RESULTS

Among 151 patients, first-pass conduction block was achieved in 120 (80%) patients in the AI group (67% in the non-AI group, P = 0.152) with a shorter fluoroscopy time of 0.2 ± 0.4 min (1.7 ± 2.0 min in the non-AI group, P < 0.001). Conduction gaps were located at the atrial aspects near the inferior vena cava in 24 of 31 (78%) patients without first-pass conduction block. The AI group received 11 ± 5 (12 ± 4 in the non-AI group, P = 0.098) radiofrequency (RF) applications, and the RF time was 4.2 ± 2.4 (5.1 ± 2.5 min in the non-AI group, P = 0.011). Despite the occurrence of steam pop in 3 (2%) patients, none of them developed cardiac tamponade. No patients had recurrence within 6 months of follow-up.

CONCLUSIONS

AI-guided CTI ablation in combination with CU was feasible and effective in reducing radiation exposure in patients with AFL.

Impact of Contact Force-Sensing Catheters on Fluoroscopy Time in Interventional Electrophysiology: A European Survey

This multicenter European survey systematically evaluated the impact of using contact force-sensing catheters (CFSCs) on fluoroscopy and procedure time in interventional electrophysiology. Data from 25 participating centers were collected and analyzed, also considering important confounders. With the use of CFSCs, fluoroscopy time was reduced for right- and left-sided atrial ablations (median −6.4 to −9.6 min, p < 0.001 for both groups), whereas no such effect could be found for ventricular ablations. Moreover, the use of CFSCs was associated with an increase in procedure time for right-sided atrial and ventricular ablations (median +26.0 and +44.0 min, respectively, p < 0.001 for both groups), but not for left-sided atrial ablations. These findings were confirmed independent of career level and operator volume, except for very highly experienced electrophysiologists, in whom the effect was blunted. In the subset of pulmonary vein isolations (PVIs), CFSCs were shown to reduce both fluoroscopy and procedure time. In conclusion, the use of CFSCs was associated with a reduced fluoroscopy time for atrial ablations and an increased procedure time for right atrial and ventricular ablations. These effects were virtually independent of the operator experience and caseload. When considering only PVIs as an important subset, CFSCs were shown to reduce both fluoroscopy and procedure time.

Outcome and safety of intracardiac echocardiography guided left atrial appendage closure within zero-fluoroscopy atrial fibrillation ablation procedures

BACKGROUND

Simultaneous atrial fibrillation (AF) catheter ablation and left atrial appendage closure (LAAC) is sometimes recommended for both rhythm control and stroke prevention. However, the advantages of intracardiac echocardiography (ICE) guidance for this combined procedure have been scarcely reported. We aim to evaluate the clinical outcomes and safety of ICE guided LAAC within a zero-fluoroscopy catheter ablation procedure.

METHODS AND RESULTS

From April 2019 to April 2020, 56 patients with symptomatic AF underwent concomitant catheter ablation and LAAC. ICE with a multi-angled imaging protocol mimicking the TEE echo windows was used to guide LAAC. Successful radiofrequency catheter ablation and LAAC were achieved in all patients. Procedure related adverse event rate was 3.6%. During the 12-month follow-up, 75.0% of patients became free of arrhythmia recurrences and oral anticoagulants were discontinued in 96.4% of patients. No ischemic stroke occurred despite two cases of device-related thrombosis versus an expected stroke rate of 4.8% based on the CHA₂ DS₂ -VASc score. The overall major bleeding events rate was 1.8%, which represented a relative reduction of 68% versus an expected bleeding rate of 5.7% based on the HAS-BLED score of the patient cohort. The incidence of iatrogenic atrial septal defect secondary to a single transseptal access dropped from 57.9% at 2 months to 4.2% at 12 months TEE follow-up.

CONCLUSION

The combination of catheter ablation and LAAC under ICE guidance was safe and effective in AF patients with high stroke risk. ICE with our novel protocol was technically feasible for comprehensive and systematic assessment of device implantation. This article is protected by copyright. All rights reserved.

Recurrent atrial arrhythmia in a randomised controlled trial comparing contact force-guided and contact force-blinded ablation for typical atrial flutter

BACKGROUND

Contact force (CF)-guided catheter ablation (CA) is a novel technology developed to improve efficacy and reduce complications. In a randomised controlled trial (RCT), we previously documented that after 3 months, rate of persistent conduction block was similar with and without using CF while performing CA for typical atrial flutter (AFL). Clinical effect of CF on recurrent arrhythmia is unknown. Our objective is to study recurrent atrial arrhythmia during 12-month follow-up in a RCT investigating whether CF-guided CA for typical AFL is superior to CF-blinded CA.

METHODS

Patients were randomised 1:1 to CA guided by CF (intervention group) or blinded to CF (control group). After 12 months, patients attended clinical check-up preceded by a 5-day ambulatory Holter monitor recording. Primary outcome was any recurrent atrial arrhythmia ≥ 30 s within 12 months and documented in 12-lead ECG or Holter monitor recording.

RESULTS

We included 156 patients, four patients withdrew consent and two died during follow-up. Thus, 150 patients were included in final analysis. Recurrent arrhythmia was detected in 36 of 77 (47%) patients in the intervention group, and 32 of 73 patients (44%) in the control group (p = 0.51). Atrial fibrillation was detected in 23 (30%) and 29 (40%) patients in the intervention and control groups respectively. AFL was detected in 11 (14%) and 5 (7%) patients in the intervention and control groups respectively.

CONCLUSIONS

Contact force-guided ablation for typical atrial flutter does not reduce recurrent atrial arrhythmia after 12-month follow-up as compared with ablation blinded for contact force.

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.

Relationship between ablation index and myocardial biomarkers after radiofrequency catheter ablation for atrial fibrillation

Background

Further in-vivo evidence is needed to support the usefulness of ablation index (AI) in guiding atrial fibrillation (AF) ablation. We aimed at evaluating the relationship between AI and other lesion indicators and the release of myocardial-specific biomarkers following radiofrequency AF ablation.

Methods

Forty-six patients underwent a first-time radiofrequency AF ablation and were prospectively enrolled in this study. Pulmonary vein isolation was performed by six experienced electrophysiologists with a point-by-point approach, guided by strict Visitag criteria and consistent AI target values. Myocardial-specific biomarkers troponin T and creatine kinase myocardial band were measured after 6 (TnT6 and CKMB6) and 20 h (TnT20 and CKMB20) following sheath removal. Ablation duration, impedance drop (ID), force-time integral (FTI) and AI were registered automatically and analyzed offline.

Results

TnT release was 985 ± 495 ng/L and 1038 ± 461 ng/L (p = ns) while CKMB release was 7.3 ± 2.7 μg/L and 6.5 ± 2.1 μg/L (p < 0.001) at 6 and 20 h respectively. Ablation duration, ID, FTI and AI were all significantly correlated with the release of myocardial-specific biomarkers both at 6 and 20 h. Ablation index showed the highest degree of correlation with TnT6, TnT20, CKMB6 and CKMB20 (Pearson's R 0.69, 0.69, 0.61, 0.64 respectively, p < 0.001). Multiple regression analysis demonstrated that AI had the strongest association with TnT6, TnT20, CKMB6 and CKMB20 (β 0.43, β 0.71, β 0.44 and β 0.43 respectively).

Conclusion

Ablation index appears as the strongest lesion indicator as measured by the release of myocardial-specific biomarkers following radiofrequency catheter ablation for AF.

Ablation Index-guided point-by-point ablation versus Grid annotation-guided dragging for pulmonary vein isolation: A randomized controlled trial

Introduction

Radiofrequency (RF) atrial fibrillation (AF) ablation using a catheter dragging technique may shorten procedural duration and improve durability of pulmonary vein isolation (PVI) by creating uninterrupted linear ablation lesions. We compared a novel AF ablation approach guided by Grid annotation allowing for “drag lesions” with a standard point‐by‐point ablation approach in a single‐center randomized study.

Methods

Eighty‐eight paroxysmal or persistent AF patients were randomized 1:1 to undergo RF‐PVI with either a catheter dragging ablation technique guided by Grid annotation or point‐by‐point ablation guided by Ablation Index (AI) annotation. In the Grid annotation arm, ablation was visualized using 1 mm³ grid points coloring red after meeting predefined stability and contact force criteria. In the AI annotation arm, ablation lesions were created in a point‐by‐point fashion with AI target values set at 380 and 500 for posterior/inferior and anterior/roof segments, respectively. Patients were followed up for 12 months after PVI using ECGs, 24‐h Holter monitoring and a mobile‐based one‐lead ECG device.

Results

Procedure time was not different between the two randomization arms (Grid annotation 71 ± 19 min, AI annotation 72 ± 26 min, p = .765). RF time was significantly longer in the Grid annotation arm compared with the AI annotation arm (49 ± 8 min vs. 37 ± 8 min, respectively, p < .001). Atrial tachyarrhythmia recurrence was documented in 10 patients (23%) in the Grid annotation arm compared with 19 patients (42%) in the AI annotation arm with time to recurrence not reaching statistical significance (p = .074).

Conclusions

This study shows that a Grid annotation‐guided dragging approach provides an alternative to point‐by‐point RF‐PVI using AI annotation.

Effectiveness of Radiofrequency Catheter Ablation Using Ablation Index Versus Second Generation Cryoballoon in the Treatment of Persistent Atrial Fibrillation: A Matching-Adjusted Indirect Comparison

Introduction

Both radiofrequency (RF) and cryoballoon (CB) ablation are treatment options for persistent atrial fibrillation (PsAF). An important recent innovation in RF ablation is Ablation Index (AI), known also as the VISITAG SURPOINT™ Module, a composite lesion quality marker whose use has been shown to significantly reduce the incidence of acute and late pulmonary vein (PV) reconnection and the recurrence of atrial arrhythmias in PsAF. Due to a lack of direct comparative evidence between the latest generations of technologies, there is uncertainty regarding the best treatment option in PsAF. The objective of the present study was to conduct a matching-adjusted indirect treatment comparison (MAIC) using individual patient-level data (IPD) to assess the comparative effectiveness of the THERMOCOOL SMARTTOUCH™ Catheter or the THERMOCOOL SMARTTOUCH™ SF Catheter with AI/VISITAG SURPOINT™ Module (STAI) versus the second-generation CB catheter (Arctic Front Advance™; herein referred to as CB) with respect to 12-month atrial arrhythmia recurrence, fluoroscopy time, and procedural efficiency.

Methods

IPD for STAI were obtained from four investigator-initiated studies and were pooled. Comparable CB studies identified from a systematic literature review were also pooled. In the absence of a common treatment arm between STAI and CB studies, an unanchored MAIC was conducted. The primary analysis compared the pooled STAI IPD to the pooled CB cohort, with corrections for differences across trials, including eligibility criteria and patient baseline characteristics. Scenario and sensitivity analyses were conducted to assess the robustness of the primary analysis.

Results

In the primary analysis, which was adjusted for left atrial diameter (LAD), age, diabetes, and sex, STAI was associated with a statistically significant 65% relative reduction in the rate of arrhythmia recurrence compared to CB at 12-month follow-up (HR 0.35; 95% CI 0.23, 0.52). STAI was associated with shorter total fluoroscopy time than CB but longer procedure time. Results were consistent across scenario and sensitivity analyses.

Conclusion

Radiofrequency ablation with AI significantly reduced atrial arrhythmia recurrence at 12-month follow-up and fluoroscopy time compared to CB, with longer procedure times.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01846-z.