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

Efficacy and Safety of Pulsed-Field Versus High-Power Short-Duration Ablation for Atrial Fibrillation: A Systematic Review and Meta-Analysis With Reconstructed Time-to-Event Data

BACKGROUND

Pulsed-field ablation (PFA) and high-power short-duration (HPSD) ablation (45-90 W) are emerging technologies in atrial fibrillation (AF) treatment, both achieving durable pulmonary vein isolation. We aim to investigate the efficacy and safety of PFA versus HPSD ablation.

METHODS

We comprehensively searched PubMed, Web of Science (WOS), Scopus, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) through July 2024. Pairwise meta-analysis with reconstructed time-to-event analysis were performed using R version 4.3.1 (PROSPERO ID: CRD42024576031).

RESULTS

Seven observational studies, including 1904 patients, were included. PFA was significantly associated with lower atrial tachyarrhythmia recurrence compared to HPSD ablation (45-90 W) at the longest follow-up (RR: 0.73, 95% CI [0.60, 0.88], p < 0.01). Subgroup analysis revealed a significant reduction in atrial tachyarrhythmia recurrence with PFA versus HPSD ablation (45-50 W) (RR: 0.69, 95% CI [0.54, 0.88], p < 0.01), but not compared to vHPSD ablation (70-90 W). Reconnected pulmonary vein rates were significantly lower with PFA compared to HPSD (45-50 W) (p = 0.03), while no significant difference was observed compared to vHPSD (70-90 W). PFA was significantly associated with reduced procedural duration (MD: -33.15 with 95% CI [-40.93, -25.36], p < 0.01) and left atrial dwell time (MD: -32.16 with 95% CI [-45.55, -18.77], p < 0.01), although fluoroscopy time increased (MD: 7.48 with 95% CI [4.29, 10.68], p < 0.01) compared to HPSD ablation (45-90 W). Safety profiles were comparable, but pericarditis rates were significantly lower with PFA versus HPSD (45-50 W) (p = 0.003) and vHPSD (70-90 W) (p = 0.019). Kaplan-Meier analysis showed a 28% lower risk of atrial tachyarrhythmia recurrence with PFA compared to HPSD ablation (45-90 W) (HR: 0.72, 95% CI [0.57, 0.91], p = 0.006) over an 18-month follow-up.

CONCLUSION

PFA and HPSD ablation (45-90 W) are effective and safe for AF ablation. PFA was significantly associated with lower atrial tachyarrhythmia recurrence, shorter procedural duration, reduced left atrial dwell time, increased fluoroscopy time, and comparable safety, with lower rates of pericarditis compared to HPSD ablation.

Safety and efficacy of high- and very high-power short-duration ablation in overweight and obese patients with atrial fibrillation

Atrial fibrillation (AF) is a common arrhythmia with increasing prevalence, especially in overweight and obese individuals. Pulmonary vein isolation (PVI) using high-power short-duration (HPSD) and very high-power short-duration (vHPSD) ablation has shown effectiveness, but data on the use of these techniques in obese and overweight patients remain limited. This study aimed to evaluate whether body mass index (BMI) influences procedural characteristics, safety, and clinical outcomes of PVI performed using HPSD and vHPSD ablation in patients with symptomatic AF. We retrospectively analyzed 367 patients (119 obese, 138 overweight, 110 normal weight) who underwent HPSD or vHPSD PVI at Ostalb-Klinikum Aalen between 2019 and 2023. Procedural parameters, complications, and 12-month AF recurrence were assessed across BMI groups. Groups were comparable except for age (normal: 68.2 ± 12, overweight: 68 ± 9.7, obese: 64 ± 10.7; p < 0.01), hypertension (54.6%, 70.3%, 73.1%; p < 0.01) and diabetes (12.7%, 11.6%, 22.7%; p = 0.03). Procedure times, fluoroscopy times, and acute PVI success rates (100%) were similar. Base impedance was significantly higher in overweight (122.8 ± 14.1) and obese (123.9 ± 17.6) than in normal weight patients (113.8 ± 21.7; p < 0.01). AF recurrence rates were similar (normal: 20%, overweight: 18.1%, obese: 20.1%; p = 0.9), with no significant BMI correlation (Spearman = - 0.02). Complications were rare (p = 0.54). HPSD and vHPSD ablation are safe and effective in overweight and obese AF patients, with comparable recurrence rates and outcomes to normal-weight patients. Higher base impedance did not impact recurrence or complications.

Clinical impact of very high-power-short-duration catheters on biomarkers after atrial fibrillation ablation

Background

Very high-power short-duration (vHPSD) catheters are associated with less irrigation fluid load than standard (STD RF) ablation catheters. However, the impact of this fluid reduction on biomarkers in pulmonary vein isolation (PVI) for atrial fibrillation (AF) remains unknown.

Methods and Aim

Biomarkers of heart failure, myocardial injury, and systemic inflammation status as Brain Natriuretic Peptide (BNP), high-sensitivity Troponin I (hsTnI), and C-reactive protein (CRP) were collected pre- and post-procedure of PVI for symptomatic AF. The study aimed to assess the impact of vHPSD catheter compared to an STD catheter (respectively irrigation of 8 vs. 15 mL/min during ablation) on biomarker alterations.

Results

The study included 83 consecutive patients (59 males [71.1%], mean age 62.6 ± 11 years), with vHPSD catheters used in 53 cases (63.9%). No significant baseline differences were observed between groups.Fluid irrigation resulted in significantly lower with vHPSD catheter than STD RF (434.8 ± 105.6 vs. 806.6 ± 256.5 mL, p < .001). Correspondingly, BNP variation was significantly lower in the vHPSD group than in the STD RF group, both in absolute change (12 [IQR -9-47] pg/mL vs. 44.5 [IQR 21-88.7] pg/mL, p = .002) and percentage change (16.3 [IQR -13.2-108.6] % vs. 84.1 [IQR 32.5-172.1] %, p = .012). When considering absolute values, a statistically significant increase in BNP was found only in the STD catheter group (from 52 [IQR 35.2-113.5] to 113 [IQR 66.7-189.5] pg/mL, p < .001), whereas no significant increase was observed in the vHPSD group (p = .06). CRP levels increased post-PVI in both groups, but the delta was significantly lower in the vHPSD group (p = .025). No significant differences in post-procedural hsTnI were detected between groups.

Conclusion

The use of a vHPSD catheter is associated with reduced fluid irrigation and a correspondingly smaller increase in BNP, a biomarker indicative of fluid overload and heart failure.

Efficacy of an alternative positioning of intracardiac defibrillation catheters in atrial fibrillation ablation

Background

In pulmonary vein isolation (PVI) for atrial fibrillation (AF), intraoperative defibrillation is often required. Intracardiac defibrillation catheters (ICDCs) are most effective when positioned to enclose the heart between the coronary sinus (CS) and right atrium (RA) (CS/RA configuration). However, achieving this positioning via the inferior vena cava (IVC) can be challenging, and alternative configurations remain underexplored.

Methods

This study included patients with paroxysmal or persistent AF who underwent cryoballoon ablation followed by intracardiac cardioversion using an ICDC via the IVC. The catheter was initially positioned with distal electrodes in the CS and proximal electrodes in the IVC (CS-only configuration). If cardioversion failed, the catheter was repositioned to place distal electrodes in the superior vena cava (SVC configuration). A maximum of 30 J of energy was used for all cardioversion attempts.

Results

A total of 81 patients were included. Cardioversion in the CS-only configuration restored sinus rhythm in 11% (9/81) of patients. Repositioning to the SVC configuration achieved successful cardioversion in 93.1% (67/72) of the remaining cases without complications. Patients requiring the SVC configuration had a significantly higher prevalence of persistent AF (33.3% vs. 80.6%; p = 0.045). No adverse events were observed following cardioversion in the SVC configuration.

Conclusions

While the CS-only configuration offers ease of placement, its efficacy is limited. Repositioning to the SVC configuration significantly enhances cardioversion success and represents a safer, more effective alternative for ICDC use during AF ablation.

Very High-Power Short-Duration Ablation for Atrial Fibrillation in Adults With Congenital Heart Disease

INTRODUCTION

Data regarding safety and long-term outcome of very high-power-short duration (vHPSD) ablation in adult congenital heart disease (ACHD) patients with paroxysmal or persistent atrial fibrillation (AF) are lacking.

METHODS

Retrospective observational single-center study. The data of 66 consecutive ACHD patients (mean age 60 ± 12.8 years, 46% male) with mild (69.7%), moderate (22.7%), or complex (7.6%) congenital heart disease (CHD) who underwent ablation for paroxysmal (40.9%) or persistent AF (59.1%) were analyzed. Circumferential PVI was performed in all patients and additional substrate ablation in 79,4% of persistent AF patients using irrigated RF energy with vHPSD settings of 70 W/5-7 s or 60 W/7-10 s.

RESULTS

Mean procedure time was 123.6 ± 42 min with a mean RF time of 18.19 ± 10 min. No technique related adverse events occurred. Vascular access complications were detected in seven patients (10.6%) requiring intervention in four patients (6%). A median follow-up time of 491 days (IQR: 194-1054 days). Freedom from any atrial arrhythmia off antiarrhythmic drugs (AAD) at 1 year was present in 58% of patients (77.8% with paroxysmal AF, 43.6% with persistent AF).

CONCLUSION

vHPSD for ablation of paroxysmal or persistent AF in ACHD patients is safe and effective. Regardless of CHD complexity, no vHPSD ablation modality related complications occurred. Long-term outcome for paroxysmal AF after one ablation was excellent whereas results for persistent AF were limited.

Prediction of Ablation Index and Lesion Size Index for Local Impedance Drop-Guided Ablation

(1) Background: The effectiveness of RF ablation for PVI depends on the lesion location and size to achieve continuous and durable lesion lines. AI and LSI are widely accepted lesion metrics for guiding the ablation procedure. LI dynamics is another parameter that guides PVI and does not rely on input variables. Limited data are available on a direct comparison between lesion metrics. Our study aims to compare RF application durations and influencing factors during index-guided (AI and LSI) and LI-guided approaches by predicting lesion metrics using machine learning. (2) Methods: While the coefficients in AI and LSI formulas are not disclosed, we trained custom machine-learning models based on Random Forest and Gradient Boosting Regressors to predict AI and LSI metrics for LI-guided ablations. (3) Results: The median RF application durations differed significantly between the lesion metrics, with 7.32, 19.91, and 11.92 s for AI-, LSI-, and LI-guided procedures, respectively. Mean CF was found to be an important predictor of RF application duration for the AI- and LSI-guided approaches. (4) Conclusions: Depending on the metric used, the significant differences in RF application durations suggest that an AI-guide approach may allow for shorter RF application durations, followed by LSI-guided and LI-guided procedures. Further studies are needed to evaluate the safety and efficacy of these results in a clinical setting.

Significance of the local largest bipolar voltage for the optimized ablation strategy using very high-power short duration mode

PURPOSE

Very high-power short-duration (vHPSD) ablation creates shallower lesions, potentially reducing efficacy. This study aims to identify factors leading to insufficient lesions during pulmonary vein antral isolation (PVAI) with vHPSD-ablation and to develop an optimized PVAI strategy using this technology.

METHODS

PVAI was performed on 41 atrial fibrillation patients using vHPSD-ablation (90 W/4 s). Lesion parameters were recorded and analyzed to identify predictors of insufficient lesions. An optimized PVAI strategy, based on these predictors, was tested in subsequent 42 patients.

RESULTS

In total, 3099 RF-applications, including 103(3.3%) insufficient lesions, were analyzed. First-pass PVAI was achieved in 19/40(47.5%) right PVs and 24/41(58.5%) left PVs. Multivariate analysis identified significant predictors of insufficient lesions: local largest bipolar voltage (Bi-V), average contact force, baseline impedance, impedance drop, temperature rise, inter-lesion distance (ILD), and anatomical location (carina or not). An ILD:4-6 mm increased the risk of insufficient lesions 2.2-fold, and lesions at the carina increased it 3.6-fold for both ILD < 4 mm and ILD:4-6 mm. Local largest Bi-V was the strongest predictor for insufficient lesions. The optimized PVAI approach, utilizing vHPSD-ablation with an ILD < 4 mm in non-carinal areas with Bi-V < 4 mV, and high-power ablation-index guided ablation (HPAI, 50 W, ablation-index:450-550) in remaining areas, achieved first-pass PVAI in 92.7% of right PVs and 88.1% of left PVs, using vHPSD-ablation in approximately 65% of total RF-applications. The optimized PVAI achieved significantly higher first-pass PVI rate (p < .0001) with shorter ablation time (p = .04).

CONCLUSION

Appropriate use of vHPSD and HPAI, based on local largest Bi-V and anatomical information, may achieve high first-pass PVAI rates in shorter ablation time with minimal energy delivery.

Impact of combining ablation index-guided and very high-power short-duration ablation at posterior wall adjacent to esophagus during perioperative period on procedural factors

INTRODUCTION

The impact of combining ablation index (AI)-guided and very high-power short-duration (vHPSD) ablation on procedural factors at the posterior wall near the esophagus is unclear.

METHODS

Atrial fibrillation patients who underwent initial ablation using three-dimensional mapping were enrolled. Patients were classified into two groups: those who underwent only AI-guided pulmonary vein isolation (PVI) (AI group) and those who underwent vHPSD ablation at the posterior wall adjacent to the esophagus in addition to AI-guided PVI (AI + vHPSD group). Differences in myocardial injury, inflammation, procedural characteristics, and pulmonary vein (PV) reconnection patterns were assessed between the two groups.

RESULTS

This study included 167 patients (AI group, 83 patients; AI+vHPSD group, 84 patients). No significant differences in high-sensitive troponin I or changes in inflammatory markers between pre- and Postablation were observed in either group. Total application time and total application energy were significantly lower in the AI+vHPSD group than in the AI group (p < 0.001 for both) despite no significant difference in the total number of applications between the groups. The incidence of esophagus temperature ≥40 degrees was significantly lower in the AI+vHPSD group than in the AI group (p = 0.036). However, the incidence of PV reconnections near the esophagus was significantly higher in the AI+vHPSD group than in the AI group (11.9% vs 3.6%, p = 0.046), despite no significant difference in the incidence of PV reconnections overall.

CONCLUSION

The combination of AI-guided PVI and vHPSD adjacent to the esophagus demonstrated reduced application energy requirements and maintained safety and effectiveness during the perioperative period.

Contemporary Trends in Pulsed Field Ablation for Cardiac Arrhythmias

Pulsed field ablation (PFA) is a catheter-based procedure that utilizes short high voltage and short-duration electrical field pulses to induce tissue injury. The last decade has yielded significant scientific progress and quickened interest in PFA as an energy modality leading to the emergence of the clinical use of PFA technologies for the treatment of atrial fibrillation. It is generally agreed that more research is needed to improve our biophysical understanding of PFA for clinical cardiac applications as well as its potential as a potential alternative energy source to thermal ablation modalities for the treatment of other arrhythmias. In this review, we discuss the available preclinical and clinical evidence for PFA for atrial fibrillation, developments for ventricular arrhythmia (VA) ablation, and future perspectives.

Low-Power Long-Duration Versus High-Power Short-Duration Radiofrequency Ablation of the Atrioventricular Node

BACKGROUND

Atrioventricular node (AVN) radiofrequency (RF) ablation is a highly effective treatment of atrial tachyarrhythmias that are resistant to other management modalities. To date, there is limited research that compares the properties of different RF ablation catheters. The current study aims to compare the effectiveness of several types of RF catheters in AVN ablation.

METHODS

A total of 66 patients, with a mean age of 73.27 years, underwent AVN RF ablation. The catheters used were categorized as unirrigated (UI), externally irrigated, and contact force sensing with 10 to 20 g of force. Externally-irrigated catheters were divided into 2 different settings: low-power long-duration (LPLD) (30 W, 45°C, and 60 seconds) and high-power short-duration (HPSD) (50 W, 43°C, and 12 seconds). We compared the success rate of the different RF catheters using logistic regression and lesion times using linear regression.

RESULTS

The distribution of the types of catheters used is UI in 48%, LPLD in 16%, and HPSD in 36% of patients. All ablation procedures were successful, with no immediate postprocedure complications. HPSD had a significantly shorter lesion time than UI catheters by 403.42 seconds (-631.67 to -175.17).

CONCLUSIONS

UI catheters, LPLD, and HPSD were equally safe and effective in ablation procedures. The HPSD catheter had a significantly shorter lesion time and, thus, overall decreased procedure time.

The effect of different power radiofrequency ablations in treatment and postoperative pain in patients with atrial fibrillation: a retrospective study

BACKGROUND

There has been no consensus on what power of radiofrequency energy can be used to produce the best surgical results in patients with atrial fibrillation. In addition, patients undergoing local anesthesia and fentanyl analgesia may experience pain when radiofrequency ablation is performed. This study investigated the effect of different power radiofrequency ablations in treatment and postoperative pain in patients with atrial fibrillation.

METHODS

A retrospective study was performed with 60 patients who underwent radiofrequency ablation for atrial fibrillation between January and June 2023. Patients were divided into 2 groups according to the power of the radiofrequency ablation catheter used, with 30 patients in the conventional power group (35 W) and 30 patients in the high-power group (50 W). The cardiac electrophysiological indexes and postoperative pain of the 2 groups were compared.

RESULTS

Most of the procedural key parameters between the 2 groups had no significant differences. However, the total application time during radiofrequency ablation and pulmonary vein isolation time in the high-power group were significantly shorter than those in the conventional power group (p < 0.001). Patients in the high-power group reported significantly less pain than those in the conventional power group in the immediate postoperative period and the late postoperative period (p < 0.001).

CONCLUSIONS

High-power radiofrequency ablation showed a shorter treatment time, and could reduce postoperative pain compared to conventional power ablation.

Characterizing lesion morphology of a novel diamond-tip temperature-controlled irrigated radiofrequency ablation catheter

BACKGROUND

The DiamondTemp ablation (DTA) system is a novel temperature-controlled irrigated radiofrequency (RF) ablation system that accurately measures tip-tissue temperatures for real-time power modulation. Lesion morphologies from longer RF durations with the DTA system have not been previously described. We sought to evaluate lesion characteristics of the DTA system when varying the application durations.

METHODS

A bench model using porcine myocardium was used to deliver discrete lesions in a simulated clinical environment. The DTA system was power-limited at 50 W with temperature set-points of 50 °C and 60 °C (denoted Group_50 and Group_60). Application durations were randomized with a range of 5-120 s.

RESULTS

In total, 280 applications were performed. Steam pops were observed in five applications: two applications at 90 s and three applications at 120 s. Lesion size (depth and maximum width) increased significantly with longer applications, until 60 s for both Group_50 and Group_60 (depth: 4.5 ± 1.2 mm and 5.6 ± 1.3 mm; maximum width: 9.3 ± 2.7mm and 11.2 ± 1.7mm, respectively). As lesions transition from resistive to conductive heating (longer than 10 s), the maximum width progressed in a sub-surface propagation. Using a "Time after Temperature 60 °C" (TaT60) analysis, depths of 2-3 mm occur in 0-5 s and depths plateau at 4.6 ± 0.8 mm between 20 and 30 s.

CONCLUSIONS

The DTA system rapidly creates wide lesions with lesion depth increasing over time with application durations up to 60 s. Using a TaT60 approach is a promising ablation guidance that would benefit from further investigation.

Comparing the effects of pulsed and radiofrequency catheter ablation on quality of life, anxiety, and depression of patients with paroxysmal supraventricular tachycardia: a single-center, randomized, single-blind, standard-controlled trial

BACKGROUND

Radiofrequency catheter ablation (RFCA) may lead to decreased quality of life (QOL) and increased anxiety and depression in patients with paroxysmal supraventricular tachycardia (PSVT), possibly due to the lack of selectivity of the ablation tissue and the long ablation time. In recent years, pulsed field ablation (PFA) has been used for the first time in China to treat PSVT patients because of its ability to ablate abnormal tissue sites in a precise and transient manner. This study was conducted to compare the effects of PFA and RFCA on QOL and psychological symptoms of PSVT patients.

METHODS

We have designed a single-center, randomized, single-blind, standard-controlled trial. A total of 50 participants who met the eligibility criteria would be randomly allocated into the PFA group or RFCA group in a 1:1 ratio. All participants were assessed using the 36-Item Short-Form Health Survey (SF-36) and the Hospital Anxiety and Depression Scale (HADS) at pre-procedure (T0), post-procedure (T1), and 3 months post-procedure (T2). The SPSS 21.0 software was used to analyze the data through Wilcoxon and Fisher's exact tests and repeated measures ANOVA.

RESULTS

Twenty-five in the PFA group and 24 in the RFCA group completed the trial. SF-36: (1) Between-group comparison: At T1, PFA group had significantly higher SF-36 scores on physiological function (PF) and general health (GH) than RFCA group, with a treatment difference of 5.61 points and 18.51 points(P < 0.05). (2) Within-group comparison: We found that in the PFA and RFCA groups, T2 showed significant improvement in the remaining 6 subscales of the SF-36 scale compared to T1 and T0 (P < 0.05), except for body pain (BP) and social function (SF) scores. HADS: (1) Between-group comparison: no significant difference (P > 0.05). (2) Within-group comparison: The HADS scores of the PFA and RFCA groups were statistically significant at T2 compared to T0 and T1 (P < 0.05).

CONCLUSIONS

Our study provided new and meaningful evidence that PFA was effective in significantly improving QOL and decreasing anxiety and depression in PFA patients.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2200060272.

Myocardial injury and inflammation following pulsed-field ablation and very high-power short-duration ablation for atrial fibrillation

INTRODUCTION

Pulmonary vein isolation (PVI) using radiofrequency ablation (RFA) is an established treatment strategy for atrial fibrillation (AF). To improve PVI efficacy and safety, high-power short-duration (HPSD) ablation and pulsed-field ablation (PFA) were recently introduced into clinical practice. This study aimed to determine the extent of myocardial injury and systemic inflammation following PFA, HPSD, and standard RFA using established biomarkers.

METHODS

We included 179 patients with paroxysmal AF receiving first-time PVI with different ablation technologies: standard RFA (30-40 W/20-30 s, n = 52), power-controlled HPSD (70 W/5-7 s, n = 60), temperature-controlled HPSD (90 W/4 s, n = 32), and PFA (biphasic, bipolar waveform, n = 35). High-sensitivity cardiac troponin T (hs-cTnT), creatine kinase (CK), CK MB isoform (CK-MB), and white blood cell (WBC) count were determined before and after ablation.

RESULTS

Baseline characteristics were well-balanced between groups (age 63.1 ± 10.3 years, 61.5% male). Postablation hs-cTnT release was significantly higher with PFA (1469.3 ± 495.0 ng/L), HPSD-70W (1322.3 ± 510.6 ng/L), and HPSD-90W (1441.2 ± 409.9 ng/L) than with standard RFA (1045.9 ± 369.7 ng/L; p < .001). CK and CK-MB release was increased with PFA by 3.4-fold and 5.8-fold, respectively, as compared to standard RFA (p < .001). PFA was associated with the lowest elevation in WBC (Δ1.5 ± 1.5 × 109 /L), as compared to standard RFA (Δ3.8 ± 2.5 × 109 /L, p < .001), HPSD-70W (Δ2.7 ± 1.7 × 109 /L, p = .037), and HPSD-90W (Δ3.6 ± 2.5 × 109 /L, p < .001).

CONCLUSION

Among the four investigated ablation technologies, PFA was associated with the highest myocardial injury and the lowest inflammatory reaction.

High-power short-duration versus low-power long-duration ablation for pulmonary vein isolation: A substudy of the AWARE randomized controlled trial

INTRODUCTION

Pulmonary vein isolations (PVI) are being performed using a high-power, short-duration (HPSD) strategy. The purpose of this study was to compare the clinical efficacy and safety outcomes of an HPSD versus low-power, long-duration (LPLD) approach to PVI in patients with paroxysmal atrial fibrillation (AF).

METHODS

Patients were grouped according to a HPSD (≥40 W) or LPLD (≤35 W) strategy. The primary endpoint was the 1-year recurrence of any atrial arrhythmia lasting ≥30 s, detected using three 14-day ambulatory continuous ECG monitoring. Procedural and safety endpoints were also evaluated. The primary analysis were regression models incorporating propensity scores yielding adjusted relative risk (RRa ) and mean difference (MDa ) estimates.

RESULTS

Of the 398 patients included in the AWARE Trial, 173 (43%) underwent HPSD and 225 (57%) LPLD ablation. The distribution of power was 50 W in 75%, 45 W in 20%, and 40 W in 5% in the HPSD group, and 35 W with 25 W on the posterior wall in the LPLD group. The primary outcome was not statistically significant at 30.1% versus 22.2% in HPSD and LPLD groups with RRa 0.77 (95% confidence interval [CI]) 0.55-1.10; p = .165). The secondary outcome of repeat catheter ablation was not statistically significant at 6.9% and 9.8% (RRa 1.59 [95% CI 0.77-3.30]; p = .208) respectively, nor was the incidence of any ECG documented AF during the blanking period: 1.7% versus 8.0% (RRa 3.95 [95% CI 1.00-15.61; p = .049) in the HPSD versus LPLD group respectively. The total procedure time was significantly shorter in the HPSD group (MDa 97.5 min [95% CI 84.8-110.4)]; p < .0001) with no difference in adjudicated serious adverse events.

CONCLUSIONS

An HPSD strategy was associated with significantly shorter procedural times with similar efficacy in terms of clinical arrhythmia recurrence. Importantly, there was no signal for increased harm with a HPSD strategy.

Short and Long-Term Outcomes of Lesion Index-Guided High-Power Short-Duration Approach for Atrial Fibrillation Ablation

High-power short-duration (HPSD) ablation is an increasingly used ablation strategy for pulmonary vein isolation (PVI) procedures, but Lesion Index (LSI)-guided HPSD radiofrequency (RF) applications have not been described in this clinical setting. We evaluated the procedural efficiency and safety of an LSI-guided HPSD strategy for atrial fibrillation (AF) ablation. Paroxysmal and persistent AF patients scheduled for AF ablation were prospectively enrolled and divided into two groups, according to the ablation power used (≥45 W for the LSI-HP Group and ≤40 W for the LSI-LP group). All patients underwent only PVI LSI-guided ablation (5.5 to 6 anteriorly; 5 to 5.5 superiorly, 4.5 to 5 posteriorly) with a point-by-point strategy and an inter-lesion distance <6 mm. Forty-six patients with AF (25 in the LSI-HP Group vs 21 in the LSI-LP Group)-59% paroxysmal, 78% male, with low-intermediate CHA2DS2-Vasc scores (2 [1-3]), a preserved ejection fraction (65 ± 6%) and a mean left atrial index volume of 39 ± 13 mL/m2 were prospectively enrolled. Baseline clinical characteristics were comparable between groups. PVI was successful in all patients. The RF time (29 (23-37) vs. 49 (41-53) min, p < 0.001), total procedure time (131 (126-145) vs. 155 (139-203) min, p = 0.007) and fluoroscopy time (12 (10-18) vs. 21 (16-26) min, p = 0.001) were significantly lower in the LSI-HP Group. No complications or steam pops were seen in either group. LSI-HP AF ablation significantly improved procedural efficiency-reducing ablation time, total procedural duration, and fluoroscopy use, while maintaining a comparable safety profile to lower-power procedures.

How the new technologies and tools will change the electrophysiology of the future

Novel technologies and therapies are evolving rapidly in the field of electrophysiology and cardiac ablation, particularly with the aim of improving the management of atrial fibrillation (AF) where pharmacologic treatment fails. High-power short-duration radiofrequency (RF) ablation, in association with the optimized cooling process of the electrode-tissue interface, is one of the most promising approaches for treating durable lesions and pulmonary vein isolation (PVI). Cryo energy, laser, and RF current are examples of novel tools used by competitive balloon catheter platforms and these tools are specifically created to properly promote an effective PVI. Specific mention deserves to be made on the linear array ablation with ultra-low temperature cryoablation that appears promising for durable lesions. It is needless to remind here about the novel evolving energy source in the form of pulsed electrical field (PFA), which results in an irreversible electroporation of myocardial tissue, sparing the surrounding tissue, and thus, apparently with a significant reduction of potential untoward effects. Furthermore, intensive research is in place to specifically investigate the activation pattern of AF so as to devise a patient-('tailored') target ablation, although with inhomogeneous results. Overall, it seems that technologies and therapies are evolving so rapidly than ever with the hope of achieving better long-term clinical results and an improved quality of life for our patients.

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.

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.

Distribution of excitation recoverable myocardium after radiofrequency ablation and its relation to energy application time and irrigation

INTRODUCTION

Radiofrequency (RF) catheter ablation induces excitation recoverable myocardium around durable core lesions, and its distribution may be different depending on energy delivery methods.

METHODS AND RESULTS

In coronary perfusing porcine hearts, pacing threshold through the ventricle was measured using eight-pole (1-mm distance) needle electrodes vertically inserted into myocardium before, within 3 min after and 40 min after 40 W ablation with 10-g catheter contact (Group 1: irrigation catheter for 15 s, Group 2: irrigation catheter for 40 s, Group 3: nonirrigation catheter for 15 s, Group 4: nonirrigation catheter for 40 s). Ablation was accomplished in all 12 ablations in Groups 1-3 whereas in 8/12 ablations in Group 4 because of high-temperature rise. Within 3 min after ablation, 10.0 V pacing uncaptured electrodes were distributed from the surface to inside the myocardium, and its depth was deeper in 40 s than in 15 s ablation. 40 min after ablation, excitation recovery at one or more electrodes below the durable lesion was observed in all Groups. Excitation recovery electrodes were also observed on the surface in Group 1 but not the other Groups. Accordingly, the number of excitation-recovered electrodes were larger in Group 1 than the other Groups.

CONCLUSIONS

Regardless of the ablation methods, excitation recoverable myocardium was present around 1.0 mm below the durable lesions. Lesions created by short application time using an irrigation catheter may have included large excitation recoverable myocardium soon after ablation because of the presence of reversible myocardium on well-irrigated myocardial surfaces.

Temporal trends in atrial fibrillation ablation procedures at an academic medical center: 2011-2021

INTRODUCTION

Radiofrequency ablation technology for treating atrial fibrillation (AF) has evolved rapidly over the past decade. We investigated the impact of technological and procedural advances on procedure times and ablation outcomes at a major academic medical center over a 10-year period.

METHODS

Clinical data was collected from patients who presented to NYU Langone Health between 2011 and 2021 for a first-time AF ablation. Time to redo AF ablation or direct current cardioversion (DCCV) for recurrent AF during a 3-year follow-up period was determined and correlated with ablation technology and practices, antiarrhythmic medications, and patient comorbid conditions.

RESULTS

From 2011 to 2021, the cardiac electrophysiology lab adopted irrigated-contact force ablation catheters, high-power short duration ablation lesions, steady-pacing, jet ventilation, and eliminated stepwise linear ablation for AF ablation. During this time the number of first time AF ablations increased from 403 to 1074, the percentage of patients requiring repeat AF-related intervention within 3-years of the index procedure dropped from 22% to 14%, mean procedure time decreased from 271 ± 65 to 135 ± 36 min, and mean annual major adverse event rate remained constant at 1.1 ± 0.5%. Patient comorbid conditions increased during this time period and antiarrhythmic use was unchanged.

CONCLUSION

Rates of redo-AF ablation or DCCV following an initial AF ablation at a single center decreased 36% over a 10-year period. Procedural and technological changes likely contributed to this improvement, despite increased AF related comorbidities.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Ablation index-guided high-power vs. moderate-power cavotricuspid isthmus ablation

Ablation index (AI)-guided ablation is useful for pulmonary vein isolation (PVI) and cavotricuspid isthmus (CTI) ablation. However, the impact of radiofrequency (RF) application power on CTI ablation with a fixed target AI remains unclear. One-hundred-thirty drug-refractory atrial fibrillation and/or atrial flutter patients who underwent AI-guided CTI ablation with or without PVI between July 2020 and August 2021 were randomly assigned to high-power (45 W) and moderate-power (35 W) groups. We performed CTI ablation with the same target AI value in both groups: 500 for the anterior 1/3 segments and 450 for the posterior 2/3 segments. In total, first-pass conduction block of the CTI was obtained in 111 patients (85.4%), with 7 patients (5.4%) showing CTI reconnection. The rate of first-pass conduction block was significantly higher in the 45 W group (61/65, 93.8%) than in the 35 W group (50/65, 76.9%, P = 0.01). CTI ablation and CTI fluoroscopy time were significantly shorter in the 45 W group than in the 35 W group (CTI ablation time: 192.3 ± 84.8 vs. 319.8 ± 171.4 s, P < 0.0001; CTI fluoroscopy time: 125.2 ± 122.4 vs. 171.2 ± 124.0 s, P = 0.039). Although there was no significant difference, steam pops were identified in two patients from the 45 W group at the anterior segment of the CTI. The 45 W ablation strategy was faster and provided a higher probability of first-pass conduction block than the 35 W ablation strategy for CTI ablation with a fixed AI target.

High-power short-duration versus low-power long-duration ablation guided by the ablation index

AIMS

To compare the two different ablation strategies, both guided by the Ablation Index (AI), in the setting of atrial fibrillation (AF) ablation: high-power short-duration (HPSD) ablation using 40 W on the posterior wall and 50 W elsewhere versus low-power long-duration (LPLD) using 25 W posteriorly and 35 W elsewhere.

METHODS

Prospective, multicenter nonrandomized, noninferiority study of consecutive patients referred for paroxysmal AF ablation from January 2018 to July 2019. Ablation was guided by the AI (≥500 for anterior segments, ≥450 for the roof and inferior segments and 400 posteriorly) and an interlesion distance (ILD) ≤ 6 mm. Patients were separated into two groups: HPSD vs LPLD. Acute reconnection (after adenosine trial) and 2-year outcomes were assessed.

RESULTS

160 patients (61% males, median age of 62 [IQR 51-69] years), fulfilled the study inclusion criteria - 80 patients (316 pulmonary veins [PV]) in the HPSD group and 80 patients (314 PV) in the LPLD. The probability of acute PV reconnection was similar between both groups: 2.2% in HPSD, 95%CI 0.6% to 3.8% vs. 3.4% in LPLD, 95%CI 1.4% to 5.4%; p < 0.001 for noninferiority. Median PV ablation time (20 min vs 30 min, p < 0.01) and procedure duration (80 min vs 100 min, p < 0.001) were shorter in the HPSD group. After a median follow-up of 26 months, arrhythmia recurrence was similar between groups (17.5% in HPSD group vs. 18.8% in LPLD group, p = 0.79).

CONCLUSIONS

In paroxysmal AF patients treated with the Ablation Index, a HPSD strategy is noninferior to the more standard LPLD ablation, while allowing for quicker procedures with shorter ablation times.

Safety profile and long-term efficacy of very high-power short-duration (60-70 W) catheter ablation for atrial fibrillation: results of a large comparative analysis

AIMS

This retrospective study sought to compare complication rates and efficacy of power-controlled very high-power short-duration (vHPSD) and conventional catheter ablation in a large cohort of patients with atrial fibrillation (AF).

METHODS AND RESULTS

We analyzed 1115 consecutive patients with AF (38.7% paroxysmal, 61.3% persistent) who received first-time catheter ablation at our centre from 2015 to 2021. Circumferential pulmonary vein isolation ± additional substrate ablation using an irrigated-tip catheter was performed with vHPSD (70 W/5-7 s or 60 W/7-10 s) in 574 patients and with conventional power (30-35 W/15-30 s) in 541 patients. Baseline characteristics were well-balanced between groups (mean age 65.1 ± 11.2 years, 63.4% male). The 30-day incidence of cardiac tamponade [2/574 (0.35%) vs. 1/541 (0.18%), P = 0.598], pericardial effusion ≥ 10 mm [2/574 (0.35%) vs. 1/541 (0.18%), P = 0.598] and transient ischaemic attack [1/574 (0.17%) vs. 2/541 (0.37%), P = 0.529] was not significantly different between vHPSD and conventional ablation. No stroke, atrio-esophageal fistula, cardiac arrest or death occurred. Procedure (122.2 ± 46.8 min vs. 155.0 ± 50.5 min, P < 0.001), radiofrequency (22.4 ± 19.3 min vs. 52.9 ± 22.0 min, P < 0.001), and fluoroscopy (8.1 ± 7.2 vs. 9.2 ± 7.4, P = 0.016) duration were significantly shorter in the vHPSD group. At 12 months follow-up, freedom of any atrial arrhythmia was 44.1% vs. 34.2% (P = 0.010) in persistent AF and 78.1% vs. 70.2% in paroxysmal AF (P = 0.068).

CONCLUSION

vHPSD ablation is as safe as conventional ablation and is associated with an improved long-term efficacy in persistent AF.

Comparison of effectiveness and safety of high-power vs. conventional-power radiofrequency ablation for treatment of atrial fibrillation

Aim

To compare high-power (HP) vs. conventional-power (CP) radiofrequency ablation for atrial fibrillation (AF).

Methods

We retrospectively enrolled AF patients undergoing CP (30-40 W, 43 patients) or HP (50 W, 49 patients) radiofrequency ablation. Immediate pulmonary vein (PV) single-circle isolation, PV-ablation time, AF recurrence, AF recurrence-free survival, and complications were analyzed.

Results

Diabetes was more common in the CP group than in the HP group (27.91% vs. 10.20%, P = 0.029). The left PV single-circle isolation rate (62.79% vs. 65.31%), right PV single-circle isolation rate (48.84% vs. 53.06%), and bilateral PV single-circle isolation rate (32.56% vs. 38.78%; all P > 0.05) did not differ between the groups. Single-circle ablation times for the left PVs (12.79 ± 3.39 vs. 22.94 ± 6.39 min), right PVs (12.18 ± 3.46 vs. 20.67 ± 5.44 min), and all PVs (25.85 ± 6.04 vs. 45.66 ± 11.11 min; all P < 0.001) were shorter in the HP group. Atrial fibrillation recurrence within 3 months (13.95% vs. 18.37%), at 3 months (11.63% vs. 8.16%), and at 6 months after ablation (18.60% vs. 12.24%; all P > 0.05) was similar in both groups. Atrial fibrillation recurrence-free survival did not differ between the groups (Kaplan-Meier analysis). Cardiac rupture and pericardial tamponade did not occur in any patient. Pops occurred in 2 and 0 patients in the HP and CP groups, respectively (4.08% vs. 0.00%, P = 0.533).

Conclusion

High-power ablation improved operation time and efficiency without increasing complications.

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.

Evaluation of Isolation Area, Myocardial Injury and Left Atrial Function Following High-Power Short-Duration Radiofrequency or Second-Generation Cryoballoon Ablation for Atrial Fibrillation

This randomized study aims to compare the left atrial (LA) lesion size, function, and tissue damage following pulmonary vein isolation (PVI) by high-power short-duration (HPSD) radiofrequency (RF) and second-generation cryoballoon (CB2) ablation. We enrolled 40 patients with paroxysmal atrial fibrillation who underwent PVI by HPSD RF (n = 21) or CB2 (n = 19). Every patient underwent LA CT angiography and transthoracic echocardiography (TTE) to assess the LA anatomy and function. Biomarker levels (hs-cTnT, hs-CRP, LDH) were compared pre- and post-procedurally. Pre- and post-ablation high-density mapping (HDM) was performed. The isolation area was defined under 0.2 mV bipolar voltage (low voltage area, LVA). We calculated the post-PVI LVA/LA surface ratio using LA CT-HDM merge images. At 3-month follow-up, TTE was performed to assess the changes in LA function. Post-ablation hs-cTnT level was significantly higher in the RF group (RF: 1249 ± 469 ng/L, CB2: 995 ± 280 ng/L, p = 0.024). Post-PVI hs-CRP (RF: 9.53 ± 10.30 mg/L, CB2: 12.36 ± 5.76 mg/L, p = 0.034) and LDH levels (RF: 349.9 ± 65.6 U/L, CB2: 451.6 ± 91.3 U/L, p < 0.001) were significantly higher following CB2 ablation. Post-PVI LVA/LA surface ratios were 8.37 ± 6.42% in the RF group and 13.58 ± 8.92% in the CB2 group (p = 0.022). LA function did not change significantly after the PVI procedure. Our data indicate that second-generation cryoballoon ablation produces a significantly larger LA lesion size compared to “point-by-point” HPSD radiofrequency. Both techniques preserve LA function. The myocardial component of tissue loss appears to be higher using HPSD radiofrequency ablation, with less collateral damage.

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.

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.

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.

Response to Letter to the Editor

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

Meta-analysis 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.