High-power Short-duration Ablation Research Articles

High‐power, short‐duration atrial fibrillation ablation compared with a conventional approach: Outcomes and reconnection patterns

The effectiveness, safety, and pulmonary vein (PV) reconnection patterns of point-by-point high-power, short-duration (HPSD) ablation relative to conventional force-time integral (FTI)-guided strategies for atrial fibrillation (AF) ablation are unknown. To compare 1-year freedom from atrial arrhythmia (AA), complication rates, procedural times, and PV reconnection patterns with HPSD AF AF ablation versus an FTI-guided low-power, long-duration (LPLD) strategy. We compared consecutive patients undergoing a first ablation procedure for paroxysmal or persistent AF. The HPSD protocol utilized a power of 50 W and durations of 6-8 s posteriorly and 8-10 s anteriorly. The LPLD protocol was FTI-guided with a power of ≤25 W posteriorly (FTI ≥ 300g·s) and ≤35 W anteriorly (FTI ≥ 400g·s). In total, 214 patients were prospectively included (107 HPSD, 107 LPLD). Freedom from AA at 1 year was achieved in 79% in the HPSD group versus 73% in the LPLD group (p = .339; adjusted hazard ratio with HPSD, 0.67; 95% confidence interval, 0.36-1.23; p < .004 for non-inferiority). Procedure duration was shorter in the HPSD group (229 ± 60 vs. 309 ± 77 min; p < .005). Patients undergoing repeat ablation had a higher propensity for reconnection at the right PV carina in the HPSD group compared with the LPLD group (14/30 = 46.7% vs. 7/34 = 20.6%; p = .035). There were no differences in complication rates. HPSD AF ablation resulted in similar freedom from AAs at 1 year, shorter procedure times, and a similar safety profile when compared with an LPLD ablation strategy. Patients undergoing HPSD ablation required more applications at the right carina to achieve isolation, and had a significantly higher rate of right carinal reconnections at redo procedures.

Lesion size and adjacent tissue damage assessment with high power and short duration radiofrequency ablation: comparison to conventional radiofrequency ablation power setting.

There is increased interest in creating high-power short duration (HPSD) ablation lesions in the field of atrial fibrillation (AF) radiofrequency ablation (RFA). We evaluated the lesion characteristics and collateral damage using two separate RFA protocols setting (HPSD: 50W and 7s vs control: 25W and 30s) in vitro model. Sixteen freshly killed porcine hearts were obtained, and the atrium and ventricle slabs were harvested for ablation. The each slabs were placed in a tissue bath with circulating 0.9% NaCl at maintained temperature 37°C. RFA was performed with 4mm tip irrigated force sensing catheter. All lesions were ablated under recording the electrical parameters using with Ensite Navx system (St. Jude Medical, St. Paul, Minnesota). After RFA, lesion characteristics were assessed for each lesion. Thirty-five lesions were made for each ablation protocol (total 70 lesions for analysis). Ablation parameters were similar between two groups (HPSD vs control; impedance drop (Ω): 34.2 ± 13.1 vs 36.1 ± 8.65 P = 0.49, contact force (g): 13.9 ± 4.37 vs 14.6 ± 5.09, P = 0.51, lesion size index: 4.8 ± 0.52 vs 4.73 ± 0.59, P = 0.62). Although the lesion volume was similar, the HPSD ablation creates wider but more shallower lesions compared to control group (HPSD vs control; lesion volume: 29.6 ± 18.1mm3 vs 35.5 ± 17.1mm3 P = 0.16, lesion diameter: 4.98 ± 0.91mm vs 4.45 ± 0.74mm P = 0.0095, lesion depth: 2.2 ± 0.76mm vs 2.8 ± 1.56mm P = 0.046). Of these, 38 lesions were assessed for adjacent tissue damage and adjacent tissue damages were more frequent seen in control group (HPSD vs control; 1/19 (5.26%) vs 6/19 (31.5%), P = 0.036). Effective lesions were made with HPSD, thereby reducing RFA procedure time. Although the lesion volume was similar between two groups, collateral damage was less seen in HPSD group attributed by lesion characteristics.

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

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

An initial ex vivo evaluation of temperature profile and thermal injury formation on the epiesophageal surface during radiofrequency ablation.

Few studies have examined heat transfer and thermal injury on the epiesophageal surface during radiofrequency application, or compared the risk of esophageal thermal injury between standard and high-power, short-duration (HPSD) ablation. We studied the thermodynamics of HPSD and standard ablation at different tissue interfaces between the left atrium and esophagus, focusing on epiesophageal temperature changes and thermal injury. Fresh porcine heart and esophageal sections were secured to a custom holder and submerged in a temperature-controlled, circulating water bath. During ablation, thermistors recorded temperatures at the catheter tip-atrial interface, epiesophageal-atrial interface, and esophageal lumen. Samples were ablated in triplicate with the following parameters: contact force (15/25g), power (10/20/30 W standard; 40/45/50 W HPSD), and duration (10/20/30 s standard; 5/10/15 s HPSD). Epiesophageal and endoluminal temperature rises were greater in HPSD than in standard ablation (epiesophageal: 5.9 ± 5.6 vs. 2.2 ± 2.0°C, p < .01; endoluminal: 0.7 ± 0.5 vs. 0.4 ± 0.2°C, p < .01). Six of 30 HPSD ablations and 1 of 26 standard ablations caused esophageal injury. The delay between the peak epiesophageal and endoluminal temperatures was greater in HPSD than in standard ablation (24.2 ± 22.1 vs. 13.0 ± 11.0 s, p = .023). Likewise, the peak epiesophageal surface temperature differed more from the concurrent endoluminal temperature in HPSD ablation (5.1 ± 5.3 vs. 1.7 ± 2.0°C, p < .01). Endoluminal temperature underestimates epiesophageal surface temperature substantially during HPSD ablation. Visible epiesophageal injury was associated with a 2.2 ± 2.1°C rise in endoluminal temperature, corresponding to a 10.2 ± 6.5°C rise in epiesophageal temperature.

High-power short-duration ablation of atrial fibrillation: A contemporary review.

Catheter ablation using radiofrequency (RF) energy has been widely used to treat patients with atrial fibrillation (AF). The optimal levels of power and duration to increase the success rate while minimizing complications have not been fully established. Different centers continue to use various power protocols for catheter ablation of AF. Herein, we present a comprehensive review of the impact of power output on efficacy and safety of RF ablation for AF. High-power short-duration (HPSD) ablation can be performed safely with similar procedural efficacy as low-power long-duration ablation strategy. HPSD ablation has the potential to shorten procedural and RF times and create more durable and localized lesions.

Incidence of ablation-induced esophageal injury associated with high-power short duration temperature-controlled pulmonary vein isolation using a specialized open-irrigated ablation catheter: A retrospective single-center study.

To evaluate short-term efficacy and incidence of ablation-induced endoscopically detected esophageal injury in patients undergoing high-power, short-duration (HPSD) pulmonary vein isolation using a novel irrigated radiofrequency ablation catheter and ablation generator setup. Atrial fibrillation (AF) patients, who underwent AF ablation using an irrigated radiofrequency ablation catheter specifically designed for a HPSD ablation approach (50 W, with a target Ablation Index of 350 at posterior wall), received postablation esophageal endoscopy after ablation. In total 45 consecutive patients (67 ± 10 years; 58% male; 42% paroxysmal AF) undergoing AF ablation using a specialized ablation catheter (QDOT) were included in the study. Thirty-one of 45 patients (69%) underwent a first-time pulmonary vein isolation (Group 1, 67 ± 11 years; 55% male; 48% paroxysmal AF). Fourteen patients (31%) underwent a redo AF procedure (Group 2, 66 ± 8 years; 64% male; 29% paroxysmal AF). Patients undergoing first-time pulmonary vein isolation were included in the final analysis. In these patients an endoscopically detected esophageal lesion (EDEL) was detected in 5 of 31 (16%) patients (erosion n = 2, ulcer n = 3). Mean contact force at posterior wall ablation sites was significantly lower in patients with postprocedural EDEL compared with patients without EDEL (11.9 ± 0.8 g vs. 15.6 ± 4.7 g). PVI using a specialized high-power ablation catheter in conjunction with a HPSD ablation approach results in a 16% incidence of EDEL in first AF ablation candidates. Future studies evaluating high-power short duration ablation strategies should include esophageal endoscopy to estimate the risk of clinically relevant esophageal complications.

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

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

Proactive Esophageal Cooling Protects Against Thermal Insults During High-Power Short-Duration Radiofrequency Ablation

Background: Atrioesophageal fistula (AEF) is a severe complication of left atrial radiofrequency (RF) ablation for the treatment of atrial fibrillation. Proactive cooling with a novel cooling device has been shown to significantly reduce thermal injury, with no AEFs yet encountered after thousands of treatments worldwide. Computer modeling suggested that lethal temperatures could be avoided with moderate-power and moderate-duration RF ablation. We aimed to evaluate the effects of proactive cooling during high-power short-duration (HPSD) ablation, and compare the computed results to clinical data and recently published experimental data. Methods: A computer model accounting for the left atrium and esophagus including the active cooling device was created. We used both the Arrhenius equation and 50oC isotherm to estimate the esophageal thermal damage during 50 W, 10 second and 90 W, 4 second RF ablations. Results: Under control conditions, temperatures across the esophageal wall exceeded the lethal isotherm, in agreement with recent experimental data. With proactive esophageal cooling in place, temperatures in the esophageal tissue were significantly reduced, with the resulting fraction of esophageal damage reduced by 74% under 50 W and 10 seconds of ablation, and by 82% under 90 W and 4 seconds of ablation. Esophageal damage was restricted to the epi-esophageal region, sparing the remainder of the esophageal tissue, including the mucosal surface. Conclusions: Proactive esophageal cooling significantly reduced temperatures and the resulting fraction of damage in the esophagus during HPSD ablation. These findings offer a mechanistic rationale explaining the absence of AEF encountered to date using proactive esophageal cooling.

Abstract 15977: Comparison of Clinical and Procedural Outcomes Between High-power Short-duration, Standard-power Standard-duration, and Temperature-controlled Non-contact Force Guided Ablation for Atrial Fibrillation

Introduction: High-power short-duration (HPSD) ablation via the St. Jude EnSite™ Velocity™ system (St. Paul, MN) utilizes 50W delivered for up to 15s, guided by a Lesion Size Index of 5-6 specific to the Velocity™ system. HPSD is a novel way to use a contact force-sensing catheter optimized for power-controlled radiofrequency ablation of atrial fibrillation (AF). Procedural and clinical outcomes of HPSD compared to standard-power standard-duration (SPSD; 20-25W until 400-500 gram seconds, up to 60s) and temperature-controlled non-contact (TCNC; 20-40W up to 60s of ablation) settings would inform this strategy. Methods: We studied consecutive cases of patients with paroxysmal or persistent AF undergoing pulmonary vein isolation (PVI) with TCNC, SPSD, and HPSD between 7/1/13 to 11/1/19. Procedural data collected include total radiofrequency time (RFT), time to isolate the left pulmonary veins (LPVT), time to isolate the right pulmonary veins (RPVT), and safety outcomes. Clinical data collected include sinus rhythm maintenance 3 and 12-months post-procedure. Results: A total of 171 patients were studied (44 TCNC, 51 SPSD, 76 HPSD). There was no difference in age, sex, or AF type between groups. RFT was shorter when comparing HPSD to SPSD (71 vs 101 min; p&lt;0.01), HPSD to TCNC (71 vs 146 min; p&lt;0.01), and SPSD to TCNC groups (101 vs 146 min; p&lt;0.01). This was driven by decreases in LPVT between the HPSD vs SPSD (34 vs 46 min; p=0.04), HPSD vs TCNC (34 vs 72 min; p&lt;0.01), and SPSD vs TCNC groups (46 vs 72 min; p&lt;0.01), as well as decreases in RPVT between the HPSD vs SPSD (42 vs 54 min; p=0.03), HPSD vs TCNC (42 vs 75 min; p&lt;0.01), and SPSD vs TCNC groups (54 vs 75 min; p&lt;0.01). There was no difference in sinus rhythm maintenance after 3 or 12-months between groups overall, and when stratified by AF type, left atrial volume, CHA 2 DS 2 -VASc score, or left ventricular EF. There was a numerical difference in safety with no adverse events in HPSD (0/76 in HPSD vs 1/51 in SPSD vs 3/44 in TCNC; p=0.06). Conclusion: AF ablation with contact force utilizing an HPSD ablation strategy reduced procedure times with similar sinus rhythm maintenance compared to SPSD and TCNC approaches. Further research is needed to determine whether clinical outcomes differ with a larger population and longer follow-up.

The First-Pass Isolation Effect in High-Power Short-Duration Compared to Low-Power Long-Duration Atrial Fibrillation Ablation: a Predictor of Success

Introduction: Different results are described after atrial fibrillation ablation and multiples predictors of recurrence are well established. Objective: Evaluate and analyze if first-pass isolation effect (FPI) during first atrial fibrillation (AF) ablation with high-power short-duration (HPSD) comparing to low-power long-duration (LPLD) can impact on late outcome. Methods: Observational, retrospective study, 144 patients submitted to HPSD and LPLD ablation. HPSD: 71 patients, 50 (70.42%) males, mean age 59.73 years, 52 (73.24%) hypertension, 44 (61.97%) obstructive apnea, 23 (32.39%) arterial disease, 20 (28.17%) diabetes, and 10(14.08%) stroke. CHADS2VASC2 2.57. CT: 73 patients, 50 (68.49%) males, mean age 60.7 years, 53 (72.60%) hypertension, 41 (56.16%) obstructive apnea, 28 (38.36%) arterial disease, 14 (19.17%) diabetes and 8 (10.96%) stroke. CHAD2SVASC2 2.22. Results: Recurrence occurred in 33 patients (22.92%) at 12 months follow-up, HPSD with 9 patients and LPLD with 24 patients. Higher rate of bilateral FPI were observed in HPSD patients with 62 of 71 patients comparing to 17 of 73 patients in LPLD (P &lt; 0.00001). At the end of study 62 (87.32%) of 71 HPSD patients were in sinus rhythm comparing to 49 (67.12%) of 73 patients in LPLD (P 0.0039). Conclusion: HPSD ablation produced higher rates of FPI comparing to LPLD. HPSD compared to LPLD showed a superiority in maintaining sinus rhythm at 12 months. At patients submitted to HPSD protocol ablation, FPI could predict higher rate of sinus rhythm at 12 months follow-up.

Changes and impacts in early recurrences after atrial fibrillation ablation in contact force era: comparison of high-power short-duration with conventional technique-FIRST experience data.

Different atrial tachyarrhythmias (AT) may be seen during follow-up after atrial fibrillation ablation. Evaluate and analyze characteristics and management of AT following first atrial fibrillation (AF) ablation with high-power short-duration (HPSD) comparing to low-power long-duration (LPLD) and its impact on late outcome. Observational, retrospective study, 144 patients submitted to HPSD and LPLD ablation. HPSD with 71 and LPLD with 73 patients and no major clinical differences between the two groups. AT occurred in 60 patients (41.67%) in entire follow-up. HPSD 22 patients had AT: 13 during blanking period (BP) and 9 after that. LPLD: 38 patients with AT, 14 during BP and 24 after that. During BP, HPSD showed high rate of atrial flutter/tachycardia in 9 (69.23) of 13 and LPLD 4 (28.57%) of 14 patients. At 12months' follow-up, 62 (87.32%) of 71 HPSD patients were in sinus rhythm comparing to 49 (67.12%) of 73 patients in LPLD. HPSD ablation produced higher rates of early than late recurrence comparing to LPLD. Regular tachyarrhythmias were most common arrhythmia during BP with HPSD ablation and AF in LPLD. HPSD compared to LPLD showed a superiority in maintaining sinus rhythm at 12months.

Is higher power shorter duration radiofrequency energy is better than lower power longer duration strategy in catheter ablation of atrial fibrillation A meta-analysis

Abstract Background An ideal strategy for radiofrequency ablation (RFA) of atrial fibrillation (AF) in the left atrium should be efficient enough to achieve transmural lesions in left atrium with no or minimal collateral tissue damage. Resistive heating of high power short duration (HPSD) RFA has been found to result in lesions larger in width but lesser in depth compared to lower power longer duration (LPLD) RFA in some experimental studies. Purpose This meta-analysis was performed to compare procedural, short-term and long-term outcomes of HPSD versus LPLD RFA of AF. Methods PubMed, Embase and Cochrane databases were systematically reviewed. Five observational studies meeting criteria were included in the meta-analysis. All the studies scored six or more points in the New-castle Ottawa scale. There were considerable variations in the ablation strategies across the studies. However, radiofrequency power more than 40W was considered as high power. Hypergeometric model with exact likelihood function was utilized for statistical analysis. Results Baseline parameters and ablation details have been depicted in Table 1. 740 patients with HPSD and 287 patients with LPLD ablation strategies, were followed up from 6 to 30 months. Total procedural time (P value &amp;lt;0.0001) and ablation time (P value &amp;lt;0.0001) were significantly lower in the HPSD group than LPLD group. However, the fluoroscopy time was similar (P value = 0.09) in both the groups (Table 2). There were no occurrences of atrio-esophageal fistula or pulmonary venous stenosis in any of the studies. Cardiac tamponade (P value = 0.56), stroke (P value = 0.70) and AF recurrences (P value = 0.81), were similar in both groups (Table 2). Conclusion Newer HPSD and conventional LPLD RFA, both the strategies are very safe procedure for treatment of RFA with low to no procedural complications. AF recurrence rates were reasonably high irrespective of ablation strategies, however, no strategy scored statistically better over the other one. Large randomized multi-centric studies with long-term follow up are needed to test the theoretical advantage of HPSD ablation over the traditional ablation strategy of AF. Funding Acknowledgement Type of funding source: None

High-power short-duration radiofrequency ablation of typical atrial flutter.

BackgroundHigh-power short-duration (HPSD) ablation has been explored for pulmonary vein isolation. Early data suggest similar efficacy with shorter procedure times and perhaps greater safety. Data are lacking on the use of this ablation strategy for other arrhythmias.ObjectiveThe purpose of this study was to evaluate the safety, efficacy, and clinical outcomes of HPSD ablation in patients with typical atrial flutter compared to those undergoing ablation with conventional settings.MethodsConsecutive patients undergoing cavotricuspid isthmus (CTI) ablation using standard power settings were compared to those performed after transitioning to HPSD ablation. Demographics, procedural details, and ablation outcomes were prospectively collected. The primary endpoint was duration of radiofrequency energy delivery. Secondary endpoints were radiation duration and analgesia requirements.ResultsA total of 114 consecutive subjects undergoing CTI ablation (57 standard power, 57 HPSD) were included. HPSD ablation and electroanatomic mapping/contact force (EAM/CF) use were associated with 66% (95% confidence interval [CI] 58%–73%) and 50% (95% CI 37%–60%) shorter ablation times compared to standard power and not using EAM/CF, respectively. Patients in the HPSD group required 50 mcg less fentanyl relative to the standard ablation arm after adjusting for sex, age, and comorbidities (P = .048). At a median follow-up of 6 months, 4 patients (7%) in the standard arm had recurrence of atrial flutter, compared to none in HPSD group (P = .057).ConclusionHPSD is a safe and effective approach to CTI ablation. This strategy may reduce ablation time and analgesia requirements. Larger studies and longer follow-up are needed to further evaluate this strategy.

Impact of High-Power Short-Duration Radiofrequency Ablation on Long-Term Lesion Durability for Atrial Fibrillation Ablation.

The goal of this study was to compare lesion durability between high-power short-duration (HP-SD) and moderate-power moderate-duration (MP-MD) ablation strategies. HP-SD radiofrequency ablation (RFA) was developed to improve pulmonary vein isolation (PVI) by reducing the effect of catheter instability inherent to MP-MD ablation strategies. However, its long-term effect on lesion durability for the treatment of atrial fibrillation is unknown. Patients with atrial fibrillation (n=112) underwent PVI using HP-SD ablation (45 to 50 W, 8 to 15 s) with contact force-sensing open irrigated catheter. Cavotricuspid isthmus, mitral annular, and roof lines were permitted. A control group (n=112) underwent ablation using MP-MD ablation (20 to 40 W, 20 to 30 s) with similar technology. Chronic PV reconnection was examined in patients who required a redo procedure (HP-SD ablation, n=18; MP-MD ablation, n=23). The rate of PVI at the completion of the initial encirclement was similar between the HP-SD and MP-MD ablation strategies (90.2% vs. 83.0%; p=0.006). The HP-SD strategy required shorter RFA time (17.2 ± 3.4min vs. 31.1± 5.6min; p<0.001). The incidence of chronic PV reconnection was lower with HP-SD ablation (16.6% vs. 52.2%; p=0.03). Areas of chronic reconnection were associated with catheter motion≥1mm for≥50% application duration. In a higher proportion of HP-SD applications, catheter motion was<1mm during≥50% duration (88.6% vs. 72.8%; p<0.001), allowing energy delivery with greater stability. Both ablation strategies were effective for cavotricuspid isthmus; however, the HP-SD strategy was less effective for mitral annular lines, requiring ablation at lower power for longer duration to avoid steam pops. HP-SD ablation may improve PVI durability, and it shortens RFA time. However, ablation in thicker myocardium often requires lower power applied for longer duration, allowing deeper lesions without tissue overheating.

Effectiveness and safety of high‐power and short‐duration ablation for cavotricuspid isthmus ablation in atrial flutter

Despite many studies on new tools and strategies for cavotricuspid isthmus (CTI) ablation, there is an unmet need to improve the CTI ablation procedure. Recently, high-power short-duration (HPSD) ablation has been widely used for pulmonary vein (PV) isolation in atrial fibrillation. We evaluated the effectiveness and safety of HPSD for CTI ablation in atrial flutter (AFL). Eighty-four patients who underwent CTI ablation with or without simultaneous PV isolation between January 2018 and February 2019 were enrolled in this prospective cohort study. We compared procedural characteristics, periprocedural complications, and recurrence of atrial tachyarrhythmia (ATa) between the HPSD group (50 W for 15s) and conventional group (30 W for 60s). A total of 84 patients were divided into the HPSD (n=42) and conventional (n=42) groups. Bidirectional CTI block was achieved in all patients and 95% achieved bidirectional block after the first-line ablation in both groups. Although there was no difference in the total number of ablation lines between the two groups (1.17 ± 0.7vs 1.38 ± 0.8, P=.067), HPSD ablation significantly reduced total ablation time compared to the conventional group (236.0 ± 85.6vs 534.2 ± 235.2s, P<.001). One pericardial tamponade was reported in the HPSD group. During the mean follow-up of 9.3 ± 4.8 months, CTI-dependent AFL recurrence occurred in one patient in the HPSD group. Recurrence of ATa developed in 14 patients with no significant difference between the groups. Our study demonstrates that HPSD CTI ablation is safe and can shorten procedure time.

High-power, short-duration ablation during Box isolation for atrial fibrillation.

BackgroundIt has been demonstrated that a high‐power, short‐duration (HPSD) ablation during pulmonary vein (PV) isolation is effective and safe. However, studies about the HPSD ablation during the posterior wall isolation, the Box isolation (BOXI), are limited. We evaluated the efficacy, feasibility, and safety of HPSD ablation during BOXI.MethodsOne‐hundred sixty patients with all types of atrial fibrillation underwent BOXI with HPSD ablation (n = 80) or conventional technique (n = 80). In the HPSD group, ablation was performed with 50 W and a target lesion size index of 5.0 using a contact force (CF) sensing catheter. Ablation near the esophagus was performed with 50 W for 5 seconds and a CF < 10 g. In the conventional group, ablation was performed with 30‐40 W for 30 seconds, but 20 W near the esophagus.ResultsThe BOXI creation (26 ± 8 minutes vs 47 ± 17 minutes, P < .0001) and procedure (65 ± 12 minutes vs 87 ± 23 minutes, P < .0001) times were significantly shorter in the HPSD group than the conventional group. The number of pacing capture sites did not differ between the two groups. No complications including gastrointestinal symptoms occurred. The atrial tachyarrhythmia‐free rate at 12‐months after a single procedure was 86.3% in the HPSD group and 76.3% in the conventional group, respectively (P = .132). The incidence of PV reconnections and gaps in the lines during the second procedure did not differ between the two groups.ConclusionThe BOXI with HPSD ablation is effective, feasible, and safe with short BOXI creation and procedure times without reducing the clinical outcomes.

Update on high-power short-duration ablation for pulmonary vein isolation.

Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. However, this procedure remains complex and time-consuming, and the recurrence of AF after PVI is still unsatisfactory. Current technologies have improved our knowledge of the association between radiofrequency lesion creation and ablation parameters (power and duration), which triggered the development of high-power short-duration (HPSD). During the past decade, several preclinical and clinical studies have been conducted to confirm the feasibility, safety, and outcome of PVI ablation with HPSD or very high-power short-duration (vHPSD) settings, which increased electrophysiologists' interests in the utility of HPSD strategies. This paper describes the theoretical basis and recent research findings of HPSD or vHPSD ablation and summarizes the state-of-the-art evidence behind the role of this strategy in PVI.

1249Acute efficacy and safety of pulmonary vein isolation for atrial fibrillation in patients alternatively assigned to high power short duration (70W, 8s) vs lesion index guided (35W) ablation

Abstract Background permanent trans-mural lesions not affecting surrounding anatomical structures is the goal of safe and effective wide antral pulmonary vein (PV) isolation in patients with paroxysmal and persistent atrial fibrillation (AF) undergoing catheter ablation (CA). Time, energy and contact force are parameters related to lesion goodness and incorporated in a complex formula (i.e. the lesion index, LSI™, Abbott). This parameter is emerging as the gold standard for PV isolation. Recently, the shallower but wider lesions created by high power short duration (HPSD) ablation has came to attention. Purpose to compare acute reconnection rate, procedural parameters, and complication rates in patients with paroxysmal or persistent AF undergoing CA. Methods one-hundred patients with paroxysmal and 100 with persistent AF will be alternatively assigned to undergo PV isolation with the FlexAbility™ (HPSD group, 70W, 41°, 8 seconds) or the TactiCath™ (LSI-group: 35W, 41°, LSI: 5-5.5 posterior wall, up to ≥6 anywhere else) catheter. A 3-D mapping system (Ensite Precision™) and a steerable sheath (Agilis™, both Abbott) were always used. Adenosine (30mg) is given after PV isolation and ≥ 20 minutes waiting time. Posterior wall isolation was added in all, and patients with persistent AF were additionally treated with mitral and cavotricuspid isthmus ablation. Results: between June and October 2019, 71 patients (68 ± 10 years old, 32 (45%) female, 44 (60%) paroxysmal AF, AF duration 58 ± 81 months) were alternatively assigned to HPSD (36, 51%) or LSI-guided (35, 49%) ablation. No difference in clinical characteristics was found between groups. After 44 ± 18 and 30 ± 14min of procedural and RF time, all PVs were isolated, and all 17 (24%) reconnections treated with an additional 4 ± 3 and 3 ± 2min, respectively. In 8 ± 3 and 7 ± 3 min of procedural and RF time, the PW was successfully isolated in all. PV isolation (34 ± 12min vs. 56 ± 16min; P&amp;lt;.0001), RF (18 ± 5min vs. 41 ± 9min; P&amp;lt;.0001), and total procedural (138 ± 34min vs. 162 ± 34min; P=.0026) time were shorter in the HPSD group. X-Ray time and effective dose did not differ. A similar rate of acute reconnections (9, 25% vs. 8 23%) was found when HPSD and LSI were compared. A higher, although statistically not significant, number of steam pops was observed in the HPSD (14, 39%) vs. LSI (8, 23%) group, possibly related to the higher incidence of moderate pericardial effusion (&amp;gt;0.5mm, &amp;lt;20mm) found the day following the ablation (10, 28% vs. 2, 6%; P=.0238). No further complications related to CA were detected. Conclusions in patients with paroxysmal and persistent AF undergoing their first CA, HPSD ablation is faster than an LSI-guided approach. Acute efficacy (reconnection rate) is similar. Although a higher rate of haemodynamically non-relevant pericardial effusions were seen in the HPSD group, these were all treated medically and the general safety profile of this approach is excellent and comparable to LSI ablation.

1247Similar rate of thermal esophageal lesions are found in patients alternatively assigned to high power short duration (70W, 8s) vs. lesion index guided (35W) ablation for atrial fibrillation

Abstract Background wide antral pulmonary vein (PV) catheter ablation (CA) in patients with atrial fibrillation (AF) is safe and effective when permanent trans-mural lesions are achieved without causing harm to surrounding anatomical structures. Atrio-esophageal fistula, due to its high mortality, is the most dreadful complication related to CA for AF, therefore alternative radiofrequency (RF) approaches to reduce or eliminate this complication are currently studied. The shallower but wider lesions of high power short duration (HPSD) ablation might represent a safe alternative. Purpose to compare the rate of thermal esophageal lesions in patients with paroxysmal and persistent AF undergoing CA assigned to the 2 different RF modality. Methods one-hundred patients with paroxysmal and 100 with persistent AF will be alternatively assigned to undergo CA with the FlexAbility™ (HPSD group: 70W, 41°, 8 seconds) or the TactiCath™ (LSI-group: 35W, 41°, LSI: 5-5.5 posterior wall, up to 6 anywhere else) catheter. A 3-D mapping system, a steerable sheath and adenosine-test (30mg) were used in all patients. Posterior wall (PW) isolation in addition to PV isolation was performed in all, and patients with persistent AF were additionally treated with mitral and cavotricuspid isthmus ablation. Insertion of an esophageal probe was always attempted, and all patients underwent upper endoscopy 24 to 48 hours after CA. Results between June and October 2019, 71 patients (68 ± 10 years old, 32 (45%) female, 44 (60%) paroxysmal AF, AF duration 58 ± 81 months) were alternatively assigned to HPSD (36, 51%) or LSI-guided (35, 49%) ablation. No differences in clinical characteristics were found between groups. After 45 ± 18min and 30 ± 14 min of procedural and RF time, all PVs were isolated, and all spontaneous and adenosine-induced reconnections treated. Successful PW isolation was achieved with an additional 8 ± 3 and 7 ± 3 min of procedural and RF time. When HPSD and LSI-guided groups are compared, a similar rate of clinically non-relevant and self-healing thermal lesions at endoscopy was found (10, 27.8% vs. 10, 28.6%). Independent of the treatment group, a higher peak temperature identified patients with esophageal lesions (43.2° vs. 42°; P=.0065). A peak temperature value of 43.1° best identify patients most likely to develop thermal lesions (AUC 0.71, SE 84%, SP 39%). Interestingly, none of the 11 patients in whom esophageal probe insertion was not possible or attempted developed thermal lesions in comparison to 20 (33%) patients who underwent esophageal temperature monitoring (P=.0046). Conclusions: no difference in thermal induced esophageal lesions were found when the two different RF approach (HPSD vs. LSI guided) were compared. Interestingly, lack of temperature monitoring with an esophageal probe is associated with no thermal lesions at endoscopy.

Esophageal temperature evolution during high power short duration ablation: Numerical simulations and clinical suggestions

In recent times electrophysiologists started considering the possibility of performing Radiofrequency (RF) ablation for the treatment of atrial fibrillation by delivering shorter pulses of larger power (e.g. 60W, 6s applications).