High-power Short-duration Ablation Research Articles

Lesion characteristics using high-frequency low-tidal volume ventilation versus standard ventilation during ablation of paroxysmal atrial fibrillation.

High-frequency low-tidal-volume (HFLTV) ventilation during radiofrequency catheter ablation (RFCA) for paroxysmal atrial fibrillation (PAF) has been shown to be superior to standard ventilation (SV) in terms of procedural efficiency, acute and long-term clinical outcomes. Our study aimed to compare ablation lesions characteristics utilizing HFLTV ventilation versus SV during RFCA of PAF. A retrospective analysis was conducted on patients who underwent pulmonary vein isolation (PVI) for PAF between August 2022 and March 2023, using high-power short-duration ablation. Thirty-five patients underwent RFCA with HFLTV ventilation and were matched with another cohort of 35 patients who underwent RFCA with SV. Parameters including ablation duration, contact force (CF), impedance drop, and ablation index were extracted from the CARTONET database for each ablation lesion. A total of 70 patients were included (HFLTV = 35/2484 lesions, SV = 35/2830 lesions) in the analysis. There were no differences in baseline characteristics between the groups. While targeting the same ablation index, the HFLTV ventilation group demonstrated shorter average ablation duration per lesion (12.3 ± 5.0 vs. 15.4 ± 8.4 s, p < .001), higher average CF (17.0 ± 8.5 vs. 10.5 ± 4.6 g, p < .001), and greater impedance reduction (9.5 ± 4.6 vs. 7.7 ± 4.1 ohms, p < .001). HFLTV ventilation group also demonstrated shorter total procedural time (61.3 ± 25.5 vs. 90.8 ± 22.8 min, p < .001), ablation time (40.5 ± 18.6 vs. 65.8 ± 22.5 min, p < .001), and RF time (15.3 ± 4.8 vs. 22.9 ± 9.7 min, p < .001). HFLTV ventilation during PVI for PAF was associated with improved ablation lesion parameters and procedural efficiency compared to SV.

Feasibility and Safety Assessment of RF Double Applications in Very High-Power Short-Duration Ablation.

The QDOT-MICRO catheter enables very-high-power and short-duration (vHPSD) ablation. However, low first-pass isolation rates have been reported, possibly due to shallow lesion formation, necessitating deeper lesions to improve treatment outcomes. This study aimed to confirm the safety and efficacy of double Radiofrequency (RF) applications of vHPSD ablation in an in vivo beating swine heart model. Eighteen swine were anesthetized and underwent vHPSD ablation with the QDOT-MICRO catheter at 90W for 4 seconds, targeting a contact force of 10g. RF applications were performed as single (SA) and double applications (DA) with 4-8 seconds rest intervals. Lesion surface area and volume were measured post-ablation. A total of 337 atrial lesions and 74 ventricular lesions were created. Both 4-6s DA and 7-8s DA produced significantly larger and deeper lesions compared to SA, with atrial surface lengths averaging 9.0mm for 4-6s DA, 9.2mm for 7-8s DA, and 8.0mm for SA. Transmurality was observed at 100% for 4-6s and 7-8s DA, while it was 94% for SA (p=0.002). Ventricular lesion metrics followed similar trends. Except for 1 event of tiny char formation in 4s DA in the ventricle, neither steam-pops nor char formation was observed in either the atrium or the ventricle. In an in vivo swine heart model, DA with 4-6s and 7-8s intervals create deeper and wider lesions than SA, suggesting its potential for clinical application in areas with thicker myocardial walls. However, DA with very short intervals may still pose a risk of excessive tissue heating.

Combined approach of high-power and very high-power, short-duration ablation in superior vena cava isolation.

The effectiveness and safety of 50 W, high-power, short-duration (HPSD) ablation in superior vena cava isolation (SVCI) for patients with atrial fibrillation (AF) have been reported. However, the acute outcomes of SVCI combined with 90 W/4 s, very high-power, short-duration (vHPSD) ablation remain unknown. In this study, we aimed to investigate a novel approach that combines 50 W-HPSD and 90 W/4 s-vHPSD ablation in SVCI and to elucidate the characteristics, outcomes, and safety of this approach by comparing SVCI with conventional ablation index (AI)-guided middle-power, middle-duration (MPMD) ablation. Overall, 126 patients who underwent AF ablation with SVCI using the QDOT MICROTM catheter were retrospectively reviewed; one group underwent SVCI with a combined approach of HPSD and vHPSD ablation (50 W/90 W group, n = 73) and another group underwent AI-guided MPMD ablation (30-40 W group, n = 53). This study compared the procedural details, radiofrequency (RF) ablation profiles, and complications. The RF settings used in the 50 W/90 W group were 50 W/7 s for the lateral segment close to the phrenic nerve and 90 W/4 s for the nonlateral segment. The 50 W/90 W group required a significantly shorter procedural time (3.2 vs. 5.9 min, p < .001), shorter RF duration (42.0 vs. 162.0 s, p < .001), and lower RF energy (2834 vs. 5480 J, p < .001) than the 30-40 W group. Procedural success, first-pass SVCI, number of RF applications, and SVC reconnection after isoproterenol loading were comparable between the groups. The maximum tip-electrode temperature of the multi-thermocouple system was significantly higher in the 50 W/90 W group than in the 30-40 W group (50.0°C vs. 47.0°C, p < .001). No complications, such as phrenic nerve injury or bleeding requiring transfusion, were observed in either group. The combined approach of 50 W/7 s-HPSD and 90 W/4 s-vHPSD ablation resulted in successful and safe SVCI with shorter procedural time, shorter RF duration, and lower RF energy.

Catheter Ablation of Atrial Fibrillation in Patients with Heart Failure: Focus on the Latest Clinical Evidence.

Atrial fibrillation and heart failure are two common cardiovascular conditions that frequently coexist, and it has been widely demonstrated that in patients with chronic heart failure, atrial fibrillation is associated with a significant increase in the risk of all-cause death and all-cause hospitalization. Nevertheless, there is no unanimous consensus in the literature on how to approach this category of patients and which therapeutic strategy (rhythm control or frequency control) is the most favorable in terms of prognosis; moreover, there is still a lack of data comparing the different ablative techniques of atrial fibrillation in terms of efficacy, and many of the current trials do not consider current ablative techniques such as high-power short-duration ablation index protocol for radiofrequency pulmonary vein isolation. Eventually, while several RCTs have widely proved that in patients with heart failure with reduced ejection fraction, ablation of atrial fibrillation is superior to medical therapy alone, there is no consensus regarding those with preserved ejection fraction. For these reasons, in this review, we aim to summarize the main updated evidence guiding clinical decision in this complex scenario, with a special focus on the most recent trials and the latest meta-analyses that examined the role of catheter ablation (CA) in rhythm control in patients with AF and HF.

Meta-analysis of high-power short-duration versus cryoballoon ablation for atrial fibrillation.

The existing literature regarding the treatment strategy for high-power short-duration (HPSD) ablation in patients diagnosed with atrial fibrillation (AF) is currently insufficient. The objective of this study is to perform a comparative analysis evaluating the effectiveness, safety, and procedural efficiency of HPSD versus cryoballoon ablation (CBA) for AF. A comprehensive search was conducted in PubMed, EMBASE, Cochrane Library, Scopus, Web of Science, and ClinicalTrials.gov databases to identify trials comparing HPSD with CBA for AF from their inception until December 25, 2023. Treatment effect measures were expressed as odds ratio (OR), mean difference (MD), accompanied by a 95% confidence interval (CI). The analysis comprised six eligible trials involving a total enrollment of 2481 patients. No statistically significant disparities were observed in recurrent atrial arrhythmia (OR 0.90; 95% CI, 0.71-1.16) or total complications (OR 0.65; 95% CI, 0.38-1.12) between the two ablation techniques examined in this study. However, HPSD technique exhibited a significantly prolonged procedure time (MD 27.42; 95% CI, 19.03 to 35.81). Conversely, no significant differences were observed between the two modalities in terms of total fluoroscopy duration (MD -4.37; 95% CI -10.70 to 1.96) and ablation time (MD 7.95; 95% CI -3.97 to 19.88). Furthermore, HPSD demonstrated significantly higher odds of extrapulmonary vein (PV) trigger ablation compared to CBA (OR 18.86; 95% CI, 5.12-69.49). The subgroup analyses revealed that CBA continued to exhibit superior procedure time (except for the paroxysmal AF subgroup: [MD 29.52; 95% CI -4.25 to 63.60]), while no significant differences in safety and efficacy (except for the HPSD ≥ 70W subgroup: [OR 0.44, 95% CI 0.20-0.97]) outcomes were still observed. Among patients undergoing ablation therapy for AF, both HPSD and CBA demonstrate comparable efficacy and safety profiles; however, HPSD is associated with longer procedural time and higher rates of extra-PV trigger ablation.

Evaluation of microembolic signals on carotid ultrasound during pulmonary vein isolation with high-power short-duration and cryoballoon ablations: When and where do bubble and solid emboli arise?

The underlying risks of asymptomatic embolization during high-power short-duration (HPSD) ablation for atrial fibrillation remain unclear. We aimed to evaluate microembolic signals (MESs) during HPSD ablation with power settings of 50and 90 W in comparison with those during cryoballoon (CB) ablation using a novel carotid ultrasound-Doppler system that classifies solid and air bubble signals using real-time monitoring. Forty-seven patients underwent HPSD ablation using radiofrequency (RF), and 13 underwent CB ablation. MESs were evaluated using a novel pastable soft ultrasound probe equipped with a carotid ultrasound during pulmonary vein isolation. We compared the detailed MESs and their timing between RF and CB ablations. The number of MESs and solid signals were significantly higher in the RF group than in CB group (209 ± 229 vs. 79 ± 32, p = .047, and 83 ± 89 vs. 28 ± 17, p = .032, respectively). In RF ablation, the number of MESs, solid, and bubble signals per ablation point, or per second, was significantly higher at 90 W than at 50 W ablation. The MESs, solid, and bubble signals were detected more frequently in the bottom and anterior walls of the left pulmonary vein (LPV) ablation. In contrast, many MESs were observed before the first CB application and decreased chronologically as the procedure progressed. Signals were more prevalent during the CB interval rather than during the freezing time. Among the 28 patients, 4 exhibited a high-intensity area on postbrain magnetic resonance imaging (MRI). The MRI-positive group showed a trend of larger signal sizes than did the MRI-negative group. The number of MESs was higher in the HPSD RF group than in the CB group, with this risk being more pronounced in the 90 W ablation group. The primary detection site was the anterior wall of the LPV in RF and the first interval in CB ablation.

Impact of different ablation strategies during very high power short duration ablation: insights from the multicentric AIR HPSD registry

Abstract Background The very high power short duration ablation by mean of the QDOT Micro catheter was demonstrated to be safe and effective to achieve pulmonary vein isolation (PVI) in atrial fibrillation (AF) patients. Data from large multicentric registries are still lacking. Purpose We sought to investigate whether different ablation approaches may impact procedural outcomes. First, the hybrid approach (Qmode+, 90 W for 4 sec, at the posterior wall of the left atrium and Qmode modality AI-guided at the anterior wall) was compared to the ablation performed exclusively with the Qmode+ modality. Second, we investigated the impact of the type of anesthesia. Methods The AIR HPSD registry is a multicentric real world data registry including patients undergoing AF ablation by mean of the QDOT Micro catheter. The ablation modality (hybrid/ Qmode+) and the type of anesthesia were left to operators’ preference. Results Overall, 330 patients were enrolled, 67% males, 71% had paroxysmal AF, the mean age was 61±11. Pulmonary vein isolation was reached in 100% regardless of the ablation modality or the anesthesia used. As for the first pass isolation (FPI) there was a trend toward higher rates in the hybrid group compared to the Qmode+ group (85% vs 74%, p=0.1). No differences in FPI were found between the general anesthesia/deep sedation group and the conscious sedation group (83% vs 81%, p=0.8), however when considering the Qmode+ group solely, the FPI was significantly higher in the general anesthesia/deep sedation group (84% vs 56%, p=0.006). As for the procedural time, this was significantly shorter in the general anesthesia/deep sedation compared to conscious sedation (82±21 vs 97±35 min, p&amp;lt;0.01), as well as in the Qmode+ group compared to the hybrid group (80±31 vs 102±30 min, p&amp;lt;0.01). Minor complications were observed in 1% of patients with no significant differences between groups. Conclusions The PVI can be safely and effectively obtained with both approaches, hybrid or Qmode+ solely, however the rate of FPI seems higher with the hybrid one. When adopting solely the Qmode+ modality the general anesthesia increases the rate of FPI.

Lock Protocol : a new robust workflow for a very high first pass pulmonary vein isolation during atrial fibrillation ablation

Abstract Introduction Pulmonary vein isolation (PVI) is the gold standard for atrial fibrillation (AF) ablation. First pass PVI is often demanding when a raw geometry reconstruction is used in combination with an inaccurate automarks annotation, accounting for discontinuous or non-transmural lesions and related AF recurrences. We hypothesized that a magnetic-post processing of left atrial geometry in combination with an LSI-guided high power short duration (HPSD) automarks annotation could improve procedural efficiency. Purpose The aim of this study was to determine the impact on procedural outcomes of the new "Lock PVI protocol" during AF ablation with the new voxel mode EnSite X mapping system. Methods We included in the study consecutive patients with AF scheduled for pulmonary vein isolation (PVI) at our Departement between January 2021 and December 2022. Patients were divided in two Groups, the Lock-PVI Group and the control No Lock-PVI Group. The "Lock PVI" Group was ablated with the new Ensite X System using the new protocol, which consisted in (1) performing a road map with contact-force annotation at potential PVI sites after High Density reconstruction, (2) shaving the magnetic geometry reconstruction to unearth true 3D location of contact points, (3) Use of 3D-Automarks color-coded with a Lesion Index (LSI) target of 5.5 (anterior) and 4.5 (posterior) (4) Inter-lesion distance &amp;lt;6 mm (5) High Power Short Duration Approach (50 W). The No-Lock PVI was represented by patients ablated with and HPSD ablation with the previous version of the EnSite Precision mapping suit as per local standard practice. Groups were compared in term of procedural duration, radiological exposure and "first pass" isolation. Results Forty-four patients (22 "Lock PVI" and 22 controls mean age 63,3±8 years, 65,9% male, 47,7% persistent AF), for a total of 88 PVI circles were enrolled. Procedural duration was similar between approaches (121,1±43,6 vs 125,3±30,1 min; P=0,72) but RF time was shorter in the "Lock PVI" group (19,6±4 vs 29,55±9,1 min; P&amp;lt;0,001), although with with a longer fluoroscopy (19,5±10,1 vs 13,4±4,9 min; P=0,01). Of note, first pass isolation was significantly higher in the "Lock PVI" group: 40/44 (90,9%) vs 28/44 (63,6%) circles (P=0,002). Conclusion The new "Lock PVI" approach resulted in consistently better first-pass isolation (&amp;gt;90%) with less RF time when compared to standard of care PVI.Graphical AbstractLock PVI

Head-to-head comparison of pulsed field ablation, very high power-short duration, cryoballoon and conventional radiofrequency ablation by LGE-MRI-based ablation lesion assessment

Abstract Background Novel concepts for pulmonary vein isolation (PVI) like pulsed field ablation (PFA) or high power-short duration ablation (HPSD) promise favourable profiles of safety and efficacy. However, clinical comparisons of ablation lesion quality are lacking. Purpose To systematically investigate lesion characteristics of novel ablation concepts, we performed a prospective head-to-head comparison between PFA, HPSD, conventional RF and latest generation cryoballoon ablation using late gadolinium enhancement (LGE)-MRI-based ablation lesion assessment. Methods This study included patients that underwent first-time PVI-only atrial fibrillation ablation - either by ablation index-guided RF ablation, cryoballoon ablation (Arctic Front Advance Pro), HPSD ablation (QDOT micro catheter, QMODE+, 90W, 4s) or PFA (Farapulse PFA system). All patients received an LGE-MRI 3 months post-ablation. LGE was quantified based on the signal intensity ratio of each voxel relative to the blood pool, applying a previously validated threshold of &amp;gt;1.2 to define LGE indicative of ablation-induced scarring using a dedicated software. LGE discontinuations of &amp;gt;3 mm were considered as gaps, and complete lesions were defined as LGE covering &amp;gt;90% of the peri-antral circumference of ipsilateral pulmonary vein (PV) pairs. Results Post-ablation LGE-MRIs from 120 patients were analysed (40 RF, 40 cryoballoon, 20 PFA, 20 HPSD). The proportion of complete PV-encircling LGE lesions was significantly higher with conventional RF than with cryoballoon ablation (50% vs. 34%; p=0.023). Importantly, HPSD ablation resulted in even more complete lesions than conventional RF (68%, p=0.004), whereas the proportion of complete LGE lesions was lowest with PFA (21%). Accordingly, the total number of gaps was lower with HPSD ablation (1.9 gaps/patient) compared to the other ablation concepts (conventional RF 2.7, cryoballoon 3.2, PFA 3.4 gaps/patient; p=0.034). As expected, large-area ablation with the cryoballoon (13.8 mm) and PFA (12.8 mm) single-shot devices resulted in the widest lesions. Of note, HPSD lesions were significantly wider than conventional RF lesions (11.1 mm vs. 8.9 mm; p=0.004). Conclusions HPSD ablation resulted in the most continuous lesions, translating in the lowest number of gaps. Of note, HPSD lesions were also significantly wider than conventional RF lesions, thus corroborating the concept of a shallower HPSD lesion geometry from experimental studies. Interestingly, conventional RF showed a higher proportion of complete PV-encircling lesions than cryoballoon ablation. While PFA lesions cover relatively large areas, comparable to cryoballoon ablation, lesions are more inhomogeneous. However, it remains to be determined, to what extent LGE discontinuities in PFA lesions indicate ineffective ablation or only reflect a different kind of remodeling compared to thermal ablation, which may be less detectable by LGE-MRI.

Very high-power short duration ablation metrics predictors of successful pulmonary vein isolation in atrial fibrillation ablation

Abstract Background Previous studies have shown that very high-power short duration (vHPSD) is a safe ablation modality, with similar rate of first pass isolation (FPI) but faster ablation times compared to standard CLOSE protocol guided ablation. While CLOSE protocol uses ablation index to guide energy titration no such index exists for vHPSD ablations yet. Purpose Our aim was to evaluate ablation metrics as predictors of FPI in atrial fibrillation ablation (AF) using vHPSD ablation modality. Methods In a single centre retrospective analysis, we analysed consecutive patients treated for paroxysmal (PAF) or persistent atrial fibrillation (PeAF) with PVI using vHPSD ablation from May 2021 to January 2023. We excluded patients with previous PVI procedures. The analysis was done via a cloud-based commercially available ablation analysis tool CARTONET. We analysed catheter stability, average contact force, absolute impedance drop, number of ablations and cumulative ablation time in relation to first pass isolation (FAAVI – first attempt all veins isolated). Results This is the first larger data study to evaluate ablation metrics in vHPSD using commercially available CARTONET (Figure 1). Based on the inclusion criteria 150 patients were included in the analysis. Baseline characteristics and procedural metrics are presented in Figure 2 - Table. We observed a numerical trend towards higher FAAVI rate with increasing patients number (p=0.10). Complication rate was low (1 pericardial effusion requiring drainage and 1 vascular access site complication). Ablation metrics analysis yielded statistical differences between FAAVI and no FAAVI groups (Figure 2 - Table). Multivariate analysis identified average contact force (odds ratio (OR) 1.001; 95% confidence interval (CI): 0.999-1.003; p=0.047) and catheter stability (OR 0.985; 95% CI: 0.973-0.997; p=0.019) to be independent predictors of FAAVI. Additionally, number of applications (OR 1.000; 95% CI: 0.999-1.000; p=0.042) and total ablation time (OR 0.995; 95% CI: 0.991-0.999; p=0.021) were also independent predictors of FAAVI, possibly indicating larger vein and/or ablation circumferent line to be predictive of no FAAVI. Catheter stability of less than 1.16mm (AUC 0.61; p=0.015) was shown to be discriminative of FAAVI, however discrimination value was poor. Average contact force was not discriminative of FAAVI (AUC 0.58; p=0.105) in our patient cohort. Conclusion Average contact force and catheter stability were predictive of first pass isolation, however only catheter stability was discriminative of FAAVI. Larger data with standardised ablation protocol (interlesion distance) and wider range of ablation metrics is needed to corroborate and further build on these early findings.

Pulsed field ablation versus very high-power short-duration radiofrequency ablation in persistent atrial fibrillation: a single-centre experience

Abstract Background Pulsed Field ablation (PFA) has recently emerged as a treatment strategy for patients with atrial fibrillation (AF) and early studies showed promising procedural data and durable pulmonary vein isolation (PVI). However, Very High-Power Short-Duration ablation (VHPSD) has previously reported good efficiency and mid-term outcomes, and only a few works compared these two procedures, especially in patients with persistent AF. Objective Our aim is to compare these different modalities of transcatheter ablation in patients with persistent AF, focusing mainly on some procedural aspects, safety and efficacy. Methods We performed a retrospective observational study enrolling all consecutive patients with persistent AF from September 2021 to May 2023 undergoing transcatheter ablation with PFA or VHPSD. In the first group, PVI was achieved by 2kV pulses with eight applications to each vein using both catheter configurations, while isolation of the posterior wall of the left atrium was achieved by applications through the only "flower" configuration; additional lesions were then added at the operator's discretion. In the second group, PVI was achieved by delivering 90W radiofrequency pulses for 4 seconds in the posterior portions of the left atrium and 50W pulses in the anterior region of the pulmonary veins; additional lesions were occasionally applied. All patients received general anaesthesia or deep sedation with fentanyl and dexmedetomidine. Results A total of 79 patients were included, n = 24 (30%) in the PFA group and N = 55 (70%) in the VHPSD one: early persistent AF (n= 2 [8,3%]; N = 7 [12,7%]), persistent AF (n= 17 [70,8%]; N = 36 [65,5%]), long-standing persistent AF (n= 5 [20,8%]; N = 12 [21,8%]). The two populations showed similar clinical features: CHA2DS2-VASc (median value 3 [0-6] in PFA vs 2 [0-6] in VHPSD, p = 0,10), indexed left atrial volume (mean value 42,6 ml/m² in PFA vs 42,4 ml/m² in VHPSD, p = 0,07) and EF (mean value 55,4% in PFA vs 54,8% in VHPSD, p = 0,33). PVI was successfully achieved in all patients. Nevertheless, the PFA group was associated with shorter procedural duration (92,1 ± 36,9 vs 134,2 ± 36,1 minutes, p = 0,00001) but longer fluoroscopy time (25,5 ± 9,3 vs 17,4 ± 11,5 minutes, p = 0,001); it also showed a lower rate of minor complications (n = 1 [4,2%] vs N = 3 [5,5%], p = 0,057), even though serious complications were not observed in either group. After a median follow-up of 14 (9-26) months, n = 19 [79.2%] in the PFA and N = 43 [78.2%] in the VHPSD population were free of any atrial arrhythmia (p = 0,92). Conclusion PFA allows faster procedures, representing a major advantage for the operator and the patient, who is at lower risk of peri-procedural complications. On the other hand, VHPSD correlates with shorter fluoroscopy times, reducing exposure to ionizing radiation. Finally, the two procedures show similar mid-term efficacy in terms of recurrence-free time.

Association between left atrial wall thickness and residual potential after first-pass pulmonary vein isolation using very high-power short-duration ablation in patients with atrial fibrillation

Abstract Background In this study, we evaluated efficacy, efficiency, and safety of pulmonary vein isolation (PVI) applying vHPSD ablation strategy in patients with atrial fibrillation (AF) and explored the association between left atrial wall thickness (LAWT) and the residual potential after first-pass PVI. Methods Between April 2, 2023 and October 6, 2023, drug refractory symptomatic AF patients who underwent AF ablation using vHPSD ablation strategy with QDOT MICRO catheter were prospectively enrolled. All patients took cardiac computed tomography (CT) a day before procedure. Using CT image, LAWT map was created. PV segments were categorized into prespecified 14 segments, and LAWT of each segment, segments with residual potential (RP) after first-pass PVI and early reconnection after 20-minute waiting after PVI were evaluated. Total procedure time, ablation time for PVI, and occurrence of procedure-related complication were collected. Results A total of 40 patients were included (mean age 64 years, 45% of persistent AF). Additional ablation other than PV was performed in 48% of patients, total procedure time was 77 minutes, and total PVI time was 9.9 minutes. With vHPSD PVI, all PVs first pass isolation rate was 60%; in terms of per PV, RSPV first-pass isolation was 88%, followed by LSPV and LIPV 85%, RIPV showed lowest first-pass isolation rate, 75% (Figure A). Most common RP sites was right carina, followed by left carina (Figure A). Compared to historical comparator, vHPSD PVI showed shorter procedure time, shorter ablation time for PVI, with numerically lower but statistically comparable first-pass PVI rate (Figure B). In total 560 PV segments in 40 patients, RSPV anterior, left carina, and right carina showed higher prevalence to be thick PV segments (over 60% of patients), followed by RPSV posterior, LSPV posterior, and RIPV anterior (over 40% of patients). Looking into ablation parameter detail, mean contact force was 10g, mean temperature was 47°C, and mean impedance drop was 8.4Ω. Compared to segments without RP, segments with RP showed thicker mean left atrial wall thickness grades, lower minimum contact force, higher maximum temperature, and lower minimum impedance drop. According to the left atrial wall thickness, thick PV segments showed higher prevalence of RP after first-pass PVI with vHPSD ablation. In segments with LAWT grade 3 or more, the RP rate was 9.1%. This thickness means thicker than 1.5 to 2.0 mm of thickness (Figure C). In 10% of patients (n=4) had audible or tactile steam-pops, visible char was confirmed in 5% of patients (n=2). There were no clinical complications. Conclusion PVI using vHPSD achieved shorter procedure time, shorter ablation time for PVI, and comparable first-pass PVI rate compared to historical comparator using ablation-index guided conventional power ablation. Thick segments had higher chance to have residual potential after first-pass PVI with vHPSD.

Optimization of high-power short-duration pulmonary vein isolation using QDOT catheter - the A-Q-RATE POWER trial

Abstract Background/Introduction The safety and efficacy of novel ablation catheter QDOT Micro, capable of delivering high-power short-duration (HPSD) radio-frequency (RF) applications, has already been demonstrated in clinical trials. It has been shown that lesions performed with 90 Watts/4 sec (vHPSD) are shallower but wider compared to HPSD (50 Watts/4 sec) or conventional ablation settings. Thus, it may be speculated that vHPSD applications may not achieve transmurality at thick (up to 4 mm) parts of anterior aspects of pulmonary vein (PV) - left atrial (LA) wall junction. Purpose To compare acute completeness of PV isolation (PVI) focused on anterior wall achieved using vHSPD versus HPSD in patients undergoing ablation for atrial fibrillation (AF). Methods Prospective, dual-center, randomized study was conducted over a 8-month period. Patients were randomized 1:1 to vHPSD versus HPSD delivered at anterior aspects of PV. Posterior parts of PV were ablated with vHPSD in both arms. The carina region between ipsilateral PVs was ablated using 35 W and ablation index of 380. Need for additional RF applications to achieve complete PVI was the primary outcome. Results 70 patients (mean age 63.5±11.2; 57.1% male) with paroxysmal (61.4%) or persistent AF (38.6%) were randomized to vHPSD (n=35) or HPSD (n=35). Additional RF touch-up applications at the anterior aspects of PV were significantly more frequently needed in the vHPSD group compared with the HPSD group (46% vs 19%, p&amp;lt;0.001) and in the right PVs (57% vs 20%, p=0.001) versus left PVs (34% vs 17%, p=0.1). Median procedure duration, LA dwell time and fluoroscopy time were similar in both groups [112 (IQR 90, 130) min vs 107 (IQR 90,125) min, p= 0.58; 95 (IQR 70,106) min vs 90 (IQR 71,100) min, p=0.55; and 28 (IQR 14,69) sec vs 46 (IQR 0,89) sec, p=0.97, respectively). In one patient in vHPSD we were not able to isolate right superior pulmonary vein (RSPV) despite additional RF touch-up applications. Conclusions vHPSD RF applications using the QDOT Micro catheter may not achieve transmurality in a significant proportion of anterior parts of PV. The proposed hybrid strategy consisting of HPSD delivery at anterior aspects of PV with vHPSD delivered at other parts of PV ostia is associated with significantly higher rate of first-pass PVI without extending procedural and fluoroscopy duration.

Application of high-power ablation mode in patients with idiopathic ventricular extrasystole

Background. A new method of high-power short-duration ablation (HPSDA) with high impact energy, ranging from 60 to 90 W, is becoming widespread in the world. However, the number of studies on the use of HPSDA in patients with idiopathic ventricular arrhythmias (IVA) is limited. It is relevant to study the feasibility of using HPSDA to improve the outcomes of radiofrequency ablation (RFA) in patients with IVA. The aim of the study: to evaluate the immediate results of HPSDA in RFA for IVA and to compare it with the classic ablation mode. Materials and methods. We have retrospectively analyzed the results of RFA in 54 patients with symptomatic IVA. Their average age was 45.0 ± 11.7 years. The majority were men (72.3 %). Given the possible effect of intracardiac mapping on the results of ablation, the patients were divided into two groups. Group I include 27 (50 %) participants in whom mapping was performed using 3D navigation. Group II include 27 (50 %) patients in whom 3D navigation was not used. The decision to use HPSDA or classic ablation was made empirically, without considering any factors or characteristics of a patient. The following ablation parameters were used during HPSDA: temperature 45 °C, exposure time 7 seconds, energy 70 W. Results. In group I, where 3D navigation was used to localize the substrate, HPSDA was performed in 12 patients (44.4 %), and the classic mode was used in 15 cases (55.6 %). With conventional mapping, HPSDA was applied in 10 (37.0 %) patients, and the classic mode in 17 (63.0 %). Сlassic ablation allowed to achieve complete arrhythmia suppression in all patients, regardless of the mapping method. When using only HPSDA, the disappearance of arrhythmia was observed only in 45.5 % of cases. With the use of the classic mode, recurrence of IVA during the control time was observed in 16.6 % of patients, while with the use HPSDA in 33.3 %. Conclusions. The high-power regimen demonstrated significantly lower efficacy for permanent suppression of IVA compared to classic ablation methods (p = 0.007). The use of HPSDA to suppress IVA is associated with a high risk of arrhythmia recurrence during control time (p = 0.0010). It is advisable to convert the ablation mode for complete suppression of arrhythmia when the HPSDA is ineffective.

LOCK PROTOCOL: A NEW ROBUST WORKFLOW FOR A VERY HIGH FIRST PASS PULMONARY VEIN ISOLATION DURING ATRIAL FIBRILLATION ABLATION

Abstract Introduction Pulmonary vein isolation (PVI) is the gold standard for atrial fibrillation (AF) ablation. First pass PVI is often demanding when a raw geometry reconstruction is used in combination with an inaccurate automarks annotation, accounting for discontinuous or non–transmural lesions and related AF recurrences. We hypothesized that a magnetic–post processing of left atrial geometry in combination with an LSI–guided high power short duration (HPSD) automarks annotation could improve procedural efficiency. Purpose Aim of the study was to determine the impact on procedural outcomes of the new “Lock PVI protocol” during AF ablation with the new voxel mode EnSite X mapping system. Methods We included in the study consecutive patients with AF scheduled for pulmonary vein isolation (PVI) at our Departement between January 2021 and December 2022. Patients were divided in two Groups, the Lock–PVI Group and the control No Lock–PVI Group. The “Lock PVI” Group was ablated with the new Ensite X System using the new protocol, which consisted in (1) performing a road map with contact–force annotation at potential PVI sites after High Density reconstruction, (2) shaving the magnetic geometry reconstruction to unearth true 3D location of contact points, (3) Use of 3D–Automarks color–coded with a Lesion Index (LSI) target of 5.5 (anterior) and 4.5 (posterior) (4) Inter–lesion distance £6 mm (5) High Power Short Duration Approach (50 W). The No–Lock PVI was represented by patients ablated with and HPSD ablation with the previous version of the EnSite Precision mapping suit as per local standard practice. Groups were compared in term of procedural duration, radiological exposure and “first pass” isolation. Results Forty–four patients (22 “Lock PVI” and 22 controls mean age 63,3±8 years, 65,9% male, 47,7% persistent AF), for a total of 88 PVI circles were enrolled. Procedural duration was similar between approaches (121,1±43,6 vs 125,3±30,1 min; P=0,72) but RF time was shorter in the “Lock PVI” group (19,6±4 vs 29,55±9,1 min; P&amp;lt;0,001), even if with a longer fluoroscopy (19,5±10,1 vs 13,4±4,9 min; P=0,01). Of note, first pass isolation was significantly higher in the “Lock PVI” group: 40/44 (90,9%) vs 28/44 (63,6%) circles (P=0,002). Conclusion The new “Lock PVI” approach allowed a consistently better first pass isolation (&amp;gt;90%) with less RF time when compared to standard of care PVI.

Pulmonary Vein Isolation for Atrial Fibrillation: Comparison of a Very High-Power Very Short-Duration (vHPvSD) Ablation Protocol versus a Hybrid Ablation Approach-Procedural and Mid-Term Outcome Data.

Background: Pulmonary vein isolation (PVI) using radiofrequency ablation (RFA) is a standard-of-care treatment in the rhythm control strategy of symptomatic atrial fibrillation (AF). Ablation protocols, varying in the power and duration of energy delivery, have changed rapidly in recent years. Very high-power very short-duration ablation (vHPvSD) is expected to shorten procedural times compared to conventional ablation approaches. However, the existing data suggest that this might come at the cost of lower first-pass isolation rates, a predictor of poor ablation long-term outcomes. This study aims to compare a vHPvSD protocol to a hybrid strategy, in which the power and duration of the energy transfer are adapted depending on the anatomical location. Methods: We retrospectively analyzed procedural and outcome data from 93 patients (55 vHPvSD vs. 38 hybrid) scheduled for de novo pulmonary vein isolation. A vHPvSD ablation protocol (90 Watt (W), 4 s) was compared to a hybrid protocol using vHPvSD on the posterior wall and 50 W HPSD (high-power short-duration) ablation guided by the Ablation Index along the remaining spots. Results: Ablation times were significantly shorter in the vHPvSD cohort (5.4 min. vs. 14.2 min, p < 0.001), thus resulting in a significant reduction in the overall procedural duration (91 min vs. 106 min, p = 0.003). The non-significant slightly higher first-pass isolation rates in the vHPvSD cohort (85% vs. 76%, p = 0.262) did not affect freedom from AF 6 months after the procedure (83% vs. 87%, p = 0.622). Conclusions: vHPvSD helps in shortening the PVI procedural duration, thus neither affecting first-pass isolation rates nor freedom from atrial tachyarrhythmia recurrence at 6 months after the index procedure.

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

High-power-short-duration (HPSD) ablation is an effective treatment for atrial fibrillation but poses risks of thermal injuries to the oesophagus and vagus nerve. This study aims to investigate incidence and predictors of thermal injuries, employing machine learning. A prospective observational study was conducted at Leipzig Heart Centre, Germany, excluding patients with multiple prior ablations. All patients received Ablation Index-guided HPSD ablation and subsequent oesophagogastroduodenoscopy. A machine learning algorithm categorized ablation points by atrial location and analysed ablation data, including Ablation Index, focusing on the posterior wall. The study is registered in clinicaltrials.gov (NCT05709756). Between February 2021 and August 2023, 238 patients were enrolled, of whom 18 (7.6%; nine oesophagus, eight vagus nerve, one both) developed thermal injuries, including eight oesophageal erythemata, two ulcers, and no fistula. Higher mean force (15.8 ± 3.9 g vs. 13.6 ± 3.9 g, P = 0.022), ablation point quantity (61.50 ± 20.45 vs. 48.16 ± 19.60, P = 0.007), and total and maximum Ablation Index (24 114 ± 8765 vs. 18 894 ± 7863, P = 0.008; 499 ± 95 vs. 473 ± 44, P = 0.04, respectively) at the posterior wall, but not oesophagus location, correlated significantly with thermal injury occurrence. Patients with thermal injuries had significantly lower distances between left atrium and oesophagus (3.0 ± 1.5 mm vs. 4.4 ± 2.1 mm, P = 0.012) and smaller atrial surface areas (24.9 ± 6.5 cm2 vs. 29.5 ± 7.5 cm2, P = 0.032). The low thermal lesion's rate (7.6%) during Ablation Index-guided HPSD ablation for atrial fibrillation is noteworthy. Machine learning based ablation data analysis identified several potential predictors of thermal injuries. The correlation between machine learning output and injury development suggests the potential for a clinical tool to enhance procedural safety.

Impact of weight adjusted high frequency low tidal volume ventilation and atrial pacing in lesion metrics in high-power short-duration ablation: Results of a pilot study.

Lesion size index (LSI) was introduced with the use of Tacticath™ and as a surrogate of lesion quality. The metric used to achieve the predetermined values involves combined information of contact force (CF), power and radiofrequency time. Rapid atrial pacing (RAP) and high-frequency low-tidal volume ventilation (HFLTV) independently or in combination improve catheter stability and CF and quality of lesions. Data of the impact of body weight adjusted HFLTV ventilation strategy associated with RAP in the lesion metrics still lacking. The study aimed to compare the results of high-power short-duration (HPSD) atrial fibrillation ablation using simultaneous weight adjusted HFLTV and RAP and standard ventilation (SV) protocol. Prospective, nonrandomized study with 136 patients undergoing de novo ablation divided into two groups; 70 in RAP (100 ppm) + HFLTV with 4 mL/kg of tidal volume and 25 breaths/min (group A) and 66 patients with SV in intrinsic sinus rhythm (group B). Ablation using 50 W, CF of 5-10 g/10-20 g and 40 mL/minute flow rate on the posterior and anterior left atrial wall, respectively. No procedure-related complications. Group A: Mean LSI points 70 ± 16.5, mean total lower LSI 3.4 ± 0.5, mean total higher LSI 8.2 ± 0.4 and mean total LSI 5.6 ± 0.6. Anterior and posterior wall mean total LSI was 6.0 ± 0.4 and 4.2 ± 0.3, respectively. Mean local impedance drop (LID) points were 118.8 ± 28.4, mean LID index (%) 12.9 ± 1.5, and mean LID < 12% points 55.9 ± 23.8. Anterior and posterior wall mean total LID index were 13.6 ± 2.0 and 11.9 ± 1.7, respectively. Recurrence in 11 (15.7%) patients. Group B: Mean LSI points 56 ± 2.7, mean total lower LSI 2.9 ± 0.7, mean total higher LSI 6.9 ± 0.9, and mean total LSI 4.8 ± 0.8. Anterior and posterior wall mean total LSI was 5.1 ± 0.3 and 3.5 ± 0.5, respectively. Mean LID points were 111.4 ± 21.5, mean LID index (%) 11.4 ± 1.2, and mean LID < 12% points 54.9 ± 25.2. Anterior and posterior wall mean total LID index were 11.8 ± 1.9 and 10.3 ± 1.7, respectively. Recurrence in 14 (21.2%) patients. Mean follow up was 15.2 ± 4.4 months. Weight adjusted HFLTV ventilation with RAP HPSD ablation produced lower recurrence rate and better LSI and LID parameters in comparison to SV and intrinsic sinus rhythm.

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

High-power short-duration (HPSD) ablation has emerged as an alternative to conventional standard-power long-duration (SPLD) ablation. We aim to assess the efficacy and safety of HPSD versus SPLD for atrial fibrillation (AF) ablation. A systematic review and meta-analysis of randomized controlled trials (RCTs) retrieved from PubMed, WOS, SCOPUS, EMBASE, and CENTRAL were performed through August 2023. We used RevMan V. 5.4 to pool dichotomous data using risk ratio (RR) and continuous data using mean difference (MD) with a 95% confidence interval (CI). CRD42023471797. We included six RCTs with a total of 694 patients. HPSD was significantly associated with a decreased total procedure time (MD: -22.88 with 95% CI [-36.13, -9.63], P = 0.0007), pulmonary vein isolation (PVI) time (MD: -19.73 with 95% CI [-23.93, -15.53], P < 0.00001), radiofrequency time (MD: -10.53 with 95% CI [-12.87, -8.19], P < 0.00001). However, there was no significant difference between HPSD and SPLD ablation with respect to the fluoroscopy time (MD: -0.69 with 95% CI [-2.00, 0.62], P = 0.30), the incidence of esophageal lesions (RR: 1.15 with 95% CI [0.43, 3.07], P = 0.77), and the incidence of first pass isolation (RR: 0.98 with 95% CI [0.88, 1.08], P = 0.65). HPSD ablation was significantly associated with decreased total procedure time, PVI time, and radiofrequency time compared with SPLD ablation. On the contrary, SPLD ablation was significantly associated with low maximum temperature.

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

Through systematic scientific rigor, the CLOSE guided workflow was developed and has been shown to improve pulmonary vein isolation durability. However, this technique was developed at a time when using power-controlled ablation catheters with conventional power ranges was the norm. There has been increased adoption of a high-power and very high-power short-duration ablation practice propelled by the availability of the temperature-controlled radiofrequency QDOT MICRO catheter. There are fundamental differences in biophysics between very high-powered temperature guided ablation and conventional ablation strategy that may impact patient outcomes. The catheter's design and ablation modes offer flexibility in technique while accommodating the individual operator's clinical discretion and preference to deliver a durable, transmural, and contiguous lesion set. Here, we provide recommendations for 3 different workflows using the QDOT MICRO catheter in a step-by-step manner for pulmonary vein isolation based on our cumulative experience as early adopters of the technology and the data available in the scientific literature. With standardization, temperature-controlled ablation with the QDOT MICRO catheter provides operators the flexibility of implementing different ablation strategies to ensure durable contiguous pulmonary vein isolation depending on patient characteristics.