Focal Ablation Research Articles

Focal pulsed field ablation for organised atrial tachyarrhythmias: one to rule them all

Abstract Background Focal pulsed field ablation (fPFA) has emerged as a versatile and innovative strategy for ablating atrial tachyarrhythmias (1). The primary objective of this study is to present the short-term safety characteristics, feasibility and procedural outcomes of fPFA in the management of organised atrial tachyarrhythmias. This report focuses on the commercial use of an innovative pulsed field ablation (PFA) generator, utilized in conjunction with commercially available focal, solid-tip ablation catheters, and complemented by 3D electro-anatomical mapping (3D-EAM). Methods Patients with organised atrial tachycardia treated using fPFA between August 2022 and September 2023 at our center were included in this retrospective analysis. Tachycardia mechanisms were identified with high-definition, multi-electrode mapping catheter paired with 3D-EAM system. Ablation lines, when targeting macro-reentrant arrhythmias were strategicaly positioned to adress critical isthmi when recognised or they were empirically placed between the anatomical obstacles ( including LA roof, anterior, mitral isthmus, upper septal and cavotricuspid line as deemed appropriate). Positioning of the fPFA catheter was guided by 3D-EAM, intracardiac ultrasound, and fluoroscopy (Figure 1). Bidirectional block verification was performed using standard criteria to assess acute procedural success. Glyceryl trinitrate boluses were administered prior to ablation in proximity to coronary arteries. Results In a cohort of 36 patients (median age 62 years; 12 females), we effectively mapped and treated a total of 51 distinct organised atrial tachyarrhythmias. These included 18 typical flutters, 3 roof-dependent macro-reentries, 4 posterior-wall micro-reentries, 15 peri-mitral macro-reentries, 8 anterior-wall micro-reentries and 3 biatrial macro-reentries via Bachman bundle. Our ablation strategy involved creating 21 cavotricuspid isthmus lines, 3 roof lines, 18 posterior wall lines, 11 anterior lines, 8 septal lines, and 15 mitral isthmus lines (Figure 2). Impressively, first-pass acute isolation with bidirectional block was achieved in 93% (54 of 58) of isthmus ablations and 94% (17 of 18) of left posterior wall lines. No ST segment alterations or other complications were observed during the periprocedural period. Conclusion In our cohort fPFA proved as a feasible, effective, and safe approach for treating organised atrial tacharrhythmias. The primary reason for designating this setup as our preferred choice for redo procedures lies in its versatility in addressing a wide range of arrhythmias. As ultra-fast pulmonary vein isolation (PVI) procedures become more prevalent with the expansion of PFA, the demand for an ideal setup capable of effectively targeting various substrates will become even more pronounced (2). Notably, our findings suggest superior suitability and efficacy when compared to bulkier, single-shot design PFA devices (3).Figure 1Figure 2

First experience of focal pulsed field ablation for premature ventricular contractions

Abstract Introduction Pulsed field ablation (PFA) has emerged as a novel strategy to achieve ablation of cardiac tissue. Clinical evidence suggests a remarkable lesion durability and safety profile for AF ablation. Nonetheless, a growing interest exists in broadening its field of application for catheter ablation of ventricular arrhythmias (VA). The CENTAURI system arises as a promising PFA system for targeting VA as it allows pulsed electric field (PEF) delivery via standard, commercially available focal ablation catheters and concomitant coupling with their mapping systems. Purpose To assess, for the first time, the feasibility of focal PFA via the CENTAURI system for premature ventricular complex (PVC) ablation. Methods We conducted a prospective analysis of patients with either high burden (>10%) or symptomatic idiopathic PVC undergoing focal PFA using CENTAURI system at our institution. Procedures were performed between December 2022 and August 2023. Acute and long-term success were defined as no PVC recurrence during a 24h in-hospital monitoring period, and ≥80% burden reduction with absence of symptoms after at least 30 days post-ablation, respectively. PVC monitoring was performed by implantable loop recorder (ILR) or surface ECG Holter monitoring. Results Fourteen patients (age range: 16-87 years; 10 females) were included. Procedures were performed via the CENTAURI system in combination with CARTO 3 system and EnSite X EP system in 4 (28.6%) and 10 cases (71.4%) respectively. Targeted ablation sites were the right ventricular outflow tract (6 cases), right moderator band (2 cases), left postero-medial papillary muscle -PM- (2 cases), and right posterior PM, tricuspid annulus, left posterior fascicle and aortomitral continuity (AMC) in one case. On average, 6.5 applications were delivered to the site of origin with a mean contact force of 11g. Procedural duration and fluoroscopy time were 102 and 8.9 minutes. Two minor complications were observed: one transitory ST depression (solved after i.v. nitrate administration) after repeated applications to AMC, and a femoral pseudoaneurysm. The remaining 12 procedures were uneventful. Although most of the procedures were performed under general anesthesia due to concerns about potential significant muscular contraction, 3 cases (21.4%) were successfully managed with light sedation, without significant muscular contraction nor map shift. Incomplete abolishment of PVC during first 24 h was observed in 2 patients (14.3%). After a median follow-up of 113 days (IQR: 83-188), recurrences were detected in one patient (7.14%). Conclusion Herein we report the feasibility and efficacy of PVC ablation using a focal PEF delivery system (CENTAURI). Furthermore, we describe the possibility of performing PVC ablation with this technology under light sedation, which might be important for minimizing anesthesia impact on PVC burden.Table of characteristicsPVC morphologies

Feasibility and efficacy of single-shot PFA technology for redo procedures after a previous atrial fibrillation ablation procedure

Abstract Introduction Despite significant technological advancements and a better understanding of atrial tachyarrhythmia pathophysiology, a non-negligible percentage of atrial fibrillation (AF) patients undergoing catheter ablation experiences arrhythmia relapse. Repeat procedures have been traditionally performed via thermal energy systems, which carry a certain risk of collateral damage to adjacent tissues. Pulsed Field Ablation (PFA) has emerged as an alternative non-thermal energy source for cardiac ablation. The main advantage is its selectivity to cardiac tissue. FarapulseTM is the first PFA technology to have received regulatory approval and includes a pentaspline PFA catheter. Although designed for pulmonary vein isolation, its use for extrapulmonary vein site ablation has been previously documented. Purpose To evaluate the feasibility and efficacy of the pentaspline FarawaveTM for redo procedures. Methods Patients referred for a redo procedure using FarapulseTM system were enrolled in 3 high-volume European centers. A workflow (Figure 1.A) was established based on rhythm at presentation (Group 1: sinus rhythm; Group 2: AFL; Group 3: AF). Results A total of 117 patients were included (64 in Group 1, 18 in Group 2, and 35 in Group 3). The mean number of previous procedures was 1.26, and 23 patients (19.66%) had already undergone ≥2 procedures. Previous ablation targets included PVI, either alone (46.15%) or in combination with other targets, including posterior mitral line (39.32%), posterior wall (6.84%), or anterior mitral line (2.56%). Electroanatomical mapping (EAM) was adopted in 15.38% of the cases. Specifically, in 27.78% (n=5) of group 2, 15.63% (n=10) of group 1 and 8.57% (n= 3) of group 3 cases. Additional focal radiofrequency ablation was required in 4 patients for CTI line ablation. Lesion sets are depicted in Figure 2. Mean procedural and LA dwelling time were 95.2 ± 38.0 and 50.7 ± 36.7 minutes, respectively. There was a total of one major complication (intracranial haemorrhage) and 5 minor complications (two vascular site related, and three reversible ST segment changes, related to applications on the mitral annulus area). A total of 100 patients completed at least 3 months of follow-up (FU), with a median FU time was 7.55 months (IQR 5.18 – 11.85). The total number of recurrences was 20, including 2 during the blanking period. Survival function (excluding blanking period) was 88.6 (95% CI 79.7 – 93.8) at 6 months and 80.0% (95% CI 67.3 – 88.3) 12 months. Atrial arrhythmia free-survival was higher in patients presenting in sinus rhythm, compared to the other two groups (p = 0.0135), as displayed in Figure 1.B. Conclusion The proposed stepwise approach to repeat AF ablation procedures based on the use of the single-shot PFA system (with or without EAM) was feasible, safe, fast and effective at one year follow-up.Flow chart and Kaplan Meier curveLesion sets

Focal pulsed field ablation in complex cases of atrial tachycardia - feasibility, outcome and safety of a novel technology

Abstract Introduction The importance of pulsed-field ablation (PFA) is rising in the field of catheter ablation. Nevertheless, the use of a single-shot devices is limited to pulmonary vein isolation (PVI). Thus, significance of technologies implementing point-by-point PFA is growing. A commercially available system uses radiofrequency (RF) catheters in combination with a PFA-generator. Data on the use is sparse, especially for treating atrial tachycardia (AT). The aim of this study was to evaluate feasibility, safety and mid-term outcomes of point-by-point PFA in complex cases of AT. Methods All consecutive patients treated with a focal PFA-catheter (N = 34) suffering from AT were included. A high density map was created in all patients. Established RF catheters were employed as PFA catheters with the PFA generator. Except for the ablation generator, the standard setting at our clinic for ablation of AT was not changed. In case of sinus rhythm at the beginning, burst stimulation was performed in order to induce the clinical AT. Acute procedure success was defined as creation of ablation lesions preventing the mechanism of the clinical tachycardia and/or non-inducibility of the clinical AT. Outcome and safety was evaluated during the hospital stay and visits at our outpatient clinic, including 7d-Holter-ECG. Results In all 34 included patients, acute procedure success was achieved. Baseline characteristics are listed in table 1. In average, patients had 1,21 ± 0,88 ablations before, 67,6% of patients had linear lesions in the past. Mean procedure duration was 102,7 ± 30,3 min, the LA dwell time was 75,0 ± 24,7 min (table 2). Any desired lesion set was accomplished (pulmonary vein isolation, linear lesions or ablation of focal AT/localized reentry) with the focal PFA technology. Linear lesions were ablated in 32 (94,1%) patients, while a pulmonary vein isolation was performed in 12 patients (35,3%). Ablation of localized reentries was necessary in two patients (5,9%). In total, 51 linear lesions were created: 27 anterior lines, 18 roof lines, 5 CTI-lines and one posterior box; bidirectional block was proven in all cases. Furthermore, three patients suffered a macro-reentry due to reconnected pulmonary veins. The site of termination of the tachycardia is shown in Figure 1. No procedure-related minor or major complications occurred (no groin complications, no stroke, no pericardial tamponade). After a mean follow-up of 179,4 ± 107,8 days, 8 patients (23,5%) suffered a recurrence of any atrial arrhythmia. Conclusion Applying focal PFA with well-known radiofrequency ablation catheters is safe and efficient, also in cases of atrial tachycardia. The integration of the new system into clinical practice is feasible and did not prolong the procedures. Acute procedure success was achieved in all cases. For further evaluation of efficacy and safety, a control group of patients treated with radiofrequency or a randomized trial is needed.

Pulmonary vein isolation combined with a new protocol of linear ablation to treat persistent atrial fibrillation: a prospective cohort with 1 year follow-up

Abstract Background The clinical value of ablation strategies beyond pulmonary vein isolation (PVI) in patients with persistent atrial fibrillation (perFA) is not clearly established and the optimal strategy to cure perFA remains a challenge due to the high recurrence rate after PVI alone (up to 50% of patients during 1-year follow-up). Purpose To determine the additional therapeutic value of a new design of linear ablation in the left atrium (LA) added to PVI in patients with perFA. Methods In this prospective study consecutive patients with perFA were included and underwent PVI combined with a predefined homogeneous protocol of linear ablation in the LA: anterolateral line from the mitral annulus to the left superior pulmonary vein around the left atrial appendage, anteroseptal line and posterior wall isolation. Patients were followed during 12 months after ablation with daily 30 s single-lead ECG obtained with mobile applications. The main endpoint was the incidence of recurrences, defined as any documented, sustained (>30 s) episodes of atrial arrhythmia that occurred after a 3 months blanking period. Antiarrhythmic drugs were avoided after the blanking period. Results 59 patients were included (61 [IQR 53-69] years old, 76% male sex). Acutely successful PVI was achieved in all patients and the linear ablation protocol was performed in 52 (89,7%) patients. The linea ablation protocol was not completed in 6 patients due to the following reasons: repetitive AF triggering from the same PV in 2 patients, induction and successful focal ablation of left atrial flutter in 1 patient, respiratory failure in 1 patient with severe obstructive lung disease and excessively prolonged procedure time in 2 patients. 58 patients completed the 12 months follow-up period and 1 patient was lost due to end-stage heart failure. The survival free of atrial arrhythmia recurrences was 69.1% [95%CI 55.1-79.5] (Figure). No patient had recurrences of perAF (>7 days continuous AF). 9 (53%) patients had at least 1 episode of self-limited paroxysmal AF. In these patients the average paroxysmal AF burden during the follow-up was 24 hours/year [IQR 9-24 hours/year]. In another 8 (47%) patients the recurrent arrhythmia was atypical left atrial flutter exclusively The incidence of procedure-related complications was 6,9%: 1 pericardial bleeding, 1 acute pulmonary edema, 1 splenic infarction and 1 stroke); no patient died during the study period. Conclusions A combined strategy of PVI plus the specific linear ablation protocol used in this study is associated with a low rate of atrial arrhythmia recurrences and total absence of persistent AF after ablation. A randomized multicenter clinical trial is ongoing to validate these results.Ablation strategy.Kaplan-Meier curve: recurrences

Improved procedural workflow for catheter ablation of paroxysmal AF with high density mapping system and advanced technology: insights from a multicenter, international study

Abstract Background A high incidence of pulmonary vein (PV) reconnection has been reported in patients with clinical recurrences of AF. Low-voltage activity beyond PVs (e.g. antral activity potentials, RAP) likely represent vulnerabilities in antral lesion sets and they may contribute to ablation failures. Purpose The aim of this study is to validate a structured application of an approach that includes the complete abolition of any antral potential achieving electrical quiescence in antral regions. Methods DELETE AF is a prospective, single-arm, international post-market cohort study. Consecutive patients from 10 centers who were undergoing radiofrequency ablation of paroxysmal AF were included. The Lumipoint map-analysis tool was used sequentially on each PV component. Post-ablation, all patients were monitored with ambulatory event monitoring, starting within 30 days post-ablation to proactively detect and manage any recurrences within the 90-day blanking period, as well as Holter monitoring at 3, 6, 9, and 12 months post-ablation. Additional ECG monitoring were performed as indicated by patient symptoms. The ablation endpoint was PV isolation (PVI). Long-term outcome was the recurrence of AF over follow-up. Data are reported as median [IQ range]. Results One-hundred ten cases of AF ablation were analyzed: 28 (25.5%) females, age=63[56-69] years, 24 (21.8%) patients with a history of AT/AFL. The procedure duration was 58[24-76] min (RF delivery time=18[12-28] min, number of ablation spots=77[44-101]) and the fluoroscopy time was 13[9-19] min. Thirty-eight (34.5%) were repeat ablation: in these patients after initial mapping a total of 114 PV gaps (PVGs) in 29 (76.3%) patients and 69 RAPs in 15 patients (39.5%) were found. After ablation, a total of 5 early PVGs in 2 (1.8%) patients (all in de novo procedures) and a total of 10 RAPs in 7 (6.3%) patients (3 out 38 -7.9%- of repeat ablations vs 4 out 72 -5.6%- of de novo cases, p=0.690) were detected after first remapping. Each residual PVG was first targeted and additional focal ablations were performed at any low-voltage propagation suspected within the region of previous antral ablation. Acute procedural success was 100%, with all PVs successfully isolated and RAPs completely abolished in all study patients except for one that still exhibited a residual low-voltage antral signal after adenosine infusion with no PV conduction. Eighty-six (78.2%) patients had complete follow-up information. During the 90-day blanking period, 8 (9.2%) patients experienced an early recurrence. After the blanking period, over a follow-up of 357[190-380] days, 13 patients (15.1%) suffered an AF recurrence (time to recurrence: 207[144-300] days). No major complications or adverse events occurred. Conclusion A structured ablation workflow for catheter ablation, with consistent high-density mapping and improved diagnostic tools to guide the ablation, proved to be safe and effective in paroxysmal AF.

Pulsed field ablation of atrial fibrillation using a large area focal catheter with a novel contact detection algorithm. A first-in-human experience using the QuickShot catheter

Abstract Background/Introduction Pulsed field ablation (PFA) is emerging as a safe and effective alternative energy modality for cardiac ablation. Data have shown that while tissue contact is critical for PFA, the amount of contact force is less important. Single-shot catheters have shown comparable results to current thermal methods for pulmonary vein isolation (PVI), however, are limited to anatomical-based ablation strategies and have limited ability to detect tissue contact. The investigational QuickShot™ large-area focal catheter (Galvanize Therapeutics, Redwood City, CA) combines high-density mapping with large-area focal ablation guided by contact detection. Purpose The QuickShot PEF-AF study was a prospective, single-arm, first-in-human study performed at a single European center to evaluate the safety and performance of the QuickShot catheter (see Figure 1, panel A) combined with the CE-marked CENTAURI™ System (Galvanize Therapeutics, Figure 1, panel B) for catheter ablation of atrial fibrillation (AF). Methods Subjects with paroxysmal or persistent AF underwent a PVI procedure under deep sedation (fentanyl, midazolam, propofol) guided by Rhythmia™ HDx (Boston Scientific, Marlborough, MA, Figure 1, panel D). Irrigation was set to a constant 6 mL/min during the procedure. Focal, monopolar, biphasic PFA lesions were delivered asynchronously at 33 Amps and a 10 mm inter-lesion spacing (center to center with 10 mm lesion tag size). Catheter-tissue contact was confirmed by ICE/fluoroscopy and a novel impedance-based contact detection system (Figure 1, panel C). The acute performance endpoint was PVI, assessed by entrance and exit block using high-density mapping. Procedural safety assessments included microbubble detection via ICE, induction of VT/VF, muscle stimulation, phrenic nerve function, and NIHSS post-procedure. Results Twenty (20) subjects (60% PAF, 60 ± 12 years, 75% male, 4.3 ± 0.52 cm LA AP diameter) were enrolled and treated. Acute PVI was achieved in 100% of patients and targeted PVs (82/82), with first-pass isolation in 88% of targeted PVs. The PVI time was 31 ± 10 min with 46.7 ± 11.4 PFA applications. There were no device- or procedure-related adverse events, and no documented incidence of microbubble formation, arrhythmia induction, muscle stimulation, phrenic nerve dysfunction, esophageal injury, or change in NIHSS post-procedure. Conclusion The QuickShot catheter enables safe and effective large-area focal PFA for subjects requiring PVI. The catheter design enables efficient and flexible focal lesion placement with the ability to ensure adequate apposition to targeted tissues using its novel contact detection algorithm. Future studies will investigate the use of this novel catheter for PFA strategies beyond PVI.

Influence of tissue-electrode distance on unipolar and bipolar voltage for large-tip, ring-, and mini-electrodes

Abstract Background The characteristics of intracardiac unipolar and bipolar voltage electrograms (EGM) acquired by electrophysiological catheters depend on the electrical source and on the electrode design and configuration. Purpose The aim of the study was to assess the impact of the electrode configuration and their distance from the myocardial tissue (electric source) on the unipolar and bipolar intracardiac electrograms recorded with a multi-electrode focal ablation catheter. Methods We retrospectively analyzed left atrial 3D electroanantomical maps (EAMs) of 25 patients performed in sinus rhythm using the IntellaNav Mifi OI catheter (Boston Scientific, USA) with a 4.5 mm tip-electrode, three mini-electrodes and three 2 mm ring electrodes. The unipolar and bipolar EGMs were characterized based on the peak-to-peak amplitude (amp), the signal duration (width), the maximal slope, and the relative high power spectrum (HF_rel) as ratio of the power spectrum of frequencies above and below 50Hz. Distances of the electrode from the tissue were calculated from the electroanatomic reconstruction. Except for the HF_rel with absolute values are reported, all characteristics are normalized using the tip-electrode for unipolar or tip-to-ring electrode values for bipolar measures. EGMs with bipolar voltage amplitude of >0.5 mV were included to focus on healthy tissue. Results We analyzed the EGMs of 5183 catheter positions with horizontal to perpendicular orientation. From horizontal catheter orientation with a similar distance from the tissue for all electrodes, the unipolar EGM of the ring electrodes showed an increased amplitude (140%), slope (150%) and HF_rel (16% vs 11%) compared to the tip- and mini-electrodes. For bipolar EGM, however, the tip- ring pair showed the largest amplitude, width, and slope. The HF_rel was larger for the ring electrode pairs compared to the tip-ring electrode (58% to 39%). The median amplitude (amp), slope, and HF_rel for the ring electrodes showed a strong power-law decay function with distance, whereas the width increases linearly with distance from the surface (Figure, blue dotted lines). The intersection (red circle) of the steep linear decline at close distance to the tissue (reflecting a strong influence on the EGM) with the flat line at larger distances (dash-dotted lines) was considered as nearfield boundary. A HF_rel cutoff of >10% for unipolar (Figure, red arrow) and >30% for bipolar EGMs might be used to identify this boundary. Conclusion We confirmed a higher amplitude for small ring-electrodes compared to larger tip electrodes in unipolar amplitude but not for bipolar electrograms. Furthermore, a strong decay of the amplitude, slope and HF_rel with distance could be observed. The decay functions are suggestive for a nearfield boundary distance below 4mm from the tissue. Further studies are warranted to confirm this observation.Summary of characteristics over distance

Dual energy for pulmonary vein isolation using dual-energy focal ablation technology integrated with a three-dimensional mapping system: SmartfIRE 3-month results.

Contact force (CF)-sensing radiofrequency (RF) catheters with an ablation index have shown reproducible outcomes for the treatment of atrial fibrillation (AF) in large multicentre studies. A dual-energy (DE) focal CF catheter to deliver RF and unipolar/biphasic pulsed field ablation (PFA), integrated with a three-dimensional (3D) mapping system, can provide operators with additional flexibility. The SmartfIRE study assessed the safety and efficacy of this novel technology for the treatment of drug-refractory, symptomatic paroxysmal AF. Results at 3 months post-ablation are presented here. Pulmonary vein isolation (PVI) was performed using a DE focal, irrigated CF-sensing catheter with the recommendation of PFA at posterior/inferior and RF ablation at the anterior/ridge/carina segments. Irrespective of energy, a tag size of 3 mm; an inter-tag distance ≤6 mm; a target index of 550 for anterior, roof, ridge, and carina; and a target index of 400 for posterior and inferior were recommended. Cavotricuspid isthmus ablation was permitted in patients with documented typical atrial flutter. The primary effectiveness endpoint was acute procedural success. The primary safety endpoint was the rate of primary adverse events (PAEs) within 7 days of the procedure. A prespecified patient subset underwent oesophageal endoscopy (EE; 72 h post-procedure), neurological assessment (NA; pre-procedure and discharge), and cardiac computed tomography (CT)/magnetic resonance angiogram (MRA) imaging (pre-procedure and 3 months post-procedure) for additional safety evaluation, and a mandatory remapping procedure (Day 75 ± 15) for PVI durability assessment. Of 149 patients enrolled between February and June 2023, 140 had the study catheter inserted (safety analysis set) and 137 had ablation energy delivered (per-protocol analysis set). The median (Q1/Q3) total procedure and fluoroscopy times were 108.0 (91.0/126.0) and 4.2 (2.3/7.7) min (n = 137). The acute procedural success rate was 100%. First-pass isolation was achieved in 89.1% of patients and 96.8% of veins. Cavotricuspid isthmus ablations were successfully performed in 12 patients [pulsed field (PF) only: 6, RF only: 5, and RF/PF: 1]. The PAE rate was 4.4% [6/137 patients; 2 pulmonary vein (PV) stenoses, 2 cardiac tamponades/perforations, 1 stroke, and 1 pericarditis]. No coronary artery spasm was reported. No oesophageal lesion was seen in the EE subset (0/31, 0%). In the NA subset (n = 30), microemboli lesions were identified in 2 patients (2/30, 6.7%), both of which were resolved at follow-up; only 1 was symptomatic (silent cerebral lesion, 3.3%). In the CT/MRA subset (n = 30), severe PV narrowing (of >70%) was detected in 2 patients (2/30, 6.7%; vein level 2/128, 1.6%), of whom 1 underwent dilatation and stenting and 1 was asymptomatic; both were associated with high index values and a small inter-tag distance. In the PV durability subset (n = 30), 100/115 treated PVs (87%) were durably isolated and 18/30 patients (60.0%) had all PVs durably isolated. A DE focal CF catheter with 3D mapping integration showed a 100% acute success rate with an acceptable safety profile in the treatment of paroxysmal AF. Prespecified 3-month remapping showed notable PVI durability. ClinicalTrials.gov Identifier: NCT05752487.

High-intensity focused ultrasound strategies for treating prostate cancer.

Prostate cancer (PCa) is a significant health concern globally, necessitating effective treatment options. Typical treatment methods for early stage, particularly localized PCa, encompass radical procedures, such as radical prostatectomy (RP) and radiotherapy (RT), and nonradical focal therapy (FT). FT is a focused approach mainly used for treating small lesions limited to a specific zone of the prostate. Its objective is to achieve cancer control when minimizing damage to benign tissue. High-intensity focused ultrasound (HIFU) is one of the most used modalities in FT for the management of PCa. The progress in HIFU technology showcases continuous advancements, offering clinicians a variety of strategies to cater to diverse patient requirements. The advancements include the development of transrectal and transurethral HIFU machines that offer enhanced treatment distances, magnetic resonance imaging (MRI) fusion capabilities, real-time monitoring, and precise ablation. These improvements contribute to increased treatment effectiveness and better outcomes for patients. This narrative review aims to summarize the use of HIFU technology and its evolution, offering diverse options to clinicians, and explores the safety, effectiveness, and quality of different HIFU strategies, such as whole-gland ablation, hemigland ablation, and focal ablation. We conclude that nonwhole-gland HIFU offers similar cancer control with better short-term functional outcomes and fewer complications compared to whole-gland ablation. Combining HIFU with transurethral resection of the prostate (TURP) improves urinary function and reduces catheterization time. Focal ablation and hemigland ablation show promise in achieving cancer control when preserving continence and potency.

Update on applications of endoscopic cryotherapy in the gastrointestinal tract.

Endoscopic cryotherapy has emerged as a minimally invasive procedure for targeted tissue ablation within the gastrointestinal tract. This review aims to provide a comprehensive overview of current clinical applications of EC with a review of the pertinent literature. Endoscopic cryotherapy has demonstrated safety and efficacy for various gastrointestinal conditions. Recent studies have highlighted the efficacy of endoscopic cryotherapy, including both liquid nitrogen-based spray cryotherapy and the novel cryoballoon focal ablation system, in achieving complete eradication of dysplasia and neoplasia in Barrett's esophagus. Endoscopic cryotherapy has also shown promise as a second-line treatment option for patients with dysplastic Barrett's esophagus refractory to radiofrequency ablation and as an alternative to surgical resection for duodenal adenomas, when endoscopic resection is not feasible. Innovative applications for the treatment of gastrointestinal bleeding and management of benign refractory esophageal strictures have also been reported. Endoscopic cryotherapy represents a safe, effective, and well tolerated therapeutic option for various clinical scenarios in gastrointestinal endoscopy, including challenging disease states such as refractory Barrett's esophagus and advanced esophageal cancer. Advancements in cryotherapy technology and ongoing research continue to explore additional clinical indications and expand the role of endoscopic cryotherapy in patient care with an aim toward improved patient outcomes.

Laser Microsurgery in Drosophila Larvae Using the MicroPoint Ablation System.

Laser microsurgery is a robust method to ablate specific cells in the nervous system and probe the functional consequences of their loss in the animal. By introducing focal lesions to small locations in the animal, laser microsurgery also enables disruptions of specific connections within neuronal circuits and the study of how the nervous system responds to precise forms of damage (for instance, damage to specific axons or dendrites, which have been found to evoke different kinds of responses in neurons). The MicroPoint laser is a pulsed dye laser that can be mounted onto any standard microscope, hence is an affordable alternative to two-photon lasers for providing high powered focal ablations. This protocol describes how to use a MicroPoint laser ablation system to induce focal injuries in Drosophila larvae. This protocol guides a user who has access to a MicroPoint laser that has already been installed onto an appropriate microscope for high-resolution imaging and configured for laser ablation using Coumarin 440 dye. The protocol covers how to use the laser to carry out surgeries or ablation, how to change the laser dye and calibrate the power settings, and how to make sure the laser is properly focused. While the protocol provides an example of axotomy (axon severing) in the peripheral nervous system of Drosophila larvae, use of the MicroPoint system can be adapted to other focal surgeries in other organisms.

The Induction of Combined Hyperthermal Ablation Effect of Irreversible Electroporation with Polydopamine Nanoparticle-Coated Electrodes.

Irreversible electroporation (IRE) is a prominent non-thermal ablation method widely employed in clinical settings for the focal ablation therapy of solid tumors. Utilizing high-voltage, short-duration electric pulses, IRE induces perforation defects in the cell membrane, leading to apoptotic cell death. Despite the promise of irreversible electroporation (IRE) in clinical applications, it faces challenges concerning the coverage of target tissues for ablation, particularly when compared to other thermal ablation therapies such as radiofrequency ablation, microwave ablation, and cryoablation. This study aims to investigate the induced hyperthermal effect of IRE by applying a polydopamine nanoparticle (Dopa NP) coating on the electrode. We hypothesize that the induced hyperthermal effect enhances the therapeutic efficacy of IRE for cancer ablation. First, we observed the hyperthermal effect of IRE using Dopa NP-coated electrodes in hydrogel phantom models and then moved to in vivo models. In particular, in in vivo animal studies, the IRE treatment of rabbit hepatic lobes with Dopa NP-coated electrodes exhibited a two-fold higher increase in temperature (ΔT) compared to non-coated electrodes. Through a comprehensive analysis, we found that IRE treatment with Dopa NP-coated electrodes displayed the typical histological signatures of hyperthermal ablation, including the disruption of the hepatic cord and lobular structure, as well as the infiltration of erythrocytes. These findings unequivocally highlight the combined efficacy of IRE with Dopa NPs for electroporation and the hyperthermal ablation of target cancer tissues.

MRI-based monitoring of prostate cancer after HIFU: Inter-reader agreement and diagnostic performance of the PI-FAB score

PurposeTo investigate inter-reader agreement, and diagnostic performance of the Prostate Imaging after Focal Ablation (PI-FAB) score applied to multiparametric MRI (mpMRI) in patients who underwent focal high-intensity focused ultrasound (HIFU) therapy for localized prostate cancer. MethodsIn this retrospective, IRB-approved, single-center study, 73 men, who underwent focal HIFU treatment and received follow-up mpMRIs with subsequent prostate biopsies, were included. The PI-FAB score was applied to follow-up MRIs at 6, 12, and 36 months post-HIFU by two radiologists with different experience levels. Inter-reader agreement was assessed using Gwet’s AC1, and the diagnostic performance of the PI-FAB score was assessed in relation to histopathologic results of subsequent prostate biopsies for each reader. ResultsPI-FAB scores showed substantial to almost perfect inter-reader agreement (AC1: 0.80–0.95) and demonstrated high specificity (Reader 1: 90–98 %, Reader 2: 87–98 %) and NPVs (Reader 1: 91–100 %, Reader 2: 88–97 %) in ruling out residual or recurrent in-field prostate cancer post-HIFU. Sensitivity (Reader 1: ≥43 %, Reader 2: ≥14 %) and PPVs (Reader 1: ≥33 %, Reader 2: ≥14 %) were mostly relatively lower, with notable disparities between the two readers, indicating the potential influence of radiologist experience. ConclusionsThe PI-FAB score provides a consistent and reliable tool for post-HIFU monitoring of prostate cancer using mpMRI. It demonstrates substantial to almost perfect inter-reader agreement and is particularly effective in excluding in-field residual or recurrent prostate cancer post-HIFU treatment. Its application can potentially enhance post-treatment patient care, emphasizing its value as a non-invasive MRI-based monitoring approach after focal ablative therapy of the prostate.

New Prostate MRI Scoring Systems (PI-QUAL, PRECISE, PI-RR, and PI-FAB): AJR Expert Panel Narrative Review.

Multiparametric MRI (mpMRI), interpreted using PI-RADS, improves the initial detection of clinically significant prostate cancer (PCa). Prostate MR image quality has increasingly recognized relevance to the use of mpMRI for PCa diagnosis. Additionally, mpMRI is increasingly used in scenarios beyond initial detection, including active surveillance and assessment for local recurrence after prostatectomy, radiation therapy, or focal therapy. Acknowledging these evolving demands, specialized prostate MRI scoring systems beyond PI-RADS have emerged, to address distinct scenarios and unmet needs. Examples include Prostate Imaging Quality (PI-QUAL) for assessment of image quality of mpMRI, Prostate Cancer Radiologic Estimation of Change in Sequential Evaluation (PRECISE) recommendations for evaluation of serial mpMRI examinations during active surveillance, Prostate Imaging for Recurrence Reporting System (PI-RR) for assessment for local recurrence after prostatectomy or radiation therapy, and Prostate Imaging after Focal Ablation (PI-FAB) for assessment for local recurrence after focal therapy. These systems' development and early uptake signal a compelling shift towards prostate MRI standardization in different scenarios, and ongoing research will help refine their roles in practice. This AJR Expert Panel Narrative Review critically examines these new prostate MRI scoring systems (PI-QUAL, PRECISE, PI-RR, and PI-FAB), analyzing the available evidence, delineating current limitations, and proposing solutions for improvement.

Transperineal Laser Ablation (TPLA) Treatment of Focal Low-Intermediate Risk Prostate Cancer.

Background: This interventional pilot study aimed to evaluate the short-term (3 years) efficacy of focal laser ablation (FLA) in treating the index lesion of low-intermediate-risk prostate cancer, along with assessing the safety of the procedure (ClinicalTrials.gov ID NCT04045756). Methods: Forty patients aged between 46 and 86 with histologically proven organ-confined prostate cancer and low-to-intermediate progression risk were included. FLA was performed under percutaneous fusion magnetic resonance/ultrasound guidance in a Day Hospital setting under local anesthesia. Patients underwent regular clinical and functional assessments through the international index of erectile function (IIEF-5) and the International Prostatism Symptom Score (IPSS), PSA measurements, post-procedure MRI scans, and biopsies at 36 months or if positive findings were detected earlier. Statistical analyses were conducted to assess trends in PSA levels and cavity dimensions over time. Results: Forty patients were initially included, with fifteen lost to follow-up. At 36 months, a mean PSA reduction of 60% was observed, and 80% of MRI scans showed no signs of in-field clinically significant residual/recurrent cancer. Biopsies at 36 months revealed no malignant findings in 20 patients. No deterioration in sexual function or urinary symptoms was recorded. Conclusions: FLA appears to be safe, feasible, and effective in the index lesion treatment of low-intermediate-risk prostate cancer, with a high rate of tumor eradication and preservation of quality of life.

Ablation of accessory pathways in different anatomic locations using focal pulsed field ablation

BackgroundAblation of accessory pathways (APs) is the cornerstone for treatment of patients with Wolff-Parkinson-White syndrome and manifestation of atrioventricular reentrant tachycardia. Pulsed field ablation (PFA) is a new type of nonthermal energy source delivered to the underlying tissue via the ablation catheter and used for ablation of arrhythmic substrates. ObjectiveThe purpose of this study was to determine the efficiency and long-term outcome of ablation of APs of different localizations using a focal pulsed electrical field. MethodsElectrophysiological study was performed in patients with indication for AP ablation. An ablation catheter was used to map the position of AP insertion. Pulsed electric field was delivered through a standard ablation catheter. In left-sided APs, the first ablation attempt was within the coronary sinus (CS). Patient follow-up was scheduled 1–3 months after the ablation. Additional check-up was performed after 6 and 12 months. ResultsFourteen 14 patients (3 pediatric) were treated. Termination of AP conduction was achieved in all procedures. The cohort consisted of 3 right free wall, 3 posteroseptal, and 8 left-sided APs. Ablation through CS was successfully used in 7 of 8 patients with left-sided APs. No complications were reported. Median follow-up was 5.5 months. Conduction recurrence through AP was documented in 1 patient. ConclusionFocal PFA for AP shows promising results in terms of efficacy and safety. A high rate of successful termination of left-sided APs by ablation within CS may represent a new standard approach. The safety and efficacy profile of PFA seems to be transferable to the pediatric population.

(237) Patient Reported Outcomes in Men Received Focal Therapy for Prostate Cancer

Abstract Introduction Although focal therapy as a definite treatment modality for prostate cancer patients has been increasing in the United States, there has been paucity of patient reported outcome measures (PROM) specific to urinary, erectile, and sexual function Objective We aim to evaluate the long-term PROM in men undergone focal therapy for prostate cancer since 2019. Methods Web search was performed on the PubMed database. The search was limited to articles published in the English language and reporting focal therapy outcomes between 2019 and 2023, including randomized controlled trials, prospective and retrospective studies. The following data were extracted from each study: year, type of focal therapy, design, participants, demographic, IIEF, ED proportion, IPSS, EPIC, pad incontinence use, fistula rate, urinary retention rate, hematuria, Gleason scores, time to oncologic follow-up, recurrence, and presence of cancer after treatment. Results Twenty-three studies, consisting of cryotherapy, HIFU, TULSA, focal and microwave ablation where met the inclusion criteria and reviewed. Oncologic outcomes were reported in 17 of 23 studies. Median follow-up ranged from 3 to 42 months. Main oncologic outcomes analyzed were in-field/out-of-field recurrence and presence of prostate cancer after treatment. The two largest HIFU studies (n=90, n=101) had 9% and 24% respectively for clinically significant recurrence. The two focal microwave ablation studies (n=55, n=5) had 9% and 20% recurrence rates respectively. Functional outcomes were assessed by IPSS and IIEF. IPSS scores were consistent, with most studies reporting only minimal changes in IPSS after treatment. IIEF scores were generally consistent before and 6 months after procedure for all studies, with some reporting only marginal declines in erectile function. Complication rates among studies were low. Nine studies reported UTI rates ranging from 0% (n=6, n=41) to 30% (n=10) in a TULSA prospective study. Urinary retention rates were reported in 14 studies, with a range from 0% (n=41) to 30% (n=10). Conclusions This review suggests that focal therapies remain safe and effective treatment modality for patients with low-intermediate risk prostate cancer. PROM pertaining to urinary and erectile functions in men undergone focal therapy modality seems to be adequate without worse oncological or complication outcomes. Larger data with oncological and functional outcomes is warranted to further validate its safety and efficacy over longer follow up period. Disclosure No.

Nitroglycerin to Ameliorate Coronary Artery Spasm During Focal Pulsed-Field Ablation for Atrial Fibrillation

BackgroundIn treating atrial fibrillation, pulsed-field ablation (PFA) has comparable efficacy to conventional thermal ablation, but with important safety advantages: no esophageal injury or pulmonary vein stenosis, and rare phrenic nerve injury. However, when PFA is delivered in proximity to coronary arteries using a pentaspline catheter, which generates a broad electrical field, severe vasospasm can be provoked. ObjectivesThe authors sought to study the vasospastic potential of a focal PFA catheter with a narrower electrical field and develop a preventive strategy with nitroglycerin. MethodsDuring atrial fibrillation ablation, a focal PFA catheter was used for cavotricuspid isthmus ablation. Angiography of the right coronary artery (some with fractional flow reserve measurement) was performed before, during, and after PFA. Beyond no nitroglycerin (n = 5), and a few testing strategies (n = 8), 2 primary nitroglycerin administration strategies were studied: 1) multiple boluses (3-2 mg every 2 min) into the right atrium (n = 10), and 2) a bolus (3 mg) into the right atrium with continuous peripheral intravenous infusion (1 mg/min; n = 10). ResultsWithout nitroglycerin, cavotricuspid isthmus ablation provoked moderate-severe vasospasm in 4 of 5 (80%) patients (fractional flow reserve 0.71 ± 0.08). With repetitive nitroglycerin boluses, severe spasm did not occur, and mild-moderate vasospasm occurred in only 2 of 10 (20%). Using the bolus + infusion strategy, severe and mild-moderate spasm occurred in 1 and 3 of 10 patients (aggregate 40%). No patient had ST-segment changes. ConclusionsAblation of the cavotricuspid isthmus using a focal PFA catheter routinely provokes right coronary vasospasm. Pretreatment with high doses of parenteral nitroglycerin prevents severe spasm.

(017) Patient Reported Outcome Measures in Prostate Cancer Patients Treated with Focal Therapy Modality

Abstract Introduction Although focal therapy as a treatment modality for prostate cancer patients has been increasing in the United States, there has been a paucity of patient reported outcome measures (PROM) specific to urinary, erectile, and sexual function. Objective We aimed to systematically review the data of long-term PROM in men undergoing focal therapy for prostate cancer since 2019. Methods A web search was performed on the PubMed database. The search was limited to articles published in the English language and reporting focal therapy outcomes between 2019 and 2023, including randomized controlled trials, prospective and retrospective studies. The following data were extracted from each study: year, type of focal therapy, design, participants, demographic, IIEF, ED proportion, IPSS, EPIC, pad incontinence use, fistula rate, urinary retention rate, hematuria, Gleason scores, time to oncologic follow-up, recurrence, and presence of cancer after treatment. Results Twenty-three studies, consisting of cryotherapy, HIFU, TULSA, focal and microwave ablation met the inclusion criteria and were reviewed. Oncologic outcomes were reported in 17 of 23 studies. Median follow-up ranged from 3 to 42 months. Main oncologic outcomes analyzed were in-field/out-of-field recurrence and presence of prostate cancer after treatment. The two largest HIFU studies (n=90, n=101) had 9% and 24% respectively for clinically significant recurrence. The two focal microwave ablation studies (n=55, n=5) had 9% and 20% recurrence rates respectively. Functional outcomes were assessed by IPSS and IIEF. IPSS scores were consistent, with most studies reporting only minimal changes in IPSS after treatment. IIEF scores were generally consistent before and 6 months after procedure for all studies, with some reporting only marginal declines in erectile function. Complication rates among studies were low. Nine studies reported UTI rates ranging from 0% (n=6, n=41) to 30% (n=10) in a TULSA prospective study. Urinary retention rates were reported in 14 studies, with a range from 0% (n=41) to 30% (n=10). Conclusions This review suggests that focal therapies remain safe and effective treatment modality for patients with low-intermediate risk prostate cancer. PROM pertaining to urinary and erectile functions in men undergone focal therapy modality seems to be adequate without worse oncological or complication outcomes. Larger data with oncological and functional outcomes is warranted to further validate its safety and efficacy over a longer follow up period. Disclosure No.