Ablation Energy Research Articles

Pulmonary vein and posterior wall isolation and mitral isthmus block with radiofrequency vs electroporation: comparing a classic to a novel technique for the ablation of persistent atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Persistent atrial fibrillation (PerAF) ablation continues to be a challenge due to the wide variety of approaches and a high arrhythmia recurrence. In our center, the usual strategy for PerAF ablation comprises posterior wall isolation (PWI) and mitral isthmus block (MIB) in addition to pulmonary veins isolation (PVI), with alcoholization of the Vein of Marshall (VoM) if possible. Pulsed-field ablation (PFA) has emerged as a novel and promising source of energy for AF ablation, having proved its feasibility and safety for PVI. However, there is no evidence in terms of feasibility and safety about a combined strategy of PVI, PWI and MIB. Purpose Our aim was to assess the feasibility and safety of PVI, PWI and MIB with PFA for PerAF ablation, and compare it to the same approach carried out with radiofrequency (RF) +/- alcoholization of the VoM, in terms of procedural parameters, acute success and complications rate. Methods All patients who undergone PerAF ablation with PFA and RF between November 2021 and September 2022 were consecutively and retrospectively included in the study. Demographic data, procedural data, rate of acute access (in achieving isolation or block of the targeted substrates) and complications rate were collected. Results Ninety patients with PerAF ablation were included (45 with the classic approach [RF ± VoM] and 45 with PFA). No differences were found in mean age and gender (67.0±9.1 vs 67.0±10.02 y.o, p=0.96 and 26.6% vs 24.4% of women, p=0.8). No differences were found with regard to previous cardiopathy or other comorbidities. There were also no differences in left atrial volume (157±41.1vs145±54.8ml, p=0.26). As for the procedure, the PFA group had shorter procedural time (119.8±26.3vs 84.1±20.0 min, p=0.00) but longer fluoroscopy time (17.8±6.9vs23.6±6.7 min, p=0.0002) and higher fluoroscopy dose (36.1±25.3vs67.3±84.7 Gy.cm2, p=0.02). No differences were found in the acute success rate to achieve PVI (100% in all), PW isolation (97.7%vs100%, p=0.31) or mitral isthmus block (97.7%vs100%, p=0.31) between RF±VoM and PFA groups, respectively. Of note, among the patients in AF rhythm at the procedure, the rate of reversion to sinus rhythm during ablation was much higher in the PFA group (7.14% vs 77.7%, p=0.00), with a lower rate of cardioversion (92.8% vs 22.2%, p=0.00) during the procedure. No significant differences were found with regard to the number of complications (13.3% [6 cases] in the RF±VoM group vs 6.6% [3 cases] in the PFA group, p=0.27). Conclusions PFA shows a good feasibility and safety profile for PVI, PWI and MIB with shorter procedural time and higher rate of conversion to sinus rhythm during ablation compared to the classic strategy with radiofrequency.

Electroanatomical mapping-system guided vs. intracardiac echocardiography-guided slow pathway ablation: a randomized, single-center trial

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Radiofrequency (RF) catheter ablation of the slow pathway (SP) in atrioventricular nodal reentry tachycardia (AVNRT) is highly effective; however, it may require prolonged fluoroscopy and RF time. Procedural outcomes may improve by using electroanatomical mapping systems (EAM), and/or intracardiac echocardiography (ICE). Purpose Our aim was to compare EAM-guided vs. ICE-guided approach for SP ablation in patients with AVNRT. Methods In our single-center study, 65 patients underwent SP ablation due to AVNRT were randomized to ICE-guided or EAM-guided groups. Procedural outcomes (total procedure time, puncture-to-mapping time, mapping-to-last ablation time), fluoroscopy parameters (total fluoroscopy time, radiation dose) and ablation data (number of RF applications, total ablation time) were analyzed. Results ICE guidance reduced puncture-to-mapping time (39.6±7.6 min vs. 32.7±8.2 min; p< 0.001) and total procedure time (68.5 (62.8; 75.3) min vs. 59.5 (56;64) min; p< 0.001). Total fluoroscopy time was shorter (0 (0;0) sec vs. 79 (61; 121.5) sec; p< 0.001), and radiation dose was lower (0 (0;0) mGy vs. 3.1 (2.2; 4.5) mGy; p< 0,001) with the use of EAM. No significant difference was detected regarding mapping-to-last ablation time (6 (2.5;17,0) min vs. 3 (2; 8.3) min; p= 0.13), the number of RF applications (5 (3; 7) vs. 3.5 (3; 5.5); p= 0.30), and total ablation energy (3625 (2513; 5402) J vs. 2676 (1912.5; 5291.5) J; p= 0.10), however total ablation time was shorter in the ICE-guided group (127.5 (86.8; 181) sec. vs. 98.5 (81; 193.5) sec; p= 0.04). No complication occurred. Acute success rate was 100% and there was no recurrence during the follow up. Conclusions In our randomized trial enrolled 65 patients underwent SP ablation due to AVNRT, EAM-guided approach reduced fluoroscopy time and fluoroscopy dose, however total procedural, puncture-to-mapping time, as well as total ablation time was longer compared to the ICE-guided group.

Feasibility and proof of concept of a proprietary non-contact ablation system with low intensity collimated ultrasound

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Heailum Medical Inc. Background Utilization of collimated acoustic energy transition as an ablation energy source has the advantage of propagation through blood with negligible absorption. This allows delivery of non-contact, directional and precise ablation lesions to cardiac tissue. In addition, with dual mode ultrasound technology real-time monitoring of the tissue is possible during ablation. Aim To evaluate a proprietary ultrasound-based ablation system in swine and define the characteristics of the isolated ablation lesions and lines performed in-vivo. Methods In female large white swines, bilateral thigh muscle prep ablations were performed using different time and energy ablation parameters while tip to tissue distance measured with the imaging B-mode and set to 10mm. Lesions were analysed for maximal depth and width. Additional assessment for contiguous linear ablation was performed in the thigh muscle, SVC and within the coronary sinus with the transducer rotated to the endocardial direction. Tissue was fixed in formalin and gross pathological examination with lesion measurement was performed. Results 36 distinct ablation lesions were performed in the thigh prep model. No steam pops were observed for any of the lesions. Mean necrotic lesion depth was 5.35 ± 1.5mm, with increased time with greater influence on dimensions compared to small changes in energy delivered (Figure 1). Reversible damage influenced additional 29% of tissue depth, while 55% additional tissue width was reversible. Linear ablation performed at 2.5mm inter-lesion distance showed contiguous lines, with transmural effect in both SVC and coronary sinus. Conclusions A novel ultrasound based catheter ablation has the ability for non-contact effective ablation in cardiac tissue with directional and tailored energy selection to achieve transmural atrial ablation. Additional in-vivo experimentation will allow refinement of this tool for both isolated lesions and linear ablation while enabling tissue visualization.

Complications and local recurrence of malignant liver tumor after ablation in risk areas: a retrospective analysis.

Microwave ablation (MWA) is an effective local treatment for malignant liver tumors; however, its efficacy and safety for liver tumors adjacent to important organs are debatable. Forty-three cases with liver tumors adjacent to important organs were the risk group and 66 cases were the control group. The complications between two groups were compared by chi-square test and t-test. Local tumor recurrence (LTR) was analyzed by log-rank test. Factors affecting complications were analyzed by logistic regression and Spearman analyses. Factors affecting LTR were analyzed by Cox regression analysis. A receiver operating characteristic curve predicted pain treated with drugs and LTR. We found no significant difference in complications and LTR between two groups. The risk group experienced lower ablation energy and more antennas per tumor than control group. Necrosis volume after MWA was positively correlated with pain; necrosis volume and ablation time were positively correlated with recovery duration. Major diameter of tumor >3 cm increased risk of LTR by 3.319-fold, good lipiodol deposition decreased risk of LTR by 73.4%. The area under the curve (AUC) for necrosis volume in predicting pain was 0.74, with a 69.1 cm3 cutoff. AUC for major diameter of tumor in predicting LTR was 0.68, with a 27.02 mm cutoff. MWA on liver tumors in at-risk areas is safe and effective, this is largely affected by proper ablation energy, antennas per tumor, and experienced doctors. LTR is primarily determined by major diameter of tumor and lipiodol deposition status.

Synthesis AgO Nanoparticles by Nd:Yag Laser with Different Pulse Energies

One technique used to prepare nanoparticles material is Pulsed Laser Ablation in Liquid (PLAL), Silver Oxide nanoparticles (AgO) were prepared by using this technique, where silver target was submerged in ultra-pure water (UPW) at room temperature after that Nd:Yag laser which characteristics by 1064 nm wavelength, Q-switched, and 6ns pulse duration was used to irradiated silver target. This preparation method was used to study the effects of laser irradiation on Nanoparticles synthesized by used varying laser pulse energy 1000 mJ, 500 mJ, and 100 mJ, with 500 pulses each time on the particle size. Nanoparticles are characterized using XRD, SEM, AFM, and UV-Visible spectroscopy. All the structural peaks determined by the XRD test can be indexed as face-centered cubic (FCC) type, the stronger crystalline orientation is located in the (111) plane. The nanoscale particles have an almost spherical shape as inferred from the SEM images. In (1000) mJ laser pulse energy the best smallest particle size was produced. According to AFM results of all films, the particle size 32.45nm, 64.3nm, and 67.86nm respectively for 1000 mJ, 500 mJ, and 100 mJ , the surface roughness affected and increased as increase the laser energy because the increase particle size and aggregation of partials. UV-Visible spectroscopy measured the absorbance of the silver nanoparticle prepared which is increased as increase pulsed laser ablation energy at wavelength 440 nm.

Safety and Effectiveness of Pulsed Field Ablation to Treat Atrial Fibrillation: One-Year Outcomes From the MANIFEST-PF Registry.

Pulsed field ablation is a novel nonthermal cardiac ablation modality using ultra-rapid electrical pulses to cause cell death by a mechanism of irreversible electroporation. Unlike the traditional ablation energy sources, pulsed field ablation has demonstrated significant preferentiality to myocardial tissue ablation, and thus avoids certain thermally mediated complications. However, its safety and effectiveness remain unknown in usual clinical care. MANIFEST-PF (Multi-National Survey on the Methods, Efficacy, and Safety on the Post-Approval Clinical Use of Pulsed Field Ablation) is a retrospective, multinational, patient-level registry wherein patients at each center were prospectively included in their respective center registries. The registry included all patients undergoing postapproval treatment with a multielectrode 5-spline pulsed field ablation catheter to treat atrial fibrillation (AF) between March 1, 2021, and May 30, 2022. The primary effectiveness outcome was freedom from clinical documented atrial arrhythmia (AF/atrial flutter/atrial tachycardia) of ≥30 seconds on the basis of electrocardiographic data after a 3-month blanking period (on or off antiarrhythmic drugs). Safety outcomes included the composite of acute (<7 days postprocedure) and latent (>7 days) major adverse events. At 24 European centers (77 operators) pulsed field ablation was performed in 1568 patients with AF: age 64.5±11.5 years, female 35%, paroxysmal/persistent AF 65%/32%, CHA2DS2-VASc 2.2±1.6, median left ventricular ejection fraction 60%, and left atrial diameter 42 mm. Pulmonary vein isolation was achieved in 99.2% of patients. After a median (interquartile range) follow-up of 367 (289-421) days, the 1-year Kaplan-Meier estimate for freedom from atrial arrhythmia was 78.1% (95% CI, 76.0%-80.0%); clinical effectiveness was more common in patients with paroxysmal AF versus persistent AF (81.6% versus 71.5%; P=0.001). Acute major adverse events occurred in 1.9% of patients. In this large observational registry of the postapproval clinical use of pulsed field technology to treat AF, catheter ablation using pulsed field energy was clinically effective in 78% of patients with AF.

LB-456091-3 EUROPEAN REAL WORLD OUTCOMES WITH PULSED FIELD ABLATION IN PATIENTS WITH SYMPTOMATIC ATRIAL FIBRILLATION - LESSONS FROM THE MULTICENTER EU-PORIA REGISTRY

Pulsed field ablation (PFA) is a new non-thermal ablation energy modality for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). The multi-center EU-PORIA (EUropean Real World Outcomes with Pulsed Field AblatiOn in Patients with Symptomatic AtRIAl Fibrillation) registry sought to determine the safety, efficacy, and learning curve characteristics for a novel pentaspline multielectrode catheter.

PO-01-005 GANGLIONATED PLEXI MEDIATED BRADYCARDIA RESPONSES: A PRE-CLINICAL STUDY OF DIFFERENCES BETWEEN PULSED FIELD AND RADIOFREQUENCY ABLATION IN THE LEFT ATRIUM

During left atrial catheter ablation procedures, the peri-atrial neural network of ganglionated plexi (GP) can be affected by the ablative energy. Bradycardic responses (BR) from GP stimulation have been reported during both radiofrequency (RF) and pulsed field (PF) ablation procedures. To assess differences in BR between RF and PF during canine left atrial ablation. Healthy canines (n=14) underwent transeptal access under general anesthesia. A multielectrode spherical array catheter (Globe PF System; Kardium Inc., Canada) capable of both cardiac mapping and ablation with either RF or PF was deployed in the left atrium. For each application, electroanatomic maps with ostial tags, contact maps based on blood flow detection, and animated voltage maps were created to help verify isolation. Either temperature-controlled RF ablation (63°C for 3 minutes) or PF ablation (1.7-1.8 kV) was used to circumferentially isolate two PVs/animal and create a linear and focal lesion along the posterior wall and roof of the left atrium. GP stimulation as evidenced by BR was recorded if either sinus bradycardia or AV block was noted during and/or immediately after the pulse train (Figure). A total of 11 and 3 animals underwent PF and RF ablation, respectively. All ablations were successfully delivered to all locations without adverse events. Of the animals treated with RF, none (0 of 3) displayed any evidence of GP stimulation at any locations. All animals treated with PF showed evidence of GP stimulation: all animals (11 of 11,100%) exhibited BR during ablation at the inferior common vein, with 6 of 10 (60%) animals demonstrating BR at the roof and posterior wall (Table). BR of less severity was noted during subsequent pulse trains but remained most frequent at the inferior common vein. Ganglionated plexi-mediated bradycardic responses occur with PF ablation, with evidence of some degree of stunning when repeated pulse trains are delivered. This pre-clinical model with ablation at this location will serve as a good model to further our understanding of this phenomenon. The lack of any bradycardic responses with RF either represents a lack of stimulation (perhaps because of the inability of the RF energy to reach the epicardial GPs, unlike the volumetric nature of the pulsed electrical fields) or, complete ablation without stimulation. Further work is needed to explore these differences.

PO-03-042 A COOL DRINK OF WATER: CONVECTIVE ESOPHAGEAL COOLING PREVENTS THERMAL INJURY FROM RADIOFREQUENCY HEATING IN AN EX VIVO SWINE ESOPHAGUS MODEL

Esophageal heating and subsequent thermal injury are concerning adverse effects of radiofrequency (RF) energy ablation on the posterior wall of the left atrium. Active intraluminal esophageal cooling may provide thermal protection, allowing for effective delivery of RF energy to overlying myocardium without collateral damage to the underlying esophagus. To evaluate the impact of esophageal luminal cooling with a closed loop continuous flow irrigation on esophageal heating and thermal injury using an ex vivo model. A flexible tube was placed through the lumen of a swine esophagus and connected to a closed loop circuit consisting of a pump and water bath (Figure 1, panel A). The esophagus was submerged in a saline bath with a temperature of 36 °C and an impedance of 140 ohms. Ten non-contiguous RF lesions were delivered at 50 watts for 8 seconds directly on the outer esophageal wall with 4 mm irrigated RF ablation catheter. This was performed without irrigation (control), irrigation at 1.5 L/min with room temperature water (20 °C), and irrigation at 1.5 L/min with ice water (0 °C). Esophageal tissue samples were obtained from immunohistochemistry and the esophagus was cross sectioned and lesions were measured with digital calipers. Closed loop continuous flow esophageal irrigation with ice water yielded esophageal lesions with the smallest surface area (Figure 1, panel A), depth, and volume (Figure 1, panel B). Continuous esophageal irrigation with room temperature water resulted in the second smallest lesions. RF lesions without esophageal irrigation resulted in the largest and deepest lesion, as well as evidence of luminal esophageal injury (Figure 1, panel C & D). Histology showed preserved smooth muscle, glands, basement membrane and epithelium with cooled esophagus and transmural lesions with non-irrigated esophagus (Figure 1, panel C & D). Continuous endoluminal esophageal cooling reduced lesion size with RF energy delivery. There was no luminal injury with room temperature and ice water esophageal irrigation. Thus, both may be useful in prevention of endoluminal esophageal injury during poster wall RF ablation.

PO-04-073 ELECTRON MICROSCOPIC INSIGHTS FROM AN ACUTE PULSED FIELD MYOCARDIAL LESION

Pulsed field ablation (PFA) is a nonthermal ablative energy modality that increases membrane permeability by creating pores and causing chemical changes to the lipids and proteins on the cell membrane. However, little is known about its effect on cell membrane, organelle structure and time course of lesion formation. To evaluate cell membrane and organelle structure after PFA and assess lesion differences between 1- and 4-hour after PFA. Healthy swine underwent endocardial PFA using an 11 Fr circular, multielectrode catheter (CellFX, Pulse Biosciences) in nanosecond pulsing mode. Pulses were delivered to the left ventricle under general anesthesia with fluoroscopic and intracardiac echocardiography guidance. Two discrete PFA lesions were sampled 1 and 4 hours after PFA. Transmission electron microscopy assessment was performed after fixation using paraformaldehyde and glutaraldehyde. At 1-hour post-PFA, healthy myocytes with normal sarcomeric structure, clear Z band, and A band were noted adjacent to ablated myocytes (Figure). Mitochondria inside the healthy myocyte were aligned in parallel with sarcomere filaments. Ablated myocytes on the other hand demonstrated disrupted sarcomeric structures and were randomly clustered and misaligned. Cell membranes of the ablated myocyte at the lesion border were relatively preserved compared to ablated myocytes from within the core of the PFA lesion. At 4-hour post-PFA, the PF lesion was noticeably more edematous and areas of coagulum could be seen adjacent to the capillaries. Alignment of cell membranes at the 4-hour timepoint was further disorganized. Fewer mitochondria per section were observed at 4-hour post-PFA, and noted to be randomly scattered amongst damaged myocytes. There were no normal sarcomeres noted anywhere within the lesion at 4 hours. This electron microscopy study demonstrates significant rapid disappearance of myocytes after PFA (∼ 1 hour). The cell membrane structure and organelle structure progressively deteriorate by 4 hours post ablation.

PO-04-039 DIELECTRIC IMAGING-GUIDED ULTRA-LOW TEMPERATURE CRYOABLATION FOR ATRIAL FIBRILLATION

Ultra-low temperature cryoablation(ULTC) can be used to create transmural ablation lesions in the left atrium (LA). With a circular catheter configuration, this energy modality can be used to create continuous ablation lesions around the pulmonary veins(PVs). The same catheter configuration can be used to isolate the posterior wall(PW) by creating multiple overlapping circular ablation lesions. Isolation of the PVs and the PW can be assessed using pacing maneuvers. Three-dimensional voltage mapping may provide additional information on the extent of the ablation lesions. A recently introduced dielectric imaging-based mapping system can be used to generate voltage maps and to visualize the ULTC ablation catheter. To evaluate the feasibility of ULTC, guided by dielectric imaging-based electroanatomic mapping. Patients with atrial fibrillation were consented for catheter ablation with the iCLAS cryoablation system(Adagio Medical, Laguna Hills, USA). Ablation included isolation of the PV’s and LA PW if deemed necessary. The KODEX-EPD system(EPD Solutions, Best, the Netherlands) was used in conjunction with a circular mapping catheter to create pre- and postablation voltage maps. If the postablation voltage map revealed incomplete ablation lesions, additional energy applications were applied. Patients visited the outpatient clinic at 3 months post ablation. All patients were enrolled in a prospective registry study that was approved by the local ethics committee. Six patients (4 male, 4 persistent AF, age 66±7 years, LAVI 38±14ml/m2) were treated. The PVs were targeted in all patients, while the PW was targeted in 5 patients. A postablation voltage map was generated in 5 patients, which revealed incomplete PV isolation in 2 patients and incomplete PW isolation in 1 patient. Additional ablation in these patients resulted in acute electrical isolation of all targets. Isolation of the PVs was achieved using a median of 11[IQR:9-15] energy applications and 11[8.5-14] minutes of ablation. Isolation of the PW required 6[6-7] applications and 3[3-3.5] minutes of ablation energy. Total mapping time was 14.5[12.5-22.5] minutes, total fluoroscopy time was 16[12.5-18.5] minutes, and the total procedure time was 107.5[67.25-123.5] minutes. At 3 months follow up, only 1 patient had recurrence of atrial arrhythmia. Longer follow up is ongoing. Dielectric imaging-based electroanatomic mapping can be used to evaluate lesions of ULTC.

PO-04-042 GENDER DIFFERENCES IN CLINICAL OUTCOMES AFTER PULSED FIELD ABLATION OF ATRIAL FIBRILLATION: INTERIM ANALYSIS OF THE MANIFEST-PF EFFICACY REGISTRY

Prior studies have shown that atrial fibrillation (AF) ablation with conventional thermal ablative modalities, radiofrequency (RF) or cryo, is associated with a higher risk of complications in women compared with men, and a lower success rate of freedom from AF recurrences. Pulsed-field ablation (PFA) is a novel AF ablation energy modality which, in first-in-human clinical trials, has demonstrated preferential myocardial tissue ablation with a unique safety profile. We performed an interim analysis of the MANIFEST-PF registry to explore gender differences in real-world outcomes after PFA of AF. MANIFEST-PF is a retrospective patient-level registry from the first 23 European centers performing clinical PFA procedures, including all consecutive patients who received first-ever ablation for paroxysmal or persistent AF between March to December 2021 using the pentaspline PFA catheter (Farawave, Farapulse-Boston Scientific Inc). We compared baseline and procedural characteristics, and clinical outcomes between men and women. The efficacy endpoint was freedom from atrial arrhythmia (AF/atrial flutter/atrial tachycardia) recurrence ≥30 seconds after a 3 month-blanking period. Safety endpoints included major/minor adverse events (AEs <7 days post-procedure). Binary logistic regression model was created using -- Age, CAD, CHF, Sleep apnea, LVEF, LAD, Non-parox AF, Female, diabetes, HTN and stroke/TIA. Of the 1,332 AF pts who underwent an AF ablation, 454 (34%) were female. Woman, compared to men, were older (67±10 vs 62±11 yrs) and had more paroxysmal AF (72% vs 61%), but less comorbidities such as coronary disease, heart failure and sleep apnea. (Figure A) Following ablation, there was no significant difference in major (2.6% vs 1.1%, p=0.14) or minor (3.3% vs 4.4%, p=0.18) AEs between groups. Multivariable analysis showed that women (Odds ratio 4.1, 95% CI [1.21–13.78], p=0.02) were more likely to have a higher risk of acute major AEs. After a mean follow-up of 196 days, there was no difference in recurrence of atrial arrhythmia (14.5% vs 18%, p=0.14) or redo-ablations (5.1% vs. 7.7%, p=0.07) between women and men, respectively, even after adjusting for the type of AF (ie, PAF vs PerAF). (Figure B) As compared with men, women undergoing PFA to treat AF experience more acute major procedural complications, though the overall rate of complications was low with PFA. On the other hand, women have a similar success rate of freedom from recurrent atrial arrhythmias.

MP-453081-11 PULSED FIELD ABLATION OF ATRIAL FIBRILLATION: SAFE TECHNOLOGY WITHOUT COLLATERAL DAMAGE TO THE ESOPHAGUS? FINDINGS OF POST-PROCEDURAL ENDOSCOPY

Severe injuries of the esophagus causing major complications after catheter ablation (CA) of atrial fibrillation are rare. However, endoscopically detected esophageal lesions (EDEL) have been described in up to 30% after radiofrequency current energy ablation. The novel non-thermal ablation technology pulsed field ablation (PFA) allows for unique ablation of the myocardium, sparing adjacent tissues, including the esophagus. Due to the proximity of the esophagus to the left atrial posterior wall (LAPW), this study sought to investigate the safety profile of PFA after left atrial posterior wall isolation (LAWPI) in patients undergoing catheter ablation of AF. Consecutive patients underwent PFA-guided catheter ablation for AF/atrial tachycardia including LAPWI. No esophagus probe was used due to the non-thermal energy form of PFA. To rule out esophageal lesions, all patients underwent post-procedural esophageal endoscopy, possibly, the next day. In total, 44 patients were included in the study. Patients’ mean age was 68 ± 13 years, 32 of 44 patients were male (72.7%) with a median CHA2DS2-VASc Score of 2 (q1-q3:1.5-4). Of all 44 PFA procedures, 13 (29.5%) were first ablation procedures for persistent AF and 31 (70.5%) were re-ablation procedures, including AF and AT. All patients underwent PFA-guided CA with a procedure duration of 113 ± 35.2 mins and a fluoroscopy time of 14.0 ± 5.7 mins. Pulmonary vein isolation (PVI) and/or Re-PVI was performed in 32 (72.3%) of patients. Successful LAPWI with PFA was performed in all patients (100%) including one (1/44, 2.3%)% early reconnection during remapping that required additional PFA. Additional PFA (including roof line, anterior line and mitral isthmus ablation) was performed in 22/44 patients (50%). Post-procedural endoscopy was performed at a median of one day after the procedure (q1-3: 1-2 days). No ablation-associated esophageal lesion was found (0%). There was no tamponade, and only one minor groin complication (2.3%, AV fistula not requiring intervention). After pulsed field ablation, no EDEL were detected on post-procedural esophageal endoscopy. Therefore, AF ablation including left posterior wall isolation performed by pulsed field ablation seems to be safe regarding any collateral damage to the esophagus.

Graphene Biointerface for Cardiac Arrhythmia Diagnosis and Treatment.

Heart rhythm disorders, known as arrhythmias, cause significant morbidity and are one of the leading causes of mortality. Cardiac arrhythmias are frequently treated by implantable devices, such as pacemakers and defibrillators, or by ablation therapy guided by electroanatomical mapping. Both implantable and ablation therapies require sophisticated biointerfaces for electrophysiological measurements of electrograms and delivery of therapeutic stimulation or ablation energy. In this work, a graphene biointerface for in vivo cardiac electrophysiology is reported for the first time. Leveraging sub-micrometer-thick tissue-conformable graphene arrays, sensing and stimulation of the open mammalian heart are demonstrated both in vitro and in vivo. Furthermore, the graphene biointerface treatment of atrioventricular block (the kind of arrhythmia where the electrical conduction from the atria to the ventricles is interrupted) is demonstrated. The graphene arrays show effective electrochemical properties, namely interface impedance down to 40Ω cm2 at 1kHz, charge storage capacity up to 63.7mCcm-2 , and charge injection capacity up to 704µCcm-2 . Transparency of the graphene structures allows for simultaneous optical mapping of cardiac action potentials, calcium transients, and optogenetic stimulation while performing electrical measurements and stimulation. The report presents evidence of the significant potential of graphene biointerfaces for advanced cardiac electrophysiology and arrhythmia therapy.

First Clinical Experience of a Novel Pulsed Solid-State Thulium:YAG Laser during Percutaneous Nephrolithotomy.

Laser lithotripsy during Mini-PCNL is one treatment option in urinary stone disease. In recent years, a new era in stone treatment has been initiated with the introduction of new pulsed thulium lasers. The aim of this study was to investigate the safety and efficacy of laser lithotripsy with a new pulsed solid-state thulium:YAG laser during mini-PCNL. All patients, regardless of stone size, who were treated with a Mini-PCNL using the new pulsed thulium laser were prospectively enrolled. Operation times, stone size, laser time, and laser settings were noted. The stone-free rate was assessed postoperatively with sonography and either X-ray or computed tomography as a clinical standard. The complications were analyzed using the Clavien-Dindo classification. A total of 50 patients with a mean age of 52 years were included. 31 (62 %) patients were male. The average stone size was 242.3 (±233.1) mm2 with an average density of 833 (±325) Hounsfield units. The mean operating time was 30.56 (±28.65) min, and the laser-on-time was 07:07 (± 07:08) min. The most commonly used settings were 0.4 J and 115 Hz (46 W). The mean total energy for stone ablation was 14,166 (±17,131) kJ. The total stone-free rate was 84 %, with an overall complication rate of 32% according to Clavien-Dindo (grade 1: n = 9, grade 2: n = 6, 3b: n = 1). In the group of patients with singular stones (n = 25), the stone-free rate was 88%. The new pulsed solid-state Thulium:YAG laser allows a safe and effective lithotripsy during Mini-PCNL. The stone-free rates were high regardless of stone size with a comparable low rate of complications.

Efficacy, Safety and Feasibility of Superior Vena Cava Isolation in Patients Undergoing Atrial Fibrillation Catheter Ablation: An Up-to-Date Review.

Pulmonary vein isolation (PVI) is the cornerstone in atrial fibrillation (AF) ablation; yet, the role of arrhythmogenic superior vena cava (SVC) is increasingly recognized and different ablation strategies have been employed in this context. SVC can act as a trigger or perpetuator of AF, and its significance might be more pronounced in patients undergoing repeated ablation. Several cohorts have examined efficacy, safety and feasibility of SVC isolation (SVCI) among AF patients. The majority of these studies explored as-needed SVCI during index PVI, and only a minority of them included repeated ablation subjects and non-radiofrequency energy sources. Studies of heterogeneous design and intent have explored both empiric and as-needed SVCI on top of PVI and reported inconclusive results. These studies have largely failed to demonstrate any clinical benefit in terms of arrhythmia recurrence, although safety and feasibility are undisputable. Mixed population demographics, small number of enrollees and short follow-up are the main limitations. Procedural and safety data are comparable between empiric SVCI and as-needed SVCI, and some studies suggested that empiric SVCI might be associated with reduced AF recurrences in paroxysmal AF patients. Currently, no study has compared different ablation energy sources in the setting of SVCI, and no randomized study has addressed as-needed SVCI on top of PVI. Furthermore, data regarding cryoablation are still in their infancy, and regarding SVCI in patients with cardiac devices more safety and feasibility data are needed. PVI non-responders, patients undergoing repeated ablation and patients with long SVC sleeves could be potential candidates for SVCI, especially via an empiric approach. Although many technical aspects remain unsettled, the major question to answer is which clinical phenotype of AF patients might benefit from SVCI?

Clinical characteristics and electrophysiological features in patients with persistent atrial fibrillation undergoing radiofrequency energy ablation

Objective: To investigate the clinical and paraclinical characteristics and electrophysiological features after cardioversion in patients with persistent atrial fibrillation (AF). Subejct and method: This was a prospective study of 40 patients with persistent AF who underwent catheter ablation of AF using a three-dimensional (3D) system at the Vietnam Heart Institute, Bach Mai Hospital. Result: The mean age of the patients was 54.25 ± 12.54 years, and 80% of patients were male, the symptoms (according to EHRA) of patients ranged from grade IIb (67.5%) to grade III (32.5%). Hypertension (42.5%) and alcohol abuse (37.5%) were the most common risk factors. After cardioversion, patients with persistent AF exhibited longer sinus node recovery time (SNRT) (1445.11 ± 547.33ms) and corrected SNRT (667.03 ± 517.21ms) than healthy controls. Conclusion: Persistent AF is common in the elderly, especially men, with prevalent risk factors, such as hypertension and alcohol abuse. After cardioversion, patients with persistent AF have an SNRT longer than normal.

Multilayer In Vitro Human Skin Tissue Platforms for Quantitative Burn Injury Investigation.

This study presents a multilayer in vitro human skin platform to quantitatively relate predicted spatial time-temperature history with measured tissue injury response. This information is needed to elucidate high-temperature, short-duration burn injury kinetics and enables determination of relevant input parameters for computational models to facilitate treatment planning. Multilayer in vitro skin platforms were constructed using human dermal keratinocytes and fibroblasts embedded in collagen I hydrogels. After three seconds of contact with a 50-100 °C burn tip, ablation, cell death, apoptosis, and HSP70 expression were spatially measured using immunofluorescence confocal microscopy. Finite element modeling was performed using the measured thermal characteristics of skin platforms to determine the temperature distribution within platforms over time. The process coefficients for the Arrhenius thermal injury model describing tissue ablation and cell death were determined such that the predictions calculated from the time-temperature histories fit the experimental burn results. The activation energy for thermal collagen ablation and cell death was found to be significantly lower for short-duration, high-temperature burns than those found for long-duration, low-temperature burns. Analysis of results suggests that different injury mechanisms dominate at higher temperatures, necessitating burn research in the temperature ranges of interest and demonstrating the practicality of the proposed skin platform for this purpose.

Pulmonary vein isolation-induced vagal nerve injury and gastric motility disorders detected by electrogastrography: The side effects of pulmonary vein isolation in atrial fibrillation (SEPIA) study.

Safety of pulmonary vein isolation (PVI) has been established in clinical studies. However, despite prevention efforts the incidence of damage to (peri)-esophageal tissue has not decreased, and the pathophysiology is incompletely understood. Damage to vagal nerve branches may be involved in lesion progression to atrio-esophageal fistula. Using electrogastrography, we assessed the incidence of periesophageal vagal nerve injury (VNI) following atrial fibrillation ablation and its association with procedural parameters and endoscopic results. Patients were studied using electrogastrography, endoscopy, and endoscopic ultrasound before and after cryoballoon (CB) or radiofrequency (RF) PVI. The incidence of ablation-induced neuropathic pattern (indicating VNI) in pre- and postprocedural electrogastrography was assessed and correlated with endoscopic results and ablation data. Between February 2021 und January 2022, 85 patients (67 ± 10 years, 53% male) were included, 33 were treated with CB and 52 with RF (38 with moderate power moderate duration [25-30 W] and 14 with high power short duration [50 W]). Ablation-induced VNI was detected in 27/85 patients independent of the energy form. Patients with VNI more frequently had postprocedural endoscopically detected pathology (8% mucosal esophageal lesions, 36% periesophageal edema, 33% food retention) but there was incomplete overlap. Pre-existing esophagitis increased the likelihood of VNI. Ablation data and esophageal temperature data did not predict VNI. PVI-induced VNI is quite common and independent of ablation energy source. VNI is part of (peri)-esophageal damage and only partially overlaps with endoscopic findings. VNI-associated acidic reflux may be involved in the complex pathophysiology of esophageal lesion progression to fistula.

Toward mechatronic MRI-guided focal laser ablation of the prostate: Robust registration for improved needle delivery.

Multiparametric MRI (mpMRI) is an effective tool for detecting and staging prostate cancer (PCa), guiding interventional therapy, and monitoring PCa treatment outcomes. MRI-guided focal laser ablation (FLA) therapy is an alternative, minimally invasive treatment method to conventional therapies, which has been demonstrated to control low-grade, localized PCa while preserving patient quality of life. The therapeutic success of FLA depends on the accurate placement of needles for adequate delivery of ablative energy to the target lesion. We previously developed an MR-compatible mechatronic system for prostate FLA needle guidance and validated its performance in open-air and clinical 3T in-bore experiments using virtualtargets. To develop a robust MRI-to-mechatronic system registration method and evaluate its in-bore MR-guided needle delivery accuracy in tissue-mimicking prostatephantoms. The improved registration multifiducial assembly houses thirty-six aqueous gadolinium-filled spheres distributed over a 7.3 × 7.3 × 5.2 cm volume. MRI-guided needle guidance accuracy was quantified in agar-based tissue-mimicking prostate phantoms on trajectories (N = 44) to virtual targets covering the mechatronic system's range of motion. 3T gradient-echo recalled (GRE) MRI images were acquired after needle insertions to each target, and the air-filled needle tracks were segmented. Needle guidance error was measured as the shortest Euclidean distance between the target point and the segmented needle trajectory, and angular error was measured as the angle between the targeted trajectory and the segmented needle trajectory. These measurements were made using both the previously designed four-sphere registration fiducial assembly on trajectories (N = 7) and compared with the improved multifiducial assembly using a Mann-Whitney Utest. The median needle guidance error of the system using the improved registration fiducial assembly at a depth of 10 cm was 1.02 mm with an interquartile range (IQR) of 0.42-2.94 mm. The upper limit of the one-sided 95% prediction interval of needle guidance error was 4.13 mm. The median (IQR) angular error was 0.0097 rad (0.0057-0.015rad) with a one-sided 95% prediction interval upper limit of 0.022 rad. The median (IQR) positioning error using the previous four-sphere registration fiducial assembly was 1.87 mm (1.77-2.14mm). This was found to be significantly different (p = 0.0012) from the median (IQR) positioning error of 0.28 mm (0.14-0.95 mm) using the new registration fiducial assembly on the same trajectories. No significant difference was detected between the medians of the angular errors (p = 0.26). This is the first study presenting an improved registration method and validation in tissue-mimicking phantoms of our remotely actuated MR-compatible mechatronic system for delivery of prostate FLA needles. Accounting for the effects of needle deflection, the system was demonstrated to be capable of needle delivery with an error of 4.13 mm or less in 95% of cases under ideal conditions, which is a statistically significant improvement over the previous method. The system will next be validated in a clinicalsetting.