Preprocedural imaging can improve the success rate of ventricular tachycardia (VT) ablation. Left ventricular wall thickness (LVWT) measured by cardiac computed tomography (CT) can be used to identify infarct regions. We sought to determine whether an association exists between left ventricular wall thickness (LVWT) as obtained from CT imaging and the presence of decrement evoked potentials (DeEPs) as obtained from electroanatomic mapping. In this single-center, retrospective analysis, 14 patients with ischemic heart disease who underwent a VT ablation in the University Medical Center Groningen (UMCG) between January 2021 and March 2023 were included. CT images as well as electroanatomic maps were obtained and processed, after which a 3D model of the left ventricle was obtained and segmented in 17 segments. The primary outcome was the presence of DeEPs, defined as late potentials exhibiting a decremental delay response longer than 20ms after S2 extrastimulus delivery (with the extrastimulus delivered at 50ms above the ventricular effective refractory period [VERP]), in each of the left ventricular segments. The mean segment LVWT and coefficient of variation of LVWT, defined as the standard deviation of the LVWT of each segment divided by the mean segment LVWT, were analyzed as determinants of the primary outcome. The mean age was 69 ± seven years and 13 (92.9%) patients were male. The mean LVWT was significantly associated with the presence of DeEPs in left ventricular segments [odds ratio (OR) 0.65 (95% confidence interval (CI) 0.55 - 0.78); p < 0.001], as was the coefficient of variation of LVWT [OR 1.10 (95% CI 1.06 - 1.15); p < 0.001]. The mean and coefficient of variation of LVWT were significantly associated with the presence of DeEPs. This may possibly allow for the preprocedural identification of arrhythmogenic regions as potential targets for VT ablation.

Photosensitizer with near-infrared emission employing lysosome as therapeutic target for cancer cell ablation

Cardiac magnetic resonance imaging (MRI) aids the identification of the critical substrate in scar-dependent ventricular tachycardia (VT). Anatomic assessment (AA) of MRI images detects channels that may sustain VT and are viable targets for ablation. Heart digital twins (DTs) combine anatomic data with functional assessment to identify the VT isthmus. This study aimed to assess the additional benefit of combining functional data with anatomy using a DT compared with purely AA in identifying the critical substrate in VT. 18 patients with scar-dependent VT planned for catheter ablation underwent contrast-enhanced cardiac MRI. AA to derive conducting channels was performed. Simultaneously, heart DT models combining personalized heart geometry and functional properties were generated and tested for VT inducibility, and optimum ablation lesion sites were predicted. Patients underwent invasive VT ablation. Detection of scar and critical substrate was compared between AA and DT. Scar identification was similar between AA and DT. The total area predicted for ablation was similar between AA and DT (9.94 cm2 [±9.46 cm2] vs 9.84 cm2 [±3.23 cm2]; P = .96). The sensitivity for detection of abnormal electrograms was greater with DT than AA (51.4% [±17.6%] vs 25.3% [±25.4%]; P = .002). The sensitivity of detection of deceleration zones, mid-diastolic potentials, and sites of VT termination with ablation was higher with DT than AA, with DT correctly identifying 13 of 16 mid-diastolic potentials (81.3%) compared with 8 of 16 by AA (50.0%). The addition of functional data improves detection of the critical substrate above purely AA in scar-dependent VT. DTs are a potentially useful aid in VT ablation.

Functional Conduction Block During Extrastimulus Mapping Masks Deceleration Zones and Reveals Additional VT Substrate.

High-fidelity postmyocardial infarction ventricular tachycardia simulation for intraprocedure ablation guidance.

Thermal ablation therapy has emerged as a promising strategy for treating tumors that are difficult to resect surgically, such as deep-seated glioblastoma. Recent advances in imaging modalities, particularly photoacoustic and ultrasound imaging, have demonstrated the feasibility of direct necrosis monitoring, offering more accurate assessments than traditional temperature-based methods. Building on these developments, the integration of real-time necrosis feedback (NFB) into ablation control has been introduced. However, several existing NFB control studies neglected the influence of residual heat after ablation is terminated. Furthermore, NFB itself lacks temperature monitoring capabilities, raising key questions regarding how residual heat affects ablation outcomes and how it should be effectively managed. Model predictive control (MPC) offers a potential solution for managing residual heat, but its effectiveness depends on the accurate identification of patient-specific thermal parameters. To address these challenges, we propose a Direct Necrosis-Monitoring-based Adaptive Model Predictive Control (DNaMPC) framework. This method leverages real-time NFB while accounting for residual heat and adaptively identifies patient-specific parameters using a hierarchical Extended Kalman Filter (EKF) architecture. The approach employs a novel parameter absorption strategy, where a single highly observable parameter (thermal damage threshold, ) is adaptively estimated to compensate for uncertainties in both thermal diffusivity ( ) and itself, circumventing the identifiability challenges of simultaneous multi-parameter estimation. In simulations based on a one-dimensional (1D) finite difference model of brain tissue, which serves as a thermodynamic worst-case scenario for residual heat management, DNaMPC was compared against proportional (P) control and Recursive Least Squares (RLS)-based adaptive MPC (RLS-MPC). DNaMPC eliminated post-shutdown excessive ablation observed with P-control and outperformed RLS-MPC in terms of targeting accuracy and input energy economy. Further evaluation under model uncertainties demonstrated the framework's robustness, achieving the target ablation ratio of 1 despite up to mismatch in thermal diffusivity ( ) and to mismatch in the thermal damage threshold ( ). The adaptive control demonstrated superior performance in terms of both median accuracy and reduced variability compared to non-adaptive approaches across the expected range of patient parameter variations, maintaining robustness against sensing noise levels up to 20%. These results demonstrate that DNaMPC can effectively utilize residual heat, suppress sensing errors, and adapt to patient-specific variability during the procedure, thereby laying the foundation for precise, individualized thermal ablation therapies.

Lesion characteristics created by bipolar radiofrequency ablation; right- vs. left-side of septum and epicardium vs. endocardium in the free wall.

Activation signature valleys are predictive of macroreentrant atrial tachycardia bottlenecks where uniform low voltage and uniform slow conduction reside.

To quantitatively assess the influence of target temperature and ablation duration on the quality of proton resonance frequency shift (PRFS)-based MR thermometry during microwave ablation (MWA) in a controlled ex vivo model, and to identify parameter ranges associated with improved thermometry performance. Thirty-two MWAs were performed in 10 ex vivo bovine livers in a 1.5-tesla MRI system with multi-slice volumetric real-time thermometry yielding temperature and thermal dose maps. The experiments were conducted twice using all combinations of four target temperatures (60; 80; 100; 120 °C) and four ablation times (5:00; 7:30; 10:00; 15:00 min). Thermometry quality was rated on a 5‑point Likert scale. Ablation areas were compared with histopathology (hematoxylin and eosin, H&E; and nicotinamide adenine dinucleotide, NADH‑diaphorase) and correlated using Spearman coefficients. Likert scores were compared across temperatures using Kruskal-Wallis and Mann-Whitney U tests. All evaluations were performed independently by two readers. Lesion areas varied from 2.6 to 12.9 cm², increasing primarily with target temperature. Ablation areas from temperature and thermal dose maps correlated strongly with macroscopically visual necrosis (p < 0.01). Likert scores differed significantly across temperatures (p < 0.05). The highest image quality was achieved at 60 °C for 7:30 min, showing comparable scores as at 80° for 15:00 min, but significantly differing from 100 °C to 120 °C. In this controlled ex vivo setting, lower target temperatures were associated with improved MRI thermometry quality, providing more reliable visualization of ablation zones; however, ablation volumes decreased at lower temperatures. Furthermore, these empirical ex vivo observations suggest that a staged two-level approach may support a clinical workflow strategy aimed at balancing thermometry image quality and ablation volume. Given the absence of perfusion and motion effects, these findings require further validation before clinical translation.

Magnetic resonance-guided focused ultrasound (MRgFUS) is a novel, noninvasive therapeutic approach that shows potential in treating movement disorders, such as essential tremor, Parkinson's disease, and dystonia. This technique combines high-intensity focused ultrasound with real-time magnetic resonance imaging, allowing for accurate targeting and thermal ablation of deep brain areas without incisions or exposure to ionizing radiation. MRgFUS provides precise lesioning with intraoperative feedback, enabling immediate assessment of symptoms. Clinical trials and initial clinical applications have shown significant enhancements in motor symptoms and quality of life, boasting a favorable safety profile with fewer adverse effects compared to traditional surgical methods like deep brain stimulation (DBS). For patients who are not candidates for surgery or who prefer less invasive treatments, MRgFUS represents a valuable alternative. This brief overview serves as a useful resource for general neurologists.

Catheter ablation for persistent atrial fibrillation (AF) exhibits suboptimal outcomes after pulmonary vein isolation (PVI) alone. The vein of Marshall (VOM) has emerged as an adjunctive ablation target, through which ethanol infusion can achieve transmural lesions in regions resistant to radiofrequency ablation. To evaluate the efficacy and safety of adjunctive VOM ethanol infusion in patients undergoing catheter ablation for persistent AF. We conducted a meta-analysis of randomized controlled trials (RCTs) comparing PVI ± linear ablation with versus without VOM ethanol infusion for persistent AF. The primary outcome was freedom from AF recurrence, analyzed using odds ratios and hazard ratios for time-to-event data. Secondary outcomes included procedural metrics and complications. Data were pooled using random-effects models. Four RCTs (n = 1045 patients) were included. VOM ethanol infusion significantly improved sinus rhythm maintenance (65.8%vs. 48.6%; absolute difference 17.2%; OR: 1.68, 95% CI: 1.13-2.49, p = 0.025). Time-to-event analysis showed consistent benefit of maintaining sinus rhythm during the first post-procedure year (pooled HR: 0.73, 95% CI: 0.59-0.91, p = 0.005) with high mitral isthmus block rates (90%). Subgroup analysis showed consistent sinus rhythm maintenance whether ethanol was added to PVI alone (OR: 1.66) or PVI with linear ablation (OR: 1.69). Fluoroscopy time was longer (+10.3min, p = 0.0009) with VOM ethanol infusion. Complication rates were similar (OR: 1.55, p = 0.46). Adjunctive VOM ethanol infusion significantly improves ablation outcomes in persistent AF without increasing major complications. It represents a promising strategy to enhance durable rhythm control. Further research is required to evaluate long-term outcomes.

Tin oxide thin films were deposited by the pulsed laser ablation of a metallic Sn target at different oxygen partial pressures, ranging from 10 to 40 mTorr. Langmuir plasma probe diagnostics were performed to evaluate the effect of pressure on mean kinetic energy and density of Sn ions. It was observed that the mean kinetic energy decreased from 34 to 11 eV while the ion density decreased from 10 to 1.5 × 1013 cm−3 with increasing pressure. The films exhibited enhanced optical transmittance, increasing from 10% for the sample grown at 10 mTorr to 70% for the film deposited at 40 mTorr. Furthermore, higher deposition pressures led to wider band gap values, increasing from 1.6 to 3.9 eV for direct transitions and from 2.2 to 3.2 eV for indirect transitions with increasing oxygen pressure. These trends are consistent with progressive oxidation and partial transparency characteristic of semiconducting tin oxides. Structural characterization, based on X-ray diffraction, revealed predominantly metallic Sn diffraction peaks across the entire oxygen pressure range. However, despite this structural signature, the films exhibited optical and electronic properties characteristic of tin oxides. This apparent discrepancy suggests the coexistence of metallic nanoparticles embedded within an amorphous or nanocrystalline SnO2/SnOx matrix. These findings provide insights into the non-equilibrium oxidation dynamics of tin and the formation of metastable SnOx phases during pulsed laser deposition.

Colloidal solutions containing silica-coated silver nanoparticles (Ag@SiO2) were synthesized through a two-step process integrating physical and chemical mechanisms. In the first step, laser ablation of a silicon target submerged in deionized water generated an H2O–SiO2 colloid, termed the as-cast colloid. This contained nanometric SiO2 particles alongside micrometer-sized or larger silicon fragments produced by laser shockwave-induced target surface fragmentation. To refine particle size distribution and elevate nanometric SiO2 concentration, the as-cast colloid underwent secondary laser irradiation, effectively fragmenting larger particles. The second step involved adding ionic silver to both as-cast and irradiated colloids, yielding Ag@SiO2 nanoparticles. Structural properties were probed via XRD and TEM; optical characteristics via UV–Vis spectroscopy; and electrophoretic mobility via zeta potential measurements, both pre- and post-silver incorporation, to elucidate irradiation’s influence on synthesis. For controlled agglomeration, AlCl3 was used to modify surface charge, neutralizing silanol groups on the silica shell and minimizing electrostatic repulsion through aluminum ion interactions. These findings demonstrate tunable Ag@SiO2 colloids with precise surface properties for future development of advanced nanomaterials suitable for microbicidal applications.

Abstract We present results from a new experiment, fielded on the MAGPIE pulsed power generator, producing a rotating, boundary-free plasma with no pre-imposed magnetic field. Angular momentum is introduced to the rotating system by the oblique collision of multiple plasma flows, which are driven by x-ray ablation of solid targets using the soft x-rays emitted from the implosion of wire array z-pinches. This produces a hydrodynamically stable plasma which undergoes ∼ 2 − 3 rotations over the duration of the experiment, significantly more than previous pulsed-power platforms. Estimating the angular frequency from the electron density profile in the inner part of the rotating plasma shows that it has a quasi-Keplerian rotation profile. The system also allows for the addition of a controllable magnetic field. This, combined with the sufficiently large Reynolds ( ∼ 10 5 ) and magnetic Reynolds ( ∼ 10 ) numbers, will enable investigation of the effect of magnetic field on the structure and stability of the rotating plasma.

In the presence of sustained monomorphic ventricular tachycardia (VT), catheter ablation may be an option in congenital heart disease. However, the heterogeneity of underlying congenital heart disease and previous cardiac surgeries is associated with a unique and particularly complex substrate. The aim of the study was to investigate whether preprocedural 3-dimensional anatomic and substrate reconstruction based on cardiac computed tomography scan or magnetic resonance imaging could reliably identify VT substrate and ablation targets. Consecutive patients with cardiac computed tomography or magnetic resonance imaging referred for VT ablation in 5 congenital electrophysiology centers were included. Three observers, electrophysiologists, blinded to the ablation procedure and each other, annotated potential ablation targets on 3-dimensional imaging reconstructions with a dedicated software (InHeart). Once completed, the annotations were compared between observers and with the ablation target(s) on the electroanatomical mapping generated during the procedures. Forty patients (mean age, 38±12 years; 67.5% male) underwent VT ablation, including 28 with a history of spontaneous sustained VT. VT was inducible in 97.5% of cases, with an acute success rate of ablation of 92.5%. Preprocedural imaging identified VT substrate in concordance with electroanatomical mapping in 87.5% of cases. There was a high degree of agreement between the observers. Positive interobserver agreement was complete in 65.0% of cases, moderate in 22.5%, and poor in 5.0%. Considering the total number of isthmuses identified by imaging in comparison with electroanatomical mapping, the sensitivity of imaging was 87.0%, and its positive predictive value was 77.0%. In our series, 3-dimensional anatomic reconstruction enabled identification of the critical VT substrate in most patients with complex congenital heart disease, particularly those with anatomically based reentrant circuits. Substrate target can be identified by operators with good interobserver reproducibility. This approach may guide VT ablation in these challenging cases.

Abstract Background Catheter ablation for ventricular tachycardia (VT) in structural heart disease is often limited by challenges in accurately identifying arrhythmogenic substrates. Cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) enables detailed scar visualization and may improve ablation targeting. In CMR-guided ablation, imaging data are directly integrated into electroanatomical mapping systems, allowing precise scar-based ablation. In contrast, CMR-aided ablation uses CMR data qualitatively to inform but not guide ablation. The comparative effectiveness of these two strategies remains uncertain. Purpose This meta-analysis aims to evaluate clinical outcomes of CMR-guided versus CMR-aided VT ablation. Methods PubMed, Scopus and Cochrane databases were searched for randomized controlled trials and observational studies comparing CMR-guided versus CMR-aided VT ablation in patients with ischemic and non-ischemic cardiomyopathy. Outcomes assessed were: (1) recurrent ventricular tachyarrhythmias at 12 months of follow-up; (2) residual VT after first substrate ablation; (3) complete and partial procedural success; and (4) radiofrequency ablation time and fluoroscopy time. A random-effects model was applied. Risk ratios (RR) with 95% confidence intervals (CI) were calculated for each outcome. Across all analysed variables, Tau² was 0.00 and I² showed 0% heterogeneity with a non-significant Cochran’s Q test result. This strongly reinforces that our results will be consistent with the larger population. Results Three prospective non-randomized studies comprising 386 patients were included, of whom 145 (37.6%) underwent CMR-guided ablation. Mean follow-up ranged from 12 to 20 months. Recurrence of VT at 12 months of follow-up (RR 0.41; 95% CI: 0.32-0.52; Figure 2) was significantly lower in the CMR-guided group and complete procedural success favored CMR-guided ablation (RR 1.13; 95% CI: 1.05-1.21; Figure 3). Residual VT after first substrate ablation (RR 0.54; 95% CI: 0.30-0.99; Figure 4) was also reduced in CMR-guided ablation. Partial procedural success (RR 0.71; 95% CI 0.30-1.66) and unsuccessful procedure (RR 0.54; 95% CI: 0.04-7.67) were not significantly different between groups. Conclusion CMR-guided VT ablation is associated with significantly lower arrhythmia recurrence and higher procedural success compared to aided-CMR. These findings support the integration of CMR in pre-ablation planning for patients with both ischemic and non-ischemic cardiomyopathy.Figure 1.PRISMA flow diagram Figure 2.Forest Plots of Outcomes

Joint replacement is standard of care for chronic knee osteoarthritis, but can cause persistent postsurgical pain. Radiofrequency denervation helps treat chronic knee pain, though its effectiveness is lower in patients with knee arthroplasty than in those with native knees. Our goal was to compare genicular nerve targets in native and prosthetic cadaveric knees and see if targets need modification after arthroplasty. 10 native and 10 prosthetic knees from deceased donors underwent latex arterial injection and detailed dissection of the genicular nerves, comparing their origin, course, target points, diameter, and proximity with arterial blood vessels. Minimal differences among genicular nerve targets were observed between the two groups. The prosthetic knees had fibrotic adhesions of the infrapatellar branch of the saphenous nerve (IPBSN) due to previous surgery, potentially causing postsurgical neuromas and neuritis. The average nerve diameter at target points was smaller in prosthetic than native knees. The distance from the target point to the joint line was shorter for the superomedial genicular nerve in the prosthetic knee group (4.00±0.43 cm vs 4.53±0.75 cm, p=0.005). Nine native and eight prosthetic knees lacked an arterial branch near the target point of the superolateral genicular nerve (SLGN). Prosthetic knees share comparable genicular nerve anatomic locations with native knees but exhibit smaller nerve diameters and fibrosis of the IPBSN. The absence of a nearby arterial branch to the SLGN may reduce ultrasound targeting accuracy. Anatomical differences alone, however, do not fully explain the diminished pain relief observed after radiofrequency ablation.

While very high-power short-duration (vHPSD) ablation has been shown to be safe and effective for ablation of atrial fibrillation, the utility of vHPSD ablation for targeting premature ventricular complexes (PVCs) remains unclear. We aimed to describe our experience of PVC ablation using vHPSD ablation targeting areas with suboptimal catheter contact. We included 8 patients (mean age 66.5 ± 11.3 years, 77% female gender, mean LV ejection fraction 52.8 ± 8.2%, baseline PVC burden 23.3 ± 10.1% [range 9-41%]) with PVCs originating from intracavitary structures [LV papillary muscle(s) (n = 7), RV papillary muscle (n = 1)] which were successfully eliminated with vHPSD ablation using a temperature-controlled ablation catheter (QDOT-MICRO; Biosense Webster, Irvine, California, USA) with lesions delivered at 90 W for 4 seconds using QMODE+ mode. Mean QMODE+ lesions delivered in each patient was 28 ± 15.1 with a mean total QMODE+ RF time of 112 ± 60.4 seconds. There were no procedural complications. Durable PVC suppression was confirmed on post-ablation monitoring in all patients (mean post-ablation PVC burden < 1% [range 0-2.3%]). Ablation with vHPSD using a temperature-controlled radiofrequency ablation catheter can be safe and effective for PVC ablation in regions with poor catheter stability such as RV and LV papillary muscles.

ABSTRACT Silicon carbide nanoparticles (SiC NPs) were synthesized via pulsed Nd: YAG laser ablation of a SiC target in deionized water. With the effects of laser fluence, wavelength and ablation time, a 2.51–12.78 nm size range of nanoparticles was produced. This size range yields an energy gap of 4.74–3.19 eV. FTIR confirmed SiC formation through characteristic bands in the 400–900 cm⁻¹ region, coupled with Si-O-Si and O-H groups formed by partial surface oxidation, while XRD identified the crystalline 6H–SiC polytype. The most stable colloids were obtained at 1064 nm and 4.7 J/cm². EDS verified the presence of Si, C and O. The size-dependent band gap behavior aligned with quantum confinement theory. Overall, the study demonstrates that tuning laser parameters enables controlled synthesis and improved stability of SiC NPs for advanced nanomaterial applications.

Cardiac arrhythmias are a major cause of morbidity and mortality increasing the risk of stroke, heart failure, and sudden cardiac death. Imageless electrocardiographic Imaging has emerged as an accessible non-invasive alternative for cardiac electrical mapping from body surface potentials. However, conventional electrocardiographic imaging is restricted to epicardial reconstructions, reducing its reliability in accurately identifying arrhythmias arising from deeper myocardial structures. We aim to overcome this limitation by reconstructing three-dimensional cardiac activity. We introduce a volumetric formulation, which extends beyond epicardial potential estimation by solving an inverse source problem using Green's functions. This technique enables three-dimensional reconstructions of cardiac activation, improving arrhythmia localization in anatomically complex regions. We evaluate the method on simulated premature ventricular beats and on four patients representing clinical challenges, including a premature ventricular contraction from the right ventricular outflow tract, a left bundle branch block, a ventricular tachycardia, and a Wolff-Parkinson-White. We also assess performance on an open-source dataset for myocardial infarction estimation. Our results indicate that volumetric electrocardiographic imaging reconstructs three-dimensional activation and enhances the localization of arrhythmia origins, yielding a 59.3% reduction in geodesic error between the estimated and simulated origins compared to surface-only approaches. In patient cases, the recovered activation patterns are consistent with the clinical diagnoses. Imageless volumetric electrocardiographic imaging enables non-invasive, accessible, three-dimensional mapping of cardiac activation, addressing a fundamental limitation of surface-restricted methods. This capability may support more accurate pre-procedural planning, may help guide ablation targets, and could refine selection and optimization of cardiac resynchronization therapy candidates.