RF Applications Research Articles

Optimized workflow for pulmonary vein isolation using very high power short duration radiofrequency ablation

Abstract Background Point-by-point radiofrequency ablation is the most used invasive treatment of atrial fibrillation (AF). However, single-shot technologies are largely widespread due to their proved safety and efficacy. QDOT MICRO (QDM) is a novel contact force–sensing catheter optimized for temperature-controlled radiofrequency (RF) ablation that allows to maintain target temperature during 90 W ablations for ≤4 seconds. Purpose This study evaluates procedural safety and effectiveness as well as long-term effects of an optimized procedural workflow using QDM catheter to perform wide atrial circumferential ablation in patients with paroxysmal AF. Methods Consecutive patients referred for paroxysmal AF first ablation through pulmonary vein isolation (PVI) were prospectively enrolled. Every procedure was performed in general anesthesia by using CARTO3 Electroanatomical Mapping System BiosenseWebster QDM catheter and Deflectable Sheet VIZIGO as single sheet in left atrium. VHPSD was performed to encircling the posterior wall, while conventional-power temperature-controlled (CPTC) mode was used to encircling the anterior wall. The primary safety endpoint was incidence of primary adverse events within ≤7 days of ablation. The primary effectiveness endpoint was freedom from documented atrial tachyarrhythmia recurrence and acute procedural, repeat ablation, and antiarrhythmic drug failure. Results 120 enrolled participants (61 ± 12 years, 45% female) met eligibility criteria. Median procedural skin-to-skin time and RF application for ablating PVs were 56 and 17 minutes, respectively. Median ablation time was 22 minutes. First-pass isolation (entrance and exit block validation) was obtained in 98 % and inter-lesion distance was 4,8 ± 0,8 mm. In 100% of patients PVI was obtained without adverse events. The Kaplan-Meier estimated 12-month rate for clinical success (freedom from symptomatic recurrence of AF) was 93%, freedom from AF was 89% Conclusions PVI performed with point by point optimized workflow using VHPSD RF catheter in combination with steerable sheet is highly efficient and effective without compromising safety.

Differential and synergistic effects of left and right atrial ablation of paraseptal ganglionated plexuses in a cohort of consecutive patients undergoing cardioneuroablation

Abstract Background Cardioneuroablation (CNA) treats reflex syncope by ablating the main epicardial ganglionated plexuses (GPs) conveying vagal outputs to the sino-atrial (SA) and atrio-ventricular (AV) nodes. The two main GPs, superior paraseptal (SPSGP) and inferior paraseptal (IPSGP), regulate vagal tone to SA and AV nodes, respectively. Both GPs can be targeted with radiofrequency energy (RF) from the right (RA) and left atrium (LA). It is unclear if bi-atrial ablation yields more effective GP ablation or if the ablation sequence affects GP response. Purpose We aimed to assess the added efficacy of ablating the SPSGP and IPSGP in the LA after initial RA ablation, and vice versa, in a separate group of patients. Methods In a consecutive patient population undergoing CNA we evaluated the acute efficacy of RF delivery on the SPSGP and the IPSGP. The population was divided into two consecutive groups: one receiving RF initially in the RA and then in the LA (group 1), and the other in the reverse order (group 2). The acute effect of RF applications was measured as percentage increase in heart rate (HR) for the SPSGP and as reduction of PR interval for the IPSGP. Results Sixty-one patients (50±15 years; 61% males) underwent CNA. Of these, 17 underwent ablation of the SPSGP and IPSGP starting from the RA and completing the procedure in the LA (group 1), while in 44 patients, the procedure was performed in the opposite order (group 2). In group 1, RF delivery on the SPSGP from the RA prompted an increase in HR (54.1±11.1 vs 60.6±14.7 bpm; p=0.03; median HR increment 3.8%, IQR 0-38.3) that was further enhanced after LA ablation (from 57.5±11.9 to 64.5±13.5 bpm; p<0.001; median HR increment: 8.0%, IQR: 2.0-13.5). In group 1, RA ablation of the IPSGP reduced PR interval in a single patient (from 224 to 184 ms), without further shortening after LA ablation. Final CNA success was 82% in group 1. In group 2, RF delivery on the SPSGP from the LA induced a marked increase in HR (58.4±13.1 vs 76.8±16.1 bpm; p<0.001; median HR increase 30.0%, IQR 14.0-43.0). In the same patients, additional ablation from the RA prompted further but lower incremental effect (from 70.0±17.3 to 76.9±17.9 bpm; p<0.001; median HR increment 8.3%, IQR: 0-16.4). In group 2, 4 (9%) patients had PR shortening after LA ablation of the IPSGP (241±93 vs 172±14 ms; p value). Of these, a single patient had further PR reduction after IPSGP RA ablation (from 189 to 161 bpm). Final CNA success was 93% in group 2. Symptoms-free survival was 88% at 16±5 months in group 1 and 89% at 19±7 months in group 2 (p= ns). Conclusions Bi-atrial ablation of the SPSGP and IPSGP provides incremental acute efficacy compared to ablation from either the RA or the LA alone. LA ablation of the main GPs seems an essential component of CNA. The physiological significance of these findings requires further investigationGanglionated Plexuses Segmentation

Left atrial appendage clipping during hybrid atrial fibrillation ablation: a very long-term, single-center experience

Abstract Background/introduction Epicardial left atrial appendage (LAA) clipping is an effective strategy for stroke prophylaxis in high thromboembolic (TE) and bleeding risk patients with atrial fibrillation (AF). In addition to LAA exclusion from systemic circulation, clipping promotes concomitant appendage isolation, which might have positive impacts on arrhythmia control. Purpose The aim of this study was to report safety, success rate, and the long-term clinical outcomes of LAA clipping in a large cohort of AF patients undergoing concomitant hybrid ablation. Methods Consecutive patients undergoing hybrid AF ablation between 2013 and 2023 were enrolled. Hybrid ablation was performed in a one-step procedure consisting of thoracoscopic epicardial radiofrequency (RF) ablation followed by endocardial mapping and ablation, if needed. Ablation lesion set included pulmonary vein (PV) and posterior wall (PW) isolation, as well as RF applications to the LAA/posterolateral ridge. LAA clipping was performed via Atriclip exclusion system (Atricure, Inc., The Nederlands) after epicardial ablation. Additional endocardial lesions were performed in case of incomplete epicardial ablation or at physician’s discretion. Results A total of 130 patients were included (mean age: 65±9.4; 72.3% males); among them, 19.2% and 55.4% had persistent or long-standing persistent AF, respectively. Mean CHA2DS2-VASC and HAS-BLED were 3.1±1.1 and 2.3+-0.5. Five patients (3.8 %) had absolute contraindication to long-term oral anticoagulation, 3 (2.3%) had previous life-threatening bleeding events, 17 (13.1%) had a previous TE event. The final clip size was 35mm in 90.7% cases. Acute success was achieved in 97.7%; failure was due to LAA size (n=1), proximity to phrenic nerve (n=1), or bypass graft (n=1). One patient had incomplete occlusion due to a large secondary lobe, which required a second clip. No periprocedural complications related to clipping were documented. At a mean follow-up of 51±35 months, one (0.8%) patient had a stroke and 3 (2.3%) a transient ischemic attack (4 events per 552 patient/years; 0.7%). One patient had a microreentrant tachycardia mapped from the area near the LAA clipping. Conclusion In a large cohort undergoing hybrid AF ablation, epicardial LAA clipping was safe and highly successful. Acute failure was rare and due to LAA morphology or proximity to phrenic nerve and bypass graft. Thromboembolic event rate was very low.

Catheter ablation of papillary muscle arrhythmias: procedural characteristics and long term outcome

Abstract Background Ventricular arrhythmias (VA) originating from the papillary muscles can occur both in patients with and without structural heart disease. Although catheter ablation is the treatment of choice, ablation success remains challenging and long-term outcomes for this origin of VA are still unsatisfactory. Methods and Results All patients undergoing catheter ablation for premature ventricular contractions or ventricular tachycardia between june 2009 and november 2022 were analyzed. 66 patients (26 female (39%), mean age 60±15 years) undergoing catheter ablation of VA originating from the papillary muscle were identified. 21/66 (32%) patients had a reduced or mildly reduced left ventricular ejection fraction at time of initial presentation. While mitral valve regurgitation was present in 32/66 (48%) patients, mitral valve prolapse was observed in only 2/66 (3%) patients. 6/66 (9%) patients presented with non-sustained ventricular tachycardia (VT) and 1/66 (2%) patient presented with sustainend VT prior to catheter ablation. 61/66 (92%) patients underwent ablation of PVCs of the left ventricular papillary muscles (22/66 (33%) patients anterolateral; 39 (59%) patients posteromedial). 5/66 patients underwent ablation of premature ventricular complex (PVC) originating from the papillary muscles of the right ventricle. In 13/66 (19.7%) patients only a retrograde approach was used, in 26/66 (39.5%) patients a retrograde and an additional transeptal approach and in only 10/66 (15.2%) patients solely a transeptal approach. Mean PVC QRS duration was 152.5 ± 3.5 msec. Ablation was acutely successful in 44/66 (67%) patients. Mean procedure time was 145.8 ± 63.7 minutes and mean number of radiofrequency applications was 21.3 ± 16.7 (25 to 55 Watts, 37764.2 ± 27824.1 Joules). Overall, procedural complications occurred in 4/66 (6%) patients Follow up data were obtained from Holter ECGs, review of medical records, patient consultation, or via structured follow-up within the prospective TRUST registry. All information was combined to assess recurrence of PVC/VT. Recurrence of VA originating from the papillary muscles occurred in 11/66 (17%) patients. 9/66 patients (14%) underwent re-ablation due to recurrence of VA originating from the papillary muscles after previous ablation procedures. Conclusion Catheter ablation of papillary muscle arrhythmias is associated with a single procedural success rate of 67% with a procedural complication rate of 6%. 14% of patients underwent re-ablation due to recurrence of papillary muscle arrhythmias.

Feasibility of catheter ablation with zero-fluoroscopy in congenital heart disease

Abstract Background Catheter ablation (CA) with zero and near-zero fluoroscopy has been shown to be safe and effective in patients (pts) without structural heart disease, but there are limited data regarding CA in congenital heart disease (CHD). Aim Our aim was to compare the safety and outcome of zero-fluoroscopy (ZF) and fluoroscopy (non-ZF) CA of CHD pts. Methods This is a single-center retrospective study of CHD pts who underwent CA at our center between 2006-2020. The ZF and non-ZF groups were compared for the complexity of anatomy, arrhythmia substrate, difficulties of vascular access, transseptal or transbaffle puncture, intracardiac pacemaker/ICD, procedural parameters, complications, and acute outcome. Near-ZF CAs (effective dose ≤1 mSv) were assigned to the ZF group. Results The ZF group included 22 pts (age: 22±13 years) and the non-ZF group 48 pts (age: 31±12 years). The distribution of CHD anatomical complexity (mild/moderate/severe) was 18.2%-68.2%-13.6% in the ZF group and 14.6%-68.7%-16.7% in the non-ZF group. Arrhythmia diagnoses were focal atrial tachycardia (ZF: 4.6%), atrial flutter (ZF: 45.4%, non-ZF: 75.0%), atrioventricular reentry tachycardia (AVRT) via manifest accessory pathway (AP) (ZF: 31.8%, non-ZF: 10.4%), AVRT via concealed AP (ZF: 4.6%, non-ZF: 8.3%), and atrioventricular nodal reentry tachycardia (ZF: 13.6%, non-ZF: 6.3%). Difficulties in vascular access occurred in 4.5% of the ZF group and 18.8% of the non-ZF group (p=0.10). The rate of transseptal/transbaffle puncture was significantly higher in the non-ZF group (22.9% vs. 4.6%, p=0.04). In the ZF group 13.6% and in the non-ZF group 20.8% of pts had pacemaker or ICD (p=0.22). Electroanatomical mapping was used in all CAs in both groups. There was no significant difference in procedure time, ablation time and the number of radiofrequency applications (ZF group: 169±53 min, 1205±906 sec, 28±15 vs. non-ZF group: 203±74 min, 1459±940 sec, 34±16, p>0.05). The acute success rate was 100% in both groups. No complications occurred in any group. Conclusion Zero fluoroscopic CA was feasible in 1/3 of the pts with CHD and as safe and effective as fluoroscopic ablation. No significant differences were found in the non-fluroscopy related procedural data between the two groups.

Long-term outcome after catheter ablation for fascicular ventricular tachycardia in a single high-volume center in Germany

Abstract Background Idiopathic Fascicular Ventricular Tachycardia (IFVT) accounts for less than 10% of all VTs and represents the most common idiopathic ventricular tachycardia of the left ventricle. This study reports on clinical and procedural characteristics and the long-term outcome of patients undergoing catheter ablation of premature ventricular complexes (PVC) and ventricular tachycardias (VTs) arising in proximity of the left ventricular conduction system. Methods and results This study includes 27 patients (17 male, 45 ± 17 years; 10 females, 50 ± 11 years) who underwent electrophysiological examinations at a tertiary ablation center over a period of 14 years (2009 to 2022). Follow-up was performed via regular Holter-ECGs and clinical evaluations, or via structured follow-up within the prospective TRUST registry. In 21/27 patients (77.8%), the left posterior fascicle (LPF) was involved in the IFVT. In 4 (14.8%) the left anterior fascicle (LAF) was involved and in 2 (7.4%) patients an origin in the upper septal (US) area was demonstrated. 22/27 (81.5%) patients had a preserved left ventricular ejection fraction (LVEF) and only 5 (18.5%) patients had a LVEF less than 50% at the time of presentation. 14/27 (51.9%) patients presented with PVC or non-sustained VTs with the following distribution: 10 (71.4%) originating from the LPF, 3 (21.4%) from the LAF and 1 (7.1%) from the US. 21/27 (77.8%) patients presented with sustained VTs: 16 (76.2%) arising from the LPF, 4 (19%) from the LAF and 1 (4.8%) from the US. However, only 2 (7.4%) patients presented in sustained VT at the beginning of the EP procedure. In 16 (59.3%) patients a sustained VT was induced during the EP study via isoprenaline and/or programmed ventricular stimulation. Mean QRS duration of the VT was 124.5 ± 14.6 msec. In 21 (77.7%) patients only a retrograde approach was used, in 3 (11.1%) patients a retrograde and an additional transeptal approach and in only 3 (11.1%) patients solely a transeptal approach. Mean number of radiofrequency applications was 11.8 ± 12.6 (30 to 40 Watts, 27545.6 ± 30524.4 Joules). FVT ablation was acutely successful in 24 patients (88.9%). In 2 patients (7.4%) no ablation was performed due to inability to induce VT under sedation. 3/27 patients (11.1%) underwent re-ablation due to FVT recurrence after previous ablation procedures. Moreover, 3 (11.1%) additional patients underwent repeated VT ablations during follow-up, but the arrhythmia originated from a different LV area. No procedure-related complication occurred. In 4 patients (14.8%) left fascicular posterior block was caused by ablation and in 3 (11.1%) patients a complete left bundle block. Mean procedure time was 130 ± 48.9 minutes. Conclusion Ablation of FVT in a tertiary ablation center is associated with a high single procedural success rate of 88.9% during long-term follow-up, with a mild risk of fascicular injury. 11.1% of patients underwent re-ablation due to FVT recurrence.

A proposed index of myocardial staining for vein of marshall ethanol infusion

Abstract Background Mitral isthmus(MI) conduction block is a fundamental step in anatomical approach treatment for persistent atrial fibrillation(PeAF). However, MI block is hardly achievable with endocardial ablation only. Retrograde ethanol infusion(EI) into the vein of Marshall(VOM) facilitates MI block. Fluorographic myocardial staining(MS) during VOM-EI could be helpful in predicting procedural alcoholization outcome even if its role is qualitatively assessed in the routine. Purpose The aim was to quantitatively assess MS during VOM-EI and to evaluate its association with MI block achievement. Methods Consecutive patients undergoing catheter ablation for PeAF at our Institution from February 2022 to May 2023 were considered. Patients with identifiable VOM were included. A proposed index of MS(MSI) was retrospectively calculated in each included patient. Correlation of MSI with low voltage zones(LVZ) extension after VOM-EI and its association with MI block achievement were assessed. Results 42 patients out of 49 (85.8%) had an identifiable VOM. MI block was successfully achieved in 35 patients out of 42 (83.3%). MSI was significantly associated with the occurrence of MI block (OR 1.24 (1.03 – 1.48); p = 0.022). A higher MSI resulted in reduced ablation time (p = 0.014) and reduced radiofrequency applications (p = 0.002) to obtain MI block. MSI was also associated with MI block obtained by endocardial ablation only (OR 1.07 (1.02 – 1.13); p = 0.002). MSI was highly correlated with newly formed LVZ extension (r = 0.776; p = 0.001). Conclusion In our study cohort, optimal MSI predicts MI block and facilitates its achievement with endocardial ablation only.Myocardial stainingSpline plots

Using the impedance map to identify non-conductive structures during cavo-tricuspidal isthmus ablation

Abstract Background The ablation of the cavo-tricuspidal isthmus (CTI) is often affected by the anatomical variability of structures made of non-conductive tissue (NCS): the Eustachian valve, tricuspid valve leaflet and Tebesio's valve, the presence of which may be associated with failure of the isthmic block despite a large number of erogations and post-ablation recurrences. Since these structures have different conductive properties from atrial tissue, it is plausible that they are characterised by their own tissue impedance, and can therefore be identified through an impedance map. Objectives The objectives of the study were: 1) to characterise CTI by impedance map, in order to identify NCS; 2) to perform ablation of CTI aimed at isolating only conductive tissue by combining impedance map with the Maximum Voltage Gradient (MVG) technique, in order to evaluate the efficacy of this strategy in acute and during follow-up. Methods From 01/2021 to 09/2023 impedance map and CTI substrate map was performed, without the use of fluoroscopy, in all patients undergoing ablation of typical atrial flutter. A 15-ohm impedance reduction from the mean atrial impedance was considered the cut-off for defining the presence of NCS. Substrate maps were constructed according to the MVG technique (0.5-2.5 mV thresholds), in particular looking for high-voltage channels in which the impedance map detected the presence of NCS. Ablation was performed only in the high-voltage channels (W45, AI500). Results Our study included 48 patients with a mean age of 68±13 years, with 92% of them being men. The mean volume of the right atrium was 153 mL, and the mean number of points per map was 1205. With the use of impedence map, we were able to identify the presence of NCS in 25 patients (52%). The distribution of non conductive structures and the mean voltage by quadrants can be seen in Figures B-C. Importantly, we found that the mean number of radiofrequency applications required to achieve isthmic block was significantly lower in patients with identified NCS compared to those without (6.3 vs. 10; p=0.007). In 60% of the patients with NCS, radiofrequency was administered in high-voltage channels that were detected in the quadrant where the NCS was present (odds ratio 3.42, p=0.04). Furthermore, we successfully achieved acute isthmic blockade in all patients, and there were no instances of recurrence during a mean follow-up period of 186 days. Conclusions Our findings demonstrate that the combination of Impedence Map and the Maximum Voltage Gradient technique is an effective approach for achieving isthmic block with a reduced number of radiofrequency applications. The identification of NCS allows for a more precise search for high-voltage channels, enabling ablations to be performed in optimal contact with the tissue. This meticulous approach is crucial for the success of the procedure.

Local ablative procedures for treatment of thyroid nodules

Thyroid nodules are very frequent in the iodine deficiency regions of central Europe and some of the affected patients are referred for definitive treatment, such as surgery and radioiodine treatment. In recent years nonsurgical and non-radioiodine techniques have been introduced to treat thyroid gland pathologies. These techniques include the probe-based techniques of radiofrequency, microwave and laser application. The only noninvasive technique is high-intensity focused ultrasound. All mentioned techniques have the goal to reduce the volume of the thyroid nodule by application of energy/heat. The knowledge of all techniques and their advantages and risks is necessary to help physicians and patients in making decisions for the appropriate method of treatment of thyroid nodules.

Low insertion loss interposer approach for RF applications based on commercial LTCC tape, alkaline-free glass and printed metallization

Materials with high RF performance are in increasing demand due to the needs of modern telecommunications. Glass and low-temperature co-fired ceramics (LTCCs) are both interesting candidates for the design of complex signal transmission systems. Glass can be processed in large panels, and has suitable structure dimensions for silicon processing, but its multilayer capability is limited. LTCC is a mature technology for complex multilayer assemblies, but the structure dimensions and conductor line resolution are restricted by the need to use screen printing technology. The approach presented here combines the advantages of both technological domains: a thin glass sheet is bonded with no additional material to a LTCC multilayer ceramic and sintered to form a tight joint. Metallization of the glass is created using printable pastes and electroplating. Two fabrication routes are compared: etching of printed thick film metal layers, and semi-additive structuring. The results of RF measurements show a low attenuation per unit length for both types of metallization, indicating that our approach is a promising one for the integration of heterogeneous systems of RF transmission modules.

ATRIAL VOLTAGE ANALYSIS FOLLOWING VEIN OF MARSHALL ETHANOL INFUSION PREDICTS MITRAL LINE BLOCK

Abstract Background The vein of Marshall (VoM) is a promising target for atrial fibrillation (AF) treatment, matching with the ‘Coumel triangle‘ by housing triggers, autonomic connections, and serving as a substrate for perimitral flutters. Lateral mitral line (ML) represents a fundamental part for AF treatment, but achieving bidirectional block through endocardial ablations is challenging. VoM ethanol infusion (VOM–EI) facilitates ML block, with the newly–formed bipolar lesion serving as an effectiveness index. Voltage analysis assessment after VOM–EI in predicting ML block is poorly investigated. Purpose To compare unipolar and bipolar low–voltage areas (LVAs) along VOM trajectory after VOM–EI, and their role in predicting ML block. Methods We enrolled 59 patients undergoing catheter ablation of persistent AF or ML–dependent atrial flutter. High–density voltage mapping of left atrium was followed by VOM–EI and LA remapping. The area width difference was obtained and defined as ΔLVA. Normal bipolar voltage cutoffs were 0.50 mV in sinus rhythm or 0.29 mV in AF. Unipolar cutoffs were 2.7 mV and 1.1 mV, respectively. After VOM–EI, anatomical lesions included PVI, linear lesion for dome and ML isthmus. Systematic lines block validation was performed, defining ML block after coronary sinus (CS) electrograms sequence inversion (septal–to–lateral) during left atrial appendage pacing. Radiofrequency (RF) applications into the CS–great cardiac vein targeted epicardial gaps if present. Ablation time for ML block (AblTime) was obtained. Results In our cohort, 94.5% achieved ML block. Bipolar and unipolar low voltage areas after VOM–EI were 9,9 ± 6,9 cm2 and 12,2 ± 5,9 cm2 respectively. Bipolar ΔLVAs were significantly lower than unipolar ΔLVA (8.2 ± 6.5 cm2 vs. 9.4 ± 6.0 cm2; p=0.03) (Fig 1). A strong linear correlation between AblTime and bipolar ΔLVA (R: 0.76), and a significant correlation between AblTime and unipolar ΔLVA (R: 0.6) were found (Fig 2). Patients requiring RF applications into the CS for ML block (13/59, 22%) showed lower ΔLVAs in logistic regression for both bipolar (p<0.01) and unipolar (p=0.03) analyses. Conclusions VOM–EI induces unipolar LVAs wider than bipolar along the mitral isthmus trajectory. Unipolar and bipolar voltage analysis predicts a short time ML block achievement. Moreover, wider unipolar and bipolar LVAs following VOM–EI correlates with higher likelihood to avoid the targeting of epicardial gaps via the CS musculature.

First Demonstration of High‐Frequency InAlN/GaN High‐Electron‐Mobility Transistor Using GaN‐on‐Insulator Technology via 200 mm Wafer Bonding

In0.17Al0.83N/GaN high‐electron‐mobility transistor (HEMT) using GaN‐on‐Insulator (GaNOI) technology via 200 mm wafer bonding technique is developed with good DC and RF performance and high fT/fmax. Measurements obtained from X‐Ray diffraction and micro‐Raman spectroscopy have demonstrated a 5% reduction in “a lattice strain,” which results in the improvement of the sheet resistance (Rsh) from 301 to 284 Ω □−1. A 120 nm gate‐length device achieves a peak fT up to 96 GHz which yields a fT × Lg value of 11.5 GHz μm, which compares favorably with reported GaN‐based HEMTs on Si. These results demonstrate that GaNOI HEMT on Si is an attractive candidate for future mm‐wave applications. The implementation of GaNOI technology facilitates the integration of GaN devices into a chip alongside complementary metal–oxide–semiconductor technology that opens up the potential for integrated high‐power and RF applications, enabling more compact and efficient systems.

Bipolar Radiofrequency and Non-Crosslinked Hyaluronic Acid Plus Calcium Hydroxyapatite in the Treatment of Stress Urinary Incontinence.

Stress urinary incontinence (SUI) causes both physical and psychological problems to women and their partners. Recently, vaginal radiofrequency (RF) application, as well as the administration of non-crosslinked hyaluronic acid (NCLHA) together with calcium hydroxyapatite (CaHA), has attracted attention for SUI treatment. The current, comparative study evaluated the efficacy and safety of these technologies acting separately and in a combined treatment. Sixty women with mild to moderate SUI, aged between 46 and 76 years (mean age 63.2) were divided into three groups intended for different treatments: group I, RF vaginal treatment only, group II, NCLHA plus CaHA periurethral injection only, group III, combined treatment including a single periurethral injection of NCLHA plus CaHA followed by four vaginal applications of RF at intervals of 3-5 days. The clinical effects of the treatments were evaluated by ICIQ-LUTSqol (Polish version) and UDI-6. The obtained results suggest that the symptoms of SUI and the quality of life of the patients improved significantly in each group after the therapies compared to the pre-treatment levels and were more persistent in the third HA + RF group compared to the HA or the RF group.

Radiofrequency ablation-Real-time visualization of lesions and their correlation with underlying parameters.

Lesion durability and transmurality are crucial for successful radiofrequency (RF) ablation. This study provides a model of real-time RF lesion visualization and insights into the role of underlying parameters, as local impedance (LI). A force-sensing, LI-sensing catheter was used for lesion creation in an ex vivo model involving cross-sections of porcine cardiac preparations. During 60 s of RF application, one measurement per second was performed regarding lesion size and available ablation parameters. In total, 1847 measurements from n=36 lesions were performed. Power (20-50W) and contact force (1-5g, 10-15g, 20-25g) were systematically alternated. Lesion formation was most prominent in the first seconds of RF application during which nonlinear lesion growth was observed (max. 1.08mm/s for lesion depth and 2.71mm/s for lesion diameter). Power levels determined the extent of lesion formation in the early phase. After 20 s, lesion size growth velocity approaches 0.1mm/s at all power levels. LI changes were also highest in the first seconds (up to - 12 Ω/s) and decreased to less than - 0.1Ω/s after prolonged application. Lesion formation in irrigated RF ablation is a nonlinear process. Final lesion size resulting from an RF application is mainly influenced by high rates of lesion growth in the first seconds of ablation. LI seems to be a good surrogate for differentiating changes in lesion formation.

Enhancing the quality factor of aerosol jet printed RF spiral inductors through gold electroplating

Aerosol jet printing (AJP) outperforms inkjet printing by significantly reducing printed line width, effectively addressing issues such as bulging and surface irregularities. This technology allows for line widths as narrow as 10–100 μm with high aspect ratios, making it well-suited for radio frequency (RF) applications. Consequently, AJP emerges as a valuable tool for direct printing in RF applications. Among conductive inks, silver nanoparticle (Ag-NP) ink is preferred for its straightforward direct printing process and lower sintering temperature requirements. However, the conductivity of printed Ag NP traces falls markedly below that of bulk silver due to significant porosity, limiting its use in RF applications where a high-quality factor is essential. The quality factor of an inductor, indicative of its efficiency in energy storage and release, inversely correlates with its resistance. Our research combines AJP with selective electroplating to reduce the resistance of printed traces, thereby enhancing the inductor’s quality factor for RF applications. We fabricated spiral inductors on alumina substrates using silver NP ink and subsequently applied selective gold electroplating to these traces. This approach led to a significant increase in the inductors’ quality factor, improving it by a factor of 3–5 in the RF frequency range of 100–700 MHz.

Peak frequency annotation algorithm–guided slow pathway ablation in typical atrioventricular nodal reentrant tachycardia

BackgroundThe slow pathway potential is difficult to annotate because it is buried within the atrial potential. Omnipolar technology near field can automatically annotate the peak frequency potential associated with acquired intracardiac electrograms. ObjectivesThis study aimed to visualize the junction between the transitional cells and the slow pathway using a peak frequency map with omnipolar technology near field and evaluate whether the high-frequency site around the tricuspid annulus (TA) is an effective target for slow pathway ablation. MethodsThis prospective observational study enrolled 37 patients with typical atrioventricular nodal reentrant tachycardia. Patients underwent slow pathway ablation using a peak frequency map (n = 17) and the conventional approach based on anatomical and electrophysiological findings (n = 20). ResultsHigh-frequency sites were distributed at the TA side of the 4–5 o’clock position in all patients mapped using the peak frequency map of OTNF. The distance to the His bundle from the successful ablation site was farther (24.0 ± 4.8 mm vs 12.7 ± 4.0 mm; P < .0001), junctional rhythm was slower (88 ± 17 beats/min vs 115 ± 12 beats/min; P < .0001), the time to junctional rhythm after radiofrequency application was shorter (3.4 ± 1.4 seconds vs 8.2 ± 4.6 seconds; P < .0001), and the elimination rate of jump ups (71% vs 30%; P = .02) was higher in the peak frequency map–guided group. ConclusionThe high-frequency site of the TA at 4–5 o’clock in the peak frequency map could be a novel target of slow pathway ablation with high safety, efficiency, and efficacy.

Effect of rare earth doping on the electromagnetic response of hard ferrites SrFe12O19 for potential application in high-frequency devices

This work explores the synthesis, characterization, and potential application of rare earth doping on hard ferrites, focusing on their unique electromagnetic properties for potential applications in radio frequency (RF) devices. This study investigates the influence of rare earth (Sm+3) doping on structural and dielectric properties of strontium ferrite. Samarium doped strontium ferrite with composition Sr1-xSmxFe12O19(x = 0.0,0.1,0.2,0.3) is prepared using the sol-gel auto combustion technique. The prepared samples' crystal structural and morphological properties were studied using an X-ray diffractometer (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and RAMAN spectroscopy. XRD patterns of rare earth substituted strontium ferrite confirmed the formation of a hexagonal phase together with an impurity phase of Fe2O3 for x = 0.3. FTIR analysis establishes metal and Oxygen (M-O) stretching vibrations in Sr1-xSmxFe12O19 due to various interstitial sites in its structure. The Raman result shows the presence of four Raman active modes in prepared powders. Meanwhile, the broadening of Raman peaks with Sm2+ doping is also observed. Electromagnetic properties were obtained in the frequency region 2–18 GHz. An increasing tendency is observed in the real part of permittivity and permeability of all doped samples in the frequency region 2–18 GHz. The reflection loss was observed for sample x = 0.2 with the maximum value of > -40 dB at 18 GHz, and the adequate absorption bandwidth is 10 GHz from 8 GHz to above 18 GHz. On the basis of these results, among all prepared samples, Sr0.8Sm0.2 Fe12O19 is found to be the most suitable candidate for microwave absorbers.

Coplanar Waveguide (CPW) Loaded with Symmetric Circular and Polygonal Split-Ring Resonator (SRR) Shapes

This paper investigates the performance of coplanar waveguide (CPW) structures loaded with symmetric circular and polygonal split-ring resonators (SRRs) for microwave and RF applications, leveraging their unique electromagnetic properties. These properties make them suitable for metamaterials, sensors, filters, resonators, antennas, and communication systems. The objectives of this study are to analyze the impact of different SRR shapes on the transmission characteristics of CPWs and to explore their potential for realizing compact and efficient microwave components. The CPW-SRR structures are fabricated on a dielectric substrate, and their transmission properties and spectrogram are experimentally characterized in the frequency range of 4 GHz to 10 GHz with the rotation angles of the SRR gap. The simulation results demonstrate that the resonant frequencies and magnitude of the transmission coefficient of the CPW-SRR structures are influenced by the geometry of the SRR shapes and the rotation angles of the SRR gap, with certain shapes exhibiting enhanced performance characteristics compared to others. Moreover, the symmetric circular and polygonal SRRs offer design flexibility and enable the realization of miniaturized microwave components with improved performance metrics. Overall, this study provides valuable insights into the design and optimization of CPW-based microwave circuits utilizing symmetric SRR shapes, paving the way for advancements in the miniaturization and integration of RF systems.

RFID Tags for On-Metal Applications: A Brief Survey

Radio-frequency identification technology finds extensive use in various industrial applications, including those involving metallic surfaces. The integration of radio-frequency identification systems with metal surfaces, such as those found in the automotive sector, presents distinct challenges that can notably affect system efficacy due to metal’s tendency to reflect electromagnetic waves, thus degrading the functionality of conventional radio-frequency identification tags. This highlights the importance of conducting research into academic publications and patents to grasp the current advancements and challenges in this field, aiming to improve the applications of radio-frequency identification tags technology on metal. Consequently, this research undertakes a concise review of both the literature and patents exploring radio-frequency identification technology’s use for on-metal tags, utilizing resources like Google Scholar and Google Patents. The research categorized crucial aspects such as tag flexibility, operating frequency, and geographic origins of the research. Findings highlight China’s prominent role in contributing to metal-focused radio-frequency identification tag research, with a considerable volume of articles and patents. In particular, flexible tags and the Ultra-High Frequency range are dominant in both scholarly and patent documents, reflecting their significance in radio-frequency identification technology applications. The research underscores a vibrant area of development within radio-frequency identification technology, with continued innovation driven by specific industrial needs. Despite the noted advances, the presence of a significant percentage of no longer valid patents suggests substantial opportunities for further research and innovation in radio-frequency identification technology for on-metal applications, especially considering the demand for flexible tags and for solutions in systems that offer specialized characteristics or are tailored for specific uses.

An optimized approach for increasing lesion size in temperature‐controled setting using a catheter with a surface thermocouple and efficient irrigation

AbstractBackgroundWe explore an optimized approach for increasing lesion size using a novel ablation catheter with a surface thermocouple and efficient irrigation in a temperature‐control setting.MethodsWe conducted radiofrequency applications at various power levels (35 W, 40 W, and 45 W), contact forces (CFs, 10 g/20 g), and durations (60 s/120 s/180 s) in perpendicular/parallel catheter orientations, with normal saline irrigation (NS‐irrigation) and Half NS‐irrigation (HNS‐irrigation) in an ex‐vivo model (Step 1). In addition, we performed applications (35 W/40 W/45 W for 60 s/120 s/180 s in NS‐irrigation and 35 W/40 W for 60 s/120 s/180 s in HNS‐irrigation) in four swine (Step 2), evaluating lesion characteristics and the occurrence of steam pops.ResultsIn Step 1, out of 288 lesions, we observed 47 (16.3%) steam pops, with 13 in NS‐irrigation and 34 in HNS‐irrigation (p = .001). Although steam pops were mostly observed with the most aggressive setting (45 W/180 s, 54%) with NS‐irrigation, they happened in less aggressive settings with HNS irrigation. Lesion size significantly increased with longer‐duration ablation but not with HNS‐irrigation. The optimal %impedance‐drop cutoff to predict steam pops was 20% with a negative‐predictive‐value (NPV) = 95.1% including NS‐ and HNS‐irrigation groups, and 22% with an NPV = 96.1% in NS‐irrigation group. In Step 2, similar to the ex‐vivo model, lesion size significantly increased with longer‐duration ablation but not with HNS‐irrigation. Steam pops were absent with NS‐irrigation (0/35) even with the largest %impedance‐drop reaching 31% at 45 W/180 s. All steam pops were observed with HNS‐irrigation (6/21, 29%). The optimal %impedance‐drop cutoff predicting steam pops was 24% with an NPV = 96.3% including both NS‐ and HNS‐irrigation groups.ConclusionsRather than using HNS‐irrigation, very long‐duration of radiofrequency applications up to 45 W/180 s may be recommended to safely and effectively increase lesion dimensions using this catheter with NS‐irrigation.