Application Of Radiofrequency Energy Research Articles

Application of radio frequency energy in processing of fruit and vegetable products.

Thermal processing is commonly employed to ensure the quality and extend the shelf-life of fruits and vegetables. Radio frequency (RF) heating has been used as a promising alternative treatment to replace conventional thermal processing methods with advantages of rapid, volumetric, and deep penetration heating characteristics. This article provides comprehensive information regarding RF heating uniformity and applications in processing of fruit and vegetable products, including disinfestation, blanching, drying, and pasteurization. The dielectric properties of fruits and vegetables and their products have also been summarized. In addition, recommendations for future research on RF heating are proposed to enhance practical applications for fruits and vegetables processing in future.

Transcoronary guidewire ablation with radiofrequency in a porcine animal model.

Transcoronary ablation of septal hypertrophy (TASH) and surgical myectomy are the recommended treatment options for patients with hypertrophic obstructive cardiomyopathy refractory (HOCM) when conventional drug treatment is not sufficient. We describe the application of radiofrequency (RF) energy via coronary guidewires in an animal model for selective occlusion of coronary side branches that mimics the principle of TASH. Transcoronary guidewire ablation of coronary vessels was performed in 5 adult pigs under general anaesthesia in an animal cathlab after successful bench testing of the ablation settings. After assessing transcoronary pacing parameters, RF energy was delivered via coronary guidewires insulated by coating or by a monorail balloon and positioned in different coronary side branches. Occlusion or patency of the specific coronary side branch was documented by coronary angiography after RF delivery. After the transcoronary RF ablation, the intended occlusion of the coronary vessel (thrombolysis in myocardial infarction [TIMI]-0 or TIMI-1 flow) could be verified by angiography in 82% of the septal branches attempted and 79% of the epicardial branches. The mean ablation duration was 10.3 seconds at 20-W power with an initial impedance of 176 ± 31 Ώ. No unintended occlusion of the main vessels occurred in any case. RF ablation via coronary guidewires is a feasible method for inducing an acute occlusion of coronary vessels and may change the interventional therapy of HOCM if the current limitations of this technique are overcome.

The benefits of ablation using TactiFlex compared with TactiCath in an ex vivo model: a face-to-face experimental comparison study.

TactiFlex is a next-generation catheter that is being used increasingly in ablation-treatment strategies. The purpose of this study was to investigate the differences in ablation lesions when the ablation power, time, and perfusion flow are varied with TactiFlex and TactiCath catheters. The TactiFlex and TactiCath catheters were contacted perpendicularly/obliquely/parallel to the swine myocardium at varying powers (30, 40, and 50 W), time points (10, 15, 20, 25, 30, and 40s), and forces (5, 10, 15, 20, and 30g); the depth, width, and area of each lesion were measured, and the number of steam pops that occurred was counted. A total of 672 (336 lesions for each catheter) radiofrequency (RF) energy applications were delivered and 648 lesions were analyzed, excluding steam pops. The surface area and volume increased significantly with an increasing contact force for the TactiCath. The TactiCath lesions were significantly deeper than those for TactiFlex in most groups with the same power and seconds. The surface area was significantly larger when the catheters were contacted obliquely/parallel to the myocardium than perpendicularly using TactiCath, whereas the difference was less significant in the case of TactiFlex. In a 10-g contact force ablation experiment, TactiFlex did not cause pops, but TactiCath caused pops in 9.8% of cases. The TactiFlex lesions were shallower than those of TactiCath. However, TactiFlex catheters reduced the steam pops during RF applications. Those data should help clinicians understand the characteristics of the catheters and develop adequate strategies.

Advances in radiofrequency ablation: mechanism of action and technology.

Radiofrequency ablation (RFA) is a minimally invasive treatment modality that utilizes high-frequency alternating current to destroy targeted tissues through thermal ablation. This manuscript provides an overview of the advancements in RFA, focusing on its mechanism of action and technological innovations. RFA technology was first introduced in the early 1900's, and its use has expanded and evolved, especially in its current utility in the treatment of painful conditions. As the technology has evolved, new techniques, applications and modalities have expanded its use and improved its efficacy. RFA works by applying radiofrequency energy through specialized electrodes, leading to resistive heating and coagulation necrosis. Its advantages include precise tissue targeting, minimal invasiveness, reduced complications, and faster recovery compared to traditional surgical interventions. Technological advancements in RFA have led to improved treatment outcomes. Multi-electrode systems allow for larger ablation zones. Image-guided RFA improves treatment planning and minimizes damage to healthy tissues. Cooled-tip and perfusion electrodes address limitations such as heat sink effects, enhancing RFA's efficacy in challenging anatomical regions. These developments have expanded RFA's applications to liver tumors, lung tumors, renal tumors, cardiac arrhythmias, and chronic pain syndromes. In conclusion, RFA has emerged as a safe and effective thermal ablation technique. Understanding its mechanism of action and integrating advanced technologies have significantly enhanced treatment outcomes. Continued research and innovation in RFA hold immense potential for further improving patient care and outcomes.

BCLA CLEAR Presbyopia: Management with corneal techniques

Corneal techniques for enhancing near and intermediate vision to correct presbyopia include surgical and contact lens treatment modalities. Broad approaches used independently or in combination include correcting one eye for distant and the other for near or intermediate vision, (termed monovision or mini-monovision depending on the degree of anisometropia) and/or extending the eye’s depth of focus [1]. This report reviews the evidence for the treatment profile, safety, and efficacy of the current range of corneal techniques for managing presbyopia.The visual needs and expectations of the patient, their ocular characteristics, and prior history of surgery are critical considerations for patient selection and preoperative evaluation. Contraindications to refractive surgery include unstable refraction, corneal abnormalities, inadequate corneal thickness for the proposed ablation depth, ocular and systemic co-morbidities, uncontrolled mental health issues and unrealistic patient expectations.Laser refractive options for monovision include surface/stromal ablation techniques and keratorefractive lenticule extraction. Alteration of spherical aberration and multifocal ablation profiles are the primary means for increasing ocular depth of focus, using surface and non-surface laser refractive techniques. Corneal inlays use either small aperture optics to increase depth of field or modify the anterior corneal curvature to induce corneal multifocality. In presbyopia correction by conductive keratoplasty, radiofrequency energy is applied to the mid-peripheral corneal stroma, leading to mid-peripheral corneal shrinkage and central corneal steepening. Hyperopic orthokeratology lens fitting can induce spherical aberration and correct some level of presbyopia.Postoperative management, and consideration of potential complications, varies according to technique applied and the time to restore corneal stability, but a minimum of 3 months of follow-up is recommended after corneal refractive procedures. Ongoing follow-up is important in orthokeratology and longer-term follow-up may be required in the event of late complications following corneal inlay surgery.

Enhanced anti-tumor activity of transferrin/folate dual-targeting magnetic nanoparticles using chemo-thermo therapy on retinoblastoma cancer cells Y79

Malignant neoplasms are one of the main causes of death, especially in children, on a global scale, despite strenuous efforts made at advancing both diagnostic and therapeutic modalities. In this regard, a new nanocarrier Vincristine (VCR)-loaded Pluronic f127 polymer-coated magnetic nanoparticles conjugated with folic acid and transferrin (PMNP-VCR-FA-TF) were synthesized and characterized by various methods. The cytotoxicity of these nanoparticles was evaluated in vitro and ex vivo conditions. The in vitro anti-tumor effect of the nanoparticles was evaluated by colony formation assay (CFA) and reactive oxygen species (ROS) in Y79 cell line. The results showed that nanoparticles with two ligands conferred greater toxicity toward Y79 cancer cells than ARPE19 normal cells. Under an alternating magnetic field (AMF), these nanoparticles demonstrated a high specific absorption rate. The CFA and ROS results indicated that the AMF in combination with PMNP-VCR-FA-TF conferred the highest cytotoxicity toward Y79 cells compared with other groups (P < 0.05). PMNP-VCR-FA-TF could play an important role in converting externally applied radiofrequency energy into heat in cancer cells. The present study confirmed that dual targeting chemo-hyperthermia using PMNP-VCR-FA-TF was significantly more effective than hyperthermia or chemotherapy alone, providing a promising platform for precision drug delivery as an essential component in the chemotherapy of retinoblastoma.

Robotic Catheter Ablation: An Evaluation and Prototyping Platform

Cardiac arrhythmia affects a large portion of the population, particularly the elderly. As the population ages, the number of patients suffering from this condition is expected to rise, underlining the importance of more efficient treatment methods. Radio-frequency (RF) catheter ablation is the treatment of choice for many cardiac arrhythmias. To recover a normal heartbeat, the abnormal pacemakers inside the heart are first identified and then isolated or destroyed by applying RF energy through the use of an ablation catheter. While the catheter’s design and precise navigation are topics of significant interest, there is currently no standardized evaluation setup to compare different catheter ablation systems. This paper addresses this problem by introducing an evaluation platform including an in vitro anatomical model, a catheter tracking system, and a dedicated graphical user interface. This platform enables performance assessment of catheter ablation systems using various metrics, such as procedure duration, contact stability, ablation angle and user satisfaction. A simulation environment is also presented, allowing for rapid assessment of usability-related parameters. We demonstrate the efficacy of the evaluation platform through a proof-of-concept study, and the efficacy of the simulation environment through evaluating different control gains.

Comparison of strategies for catheter ablation of left posterior fascicular ventricular tachycardia.

Traditional ablation strategies including targeting the earliest Purkinje potential (PP) during left posterior fascicular (LPF) ventricular tachycardia (VT) or linear ablation at the middle segment of LPF during sinus rhythm are commonly used for the treatment of LPF-VT. Catheter ablation for LPF-VT targeting fragmented antegrade Purkinje (FAP) potential during sinus rhythm is a novel approach. We aimed to compare safety and efficacy of different ablation strategies (FAP ablation vs. traditional ablation) for the treatment of LPF-VT. Consecutive patients with electrocardiographically documented LPF-VT referred for catheter ablation received either FAP ablation approach or traditional ablation approach. Electrophysiological characteristics, procedural complications, and long-term clinical outcome were assessed. A total of 189 consecutive patients who underwent catheter ablation for LPF-VT were included. Fragmented antegrade Purkinje ablation was attempted in 95 patients, and traditional ablation was attempted in 94 patients. Acute ablation success with elimination of LPF-VT was achieved in all patients. Left posterior fascicular block occurred in 11 of 95 (11.6%) patients in the FAP group compared with 75 of 94 (79.8%) patients in the traditional group (P < 0.001). Fragmented antegrade Purkinje ablation was associated with significant shorter procedure time (94 ± 26 vs. 117 ± 23 min, P = 0.03) and fewer radiofrequency energy applications (4.1 ± 2.4 vs. 6.3 ± 3.5, P = 0.003) compared with the traditional group. One complete atrioventricular block and one left bundle branch block were seen in the traditional group. Over mean follow-up of 65 months, 89 (93.7%) patients in the FAP group and 81 (86.2%) patients in the traditional group remained free of recurrent VT off antiarrhythmic drugs (P = 0.157). Left posterior fascicular-ventricular tachycardia ablation utilizing FAP and traditional ablation approaches resulted in similar acute and long-term procedural outcomes. Serious His-Purkinje injury did occur infrequently during traditional ablation. The use of FAP ablation approach was associated with shorter procedure time and fewer radiofrequency energy applications, especially for non-inducible patients.

Optimization of high-power short duration catheter radiofrequency ablation for pulmonary veins isolation in patients with artiral septial defect

Objective ‒ to perform the analysis and biophysical substantiation of a new technique of catheter radiofrequency ablation (RFA) with high power and short duration based on mathematical modeling of own clinical data of the electro-thermodynamic effect of RFA on the myocardium; to investigate the morphological characteristics of the myocardium in different areas of the atrium and to determine the morphometric parameters of the display on the electroanatomical model of the heart of the ablation zone in the EnSite Precision navigation system, necessary for effective and safe high-power and short-duration RFA.Materials and methods. Clinical studies were performed in Amosov National Institute of Cardiovascular Surgery NAMS of Ukraine. Specialized high-tech medical equipment was used for the objectivity of clinical data obtained and used in the work. Morphological characteristics of the myocardium (thickness of the wall of the left atrium, distance from the back wall of the heart to the esophagus, diameters of the pulmonary veins) were evaluated on the computed tomography images of the heart of the patients, which were obtained in the radiology department on a Toshiba device (Japan) using a spiral scanning. The morphometric parameters of the ablation zone, which were later used to evaluate the effectiveness of RFA and which formed the basis of standardized protocols for the operation, were determined for display on the electro-anatomical maps of the patients' hearts in the EnSite Precision system (Abbott, USA). Biophysical substantiation of the RFA technique with high power and short duration was performed using mathematical modeling of the electro-thermodynamic effect of RFA on the myocardium and own clinical data in the Comsol Multiphysics automated simulation of biophysical processes.Results. It is proposed for a group of patients with combined atrial fibrillation with an atrial septal defect to perform RFA using a new ablation technique with high power and short duration at one point of application of radio frequency energy. Achieving transmurality of ablation in a shorter time makes it possible to hold the electrode more precisely and stably in this area when isolating the pulmonary veins in a complex geometry and without support for the electrode in case of a defect. The morphological characteristics of the myocardium were studied and the morphometric parameters of the display on the electroanatomical heart model of the ablation zone, necessary for effective and safe RFA, were determined. These include: the diameter of the point-label of radiofrequency ablation on the anatomical model of the heart, which must correspond to the real data of the size of the destruction; the percentage of overlap of RFA points for the formation of an effective transmural line; estimated number of ablation points to standardize the evaluation of the effectiveness of the procedure.Conclusions. The conducted research made it possible to solve the current problems of catheter radiofrequency ablation in patients with atrial fibrillation and atrial septal defect, namely to increase the efficiency and safety of pulmonary vein isolation. Transmurality and integrity of the isolating line was achieved due to the determined morphological characteristics of the myocardium and the calculated morphometric parameters of the ablation zone. The obtained data are adapted to a real display visible to the surgeon on the electro-anatomical map of the heart in the EnSite Precision navigation system. This system is actively used in clinical practice, but it was necessary to optimize the clinical protocols of RFA with high power and short duration, which was achieved as a result of this work.

Electrophysiological findings in patients undergoing left atrial appendage occlusion following previous electrical isolation

Abstract Funding Acknowledgements Type of funding sources: None. Background Left atrial appendage electrical isolation (LAA) is an important adjunctive ablation strategy in patients with nonparoxysmal atrial fibrillation. If impaired mechanical function following isolation is observed, long-term oral anticoagulation (OAC) or, as an alternative, LAA occlusion are required. Although focal electrical potentials from the LAA do not result in normalization of appendage mechanical function, they may potentially be a source of arrhythmogenic triggers. Those focal areas might be challenging to ablate after LAA occlusion device implantation. Purpose We sought to report the incidence of focal electrical potentials in patients with a previously isolated LAA and transesophageal echocardiography (TEE) evidence of severely impaired LAA mechanical function undergoing endocardial LAA occlusion. Methods In 124 patients undergoing LAA occlusion following LAA isolation, a circular mapping catheter (CMC) was used before occlusion to document any residual LAA electrical activity. Results At preprocedural TEE, the median LAA contraction velocity was 0.13 m/s (IQR: 0.05-0.19) and was significantly impaired in all patients. Of the 124 patients (mean age: 69±8 years; 71.7% males), 61 (49.2%) did not display any evidence of residual LAA electrical activity. In the remaining 63 (50.8%) patients, residual electrical potentials resulting in LAA reconnection were recorded on the CMC positioned into the appendage. On average, 4.9±1.7 radiofrequency energy applications (45W, mean duration of each RFA: 14.2±3.4s) were required to re-achieve complete isolation. Subsequent appendage occlusion was successful in all patients. No leaks ≥5mm and 3 (2.4%) 3-4mm-leaks were documented at 45day-TEE. Conclusions Focal electrical activity from the LAA was documented in approximately half of our patients. Although focal electrical potentials do not result in normalization of LAA mechanical function, they may potentially act as arrhythmogenic triggers. Since it may be challenging after device implantation, assessment and ablation of those areas should be considered before occlusion device deployment.

The critical isthmus of left atrial anterior wall flutter is mostly circumscribed into a small area immediately behind the aortic root. Implications for catheter ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Left atrial flutters (LAFL) are typically observed in patients with previous ablation lines or surgery in the left atrium (LA). Less frequently, scar-related left atrial anterior wall (LAAW) flutters may occur. Although the presence of low-voltage areas (LVAs, a surrogate of scar) in the LA is considered an arrhythmogenic substrate and a marker of atrial cardiomyopathy, the pathophysiologic factors responsible for its formation remain unclear. We hypothesized that compression of the LAAW by the aortic root could be responsible of LVAs found in the LAAW, and therefore, be the substrate for the development of LAAW flutter. Purpose We aimed to describe: 1) the relationship between the aortic root and the presence of LVAs in the LAAW, which is the substrate for reentry; and 2) the clinical and electrophysiological characteristics of LAAW atrial flutter. Methods Consecutive patients referred for LAFL ablation between April 2019 and September 2022 in a single center were retrospectively collected. Among 55 patients with LAFL, 10 (18%) demonstrated a macroreentrant circuit with a critical isthmus identified in the LAAW, in the absence of previous ablation lines or surgery, and were included in the analysis. Previous pulmonary vein isolation (PVI) was not an exclusion criterion. All patients underwent a multidetector computerized tomography (MDCT) prior to the procedure and the images were analyzed using ADAS 3DTM imaging platform. Activation mapping was performed in all patients using a multielectrode mapping catheter and CARTO 3 navigation system. Results 9 of 10 patients were male (mean age 74,3 ± 6,3 years). LA enlargement was present in all patients (48,3 ± 4,7 mm) and the mean aortic root diameter was 34,8 ± 3,4 mm. The mean LAAW flutter cycle length was 293,4 ± 68,3 ms. In 9 of the patients (90%), the LAAW flutter critical isthmus was just behind the aortic root, separated by &amp;lt; 1 mm according to the LA-aortic root fingerprinted isodistance map (mean fingerprinted isodistance area was 5,8 ± 2,5 cm2). The remaining patient had the critical isthmus just below the aortic root, between the area in contact with the latter and the mitral annulus. Furthermore, in all cases, the critical isthmus was immersed in LVAs. All but 1 LAAW flutter terminated during radiofrequency (RF) energy applications and rendered it non-inducible. After a median follow-up of 13,6 months (IQ range 5,3-21,6), 7 patients (70%) remained without recurrences. Conclusion In patients with LAAW atrial flutter, the presence of LVAs and the critical isthmus of the tachycardia are mostly circumscribed into small areas immediately behind the aortic root. Knowledge of this close relationship and the use of the isodistance map could be useful when mapping and ablating LAAW flutter, helping to straightforward the ablation procedure.

Left atrial appendage anatomical changes following radiofrequency-based ostial isolation

Abstract Funding Acknowledgements Type of funding sources: None. Background Left atrial appendage (LAA) electrical isolation (ei) may be achieved via radiofrequency (RF) energy applications at the level of the appendage ostium targeting the sites of earliest activation recorded by a mapping catheter. Notably, RF has long been used in vascular, orthopedic, and aesthetic surgery to promote thermal-induced collagen matrix contraction, fibrosis, and tissue retraction. LAA anatomical changes associated to RF-induced tissue retraction have never been reported. Purpose To quantify the anatomical changes of the LAA ostium following RF-based LAAei. Methods Thirty-four consecutive patients requiring AF ablation with LAAei underwent transesophageal echocardiography (TEE) within 7 days before (baseline TEE) and apx 6 months after (follow-up TEE) ablation. The diameter of LAA orifice and landing zone were measured at 4 different views (0°, 45°, 90°, 135°). Measurements were performed by two independent reviewers blinded to the patient’s identity. Results Among 43 AF patients (67±6yrs, 72.1% males), the LAA morphology was classified as chicken wing in 19 (44.2%) patients, windsock in 12 (27.9%), cactus in 8 (18.6%), and cauliflower in 4 (9.3%). At baseline TEE, the mean maximum and mean minimum ostial diameters were 25±4mm and 22±4mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 26±4mm and 23±3mm, respectively. On average, LAAei was achieved after 17±6 minutes of RF at a power of 45W. Follow-up TEE was performed 294±136 days after LAAei. The median LAA contraction velocity was 0.1 m/s (IQR: 0.02-0.18) and was significantly impaired in all patients. At follow-up TEE, the mean maximum and mean minimum ostial diameters were 19±4mm and 17±3mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 20±4mm and 18±4mm, respectively. The mean relative reduction of the ostium and the landing zone was -24.4% and -22.5%, respectively. Box-Whisker plots of the maximum and minimum ostial diameters before and after LAAei are reported in Fig.1. Conclusion RF led to a &amp;gt;20% reduction of the diameters of the ostium and the landing zone. These changes may have important implications for a successful percutaneous occlusion procedure and justify a staged approach of isolation and occlusion.

Dielectric response in relation to other ablation parameters

Abstract Funding Acknowledgements Type of funding sources: None. Background Dielectric imaging is used by the KODEX-EPD system to provide information that can be used to guide catheter ablation of cardiac arrhythmia. This includes assessment of catheter-tissue contact (No touch, Touch, or High touch) and local atrial wall thickness (mm). Additionally, the system can detect changes in local dielectric tissue properties to assess the effect of a radiofrequency energy application. This assessment is used to classify ablation points into low or high dielectric response (LDR or HDR), which was designed to indicate the extent of lesion transmurality. Objectives To evaluate the relation between dielectric response and other ablation parameters. Methods The KODEX-EPD system was used to guide ablation in patients with prior pulmonary vein isolation. Ablation included re-isolation of the pulmonary veins and isolation of the superior vena cava if deemed necessary. We downloaded system data from all procedures that were performed with software that provided dielectric response (version 1.5.0, 1.5.0a, 1.5.1 and 1.5.1a) and analyzed the parameters of all individual ablation points. Results The cohort includes 55 patients, in which 135 pulmonary veins and 19 superior venae cavae were targeted. A total of 860 energy applications were applied, resulting in 1458 ablation points. The system classified 31% of ablation points as HDR and 19% as LDR. The system did not provide a dielectric response in 49%. The system’s ability to determine dielectric response was related to the software version(oldest version 71% no DR, newest version 18%) and duration of ablation. High dielectric response (versus LDR or no DR) was multivariably associated with longer energy applications, higher mean ablation power and lower local wall thickness (Table). Mean ablation temperature and impedance drop were not multivariably associated with dielectric response. Conclusion Dielectric response is independently associated with local wall thickness, ablation power and duration, but not with ablation temperature and impedance drop. Newer software versions have reduced the proportion of ablation points for which no dielectric response was provided.

Safety, tolerability and short-term efficacy of transvaginal fractional bipolar radiofrequency therapy for symptoms of stress and or mixed incontinence in conjunction with genitourinary syndrome of menopause.

Radiofrequency (RF) energy application stimulates collagen and elastin remodeling to restore the elasticity, and moisture of the superficial vaginal mucosa. This is the first study to report on the use of microneedling to deliver RF energy to the vaginal canal. Microneedling increases the response of the collagen contraction and neocollagenesis in deeper layers of tissue, thus increasing the support to the surface. The novel intravaginal microneedling device used in this study allows penetration of the needles to 1, 2, or 3 mm. A prospective study to evaluate the safety and short-term outcome of a single fractional RF treatment of the vaginal canal in a series of women with coexistent stress or mixed incontinence (MUI) and genitourinary syndrome of menopause (GSM). Twenty women who had symptoms of SUI and or MUI in conjunction with GSM were given a single vaginal treatment that consisted of fractional bipolar RF energy using the EmpowerRF platform with the Morpheus8V applicator (InMode). RF energy was delivered into the vaginal walls via 24 microneedles, at a depth of 1, 2, and 3 mm. Outcomes were evaluated by "cough" stress test, questionnaires (MESA SI, MESA UI, iQoL, UDI-6) and evaluation of vaginal tissue through the VHI scale at 1-, 3-, and 6-months post-treatment compared to baseline. Biopsies were performed at baseline and 3-months on five patients for histological reference and tissue evaluation. Eight out of eight outcomes measured from baseline to 6-months post-treatment showed improvement. The parameters scored in the questionnaires including frequency, urgency, nocturia, urge incontinence, and stress incontinence showed significant improvement in all areas at the 1-, 3-, and 6-month follow-up sessions compared to baseline. The results showed evidence that fractional RF energy delivered vaginally is safe, well tolerated, and provide short term improvement of SUI and or MUI in conjunction with GSM.

Laser and Radiofrequency Energy Applications in the Percutaneous Endoscopic Surgical Treatment of Degenerative Disc Disease: Should be abandoned?

Laser and Radiofrequency Energy Applications in the Percutaneous Endoscopic Surgical Treatment of Degenerative Disc Disease: Should be abandoned?

Catheter-Based Renal Denervation: 9-Year Follow-Up Data on Safety and Blood Pressure Reduction in Patients With Resistant Hypertension.

Recent sham-controlled randomized clinical trials have confirmed the safety and efficacy of catheter-based renal denervation (RDN). Long-term safety and efficacy data beyond 3 years are scarce. Here, we report on outcomes after RDN in a cohort of patients with resistant hypertension with an average of ≈9-year follow-up (FU). We recruited patients with resistant hypertension who were previously enrolled in various RDN trials applying radiofrequency energy for blood pressure (BP) lowering. All participants had baseline assessments before RDN and repeat assessment at long-term FU including medical history, automated office and ambulatory BP measurement, and routine blood and urine tests. We analyzed changes between baseline and long-term FU. A total of 66 participants (mean±SD, 70.0±10.3 years; 76.3% men) completed long-term FU investigations with a mean of 8.8±1.2 years post-procedure. Compared with baseline, ambulatory systolic BP was reduced by -12.1±21.6 (from 145.2 to 133.1) mm Hg (P<0.0001) and diastolic BP by -8.8±12.8 (from 81.2 to 72.7) mm Hg (P<0.0001). Mean heart rate remained unchanged. At long-term FU, participants were on one less antihypertensive medication compared with baseline (P=0.0052). Renal function assessed by estimated glomerular filtration rate fell within the expected age-associated rate of decline from 71.1 to 61.2 mL/min per 1.73 m2. Time above target was reduced significantly from 75.0±25.9% at baseline to 47.3±30.3% at long-term FU (P<0.0001). RDN results in a significant and robust reduction in both office and ambulatory systolic and diastolic BP at ≈9-year FU after catheter-based RDN on less medication and without evidence of adverse consequences on renal function.

Optimal prevention method of phrenic nerve injury in superior vena cava isolation: efficacy of high-power, short-duration radiofrequency energy application on the risk points.

Superior vena cava isolation (SVCI) is widely performed adjunctively to atrial fibrillation (AF) ablation. Right phrenic nerve injury (PNI) is a complication of this procedure. The purpose of the study is to determine the optimal PNI prevention method in SVCI. A total of 1656 patients who underwent SVCI between 2009 and 2022 were retrospectively examined. PNI was diagnosed based on the diaphragm position and movement in the upright position on chest radiographs before and after SVCI. With the introduction of various PN monitoring systems over the years, the incidence of SVCI-associated PNI has decreased. However, complete PNI avoidance has not been achieved. PNI incidence according to fluoroscopy-guided PN monitoring, high-output pace-guided, compound motor action potential-guided, and 3-dimensional electro-anatomical mapping (EAM) systems was 8.1% (38/467), 2.7% (13/476), 2.4% (4/130), and 2.8% (11/389), respectively. However, a high-power, short-duration (50W/7s) radiofrequency (RF) energy application only on PNI risk points tagged by a 3-dimensional EAM system completely avoids PNI (0%; 0 /160 since April 2021). PNI showed no symptoms and recovered within an average of 188days post-SVCI, except for a few patients who required > 1year. Although PNI incidence decreased annually with the introduction of various monitoring systems, these monitoring systems did not prevent PNI completely. Most notably, the delivery of a high-power, short-duration RF energy only on risk points tagged by EAM prevented PNI completely. PNI recovered in all patients. The application of higher-power, shorter-duration RF energy on risk points tagged by EAM appears to be an optimal PNI prevention maneuver.

A Clinical Audit of Pulmonary Vein Isolation with Percutaneous Balloon Cryoablation in Refractory Atrial Fibrillation

Pulmonary vein isolations is the conventional rhythm-control therapy in treatment-resistant Atrial Fibrillation (AF). Cryoablation has emerged as a successful therapeutic option as it confers a beneficial effect on procedure time without compromising safety and efficacy due to its single-shot circumferential approach without conduction gap [1], in contrast to the conventional point-by-point application of radiofrequency energy [2]. This audit aimed to determine the clinical effectiveness of novel 28 mm cryoballoon ablation in Pulmonary Vein Isolations (PVIs) measured by freedom from AF from patients perspectives.

Esophageal cooling during ablation of persistent atrial fibrillation is associated with improved freedom from arrhythmia at one-year follow up

Abstract Background Various factors influence successful freedom from atrial arrhythmia after pulmonary vein isolation (PVI) with radiofrequency (RF) ablation for the treatment of atrial fibrillation (AF). Lesion transmurality and continuity (as measured by the Continuity Index) are two important factors, and these can be worsened by pauses in RF energy application due to esophageal overheating. Proactive esophageal cooling precludes the need for premature cessation of power, avoiding partially-formed lesions and the need to “hop-scotch” in the left atrium. The resulting improvement in lesion continuity may improve long-term freedom from atrial arrhythmia after PVI, particularly in patients with persistent AF, where more posterior wall ablation is often necessary. Purpose Determine differences in freedom from arrhythmia at one year between patients receiving LET monitoring and those receiving esophageal cooling during PVI for persistent AF. Methods We reviewed data from two healthcare systems for patient rhythm status at one-year follow up after PVI for the treatment of persistent or long-standing persistent AF. We then determined Kaplan-Meier estimates of freedom from arrhythmia (AF, atrial flutter, and atrial tachycardia), and compared these between patients receiving esophageal cooling and those treated with traditional LET monitoring. Results A total of 252 patients received PVI for persistent or long-standing persistent AF and had data available for review. Of these, 148 received LET monitoring (with either a single or multi-sensor temperature probe), and 104 received active cooling with a dedicated esophageal cooling device. Mean age and gender for each group was similar (67.2, range 21 to 88 years, 36% female for LET monitoring, and 67.8, range 32 to 89 years, 30% female for esophageal cooling). KM estimates for freedom from AF at the one-year follow-up were 44.2% for LET monitored patients and 79.3% for actively cooled patients (P=0.01). Conclusions Freedom from atrial arrhythmia at one-year after PVI for persistent AF is associated with significant improvement when using active esophageal cooling rather than LET monitoring. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): Attune Medical

Abstract P2101: Time Dependence Of Esophageal Injury With And Without Proactive Cooling During High-power Short-duration Radiofrequency Ablation

Background: Recent data suggest that luminal esophageal temperature (LET) monitoring during high-power short-duration (HPSD) ablation may be inadequate to prevent esophageal thermal injury during radiofrequency (RF) ablation. This is due in part to delayed responses to thermal latency and the continued temperature rise that occurs in tissues even after the cessation of RF energy with HPSD settings. Proactive esophageal cooling has been shown to reduce severe esophageal thermal injury during medium-power medium-duration RF ablation, but less is known about the effects in HPSD ablation. Objective: We aimed to quantify the time course of esophageal damage in scenarios with and without proactive esophageal cooling, hypothesizing a reduction in the resulting tissue damage with proactive esophageal cooling. Methods: Using a computer model of RF ablation in the left atrium adjacent to the esophagus, we calculated temperature over time using ablation power of 50 W for 10 s and 90 W for 4 s. We then determined the fraction of resulting damage to esophageal tissue via the Arrhenius equation and by the percentage of tissue above lethal isotherm temperature of 50°C. Transmurality of injury was then plotted over time, and results were compared between ablation with and without proactive esophageal cooling. Results: Esophageal damage increased even after the cessation of RF energy, suggesting significant thermal latency effects under HPSD ablation. Lesion growth continued for &gt;10 s after cessation of 50 W ablation energy, and for &gt;12 s after cessation of 90 W ablation energy without cooling. With proactive cooling, lesion growth after cessation of ablation energy was essentially halted. Without esophageal cooling, maximum injury transmurality reached 79% with 50 W, and 58% with 90 W. With esophageal cooling, injury transmurality remained below 20% with 50 W, and 10% with 90 W, representing reductions of 75% and 83%, respectively. Conclusions: RF ablation using HPSD settings demonstrates significant latency of effect, with tissue damage and lesion growth continuing beyond the cessation of application of RF energy. Proactive esophageal cooling significantly dampens this effect, reducing esophageal injury by up to 83%.