Ablation Approach Research Articles

Novel Approach for Synthesis of Graphene-like Phases by Pulsed Laser Ablation in a Flow-Mode Suspension.

The present study investigates the possibility of obtaining graphene-like phases (defected graphene, graphene oxide, and reduced graphene oxide) as fine suspensions by applying a novel pulsed laser ablation (PLA) approach in flow mode. Two types of suspensions of microcrystalline graphite in aqueous suspensions and two types of microcrystalline graphite in suspensions of 6% hydrogen peroxide solution were irradiated in a quartz tube through which they flow. The third (λ = 355 nm) and fourth harmonics (λ = 266 nm) of an Nd:YAG laser system (15 ns pulse duration and 10 Hz pulse repetition rate) were used. The morphology of the obtained particles was studied by transmission electron microscopy (TEM). Their phase composition and structure were explored by X-ray photoelectron spectroscopy, X-ray diffractometry, and Raman spectroscopy.

Indocyanine Green as a Navigational Adjunct for Laparoscopic Ablation of Liver Tumors.

Minimally invasive operative approaches for resection and thermal ablation (eg, microwave, radiofrequency) of hepatocellular carcinoma (HCC) have been successfully implemented over the last two decades, although identifying tumors can be challenging. Successfully performing laparoscopic ablation requires real-time visualization and ultrasonography skills for direct placement of the ablation probe. In this study, we introduce a novel adjunct to ultrasound imaging for tumors located near or on the surface of the liver via intravenous delivery of indocyanine green (ICG) dye. Non-resectable lesion(s) not amenable to percutaneous ablation were considered for laparoscopic microwave ablation. Each patient initially received a dose of .3125mg ICG via peripheral IV. A total of 17 patients were included. There was brisk uptake of ICG throughout the liver parenchyma in under 2minutes in 15 of 17 patients; the remaining 2 required a second dose of ICG. In 14 cases, a hypo-fluorescent perfusion pattern in the tumor was clearly identified. Integrating ICG and fluorescent imaging provides a complementary adjunct to ultrasound in identifying HCC nodules. While previous applications of ICG typically require injections several days prior to surgery or segmental injections, this study demonstrates a novel real-time application of ICG to aid surgeons with various experiences in laparoscopic-assisted ablation procedures for HCC.

Talk like a duck, walk like a duck: A cardiac surgeon's understanding of complex imaging in the management of atrial fibrillation.

The treatment of atrial fibrillation continues to evolve. The Heart Team Hybrid Ablation Approach is the latest iteration of Electrophysiology and Arrythmia surgeon collaboration that is focused on the treatment of complex (persistent and long-standing persistent) atrial fibrillation patients. Critical to this team approach is the ability to converse regarding atrial anatomy, atrial substrate and transmurality of ablation lesions. The cornerstone of these dialogs is advanced imaging techniques including; transesophageal echocardiography, enhanced magnetic resonance imaging, endocardial voltage mapping, and epicardial electrogram mapping. We herein review these techniques and their clinic implications.

Paroxysmal Atrial Fibrillation in Elderly: Worldwide Preliminary Data of Linac-Based Stereotactic Arrhythmia Radioablation Prospective Phase II Trial

<h3>Purpose/Objective(s)</h3> In elderly, paroxysmal Atrial Fibrillation (AF) is difficult to treat with drugs, or by Catheter ablation, so a non-invasive approach should be favorite. No data are published about the use or radiosurgery for AF, thus in the present analysis the preliminary data of a prospective phase-II trial Linac-based STereotectic Arrythmias Radioablation (STAR) for elderly affected by paroxysmal AF were reported. <h3>Materials/Methods</h3> Inclusion criteria were: age ≥70 years; symptomatic paroxysmal AF; intolerance or non-response to anti-arhythmic therapy (AAT). All patients performed 1-week ECG-Holter monitoring, a complete transthoracic echocardiogram before and after STAR. Patients were immobilized using a vac-lock bag and Computed Tomography (CT, 1mm slice-thickness), in the supine position were performed: CT with/without contrast; 4-Dimension CT. STAR was performed in free-breathing with a PTV prescription total dose (Dp) of 25Gy/1 fraction. Flattening Filter Free (FFF), Volumetric Modulated Arc Therapy (VMAT) plan was generated, normalizing 100% Dp to 95% of the volume, while large intra-target dose heterogeneity D2% (PTV)<150%Dp was accepted. The treatment was optimized and delivered by medical linear accelerators (technology company). Image-guided radiotherapy with Cone Beam CT and Surface-Guided RadioTherapy with Align-RT were used to reduce set-up error and to monitor patients during fraction. The primary endpoint is the 1-month post-STAR safety, as complete STAR delivery and no acute treatment-related adverse events more than G3, assessed according to the Common Terminology Criteria for Adverse Events (version 5.0). <h3>Results</h3> From May 2021 to February 2022, 11 patients were treated and followed. In all cases, AAT was stopped at 1 month after treatment. For primary endpoint, no acute treatment-related adverse events were registered (>G1). Only 1 patient experienced G1 esophagitis (7 days from STAR), improved by 5 days of medical therapy. The treatment plan was delivered with 3 no coplanar arcs, in all cases. The mean Overall Treatment Time (OTT) was 3 minutes. For all treated patients with a mean follow-up of 4 months (patients 1-6), no late side effects were reported, and at 3 months, a rare atrial ectopy was documented without AF recurrences. No patients started AAT after radiotherapy. <h3>Conclusion</h3> The present collected data are promising, showing the safety of LINAC-based STAR for AF for the first 11 patients worldwide. This new ablation approach could represent a valid non-invasive alternative for elderly who were excluded from catheter ablation. This trial is registered at ClinicalTrials.gov, NCT04575662.

Low-Voltage Myocardium-Guided Ablation Trial of Persistent Atrial Fibrillation

BackgroundClinically effective ablation approaches for patients with persistent atrial fibrillation (AF) are still being debated. So far, ablation targets and strategies beyond pulmonary vein isolation (PVI) have failed to show systematic outcome improvement in randomized controlled clinical trials.MethodsWe conducted a multicenter, randomized trial to determine whether PVI plus individualized substrate ablation of atrial low-voltage myocardium improves outcome in patients with persistent AF. We randomly assigned 324 patients in a 1:1 ratio to receive PVI alone (163 patients; PVI only) or PVI plus substrate modification (161 patients; PVI+SM). The primary study end point was the first recurrence of an atrial arrhythmia longer than 30 seconds after single ablation, with 3 months blanking, using serial 7-day electrocardiogram recordings over 12 months of observation. Patients were also encouraged to receive implantable cardiac monitors.ResultsThe primary study end point occurred in 75 PVI-only patients (50%) and in 54 PVI+SM patients (35%) (Kaplan–Meier event rate estimates: hazard ratio=0.62, 95% confidence interval [CI]=0.43 to 0.88, log rank P=0.006). Adverse events occurred in three PVI-only patients (1.8%) and in six PVI+SM patients (3.7%) (difference: −1.9 percentage points, 95% CI=−5.5 to 1.7 percentage points). Implant monitoring was used in 242 patients. Among them, 65 PVI-only patients (55%) versus 47 PVI+SM patients (39%) experienced recurrences (difference: 15 percentage points, 95% CI=3 to 28 percentage points).ConclusionsIn this randomized trial, PVI plus individualized ablation of atrial low-voltage myocardium significantly improved outcomes in patients with persistent AF. (ClinicalTrials.gov number, NCT02732626.)

Hybrid Ablation of Nonparoxysmal Atrial Fibrillation: The Convergent and Totally Thoracoscopic Approaches.

Nonparoxysmal atrial fibrillation continues to challenge electrophysiologist and surgeons alike. Stand-alone endocardial catheter ablation has resulted in less than satisfying results, and while the on-pump Cox-Maze surgery has excellent results, the invasiveness has limited its adoption amongst both referring providers and surgeons. The CONVERGE IDE trial has shed new light on this once dim problem. EPs and Surgeons are now working together in a Hybrid Team Ablation Approach to provide a combined ablation strategy that has improved patient outcomes and rekindled the collaboration necessary to better patient outcomes. We herein summarize the current Hybrid Team Ablation Approaches (CONVERGE and Totally Thoracoscopic) with nonparoxysmal atrial fibrillation.

(Digital Presentation) Bismuth and Transition Metal-Doped Bismuth Nanoparticles As Electrochemical Biosensors

Current non-enzymatic electrochemical biosensors rely heavily on transition metal-based nanomaterials, such as Pt, Ni, Co, and Cu, for molecule adsorption and charge transfer. Although high performance (sensitivity and selectivity) was usually demonstrated, these elements are generally toxic, making them less applicable for wearable/in vivo sensors.Two general strategies are approached to address such drawbacks: minimizing their usage without sacrificing the activity and searching for other elements with lower toxicity. In this study, we demonstrated that the overlooked bismuth nanoparticles (NPs) could be used for non-enzymatic electrochemical glucose sensing with comparable performance [1]. Using a laser ablation approach (see Figure 1A), stabilizer-free Bi NPs (~10 nm diameter) were prepared, showing amperometric sensitivity of 127 µA mM−1 cm−2. The synthesis approach also enabled the one-step surface doping of the Bi NPs, producing Ni and Co-doped Bi NPs with an atomic doping ratio of ~10%, and led to further sensitivity boost to 677 and 2326 µA mM−1 cm−2 (see Figure 1B). Kinetic analysis revealed that the oxidation of Bi(III) to Bi(V) species was the key to enabling glucose electrooxidation on Bi NPs. Such results demonstrate the vast potential of the overlooked bismuth in electrochemical biosensing. Figure 1 (A) Top: illustration of the laser ablation approach of preparing Bi and metal-doped Bi NPs; Bottom: TEM images of as-prepared Bi NPs and Co-Bi NPs; (B) Amperometric correlation between glucose concentration and the current density using Bi NPs and Co-Bi NPs as sensors. Reference: Zheng, W.; Li, Y.; Lee, L. Y. S., Bismuth and metal-doped bismuth nanoparticles produced by laser ablation for electrochemical glucose sensing, Sens. Actuators, B 2022, 357, 131334. Figure 1

Radiofrequency ablation of atrial fibrillation-50 W or 90 W?

This study sought to evaluate the short and midterm efficacy and safety of the novel very high power very short duration (vHPvSD) 90 W approach compared to HPSD 50 W for atrial fibrillation(AF) ablation as well as reconnection patterns of 90 W ablations. Consecutive patients undergoing first AF ablation with vHPvSD (90 W; predefined ablation time of 3 s for posterior wall ablation and 4 s for anterior wall ablation) were compared to patients using HPSD (50 W; ablation index-guided; AI 350 for posterior wall ablation, AI 450 for anterior wall ablation) retrospectively. A total of 84 patients (67.1 ± 9.8 years; 58% male; 47% paroxysmal AF) were included (42 with 90 W, 42 with 50 W) out of a propensity score-matched cohort. 90 W ablations revealed shorter ablation times (10.5 ± 6.7 min vs. 17.4 ± 9.9 min; p = .001). No major complication occurred. 90 W ablations revealed lower first pass PVI rates (40% vs. 62%; p = .049) and higher AF recurrences during blanking period (38% vs. 12%; p = .007). After 12 months, both ablation approaches revealed comparable midterm outcomes (62% vs. 70%; log-rank p = .452). In a multivariable Cox regression model, persistent AF (hazard ratio [HR]: 1.442, 95% confidence interval [CI]: 1.035-2.010, p = .031) and increased procedural duration (HR: 1.011, 95%CI: 1.005-1.017, p = .001) were identified as independent predictors of AF recurrence during follow-up. AF ablation using 90 W vHPvSD reveals a similar safety profile compared to 50 W ablation with shorter ablation times. However, vHPvSD ablation was associated with lower rates of first-pass isolations and increased AF recurrences during the blanking period. After 12 months, 90 W revealed comparable efficacy results to 50 W ablations in a nonrandomized, propensity-matched comparison.

Atrio-ventricular nodal re-entrant tachycardia ablation step by step low fluoro approach to prevent unexpected AV block

Abstract Background Slow pathway (SP) radiofrequency (RF) ablation of AVNRT has a success rate of more than 98%, but up to 2% risk of unpredictable and frustrating AV node block despite the energy being delivered to the posterior aspect of Koch's Triangle (KT) which is far from the recorded His signal. A possible explanation is an atypical location of the AV node. KT pace-mapping (KTPM) has been demonstrated to be useful to recognize when AV is abnormally located in the mid or posteroseptal aspect of the KT. In these cases cryoablation would be the best choice because it is a well-established technique for the successful treatment of AVNRT with no complications reported but with a recurrence rate around 10% at long-term follow-up. Voltage bridge mapping (VBM) is a validated and effective technique in guiding cryoablation of AVNRT, with a complete acute success rate and no recurrences at mid-term follow-up. Aim To evaluate our low-fluoro step-by-step approach for AVNRT ablation including KTPM and VBM aiming to eliminate the risk of unpredictable AV node block. Methods The right atrium and coronary sinus electroanatomical mapping was done and diagnostic catheters were positioned at His and coronary sinus. After AVNRT diagnosis, 3D KTPM was performed. We developed it according to the “conventional” one in order to evaluate and visualize atypical AV node location during low-fluoro procedures. This was achieved by stimulating with the mapping catheter in the anteroseptal, posteroseptal and midseptal region respectively. Each point has been collected on 3D System measuring the interval between the stimulus to the His deflection (Fig. 1A–C). Voltage bridge-mapping was also performed, and both have been used as reference for SP RF ablation. If 3D KTPM showed a posterior extension of the AV node, then ablation was performed using cryo-energy aiming to reduce the risk of permanent AV node iatrogenic block. Methods and results 71 consecutive patients (mean age 61.0±14.5 SD, 46% female) undergoing low-fluoro ablation of AVNRT by 3D mapping system. KTPM was achieved in all the patients. In the 67 (94.3%) pts who showed superoparaseptal location of the AV node RF ablation was successfully performed. In 4 (5.7%) pts with midseptal extension of the AV node (Fig. 1D) a voltage-bridge mapping guided cryo-ablation was successfully performed (Fig. 1E). The mean procedural time was 95±18 SD min. Mean fluoro time was zero. After a mean follow-up of 28.5±16.7 SD moths, neither recurrences nor complications were recorded. Conclusion This is the first study to show how a tailored low-fluoro AVNRT SP ablation approach including 3D-PM of KT and VBM could be helpful to eliminate the risk of unpredictable and frustrating AV block. Our preliminary results would possibly encourage larger cohort, multicenter studies. Funding Acknowledgement Type of funding sources: None.

Outcomes of catheter ablation for typical atrioventricular nodal reentrant tachycardia with low power energy

Abstract Background Atrioventricular nodal reentrant tachycardia (AVNRT) is most common supraventricular tachycardia with acceptable outcome of catheter ablation. However, the serious complication of atrioventricular block (AVB) can occur and affects 0.2% to 2.3% of patients during or after procedures. Purpose We hypothesized that slow pathway ablation with 20 watt (W) energy would facilitate acceptable clinical outcomes and low procedure related AVB needed permanent pacemaker. Methods Prospective single center trial was performed. Slow pathway ablation was performed in 212 patients (mean age 56.5±18.4 years, 131 women) from January 2017 to May 2020. Twenty watt energy was delivered at the posterior region of the triangle of Koch until accelerated junctional rhythm was obtained. Results A total of 212 patients who underwent ablation for typical AVNRT were included. The acute success rate, the mean radiofrequency pulses applied per patient were 98.1% and 8.6±6.6, respectively. Transient AVB occurred in 5 patients (2.4%) and no permanent AVB requiring permanent pacemaker implantation occurred. Those who failed 20 W ablation were younger (success group age vs failed group age 58.2±17.4 vs 31.8±17.9 years, p=0.005) and had a faster heart rate just before slow pathway ablation (success group heart rate vs failed group heart rate 69.2±11.3 vs 76.8±5.6 bpm, p=0.59). The recurrence rate of 20 W ablation was 2.6% and the follow-up period was 18.3±4.1 months. Conclusion The low power approach for slow pathway ablation is highly effective and safe. If the heart rate just before ablation is lesser than 70 bpm, slow pathway ablation with 20 W energy could be considered. Further well-designed large-randomized studies are needed to define the role and effect of catheter ablation for typical AVNRT with low power energy. Funding Acknowledgement Type of funding sources: None.

Holistic approach of ablation versus antiarrhythmic drugs for efficacy, safety, and quality of life improvement in rhythm control of atrial fibrillation: a meta-analysis of randomized trials

Abstract Background/Introduction Recent studies have shown that catheter ablation (CA) is more superior compared to the usage of the antiarrhythmic drug (AAD) regarding its efficacy in decreasing the incidence of persistent and chronic atrial fibrillation (AF). However, choosing the right rhythm control strategy to provide holistic care for the patients should be individualized on each patients condition. Purpose In this meta-analysis, the author will compare both CA and AAD regarding their efficacy, safety, and their effect on the quality of life of AF patients. Methods The authors systematically searched the relevant journals throughout PubMed, Medline, and the Cochrane Library, with a range of publications from 2010 to 2021. The primary outcomes were AF recurrence, quality of life score, and adverse events. Secondary outcomes were the rehospitalization rate and all-cause mortality. Analysis was performed using a random-effects model with the Mantel-Haenszel method, and results are presented as 95% CIs. Results A total of 23 RCTs consisted of 10,316 patients were included. Although some adverse events (pericarditis, pleural effusions, and cardiac tamponade) were found in 2.8% population of the CA group (RR: 4.15; 95% CI: 1.65, 10.41; p=0.002), the CA group was found superior in suppressing the rate of AF recurrence (RR: 0.56; 95% CI: 0.48, 0.65; p&amp;lt;0.00001). Regarding the SF-36 Mental (p&amp;lt;0.00001) and Physical Assessment (p&amp;lt;0.0001), both CA and AAD showed increased quality of life post treatment compared with baseline level (pre-treatment) for each therapy. Following the interventions, the CA group significantly showed a lower rehospitalization rate (RR: 0.82; 95% CI: 0.70,0.97; p=0.02) and also showed a lessened mortality trend (6.84%) compared to the AAD group (9.01%) even though not statistically significant. Conclusion(s) Statistically, there is no difference for both groups in their capability of reducing the mortality rate. However, CA was found to be more superior in efficacy and reducing the number of rehospitalizations. Quality of life also significantly improve same as AAD, which further might be provide a holistic outcome of rhytm control. Funding Acknowledgement Type of funding sources: None.

Improved Outcomes With Transradial Approach in Alcohol Septal Ablation.

Transradial cardiac catheterization is equally effective but has fewer vascular complications than transfemoral catheterization. There is a paucity of data on biradial approach for alcohol septal ablation (ASA). This study seeks to study the differences in procedural outcomes between the transradial vs traditional transfemoral approach in ASA. A total of 274 consecutive patients who underwent ASA were retrospectively assigned to the study subgroups (137 transradial, 137 femoral). Procedural success, reduction in left ventricular outflow tract gradient (LVOTG), contrast volume, fluoroscopy time, and complications were compared between the 2 groups. There were no differences in reduction of resting LVOTG (91% vs 92%; P=.50), provoked LVOTG (80% vs 82%; P=.47) post procedure between transradial vs transfemoral subgroups. Iodinated contrast volume was significantly lower in the transradial group (98 mL vs 111 mL; P=.04), whereas fluoroscopy time was higher in the transradial group (17.42 minutes vs 13.00 minutes; P&lt;.001). The incidence of complications was lower in the transradial group (0.13 vs 0.23; P=.04). ASA via transradial approach is equally effective and associated with significantly less contrast use and fewer complications as compared with the traditional transfemoral approach.

Bifenestral surgical and chemical labyrinthectomy, a new effective ablative surgical approach to intractable vertigo in Ménière disease elderly patients

IntroductionIn this article, the bi-fenestral surgical chemical labyrinthectomy is introduced as a surgical demolition technique for treating resisting incurable forms of Meniere’s disease in patients aged over 70 and/or with low hearing residues refractory to medical treatment. Materials and methodsThe results on participants fitting the inclusion criteria (n = 16) were reported using anamnesis (frequency of the crisis), Dizziness Handicap Inventory (DHI) and Functional Level Scale (FLS) before and after the intervention. ResultsVertigo control was achieved in all patients of this case series. A difference of 57 and 3.67 in mean DHI (from 68 (SD 16.7) to 11 (SD 14)) and FLS (from 4.68 (SD 0.7) to 0.1 (SD 0.3)) scores respectively were seen after an average of 16.28 months. Contextually tinnitus was reported to improve in seven patients (43.75%), aggravate in three (18.75%) and remain unchanged in the remaining six (37.5%). ConclusionBi-fenestral surgical chemical labyrinthectomy appears a safe, immediate, and effective demolition treatment for vertigo control in a restricted class of patients affected by intractable Meniere disease.

Successful Typical AVNRT Ablation

AVNRT is the most common regular arrhythmia in humans, and therefore the most commonly encountered during ablation attempts for regular tachycardias. Case Summary: We present a 41-year-old female patient with chest palpitations in the last 10 years, but prior to hospitalization felt heavy sensation on her chest and hospitalized due to heavy chest palpitations and documented SVT. She had no history of hypertension, diabetes mellitus, coronary heart conditions, or stroke. Physical examination showed fair general condition with GCS E4V5M6, blood pressure 130/80, pulse rate 96x / minute, breath rate 18 x / minute and saturation of 99%. Physical examinations are within normal limits. Discussion: Catheter ablation for AVNRT is the current treatment of choice in symptomatic patients. It reduces arrhythmia-related hospitalizations and costs, and substantially improves quality of life. Catheter ablation approaches aimed at the fast pathway have been abandoned; slow pathway ablation, using a combined anatomical and mapping approach, is now the method of choice. This approach offers a success rate of 95 %, has a recurrence rate of approximately 1.3 – 4.0 %, and has been associated with a low risk of atrioventricular (AV) block.

Combined Trans-Arterial Embolization and Ablation for the Treatment of Large (>3 cm) Liver Metastases: Review of the Literature

(1) Background: The aim of this review was to determine the state of clinical practice in the role of the combined approach of embolization and ablation in patients with secondary liver lesions greater than 3 cm who are not candidates for surgery, and to study its safety and efficacy. (2) Methods: Two reviewers conducted the literature search independently. Eight articles on the combined approach of embolization and ablation in secondary liver lesions were selected. (3) Results: The studies were published between 2009 and 2020. Two studies were prospective in design. The sample size was < 100 patients for all studies. All studies demonstrated the safety of the combined approach based on the low complication rate. Some studies lamented non-uniform systemic chemotherapy regimens and the variability in the sequence of embolization and ablation. (4) Conclusions: This review presents the combined approach of ablation and embolization in liver lesions greater than 3 cm as a safe therapeutic procedure with positive effects on patient survival. Prospective and multicentric studies are needed to further evaluate its efficacy.

In Situ Thermal Ablation Repair of Delamination in Carbon Fiber-Reinforced Thermosetting Composites

Repairing delamination damage is critical to guarantee the structural safety of carbon fiber-reinforced thermosetting composites. The popular repair approaches, scarf repair and injection repair, can significantly restore the in-plane mechanical performance. However, the out-of-plane properties become worse due to the sacrifice of fiber continuity in these repairing processes, leading to the materials being susceptible under service loads. Here, we propose a novel in situ delamination repair approach of controllable thermal ablation in damage removal, achieving a high repair efficiency without impairing the fiber continuity in carbon fiber/epoxy panels. The epoxy resin in the delaminated region was eliminated under the carbonization temperature in a few minutes, allowing the carbon fiber frame to retain its structural integrity. The healing agent, refilled in the damaged region, was cured by the Joule heating of designed electrodes for 30 min at 80 °C, yielding the whole repair process to be accomplished within one hour. For the delaminated carbon fiber/epoxy panels with thicknesses from 2.5 to 6.8 mm, the in-plane compression-after-impact strength after repair could recover to 90.5% of the pristine one, and still retain 74.9% after three successive repair cycles of the 6.8 mm-thick sample. The simplicity and cost-saving advantages of this repair method offer great potential for practical applications of prolonging the service life of carbon fiber-reinforced thermosetting composites.

Hybrid ablation of persistent and long-standing persistent atrial fibrillation with depressed ejection fraction: A single-center observational study

ObjectiveThe relationship between atrial fibrillation (AF) and heart failure with depressed ejection fraction (EF) is complex. AF-related tachycardia-mediated cardiomyopathy (TMC) can lead to worsening EF and clinical heart failure. We sought to determine whether a hybrid team ablation approach (HA) can be performed safely and restore normal sinus rhythm in patients with TMC and heart failure and to delineate the effect on heart failure. MethodsWe retrospectively analyzed patients with nonparoxysmal (ie, persistent and long-standing persistent) AF-related TMC with depressed left ventricular EF (LVEF ≤40%) and heart failure (New York Heart Association [NYHA] class ≥2) who underwent HA between 2013 and 2018 and had at least 1 year of follow-up. Pre-HA and post-HA echocardiograms were compared for LVEF and left atrial (LA) size. Rhythm success was defined as <30 seconds in AF/atrial flutter/atrial tachycardia without class I or III antiarrhythmic drugs. Results are expressed as mean ± SD and 95% confidence interval (CI) of the mean. ResultsForty patients met the criteria for inclusion in our analysis. The mean patient age was 67 ± 9.4 years. The majority of patients had long-standing persistent AF (26 of 40; 65%), and the remainder had persistent AF (14 of 40; 35%). All patients had NYHA class II or worse heart failure (NYHA class II, 36 of 40 [90%]; NYHA class III, 4 of 40 [10%]). The mean time in AF pre-HA was 5.6 ± 6.7 years. All patients received both HA stages. No deaths or strokes occurred within 30 days. Three new permanent pacemakers (7.5%) were placed. Rhythm success was achieved in >60% of patients during a mean 3.5 ± 1.9 years of follow-up. LVEF improved significantly by 12.0% ± 12.5% (95% CI, 7.85%-16.0%; P < .0001), and mean LA size decreased significantly by 0.40 cm ± 0.85 cm (95% CI, 0.69-0.12 cm; P < .01), with a mean of 3.0 ± 1.5 years between pre-HA and post-HA echocardiography. NYHA class improved significantly after HA (mean pre-HA NYHA class, 2.1 ± 0.3 [95% CI, 2.0-2.2]; mean post-HA NYHA class, 1.5 ± 0.6 [95% CI, 1.3-1.7]; P < .0001). ConclusionsThoracoscopic HA of AF in selected patients with TMC heart failure is safe and can result in rhythm success with structural heart changes, including improvements in LVEF and LA size.

Targeted Treatment of Inappropriate Sinoatrial Node Tachycardia Based on Electrophysiological and Structural Mechanisms

The purpose of this review is to determine the causal mechanisms and treatment of inappropriate sinoatrial tachycardia (IST), defined as a non-physiological elevation in resting heart rate. IST is defined as a resting daytime sinus rate >100 beats/minute and an average 24-hour heart rate >90 beats/minute. Potential causal mechanisms include sympathetic receptor hypersensitivity, blunted parasympathetic tone, or enhanced intrinsic automaticity within the sinoatrial node (SAN) pacemaker-conduction complex. These anomalies may coexist in the same patient. Recent ex-vivo near-infrared transmural optical imaging of the SAN in human and animal hearts provides important insights into the functional and molecular features of this complex structure. In particular, it reveals the existence of preferential sinoatrial conduction pathways that ensure robust SAN activation with electrical conduction. The mechanism of IST is debated because even high-resolution electroanatomical mapping approaches cannot reveal intramural conduction in the 3-dimensional SAN complex. It may be secondary to enhanced automaticity, intranodal re-entry, or sinoatrial conduction pathway re-entry. Different pharmacological approaches can target these mechanisms. Long-acting β blockers in IST can act on both primarily increased automaticity and dysregulated autonomic system. Ivabradine targets sources of increased SAN automaticity. Conventional or hybrid ablation may target all the described abnormalities. This review provides a state-of-the-art overview of putative IST mechanisms. In conclusion, based on current knowledge, pharmacological and ablation approaches for IST, including the novel hybrid SAN sparing ablation, are discussed.

Three-dimensional electroanatomically guided slow pathway elimination is associated with procedural improvements and clinical benefit in atrioventricular node reentrant tachycardia patients.

Slow pathway (SP) ablation, in the context of atrioventricular node reentrant tachycardia (AVNRT) treatment could result in either complete elimination or only modification of the SP with ambiguity regarding associated benefits. Three-dimensional electroanatomical mapping (3D-EAM) may be used adjunctively aiming to complete SP elimination. Our purpose was to compare a 3D-EAM-based strategy targeting SP elimination to the conventional fluoroscopic approach with respect to clinical outcomes. One hundred and two consecutive AVNRT patients (36 males, mean age 53.2 ± 13.7 years) underwent in two successive periods a conventional fluoroscopic ablation approach (n=42) or a 3D-EAM-guided ablation focusing on complete SP elimination (n=60). Several procedural parameters improved with 3D-EAM use, including fluoroscopy time (2.4 ± 4.7min vs. 13 ± 4.5min), dose-area product (1061 ± 3122 μGy × m2 vs. 5002 ± 3032 μGy × m2) and slow pathway elimination frequency (95% vs. 50%, all p < .001). Procedural time was slightly prolonged in the 3D-EAM group (101 ± 31 min vs. 87 ± 24 min, p=.013). Two major complications occurred in the conventional group. Altogether, over a mean follow-up of approximately 2.7 years, recurrence occurred in 6 of 42 (14.3%) in the conventional group as compared to 1 of 62 (1.7%) in the EAM-based group (p=.019). In the Kaplan-Meier analysis, time-to-event was significantly longer for the EAM-based patients (p < .030). Moreover, the EAM-based strategy was associated with less redo procedures' rates (9.5% in the non-EAM group vs. 0% in the EAM group, p=.026). The present study showed that an EAM-based SP elimination strategy is not only feasible and safe but it is also accompanied by improved clinical outcomes in the setting of AVNRT ablation.

Photocatalytic Performance Improvement by Doping Ag on ZnO/MWCNTs Nanocomposite Prepared with Pulsed Laser Ablation Method Based Photocatalysts Degrading Rhodamine B Organic Pollutant Dye.

ZnO/MWCNTs nanocomposite has significant potential in photocatalytic and environmental treatment. Unfortunately, its photocatalytic efficacy is not high enough due to its poor light absorbance and quick recombination of photo-generated carriers, which might be improved by incorporation with noble metal nanoparticles. Herein, Ag-doped ZnO/MWCNTs nanocomposite was prepared using a pulsed laser ablation approach in the liquid media and examined as a degradable catalyst for Rhodamine B. (RhB). Different techniques were used to confirm the formation of the nanostructured materials (ZnO and Ag) and the complete interaction between them and MWCNTs. X-ray diffraction pattern revealed the hexagonal wurtzite crystal structure of ZnO and Ag. Additionally, UV-visible absorption spectrum was used to study the change throughout the shift in the transition energies, which affected the photocatalytic degradation. Furthermore, the morphological investigation by a scanning electron microscope showed the successful embedding and decoration of ZnO and Ag on the outer surface of CNTs. Moreover, the oxidation state of the formed final nanocomposite was investigated via an X-ray photoelectron spectrometer. After that, the photocatalytic degradations of RhB were tested using the prepared catalysts. The results showed that utilizing Ag significantly impacted the photo degradation of RhB by lowering the charge carrier recombination, leading to 95% photocatalytic degradation after 12 min. The enhanced photocatalytic performance of the produced nanocomposite was attributed to the role of the Ag dopant in generating more active oxygen species. Moreover, the impacts of the catalyst amount, pH level, and contact time were discussed.