bluuebunny/crossref_metadata_2025 huggingface dataset:
Low annealing temperature effect on Structural, and optical properties of CuO nanostructure thin films
Authors: Omran Alkhayatt Adel H. , Muhammad Shawki Khalaf , Habieb Azher A. , Ali Asala H. , Mohsen Suhad H. , Munem Ruaa Radhi
Published: June 2020

In present work, the modified chemical bath deposition method (CBD) called successive ionic layer adsorption and reaction effective coast method was used for deposited copper oxide CuO nanostructured thin films. Structural, surface texture and optical characteristics of the deposited films were studied as a function of low annealing temperature (150, 200 and 250) °C. X-ray diffraction studies showed that the as-deposited and annealed films exhibited low crystallinity of polycrystalline nature in the monoclinic phase. It is observed a fixed or very little increment of peaks intensity and the crystallinity of the deposited films with the increase of annealing temperature to 250 °C. The lattice constants were calculated and show good agreement with the standard values. The crystallite size was decreased, whereas the dislocation density and the number of crystallites were increased with the increment of annealing temperature. The average grain diameter was increased and the average surface roughness decreased with the increment of annealing temperature. The optical energy gap for the as-deposited film is 1.87eV and increased to (2.03, 2.06 and 2.09) eV with the increment of annealing temperatures. The Urbach tails energy width decreased from 0.91 eV to (0.73, 0.54 and 0.46) eV for as-deposited and annealed films at low temperatures (150, 200 and 250) °C respectively. The low annealing temperatures was used because the deposition process was performs at low temperatures below 100 °C, therefore_it can be concluded that the low annealing temperatures used in this work are not suitable temperatures for the growth of CuO films and it can be above 300 °C to enhance the film crystallinity and formation of CuO phase.
Growth of 3-Dimentional MoS2-PANI nanofiber for high electrochemical performance
Authors: Ganesha H , Veeresh S , Nagaraju Y S , Vandana M , Ashokkumar S P , Vijeth H , Devendrappa H
Published: June 2020

The preparation of few layered 3D material Molybdenum/Polyaniline (MoS2/PANI) nanofiber (NF) composite synthesis via a hydrothermal process. MoS2/PANI nanofiber composite was characterized via Fourier-transform infrared (FT-IR) spectra to study the chemical functional group and their interaction, and optical properties examine by the UV-visible spectra. Formation of nanosheet and 3D hierarchical flower morphology was examined through Field emission scanning electron microscopy (FESEM), and the elemental analysis examined through Energy- dispersive x-ray (EDX), and Transmission electron microscopy (TEM). XRD studies show the properties of crystalline nature of the nanocomposite. Binding energy and composite elemental identified states measured through x-ray photon spectroscopy(X-PS). The Electrochemical technique was used to investigate cyclic voltammetry, and electrochemical catalytic activity evaluated from EIS which obtained resistance is 137.52 Ω, 66.40 Ω, and 15.25 Ω respectively. Linear sweep voltammetry, CV oxidation peak reached maximum oxidation current is 2.72 × 10–4 Amperes, and curve appeared between −4.5 to 4.5 Volt. Finally MoS2-PANI-1 Nanofiber composite is prominent material for electrochemical performance.
rGO/persulfate metal-free catalytic system for the degradation of tetracycline: effect of reaction parameters
Authors: Tran Dinh Trinh , Nguyen Van Noi
Published: June 2020

Reduced graphite oxide (rGO) was synthesized from graphene oxide (GO) by reduction process with the aid of ascorbic acid. GO was synthesized from graphite precursor by modified Hummers method. The prepared materials were characterized in terms of surface morphology, structure, functional group, and elemental compositions by different methods such as SEM/EDS, XRD, FT-IR, Raman, and BET. rGO/K2S2O8 system was used to study the impact of different reaction parameters on the degradation of tetracycline in water. The results showed that GO and rGO materials were successfully synthesized, with high purity. The prepared rGO promoted the degradation of tetracycline by sulphate radicals generated from K2S2O8 with an efficiency of two-fold higher than sole K2S2O8. More than 95% of 5 mg l−1 tetracycline were removed by rGO/K2S2O8 system after 40 min of reaction. The catalytic performance of rGO/K2S2O system in the degradation of tetracycline was dependent on pH of the solution, catalyst loading, tetracycline initial concentration, and persulfate concentration. The optimal conditions for the degradation of tetracycline in water were at pH10, with 5 mg l−1 tetracycline initial concentration, 20 mg l−1 of rGO, and 0.2 mM persulfate added. The catalytic performance of the system showed relatively stable, with about 75% tetracycline in solution were removed after 3 cycles. The degradation of tetracycline by rGO/K2S2O8 system followed the pseudo-first order kinetics, with a typical coefficient of determination above 0.95 for all experimental conditions.
Application of the Environmental Relative Moldiness Index in Indoor Marijuana Grow Operations
Authors: Root Kyle S , Magzamen Sheryl , Sharp Julia L , Reynolds Stephen J , Van Dyke Michael , Schaeffer Joshua W
Published: June 2020

Objectives

Indoor marijuana grow operations (IMGOs) are increasing due to legalization of recreational and medicinal cannabis at the state level. However, the potential exposures of IMGO workers have not been well studied. Mold exposure has been identified as a major occupational health concern. Mold-specific quantitative polymerase chain reaction (MSQPCR) can provide quantitative exposure data for fungi at the species level. The purpose of this study was to characterize the airborne fungal burden using MSQPCR and to evaluate the applicability of an airborne Environmental Relative Moldiness Index (ERMI) in IMGOs.

Methods

Air and dust samples were collected inside and outside the IMGOs and then analyzed via MSQPCR. These data were then used to calculate IMGO-specific ERMI scores. Culturable air samples were collected on agar plates and analyzed via microscopy. Differences were evaluated between indoor and outdoor concentrations, as well as between air and dust samples. The agreement between MSQPCR and culture-based methods was also evaluated.

Results

Based on the geometric means for non-zero values of each fungal species across all IMGOs, the total airborne concentration was approximately 9100 spore equivalent (SE) m−3 with an interquartile range (IQR) of 222 SE m−3. The indoor/outdoor ratio of geometric means across all 36 species per IMGO ranged from 0.4 to 6.2. Significantly higher indoor concentrations of fungal species, including Aspergillus spp., were observed. An average airborne ERMI score of 7 (IQR = 7.6) indicated a relatively high burden of mold across a majority of operations. The ERMI scores were driven by the high concentrations of Group 1 species with a mean of 15.8 and an IQR of 13. There were 63 additional species identified in the culturable air samples not included in the ERMI.

Conclusions

High concentrations of airborne fungi were identified in IMGOs. Our evaluation of the ERMI based on MSQPCR as a rapid diagnostic and risk assessment tool for industrial hygienists in the IMGO setting is equivocal. ERMI did not identify all relevant fungal species associated with this specific occupational environment. We identified several issues with using the ERMI calculation. At this time, the catalog of fungal species needs to optimized for the occupational setting to ensure adequate coverage, especially for those species expected to be found in this burgeoning industry. Further research is necessary to elucidate the link between the ERMI score of airborne samples, worker exposure and health effects in grows to generate an acceptable index score for use in occupational exposure assessments.
AntiCP 2.0: an updated model for predicting anticancer peptides
Authors: Agrawal Piyush , Bhagat Dhruv , Mahalwal Manish , Sharma Neelam , Raghava Gajendra P S
Published: June 2020

Increasing use of therapeutic peptides for treating cancer has received considerable attention of the scientific community in the recent years. The present study describes the in silico model developed for predicting and designing anticancer peptides (ACPs). ACPs residue composition analysis show the preference of A, F, K, L and W. Positional preference analysis revealed that residues A, F and K are favored at N-terminus and residues L and K are preferred at C-terminus. Motif analysis revealed the presence of motifs like LAKLA, AKLAK, FAKL and LAKL in ACPs. Machine learning models were developed using various input features and implementing different machine learning classifiers on two datasets main and alternate dataset. In the case of main dataset, dipeptide composition based ETree classifier model achieved maximum Matthews correlation coefficient (MCC) of 0.51 and 0.83 area under receiver operating characteristics (AUROC) on the training dataset. In the case of alternate dataset, amino acid composition based ETree classifier performed best and achieved the highest MCC of 0.80 and AUROC of 0.97 on the training dataset. Five-fold cross-validation technique was implemented for model training and testing, and their performance was also evaluated on the validation dataset. Best models were implemented in the webserver AntiCP 2.0, which is freely available at https://webs.iiitd.edu.in/raghava/anticp2/. The webserver is compatible with multiple screens such as iPhone, iPad, laptop and android phones. The standalone version of the software is available at GitHub; docker-based container also developed.
Functional Organization for Response Inhibition in the Right Inferior Frontal Cortex of Individual Human Brains
Authors: Suda Akimitsu , Osada Takahiro , Ogawa Akitoshi , Tanaka Masaki , Kamagata Koji , Aoki Shigeki , Hattori Nobutaka , Konishi Seiki
Published: June 2020

The right inferior frontal cortex (IFC) is critical to response inhibition. The right IFC referred in the human studies of response inhibition is located in the posterior part of the inferior frontal gyrus and the surrounding regions and consists of multiple areas that implement distinct functions. Recent studies using resting-state functional connectivity have parcellated the cerebral cortex and revealed across-subject variability of parcel-based cerebrocortical networks. However, how the right IFC of individual brains is functionally organized and what functional properties the IFC parcels possess regarding response inhibition remain elusive. In the present functional magnetic resonance imaging study, precision functional mapping of individual human brains was adopted to the parcels in the right IFC to evaluate their functional properties related to response inhibition. The right IFC consisted of six modules or subsets of subregions, and the spatial organization of the modules varied considerably across subjects. Each module revealed unique characteristics of brain activity and its correlation to behavior related to response inhibition. These results provide updated functional features of the IFC and demonstrate the importance of individual-focused approaches in studying response inhibition in the right IFC.
Long-term overlap of social and genetic structure in free-ranging house mice reveals dynamic seasonal and group size effects
Authors: Evans Julian C , Lindholm Anna K , König Barbara
Published: June 2020

Associating with relatives in social groups can bring benefits such as reduced risk of aggression and increased likelihood of cooperation. Competition among relatives over limited resources, on the other hand, can induce individuals to alter their patterns of association. Population density might further affect the costs and benefits of associating with relatives by altering resource competition or by changing the structure of social groups; preventing easy association with relatives. Consequently, the overlap between genetic and social structure is expected to decrease with increasing population size, as well as during times of increased breeding activity. Here, we use multi-layer network techniques to quantify the similarity between long-term, high resolution genetic, and behavioral data from a large population of free-ranging house mice (Mus musculus domesticus), studied over 10 years. We infer how the benefit of associating with genetically similar individuals might fluctuate in relation to breeding behavior and environmental conditions. We found a clear seasonal effect, with decreased overlap between social and genetic structure during summer months, characterized by high temperatures and high breeding activity. Though the effect of overall population size was relatively weak, we found a clear decrease in the overlap between genetic similarity and social associations within larger groups. As well as longer-term within-group changes, these results reveal population-wide short-term shifts in how individuals associate with relatives. Our study suggests that resource competition modifies the trade-off between the costs and benefits of interacting with relatives.
233Conventional fluoroscopy guided vs zero-fluoroscopy catheter ablation of supraventricular tachycardias
Authors: Prolic Kalinsek T , Pernat A , Jan M , Sorli J , Vrbajnscak M , Sinkovec M , Antolic B , Klemen L
Published: June 2020

Funding Acknowledgements

None

Introduction

Conventionally, catheter movement and placement during catheter ablation (CA) is guided by X-ray fluoroscopy. In recent years, an ‘as low as reasonably possible’ principle was established to minimize the ionizing radiation dose received by the patient and the operator. Zero-fluoroscopy approach is at the extreme end of the spectrum of this principle. With exclusion of X-ray fluoroscopy, three-dimensional electroanatomical mapping system and intracardiac echocardiography are used for catheter guidance during ablation procedures.

Purpose

The aim of our study was to assess and compare procedural parameters and clinical outcomes of conventional X-ray fluoroscopy guided and zero-fluoroscopy CA for treatment of supraventricular tachycardias.

Methods

Retrospective analysis included CA procedure between April 2014 and May 2019. Five hundred and thirteen (513) patients were selected for analysis; they had confirmed diagnosis of atrioventricular nodal reentry tachycardia (AVNRT) or atrioventricular reentry tachycardia (AVRT). Patients were divided into two groups based on the use of fluoroscopy (conventional approach group - CG; zero-fluoroscopy group - ZF). Procedural data and clinical outcomes were analyzed. Two groups were compared using chi-squared test or Mann-Whithney U test when appropriate.

Results

There were 249 patients (44.2% males) in CG group, and 260 patients (47.5% males) in ZF group. ZF group included 113 (43.5%) pediatric patients. The groups differed in mean age (53.4 ± 16.4 years vs 30.0 ± 19.8 years (CG vs ZF), p < 0.001), postprocedural use of antiarrhythmic agents or beta blockers (55.3% vs 17.0% (CG vs ZF), p < 0.001) and type of arrhythmia (72.3% vs 60.6% AVNRT (CG vs ZF), p = 0.003).

In CG group, all procedures were performed using radiofrequency (RF) energy, whereas in ZF group, cryoablation was used in 18.3% of procedures at the discretion of the operator. Mean procedural duration was longer in CG group (100.1 ± 48.8 vs 90.4 ± 83.0 minutes, p < 0.001). The mean fluroscopy time was 13.6 ± 9.3 minutes and mean dose area product was 554.1 ± 713.6 mGycm2 in the CG group. Acute success rate was higher in CG group (95.7 vs 90.7%, p = 0.027). However, the arrhythmia-free survival rate after 13.8 ± 11.0 months of follow-up was lower in the CG group (90.9 vs 96.5%, p = 0.009). Mean number of procedures per patient was 1.04 in the CG group and 1.14 in the ZF group (p < 0.001). There were no severe complications.

Conclusions

Zero-fluoroscopy CA of supraventricular tachycardias is associated with lower procedural success rate, but higher long-term arrhythmia-free survival rate when compared to conventional fluoroscopy guided procedures. It is possible, that these differences are stemming from somewhat different patient populations in both groups.
133Bipolar ablation of refractory ventricular arrhythmias originating from the close proximity of His bundle
Authors: Futyma P R , Ciapala K , Gluszczyk R , Sander J , Futyma M , Kulakowski P
Published: June 2020

Introduction

Biophysics of bipolar radiofrequency catheter ablation (Bi-RFCA) suggest more condensed and selective lesion formation when compared to conventional-unipolar approach. Whether more selective Bi-RFCA can result in safe and effective ablation of arrhythmic substrates in close proximity of His bundle has not been investigated so far.

Purpose

To determine feasibility and effectiveness of Bi-RFCA in His bundle area.

Methods

Consecutive patients after failed unipolar ablation for symptomatic premature ventricular complexes (PVC) or ventricular tachycardia (VT) originating from the vincity of His bundle underwent Bi-RFCA.

Results

We ultimately enrolled 8 patients (2 females, age 60 ± 15 years) to undergo Bi-RFCA of PVC/VT. Previous pharmacological treatment consisting of at least one antiarrhythmic drug and conventional catheter ablation failed in all. Bi-RFCA using open-irrigated and non-irrigated ablation catheters (AC) was delivered from two earliest PVC/VT activation sites located in the vincity of His bundle (Figure, panels A-B). A total number of 93 bipolar applications were delivered (mean bipolar RF time 508 ± 565s, mean power 35 ± 13W, mean impedance 163 ± 18Ω). Transient conduction disturbances occurred in 2 patients and were associated with mechanical compression of conduction system. No persistent conduction disturbances occurred. Bipolar RFCA led to acute elimination of PVC/VT in 6 (75%) patients. Follow up lasted 11 ± 5 months: two patients underwent repeat procedure using dual-irrigated Bi-RFCA, there was no VT recurrence and 72% PVC burden reduction was achieved (16200 ± 11600 pre-ablation vs 4500 ± 6200 post-ablation PVC/day, p = 0,035) (Figure, panel C).

Conclusion

Bi-RFCA performed in proximity of His bundle can be safe and effective in majority of patients.

Abstract Figure. Bipolar ablation of parahisian PVC/VT
P568Catheter ablation for atrial fibrillation with heart failure with preserved ejection fraction
Authors: Rattka M , Kuehberger A , Stephan T , Weinmann K , Felbel D , Baumhardt M , Bothner C , Pott A , Dahme T
Published: June 2020

Background

Atrial fibrillation (AF) in patients suffering from heart failure with preserved ejection fraction (HFpEF) is associated with increased symptoms and higher morbidity and mortality. Effective treatment strategies for this patient population have not yet been established.

Aim

This study aimed to compare the impact of catheter ablation for AF against the current standard therapy on patients with HFpEF.

Methods

We retrospectively compared clinical outcomes and echocardiographic parameters of patients with AF and HFpEF, who either underwent medical therapy (rate or rhythm control) or catheter ablation for AF. The primary endpoint was a composite of death and hospitalization for any cause and the secondary endpoint a composite of cardiovascular death and cardiovascular hospitalization. Additionally, we assessed NYHA-class, relevant echocardiographic parameters, current ESC diagnosis criteria for HFpEF at baseline and at the end of follow-up, as well as time-to-AF recurrence in both groups. Resolution of HFpEF was estimated, if both left ventricular mass index(LVMI) and E/e’ ratio did not fulfil the ESC-criteria at the end of follow-up. 

Results

Between January 2013 and December 2018 6.114 patients were treated for AF at our university hospital department. Of those, 752 patients suffered from heart failure symptoms and had echocardiographic diastolic dysfunction. Applying the current ESC-criteria HFpEF was diagnosed in 127 patients. While 59 patients received medical therapy only, catheter ablation for AF was performed in 68 patients. Analysis of AF recurrence in both groups revealed, that in the ablation group 82% of patients and in the medical therapy group only 25% of patients were free from any atrial arrhythmia after one year. Reevaluation of echocardiographic parameters after a mean follow-up period of 39 ± 20 months showed no difference in the medical therapy group, but revealed a significant improvement of the mitral E-wave velocity, E/E’ ratio, LVMI, interventricular septal thickness, e’ velocity and left ventricular diastolic in the catheter therapy group, suggesting reverse remodeling. Reassessment of criteria for HFpEF diagnosis showed resolution of HFpEF in 35% of invasively treated patients compared to 12% of patients who received conservative therapy only (p = 0.002). Moreover, heart failure symptoms, monitored by NYHA-class, significantly worsened in the medical therapy group, whereas there was significant improvement after catheter ablation. Furthermore, assessment of the primary and secondary endpoint displayed significant lower rates of events.

Conclusion

This is the first study comparing the effect of catheter ablation for AF with the current standard therapy in patients with concomitant HFpEF. Our results suggest that catheter ablation is able to induce reverse remodeling of HFpEF, possibly thereby reducing typical heart failure symptoms and hospitalizations.
P420Improved real time recordings using the third generation cryoballoon technology - detection of dual fascicle electrograms
Authors: Velagic V , Prepolec I , Pasara V , Kardum D , Pezo-Nikolic B , Puljevic M , Matasic R , Krpan M , Lovric-Bencic M , Puljevic D , Milicic D
Published: June 2020

Introduction

The third-generation cryoballoon has been designed with a 40% shortened tip length compared with the former second-generation CB device. Ideally, a shorter tip could result with an improved visualization of real-time (RT) recordings in the pulmonary vein (PV) due to a more proximal positioning of the inner lumen mapping catheter. Beside the high incidence of RT recordings, for the first time, we observed dual fascicle electrograms with different isolation time for each fascicle, when using the new device.

Purpose

We sought to analyze the rate of visualization of RT recordings and dual fascicle electrograms in our first series of patients with the third generation cryoballoon device.

Methods

All consecutive patients having undergone CB ablation using the third generation technology were analyzed. Procedures were performed under conscious sedation. A single transeptal puncture was preformed guided by intracardial ultrasound and a 28 mm cryoballoon was used. A single 180 seconds freeze strategy was employed.

Results

A total of 80 consecutive patients (77.5% male, 60.3 ± 10.8 years) were evaluated. Real-time recordings were detected in 275 of 320 PVs (85.9%). Specifically, RT recordings could be visualized in 68 left superior PVs (85%), 69 left inferior PVs (86.2%), 73 right superior PVs (91.2%), and 65 right inferior PVs (81.2%). Furthermore, in 14 of 320 PVs (4.3%) two different fascicles electrograms were detected. A distinctive isolation time for each fascicle could be observed both in sinus rhythm and in atrial fibrillation (Picture). Most commonly, dual fascicles were observed in left superior PV (7.5%) and right inferior PV (6.3%). In the rest of the veins this phenomenon was not so frequent. In 2.5% of right superior PV and in only 1.2% of left inferior PV dual fascicles could be observed.

Conclusion

The rate of visualization of RT recordings is significantly high during third generation CB ablation. Real-time recordings can be visualized in 85.9% of veins with this novel cryoballoon. Furthermore, for the first time, isolation of two different fascicles during a single cryoballoon lesion could be observed. Other that more proximal mapping catheter position, there is second possible explanation for the visualization of dual fascicles with this novel balloon. Shorter tip could result with poorer cryoballoon stability and weaker contact with the atrium wall, hence non-uniform freezing and isolation of different fascicles in different times.

Abstract Figure.
P451Optimizing the EP lab workflow in atrial fibrillation ablation - The use of Z stitch for groin access closure
Authors: Velagic V , Prepolec I , Pasara V , Pezo-Nikolic B , Puljevic M , Matasic R , Krpan M , Lovric-Bencic M , Puljevic D , Milicic D
Published: June 2020

Introduction

As catheter ablation became the standard therapy for atrial fibrillation (AF), the number of AF procedures has risen exponentially. Therefore, workflow optimization is crucial in order to meet the rising demands for EP interventions. Recently, instead of standard groin compression we have started using the "Z stitch" for introducers’ removal. This novel method does not necessitate protamine administration and often lengthy manual compression.

Purpose

We aim to demonstrate utilization of "Z stitch" for groin access closure in cryoballoon (CB) ablation and its impact on EP lab workflow.

Methods

We have analyzed all patients having undergone CB ablation utilizing the "Z stitch" (Z group) and the last 50 consecutive CB patients who received standard groin compression (non-Z group). Procedures were performed under conscious sedation. Both femoral veins were punctured and a single introducer was placed in each vein. A single transeptal puncture was preformed guided by intracardial ultrasound and a 28 mm cryoballoon was used. A single 180 seconds freeze strategy was employed.

In the past, protamine was slowly administered after ablation and at least 15 minute manual groin compression was applied until no visual bleeding could be detected. Elastic bandage was placed around both groins. Later on, the "Z stitch" was used around both introducers without the need for protamine administration, manual compression and bandage placement (Picture). The stitches were removed next morning.

Results

A total of 100 consecutive patients (79% male, 61.2 ± 10.6 years old) were evaluated, 50 in both groups. There was no difference in the mean procedure duration ("skin to skin") between two groups. However, a total lab time was significantly longer in non-Z group. There was no differences in complication rates, which consisted solely of phrenic nerve palsy and groin complications. There was no AV fistula or pseudoaneurysms detected in our cohort (Table).

Conclusion

Utilization of Z stitches for introduces’ removal seems safe and effective way to achieve hemostasis after cryoballoon ablation. It abolishes the need for protamine administration which can cause serious advert events. Manual compression is no longer required. Consequently, EP lab workflow is improved, since the total lab time utilization per patient is significantly shortened.

Results non-Z group Z group p Procedure duration (min) 69.4 ± 20.4 73.4 ± 24.8 0.380 Lab time (min) 129.9 ± 35.3 109.1 ± 30.6 0.002 Complications (N) 5 (2 hematoma) 4 (2 hematoma) NS

Abstract Figure. Z stich
741Pharmacological inhibition of the acetylcholine-regulated potassium channel (IK,ACh) prevents atrial arrhythmogenic changes in a rat model for obstructive sleep apnea
Authors: Linz B , Rombouts K , Thostrup A H , Hohl M , Wirth K , Linz D , Jespersen T
Published: June 2020

Background

In obstructive sleep apnea (OSA), intermittent hypoxemia and intrathoracic pressure fluctuations may increase vagal tone, resulting in an increased acetylcholine-regulated potassium current (IK,ACh). Here we elucidated acute atrial electrophysiological effects of obstructive respiratory events simulated by intermittent negative upper airway pressure (INAP) and the role of atrial IKACh activation.

Methods

In sedated spontaneously breathing rats (2% isoflurane), either IK,ACh-inhibitor (XAF-1407: 1mg/kg) or a buffer-based vehicle was perfused (Control). INAP was applied non-invasively by a negative pressure device 14 times throughout 70 minutes. Simulated apneas were maintained for one minute with a four minute resting period. Atrial effective refractory period (AERP), inducible atrial fibrillation (AF)-durations and atrial activation time were acquired by a programmed atrial pacing protocol before, during and after applied INAP throughout the study.

Results

During single INAP applications atrial activation times prolonged transiently in both groups (Control: INAP vs. pre-INAP p = 0.034; XAF-1407: INAP vs. pre-INAP p = 0.039). In control-rats, seventy minutes of repetitive INAP prolonged P-wave duration (+10.8 ± 2.7% vs. baseline, p = 0.008) and decreased AERP by 14.6 ± 3.1% (vs. baseline p = 0.001). AERP shortening correlated with the cumulative pressure applied per body weight (Pearson r= -0.773; p= 0.025). XAF-1407 could prevent P-wave prolongation and AERP shortening. Inducible AF-durations (CTR 0.94 ± 0.34s vs. XAF-1407 0.1 ± 0.09s p = 0.049) were shorter in XAF-1407 treated rats. Drops in oxygen saturation or applied INAP were comparable in control and XAF-1407 rats.

Conclusion

Short-term simulated OSA is associated with AF-related arrhythmogenic changes, which could be prevented by pharmacological IK,ACh inhibition. Moreover, the cumulative negative airway pressure applied determined aERP shortening and may represent a target for OSA treatment. These findings have important implications for the antiarrhythmic management of AF patients with OSA.
P1056Left atrial and left atrial appendage ejection fraction assessed by preprocedural cardiac CT are useful parameters for predicting the outcome of pulmonary vein isolation
Authors: Rezar R , Kaufmann R , Strohmer B , Wernly B , Lichtenauer M , Hitzl W , Hergan K , Granitz M
Published: June 2020

Introduction

Pulmonary vein isolation (PVI) is an effective but complex treatment option for atrial fibrillation (AF). Therefore preprocedural outcome prediction is of special interest. Left atrial volume (LAVmax) is a commonly used predictor for recurring arrhythmia. Several studies have investigated different parameters for the prediction of sustained rhythm control. We hypothesized that left atrial and left atrial appendage ejection fraction (LAEF & LAAEF) assessed by high-resolution CT-imaging are even more sensitive predictors of the outcome of PVI than LAVmax.

Methods

All patients who underwent PVI between 2015 and 2018 with available preinterventional cardiac CT were included in this retrospective study and separated into 2 groups: Group A comprises all patients with sinus rhythm (SR) at follow-up and group B all patients in whom recurrence of AF was observed. Volumetric analysis of the left atrium was performed in ventricular systole (30%-Phase of the cardiac cycle) and diastole (0%-Phase). Obtained data were used to calculate left atrial and left appendage ejection fractions (LAEF & LAAEF). Success of pulmonary vein isolation was defined as clinical freedom of symptomatic AF together with sinus rhythm on the available Holter-ECG recordings during follow-up examinations. Uni- and multivariate logistic regression models and NAMS RMLE tests were used to compare LAVmax to these functional parameters.

Results

In total 152 patients with symptomatic paroxsymal or persistent AF underwent PVI at our hospital from 2015 to 2018. Due to inconsistencies in archiving in our PACS-system, 98 patients had to be excluded from analysis. Four patients were excluded due to motion artifacts. 50 patients were included in the final study (41 patients without and 9 patients with recurring AF on average 254 days after ablation). Significant differences in means were found for all assessed parameters. LAEF (accuracy 94%, sensitivity 67%) and LAAEF (accuracy 90%, sensitivity 67%) had a higher sensitivity than LAVmax (accuracy 86%, sensitivity 33%), though not significant in this study population (p = 0.18). LAVmax and LAEF in combination improved sensitivity significantly from 33% to 78% (p = 0.046). Measurements on cardiac-CT showed an excellent interobserver-reliability.

Conclusion

Reduced LAEF and LAAEF were found to be significant predictors of the outcome of PVI. Furthermore we found a trend that these functional parameters might be more sensitive than LAVmax. Thus we propose that left atrial function, assessed with preprocedural cardiac CT, offers important prognostic information for successful PVI.

Abstract Figure. Surface rendering of LA and LAA
P1028Incidence and location of residual gaps identified by a high-density grid-style mapping catheter after PVI is confirmed by pacing the ablation lines
Authors: Giuggia M , Volpicelli M , Bottoni N , Gora P , Mantica M
Published: June 2020

Background

 Durable pulmonary vein isolation (PVI) is critical to the clinical success of ablation for treatment of atrial fibrillation (AF). Pacing along the ablation line (often using the ablation catheter), is one technique that is commonly used for confirmation of PVI. While this technique is common in practice, it has not been systematically evaluated against other methods for confirming PVI. A high-density grid-style mapping catheter (HD Grid) enabling simultaneous recording of adjacent bipolar EGMs in two directions (HD Wave) is now available in multiple geographies. The sensitivity of this technology for periprocedural identification of gaps in PVI lines has not previously been compared to the technique of pacing the ablation lines.

Purpose

 To assess the utility of a high-density grid-style catheter for confirming PVI, and to evaluate sensitivity for identification of gaps relative to a technique of pacing the ablation lines.

Methods

 Self-reported procedural data was prospectively collected in atrial fibrillation ablation procedures. Cases in which pulmonary vein isolation was confirmed by pacing the ablation line and subsequently assessed with HD Grid were selected for analysis. Techniques for PVI confirmation were analyzed and the incidence and location of residual gaps following PVI confirmation via pacing was quantified.

Results

 A total of 22 AF ablation procedures (age 60.1 ± 9.0 years, LVEF 59.3 ± 5.7%, CHADS 1.5 ± 1.4, hypertension 45.5%) across 5 centers in Italy and the United States were analyzed. De novo and repeat ablations represented 72.7% and 22.7% of cases, respectively (4.5% not reported). PVI was confirmed by pacing along the ablation line with an average output of 8.8 ± 1.9mV and pulse width of 2.2 ± 0.7ms (10mv at 2ms utilized in 59.1%). Subsequent PVI assessment was performed with HD Grid using the HD Wave configuration in all cases. PVI confirmation techniques included exit block confirmation (90.9%), voltage mapping (59.1%), loss of pace capture along ablation lines (40.9%), entrance block confirmation (18.2%), and activation mapping (4.5%); note: total exceeds 100% as more than one technique may be employed in a single case. The HD Grid identified a total of 30 gaps in 15 (68.2%) patients, which were initially missed by pacing along the ablation lines. No adenosine or isoproterenol use was documented in any case.

Conclusion(s): Use of the HD Grid appears to increase substantially, the sensitivity for identifying gaps in PVI lesion sets relative to a technique of pacing the ablation line. Limitations of this analysis include small sample size and workflows which consistently assessed PVI with the HD grid following confirmation of isolation by pacing the ablation lines. Despite these limitations, the high prevalence of residual gaps is quite provocative and may warrant additional study.

Abstract Figure.
P1023Comparison of gap identification using three technologies for confirmation of pulmonary vein isolation
Authors: Porterfield C , Wystrach A , Rossi P , Rillo M , Sebag F , Dorszewski A , Gora P , Nilsson K
Published: June 2020

Background

 Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. Tools and techniques used for confirmation of PVI vary greatly, and it is unclear whether the use of any particular combination of tools and techniques provides greater sensitivity for identifying gaps periprocedurally. A high-density mapping catheter enabling simultaneous recording of adjacent bipolar EGMs in two directions is now available in multiple geographies, and it has been suggested that this technology may provide improved sensitivity for gap identification.

Purpose

 To identify trends in the incidence of gaps identified in de novo PVI lines using three diagnostic catheter technologies, which may be suggestive of improved sensitivity for gap identification.

Methods

 Self-reported procedural data was prospectively collected in de novo atrial fibrillation ablation cases utilizing one of three technologies to confirm PVI: 10-pole circular mapping catheter (CMC10), 20-pole circular mapping catheter (CMC20), and Advisor HD Grid catheter (HD Grid). Techniques for PVI confirmation were analyzed for each group, and the incidence and location of gaps identified by each technology was quantified. 

Results

 Data was collected in 99 cases across 11 centers in Europe and the United States. PVI was confirmed via entrance and/or exit block in all cases. CMC10 was utilized in 30 cases, CMC20 in 36, and HD Grid in 33. Use of adenosine varied across groups (CMC10: 6.7%; CMC20: 86.1%; HD Grid: 41.7%), as did application of a waiting period (CMC10: 96.7%; CMC20: 2.8%; HD Grid: 11.1%). Gaps were identified in in 36.7%, 38.9%, and 81.8% of cases using CMC10, CMC20, and HD Grid, respectively. HD Grid identified significantly more gaps than the other two technologies (p = 0.015), identifying an average of 49.0% and 139.1% more gaps per patient than CMC20 and CMC10, respectively (HD Grid: 2.15/patient; CMC20: 1.44/patient; CMC10: 0.9/patient). The location and incidence of gaps identified by each technology is shown in Figure 1. 

Conclusions

 Significantly more gaps were identified by the Advisor HD Grid catheter, as compared to a 10-pole or 20-pole circular mapping catheter. While this does not represent a direct comparison of the sensitivity for identification of gaps across these three technologies, and results could be impacted by other factors (e.g., operator, ablation technique, PVI confirmation technique, etc.), the strong trend toward an increased number of gaps identified with the HD Grid is striking. This may warrant further study including direct comparison of gap identification across technologies, and the resulting impact on long-term clinical outcomes when these additional gaps are ablated during the index procedure.

Abstract Figure.
910Noise-related malfunctions in modern ICDs during oncologic radiotherapy: a multicentre, real-time, in-vitro observation
Authors: Di Girolamo E , Appignani M , Marini M , De Filippo P , Leidi C , Di Girolamo F , Delana A , Barbareschi A , Andreoli S , Genovesi D , Falco M D
Published: June 2020

Funding Acknowledgements

None

Background

Direct photon exposure of implantable cardioverter-defibrillators (ICDs) during radiotherapy is still considered not recommended, or even unsafe, by manufacturers and guidelines. The effects of photon beams on ICDs are unpredictable, depending on multiple factors, and electromagnetic interferences (EMIs) may present during exposure.

Purpose

To evaluate transient ICD malfunctions by direct exposure to doses up to 10 Gy during low-energy radiotherapy, 36 contemporary wireless-enabled ICDs, with at least 4 months to elective replacement indicator (E.R.I.) were evaluated in a realtime in-vitro session.

Methods

All ICDs had baseline interrogation. Single chamber devices were programmed in the VVI/40 mode and dual or triple chamber devices were programmed in the DDD/40 mode. Rate response function and antitachycardia therapies were disabled, with the ventricular tachycardia (VT)/ventricular fibrillation (VF) detection windows still working. A centering computed tomography was performed to build the corresponding treatment plan and the ICDs were blinded randomized to receive either 2, 5 or 10 Gy exposure by a low photon-energy linear accelerator (6MV) in a homemade water phantom (600 MU/min). The effective dose received by the ICDs was randomly assessed by an in-vivo dosimetry. During radiotherapy course, the devices were observed in a real-time session using manufacturer specific programmer, and ICD function (pacing, sensing, programmed parameters, detection) was recorder by the video camera in the bunker throughout the entire photon exposure. All ICDs had an interrogation session immediately after exposure.

Results

During radiotherapy course, almost all ICDs (90.9%) recorded major or minor transient EMIs. On detail, 16 ICDs (44.4%) reported EMI-related atrial and/or ventricular oversensing, with base-rate-pacing inhibition and VT/VF detection. 16 ICDs (44.4%) recorded not clinically relevant minor EMIs, and no detections were observed. Only 4 ICDs (11.2%) reported neither transient malfunction nor minor EMIs, withstanding direct radiation exposure. At immediate post-exposure interrogation, the ICDs that recorded major real-time malfunctions had VT/VF detections stored in the device memory. In none of the ICDs spontaneous changes in parameter settings were reported. EMI-related malfunctions occurred regardless of either 2, 5 or 10 Gy photon beam exposure.

Conclusions

Transient EMIs were observed in most of the contemporary ICDs. To avoid potentially life-threatening ICD malfunctions such as pacing inhibition or inappropriate shock delivery, magnet application on the pocket site or reprogramming in the asynchronous mode are still suggested in ICD patients ongoing even low energy radiotherapy exposure.
P1409Effectiveness of atrial fibrillation ablation using a contact force stability module with contact force or non-contact force catheter
Authors: Khaykin Y , Alipour P , Azizi Z , Avoulov A , Jansen C , Donegan S , Morris S , Nath S , Tamjidi S , Varah N , Pantano A , Verma A , Weaver B , Hunter T D
Published: June 2020

Funding Acknowledgements

This study was funded by Biosense Webster, Inc.

Background

Catheter ablation is a mainstream treatment option for atrial fibrillation (AF). Recently, contact force (CF) enabled ablation catheters and a stability module were developed to allow for real-time CF sensing and improvement of catheter-tissue stability, which is important for achieving an optimal clinical outcome.  We assessed the relative effectiveness of these new technologies, as well as the optimal CF stability parameters, in a real-world setting.

Purpose

To compare the clinical effectiveness of AF ablations performed with a CF catheter using location stability settings of 2.5 mm maximum distance for 12 s minimum (2.5/12) vs. a non-CF catheter with settings of 3 mm for 7 s (3/7).

Methods

Within 1/14–4/18, 176 de novo AF ablations using either a CF catheter with stability settings of 2.5/12 (n = 92, 5/16–4/18) or a non-CF catheter with stability settings of 3/7 (n = 84, 1/14–3/14) were performed by a single operator at a Canadian medical center. Patients routinely wore 48 hour Holter monitors every three months through the first year. The primary measures of effectiveness were Kaplan-Meier (KM) survival estimates of freedom from AF/atrial tachycardia (AT)/atrial flutter (AFL) recurrence after a 3-month blanking period and reablation.

Results

The CF group was 62.9 ± 10.0 years old, 57.6% male, and 66.3% paroxysmal (PAF). The non-CF group was 61.6 ± 9.9 years old, 63.1% male, and 76.2% PAF. Procedural complications consisted of a single vascular access complication in the non-CF group. The 12-month estimate of freedom from AF/AT/AFL recurrence was 79.4% in the CF group vs. 64.8% in the non-CF group (p = 0.058 for difference in survival over time). 12-month freedom from reablation was 90.4% in the CF group vs. 70.5% in the non-CF group (p = 0.002).

Conclusion

CF ablation with more stringent stability settings of 2.5/12 was more effective than non-CF ablation with stability settings of 3/7, likely attributable to the CF catheter enabling visualization of catheter-tissue contact and the stability module facilitating maintenance of CF stability during ablation.

Abstract Figure.
P375The impact of hypothyroidism on hospitalization frequency and cost-effectiveness among patients with atrial fibrillation
Authors: Lutsenko L , Panova T , Bukina G , Lebed O
Published: June 2020

Background

 thyroid disorders are a well-known fact of high risk developing of atrial fibrillation (AF). While it is established that hyperthyroidism increases AF incidence, data of the effect of hypothyroidism on AF and heart failure is contradictory. 

Purpose

 to examine effect of untreated hypothyroidism on frequency of paroxysmal AF, state of the permanent AF and chronic heart failure (CHF) which is the main cause of high rate repeated hospitalizations.

Methods

 This retrospective study was conducted among patients (pts) with AF, who were admitted to the hospital from June 2018 till June 2019. They were divided into 2 groups: 1-st group – pts with AF and hypothyroidism and 2-nd group – euthyroid pts (by using hormonal replacement therapy) with AF. All pts were surveyed about their age, gender, medical history, therapy, number and reasons for hospitalization for the past 12 months. Reference range of TSH was 0,4-4,0 mU/L.

Results

 A total of 75 pts, 57,3% (n = 43) women, 41,3% (n = 31) men, mean age 70,5 years (SD 6,7) were enrolled in the research. 1-st group consist of 66,7% (n = 24) women, 33,3% (n = 12) men,  mean age 70,3 years (SD 6,8), paroxysmal AF 38,9% (n = 14), permanent AF 61,1% (n = 22), first diagnosed hypothyroidism during hospitalization 61,1% (n = 22),  mean TSH 9,3 mU/L (SD 3,7), 33,3 % (n = 12) were re-admitted 2 and more times,  mean hospitalization duration 7,1 day (SD 1,1).

2-nd group consist of 51,3% (n = 20) women, 48,7% (n = 19) men,  mean age 70,6 years (SD 10,6), paroxysmal AF 35,9% (n = 14), permanent AF 64,1% (n = 25), mean TSH 2,1 mU/L (SD 1,12), 17,9 % (n = 7) were hospitalized 2 times,  mean hospitalization duration 5,9 day (SD 0,9). Reasons for hospitalization in the 1-st group were pharmacological cardioversion (n = 8) and decompensated CHF (n = 4), in the 2-nd group were pharmacological cardioversion (n = 2) and decompensated CHF (n = 5).

Average cost of whole hospitalization in the 1-st group was 252$ (SD 8,1), in the 2-st group – 221 $ (SD 5,2). As an example, average cost for patient with CHF and AF per month in Ukraine is 45 $.

Conclusion

 Tight control of thyroid function ensures optimal dose of hormonal replacement therapy and decrease number of repeated hospitalizations and average hospitalization duration in patients with AF and hypothyroidism. As a result, we receive improving of cost-effectiveness of hospitalization AF pts.