bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of TiO2 nanopaint for automotive application
Authors: Sakinah S Z A , Azmi W H , Alias J
Published: June 2020

Nanopaint is a coating that can modify the properties of a surface or substance according to user-defined parameters. Like ordinary paint, nanopaint is applied as a liquid and then hardens. Nanopaint is a suspension of liquid containing metal or non-metallic nanoparticles of typical size (1-100 nm) dispersed into the base coat paint. Single composite of Titanium oxide nanoparticle is consider an extension of research work for single nanopaint, which can be carry out through dispersed composites in basecoat paint. This paper presents characterization of single composition of TiO2 nanopaint for automotive application. The nanopaint mixture was prepared at volume concentration of 1.0% using two-step method. The nanoparticles used namely TiO2 is dispersed in a base fluid of polyester white paint. The investigation on the characterization for the nanopaint in the present study is conduct through adhesion cutter, SEM, Gloss meter and surface roughness meter. The findings from the investigations on the characterization of nanopaint show that the paint each all the required value for the normal paint characterization. Comparison data between 1% weight concentrations for nanopaint to the normal paint also confirm the increase in the surface roughness quality which is 0.10 less surface deviation compare to normal paint and gloss value up to 26% more glossier. It can be concluded that the nanopaint were successfully prepared and achieved good characterization.
Heat transfer characteristics of car radiator using tri-hybrid nanocoolant
Authors: Ramadhan A I , Azmi W H , Mamat R
Published: June 2020

The use of nanoparticle coolant fluid in the car radiator increases the rate of heat transfer and facilitates the reduction of the overall radiator size. In this study, heat transfer characteristics of Al2O3-TiO2-SiO2 nanofluids-based water/ethylene glycol were analysed experimentally and compared with water/ethylene glycol mixture. Four different nanofluids concentrations were prepared by adding 0.05 to 0.3 vol.% of tri-hybrid nanofluid nanoparticles dispersed a mixture of water/ethylene glycol (60:40). Experiments were carried out by varying the flow rate of coolant between 2 to 12 LPM for working temperature of 70 °C, the velocity of airflow remained at an average of 4 m/s in order to analyse the effect of coolant flow rate on heat transfer. The results showed that the heat transfer coefficient of Al2O3-TiO2-SiO2 nanofluids or tri-hybrid nanofluids increased with increasing volume concentrations and temperatures. The maximum enhancement of the heat transfer coefficient for coolant side is observed at 39.7% at 0.3% volume concentration. The pressure drop and pumping power have the same pattern which increasing in volume concentrations, the pressure drop and pumping power will increase due to the concentration of the nanofluids. The correlation is applicable for water/ethylene glycol (60:40) mixture and Al2O3-TiO2-SiO2 nanofluids with volume concentrations of 0.05 to 0.3% at 70 °C working temperature.
Fundamental study on the effect of Reynolds number on pipe frictional loss reduction by microbubbles
Authors: Alias E A , Saniman M N F , Dzaharudin F
Published: June 2020

Microbubbles (MB) injection method is undeniably a promising drag reduction device in water transport. However, the mechanism of drag reduction by MB is complicated and poorly known. This paper presents the effect of Reynolds number on the frictional reduction by MB in a piping system. A fluid friction apparatus and a hydraulic bench were used to execute the experiment. To verify the ability of MB in reducing frictional loss, experiments were carried out in two conditions, without MB and with MB. In order to investigate the effect of turbulent flows, experiments were performed in three different flow rates ranging from 9 × 10−5 to 0.008 m3/s in two types of pipe diameter (20 mm and 33 mm) to yield different Reynolds number. As the results, MB able to reduce frictional loss in pipe up to 20%. However, regarding the Reynolds number effect, no apparent tendency of the frictional reduction efficiency can be observed between Reynolds number 4000-9500. Overall, MB holds potential in reducing pipe frictional loss in turbulent flow. However, further study in wider range of Reynolds number is required to comprehend its tendency.
The development of an aftermarket intercooler spray for turbocharged vehicles using ethylene glycol and hyaluronic acid
Authors: Ma’arof M I N , Chala G T , Suresh Sathurshan , Suresh Shaheerthana
Published: June 2020

Intercooler is used in motor vehicles to cool the air compressed by a turbocharger. Engine heat and weather condition commonly influence the efficiency of the intercooler, and this in turn affects the overall engine’s power output. The objective of this study was to design and develop an autonomous cooling system for top-mounted intercooler. The system was powered by Arduino Uno microcontroller that gathers data from the temperature sensor and triggers the spraying mechanism automatically when required. Besides, the system could also be operated manually via a switch by the user. The experimental results showed that the efficiency of the normal intercooler without the spray cooling unit was improved from 56.52% to 90.72% and the minimum possible efficiency with the spray cooling unit was 32.38% more efficient. Upon using ethylene glycol as the spray medium, the system achieved 90.70% efficiency. Even so, hyaluronic acid had the most effective heat absorbing capacity as its efficiency was 90.72%. This proved that the cooling process through spray cooling unit had a vast improvement on the efficiency of the intercooling system. Generally, for all three independent variables, temperature drop increases with the increasing amount of pressure created by the additional pumps, hence, efficiency of the system increases. However, for hyaluronic acid, the efficiency is also dependent on its texture and viscosity. This newly designed portable plug-and-play intercooler spray unit would be beneficial to increase the performance of the intercooler by improving the heat exchange capacity of the unit. For future studies, other types of spray cooling medium or combinations of several cooling mediums could be tested.
Improving Diversity and Promoting Inclusion in the Society for Epidemiologic Research Through Choice of Conference Location
Authors: Johnson Candice Y , Chin Helen B
Published: June 2020

Scientific conferences provide attendees opportunities to network, share research, learn new skills and ideas, and initiate collaborations. Conference attendance is especially important for students and early-career researchers who are establishing their research careers or looking for jobs. However, attending conferences can be expensive, and the high cost of conference attendance might hit students and early-career researchers the hardest. According to a new member survey from the Society for Epidemiologic Research, early-career members are more racially and ethnically diverse than senior members, meaning that reducing financial barriers to conference participation might be an important consideration for increasing diversity among conference attendees. In this commentary, we discuss how choice of conference location—choosing less expensive cities nearer to more Society for Epidemiologic Research members—could reduce financial and other barriers to conference attendance for all members and improve diversity and inclusion in the Society.
The Society for Epidemiologic Research and the Future of Diversity and Inclusion in Epidemiology
Authors: Gilman Stephen E , Arah Onyebuchi A , Bates Lisa M , Branas Charles C , Cozier Yvette C , Datta Geetanjali D , DeVilbiss Elizabeth A , Fink David S , Hajat Anjum , Johnson Dayna A , Lopez David S , Morris Meghan D , Weuve Jennifer , Abuelezam Nadia N ,   on behalf of the Diversity and Inclusion Committee of the Society for Epidemiologic Research
Published: June 2020

“The mission of the Diversity and Inclusion Committee (D&I) in the Society for Epidemiologic Research is to foster the diversity of our membership and work towards the engagement of all members, from diverse backgrounds at all stages of their careers, in the Society’s activities, with the intent of enhancing discovery in public health.” As a foundational step in implementing our mission, the D&I Committee conducted a survey of SER membership. Here we report on the efforts we have undertaken to expand the diversity and inclusiveness of our Society and our aspirations for future efforts in support of D&I. Early on, we established the SERvisits program to conduct outreach to institutions and students that have historically been underrepresented at SER; we hope this program continues to grow in its reach and impact. We have also taken steps to increase the inclusiveness of SER activities, for example, by engaging members on issues of D&I through symposia and workshops at SER annual meetings and through social media. DeVilbiss et al. (Am J Epidemiol. 2020;189(10):998–1010) have demonstrated that there is substantial room for improvement with regards to diversity and inclusion within SER. We invite SER members to become involved and collaborate on this long-term goal.
A likelihood analysis of quantile-matching transformations
Authors: McCullagh P , Tresoldi M F
Published: June 2020

Quantile matching is a strictly monotone transformation that sends the observed response values to the quantiles of a given target distribution. A profile likelihood-based criterion is developed for comparing one target distribution with another in a linear-model setting.
Microelectrode recordings in human epilepsy: a case for clinical translation
Authors: Chari Aswin , Thornton Rachel C , Tisdall Martin M , Scott Rodney C
Published: June 2020

With their ‘all-or-none’ action potential responses, single neurons (or units) are accepted as the basic computational unit of the brain. There is extensive animal literature to support the mechanistic importance of studying neuronal firing as a way to understand neuronal microcircuits and brain function. Although most studies have emphasized physiology, there is increasing recognition that studying single units provides novel insight into system-level mechanisms of disease. Microelectrode recordings are becoming more common in humans, paralleling the increasing use of intracranial electroencephalography recordings in the context of presurgical evaluation in focal epilepsy. In addition to single-unit data, microelectrode recordings also record local field potentials and high-frequency oscillations, some of which may be different to that recorded by clinical macroelectrodes. However, microelectrodes are being used almost exclusively in research contexts and there are currently no indications for incorporating microelectrode recordings into routine clinical care. In this review, we summarize the lessons learnt from 65 years of microelectrode recordings in human epilepsy patients. We cover the electrode constructs that can be utilized, principles of how to record and process microelectrode data and insights into ictal dynamics, interictal dynamics and cognition. We end with a critique on the possibilities of incorporating single-unit recordings into clinical care, with a focus on potential clinical indications, each with their specific evidence base and challenges.
Cellular senescence is a promising target for chronic wounds: a comprehensive review
Authors: Wang Ziwen , Shi Chunmeng
Published: June 2020

Chronic wounds include, but are not limited to, radiation ulcers, pressure ulcers, vascular ulcers and diabetic foot ulcers. These chronic wounds can persist for years without healing and severe ulcers may lead to amputation. Unfortunately, the underlying pathologies of refractory chronic wounds are not fully characterized, and new treatments are urgently needed. Recently, increasing evidence has indicated that cell senescence plays an important role in the development of chronic wounds, and preventing cell senescence or removing senescent cells holds promise as a new therapeutic strategy. In this review, we aim to probe these latest findings to promote the understanding of cellular senescence in the pathological process and potential management of chronic wounds.
To Induce Immune Reconstitution Inflammatory Syndrome or Suppress It: The Spectrum of Mycobacterium genavense in the Antiretroviral Era
Authors: Manion Maura , Lynn Niamh , Pei Luxin , Hammoud Dima A , Laidlaw Elizabeth , Roby Gregg , Metzger Dorinda , Mejia Yolanda , Lisco Andrea , Zelazny Adrian , Holland Steve , Vachon Marie-Louise , Scherer Matthew , Bergin Colm , Sereti Irini
Published: June 2020

Mycobacterium  genavense is a challenging opportunistic pathogen to diagnose and manage in patients with human immunodeficiency virus (HIV). Persistent immunosuppression or protracted immune reconstitution inflammatory syndrome can lead to complicated clinical courses. We describe 3 cases of M. genavense in patients with HIV representing the spectrum between disease burden and strength of immune response.
A Double-blind, Randomized Phase 2 Controlled Trial of Intradermal Hepatitis B Vaccination With a Topical Toll-like Receptor 7 Agonist Imiquimod, in Patients on Dialysis
Authors: Hung Ivan Fan-Ngai , Yap Desmond Yat-Hin , Yip Terence Pok-Siu , Zhang Ricky Ruiqi , To Kelvin Kai-Wang , Chan Kwok-Hung , Tang Sydney Chi-Wai , Lui Sing-Leung , Levin Yotam , Kochba Efrat , Lau Johnson Yiu-Nam , Yuen Man-Fung , Chan Tak-Mao , Yuen Kwok-Yung
Published: June 2020

Background

Patients on dialysis are hyporesponsive to the hepatitis B virus vaccines (HBVv). We examined intradermal (ID) HBVv Sci-B-Vac, with topical Toll-like receptor 7 (TLR7) agonist imiquimod pretreatment in dialysis patients.

Methods

We enrolled and prospectively followed adult patients on dialysis between January 2016 and September 2018. Eligible patients were randomly allocated (1:1:1) into 1 treatment group, topical imiquimod cream followed by ID HBVv (IMQ + ID); and 2 control groups: topical aqueous cream (placebo) followed by ID HBVv (AQ + ID) or topical aqueous cream followed by intramuscular HBVv (AQ + IM). The primary endpoint was the seroprotection rate (hepatitis B surface antibody ≥10 mIU/mL) at 52 weeks.

Results

Ninety-four patients were enrolled, among which 57.4% were previous nonresponders. Seroprotection rate was significantly better at week 52 for the IMQ + ID group with 96.9% compared to 74.2% and 48.4% for AQ + ID and AQ + IM groups, respectively (P < .0001). The geometric mean concentration was significantly higher at week 52 for the IMQ + ID group: 1135 (95% confidence interval [CI], 579.4–2218.2) mIU/mL, compared to 86.9 (95% CI, 18.5–409.3) mIU/mL and 7.2 (2.0–26.5) mIU/mL for the AQ + ID and AQ + IM groups, respectively (P < .0001). IMQ + ID vaccination (odds ratio, 3.70 [95% CI, 1.16–11.81]; P = .027) was the only factor independently associated with higher 52-week seroprotection rate. Adverse reaction was infrequent.

Conclusions

Pretreatment with topical imiquimod before ID HBVv Sci-B-Vac was safe with favorable seroprotection in dialysis patients.

Clinical Trials Registration

NCT02621112.
Gastroenterologist-Lead Management of Iron Deficiency Anemia in Inflammatory Bowel Disease Is Effective, Safe, and May Increase Quality of Life
Authors: Coe Christopher L , Meyers Matthew H , Beaulieu Dawn B , Scoville Elizabeth , Schwartz David A , Horst Sara N , Dalal Robin L
Published: June 2020

Background

The effectiveness and safety of gastroenterologist (GI)-lead treatment of iron deficiency anemia (IDA) in inflammatory bowel disease (IBD) have not been well-studied.

Methods

A retrospective chart review of patients with IBD, IDA, and evidence of treatment with iron at a tertiary IBD center was conducted.

Results

In 351 patients, hemoglobin and quality of life scores increased significantly after treatment with iron. Twelve of 341 patients treated with intravenous iron had an adverse effect. Twenty-seven patients required a hematology referral.

Conclusion

GIs should consider treating patients with IBD and IDA with intravenous iron as it is safe and effective.
COVID-19 Pandemic: Which IBD Patients Need to Be Scoped—Who Gets Scoped Now, Who Can Wait, and how to Resume to Normal
Authors: Ng Siew C , Mak Joyce Wing Yan , Hitz Lara , Chowers Yehuda , Bernstein Charles N , Silverberg Mark S
Published: June 2020

Endoscopy is an essential component in the management of inflammatory bowel disease [IBD]. There is a risk of SARS-CoV-2 transmission during endoscopic procedures. The International Organization for the study of IBD [IOIBD] has developed 11 position statements, based on an online survey, that focus on how to prioritise endoscopies in IBD patients during the COVID-19 pandemic, alternative modes for disease monitoring, and ways to triage the high number of postponed endoscopies after the pandemic. We propose to pre-screen patients for suspected or confirmed COVID-19 and test for SARS-CoV-2 before endoscopy if available. High priority endoscopies during pandemic include acute gastrointestinal bleed, acute severe ulcerative colitis, new IBD diagnosis, cholangitis in primary sclerosing cholangitis, and partial bowel obstruction. Alternative modes of monitoring using clinical symptoms, serum inflammatory markers, and faecal calprotectin should be considered during the pandemic. Prioritising access to endoscopy in the post-pandemic period should be guided by control of COVID-19 in the local community and availability of manpower and personal protective equipment. Endoscopy should be considered within 3 months after the pandemic for patients with a past history of dysplasia and endoscopic resection for dysplastic lesion. Endoscopy should be considered 3–6 months after the pandemic for assessment of postoperative recurrence or new biologic initiation. Endoscopy can be postponed until after 6 months of pandemic for routine IBD surveillance and assessment of mucosal healing.
P1425Complication rate and incidence of esophageal injury after minimally invasive convergent procedure for treatment of atrial fibrillation
Authors: Prolic Kalinsek T , Gersak B , Jan M
Published: June 2020

Funding Acknowledgements

None

Introduction

Convergent procedure is a minimally invasive surgical approach for treatment of atrial fibrillation (AF) combining epicardial and endocardial radiofrequency (RF) ablation. However, there is conflicting data regarding the rate of major complications after convergent treatment of AF. Apart from common complications the esophageal injury incidence after convergent procedure is not well documented.

Purpose

Our aim was to assess major complication occurrence after convergent procedure with additional emphasis on the incidence of esophageal injury.

Methods

One hundred forty-seven consecutive patients (113 male, mean age 59 ± 9 years, BMI 29 ± 5 kg/m2) with persistent (122, 83%) and paroxysmal (25, 17%) AF were treated with convergent procedure that included epicardial RF ablation with coagulation devices (12 lesions, each for 90 s, with 30 W power), combined with endocardial RF catheter ablation for pulmonary vein isolation. The approach for epicardial ablation was diaphragmatic pericardial window through subxiphoid incision. Infusion of cooled saline into the pericardial space during epicardial ablations and monitoring of esophageal temperature with temperature probe were additional precautions to avoid esophageal overheating. All patients had endoscopy of the esophagus at least 2 days after the procedure to assess for presence of esophageal injury. Adverse events resulting in additional intervention or causing long-term disability were defined as major complication.

Results

During short-term follow-up (minimum of 5 months) major complication rate was 6.1%. Three patients had cardiac tamponade, 4 had abdominal bleeding, 1 had ischemic stroke and 1 had arterial pseudoaneurysm. Esophageal mucosal lesions were observed in 11 patients (7.5%) that did not result in major complication. All lesions were followed with additional endoscopies and resolved without any intervention.

Conclusions

Complication rate after minimally invasive convergent procedure for treatment of AF in our patient cohort is low. Prevention of esophageal overheating resulted in absence of major esophageal injury.
307Clinical outcomes of pacing induced cardiomyopathy in patients with preserved left ventricular systolic function and atrioventricular block
Authors: Dor O , Haim M , Barrett O , Novack V , Konstantino Y
Published: June 2020

Funding Acknowledgements

None

Background

Patients with preserved LVEF and atrioventricular block (AVB) who are anticipated for high-burden of right ventricular (RV) pacing possess a risk to develop pacing induced cardiomyopathy (PICM).

Aims

To evaluate the incidence and outcomes of RV-PICM in this patient"s population.

Methods

1013 patients with AVB underwent first time pacemaker (PM) implantation between 2002 and 2016. A total of 203 patients with normal LVEF were included. Follow-up echocardiography was examined for a decrease in LVEF > 10%. Alternative causes for cardiomyopathy were excluded. Patient"s characteristics, mortality and hospitalizations for heart failure (HF) were compared between the PICM and non-PICM groups. 

Results

51 patients (25%) developed PICM, with 22 patients (11%) showing LVEF < 40%. During mean follow-up of 49.2 months, the risk of HF hospitalization or all-cause mortality was significantly higher in the PICM group (35.3% vs. 19.1%, p = 0.009). LVEDD was independently associated with PICM (HR = 1.10, 95% CI: 1.03-1.17, p = 0.01) and CAD was nearly associated with PICM (HR = 2.19, 95% CI: 0.98-4.90, p = 0.06). 

Conclusions

The incidence of PICM in patients with normal LVEF and AVB is alarmingly high. PICM in patients with a previously normal LVEF is associated with unfavorable outcomes.

Table 1 Characteristics Cohort without PICM (152) n (%) Cohort with PICM (51) n(%) p Age mean ± SD 74.6 ± 10.5 71 ± 13 0.04 Gender (male) 80 (52.6) 29 (56.9) 0.6 Pacing modeDDDVDDVVI 108 (71.1) 38 (25) 6 (3.9) 34 (66.7) 15 (29.4) 2(3.9) 0.83 Hypertension 112 (73.7) 36 (70.6) 0.67 PVD 16 (10.5) 5 (8.9) 0.88 CAD 36 (23.7) 19 (37.3) 0.01 CVA / TIA 17 (11.2) 7 (13.7) 0.63 Atrial fibrillation / flutter 18 (11.8) 9 (17.6) 0.29 COPD 15 (9.9) 2 (3.9) 0.25 Diabetes Mellitus 56 (36.8) 27 (52.9) 0.04 Chronic Kidney Disease 27 (17.9) 14 (27.5) 0.14 Statins 65 (43) 30(60) 0.04 ACE inhibitors / ARBs 52 (34.4) 18 (36) 0.84 Beta Blockers 42 (28) 10 (20) 0.26 LVEDD mm 45.13 ± 5.53 48.46 ± 5.97 <0.001 LVESD mm 25.68 ± 5.28 27.72 ± 4.67 0.02 Baseline characteristics

Abstract Figure. HF and Mortality outcomes
P1163Correction of septal flash excursion with his bundle pacing
Authors: Pujol-Lopez M , San Antonio R , Jimenez Arjona R , Guasch E , Doltra A , Sitges M , Roca-Luque I , Trotta O , Quinto L , Arbelo E , Alarcon F , Garre P , Mont L , Tolosana J M
Published: June 2020

Funding Acknowledgements

Grant from the Catalan Society of Cardiology

Background

His bundle pacing (HBP) directly stimulates the conduction system and could therefore correct asynchrony and evolve as a more physiological pacing approach. Septal flash (SF) is a fast contraction and relaxation of the septum occurring during the isovolumetric contraction period. It is a specific marker of cardiac dyssynchrony.  

Purpose

Evaluate whether HBP corrects SF in patients with an indication for CRT or RV pacing.

Methods

A cohort of 20 consecutive patients undergoing HBP at our center was analyzed. HBP indications were:  Group A (n = 3): left bundle branch block (LBBB) and left ventricular (LV) dysfunction (LV ejection fraction [LVEF] < 35%); Group B (n = 14): LV dysfunction (LVEF < 50%) and atrio-ventricular block requiring permanent pacing; Group C (ablate&pace, n = 3): atrio-ventricular node ablation due to rapid atrial fibrillation.

Patients in groups B and C had a RV backup lead implanted, in line with current recommendations. The presence of SF was analyzed in 2D-echocardiography at 15 days post-implant. SF excursion was quantified using M-mode in parasternal short and long axis views as the highest amplitude of the early inward motion. Baseline SF excursion was determined during intrinsic rhythm (group A) or RV pacing (groups B and C). For each patient, the pair of measurements (baseline, HBP) in the axis with the highest baseline SF was selected.

Results

Mean LVEFs were 21 ± 8%, 32 ± 6%, and 41 ± 18% for groups A, B and C, respectively. HBP shortened QRS duration by 42 ± 15 ms and 45 ± 23 ms in groups A (Baseline QRS - HBP QRS) and B + C (RV pacing QRS - HBP QRS), respectively. At baseline, all patients except 1 had SF (Fig. 1A). The mean SF excursion was 4.3 ± 1.9 mm, with SF excursion being larger in group A than in the RV-paced groups (6.3 ± 1.5 mm vs. 3.9 ± 1.8 mm for groups A and B + C, respectively, p = 0.04). HBP abolished SF in 3 patients (15%) and, on average, decreased SF excursion by 2.3 mm (95% CI 1.3-3.2), irrespective of pacing indication (Fig. 1B). The degree of SF excursion reduction after HBP significantly correlated with QRS shortening (r = 0.53, p = 0.024) (Fig 1C).

Conclusions

In conclusion, we show that HBP results in acute correction or decrease of SF, thereby improving LBBB- or RV-induced mechanical dyssynchrony.

Abstract Figure. Septal Flash and His pacing
917Appropriate shocks in WCD patients - Results from the Austrian WCD registry
Authors: Rohrer U , Manninger M , Odeneg T , Zweiker D , Moertl D , Keller H , Dirninger A , Stix G , Alber H , Steinwender C , Binder R , Stuehlinger M , Ebner C , Zirlik A , Scherr D
Published: June 2020

Background

The wearable cardioverter-defibrillator (WCD) is a temporary treatment option for patients at high risk for sudden cardiac death (SCD) and/or for patients in whom implantation of a cardioverter defibrillator (ICD) is temporarily not possible.

Purpose

To investigate incidence and predictors of appropriate WCD shocks.

Methods

We performed a retrospective analysis of all patients with appropriate shocks delivered by a WCD in the cohort of the Austrian WCD registry between 2010 and 2018. Within this dataset, we identified predictors within the baseline characteristics, the indication for the WCD and preceding alarms automatically recorded by the WCD.

Results: Baseline

Within 879 registered in the Austrian WCD registry, 31 patients (3,5%) received appropriate WCD shocks due to ventricular tachycardia (VT) or ventricular fibrillation (VF). Compared to the total cohort, shocked patients were elder (mean age 67 ± 14 vs. 60 ± 14 years, p = 0,001) and the percentage of female patients was lower (11% vs. 21%, p = 0,262). The mean baseline LVEF at prescription was 33 ± 15% in the population with appropriate shocks compared to 32 ± 14% in the all-over cohort (p = ns).

In the Austrian WCD population, 378/879 patients had a WCD due to secondary prevention. Within this cohort 5,6% (21/378) had shocks for VT/VF again, compared to 10/501 (2%) shocked patients in the primary prevention cohort. 31/879 (3.5%) patients received 57 appropriate shocks, the per patient shock rate was 2 [1;5]. These shocks were induced by 25 ventricular tachycardia and 26 times ventricular fibrillation.

The octagenarians with 11% (7/34) shocked patients, showed a significant higher likelihood to receive shocks (p = 0,008) as well as the cohort of secondary preventive prescribed WCD-patients (p = 0,007). There were more shocks in patients, when prescribed with a WCD due to ICD associated infections (p = 0,001), when used as a bridge to ICD (p = 0,042) and in patients with ongoing risk stratification (p = 0,009).

Looking through the automatically recorded alarms preceding a WCD shock, shocked patients experienced significantly more often non sustained VTs (p < 0,0005) and sustained VTs that were haemodynamically tolerated and did not require a treatment (p < 0,0005).

Conclusion

The WCD is effective in preventing SCD and an important risk stratification tool. We identified advanced age, patients with either already confirmed indication for ICD implantation (either temporary contraindication for implantation or temporary explantation) or risk stratification of an unclear cardiomyopathy, the cohort of secondary prevention and preceding nsVTs and stable VTs as predictors for appropriate WCD therapies.
P1402Isolation of pulmonary veins with duty-cycled circular multi-polar catheter: randomized controlled clinical trial
Authors: De Sousa J , Cortez-Dias N , Carpinteiro L , Silva G , Nunes Ferreira A , Silverio Antonio P , Bernardes A , Barreiros C , Ribeiro J , Sobral S , Pinto F
Published: June 2020

Introduction

Pulmonary vein isolation (PVI) is the central element in the ablation of atrial fibrillation (AF), and can be obtained with different ablation modalities. The duty-cycled circular multi-pole catheter PVAC® (Medtronic) allows linear application of radiofrequency energy, with the production of circumferential lesions. Conceptually, it can make ablation simpler and faster in patients with favorable anatomy.

Objectives

To evaluate the safety and efficacy of ablation with a PVAC® catheter and to compare it with the conventional technique point-by-point (PbP) with irrigated catheter.

Methods

Clinical trial with single-blinded patients with AF refractory to antiarrhythmic therapy, randomized (1: 1) for ablation with PVAC® or PbP. The ablation strategy consisted of PVI, complemented with ablation of the cavo-tricuspid isthmus in patients with history of concomitant flutter. Monitoring was performed with a 7-day event loop recorder at 3, 6 and 12 months and annually from the 2nd year. Success was defined by AF-free survival or any maintained supraventricular tachycardia (duration > 30seconds).

Results

354 patients (67.5% males, 58 ± 12 years, PbP: 175, PVAC: 179) were included, of which 59.1% had paroxysmal, 26.2% short-standing persistent and 14.7% had long-standing persistent AF. Baseline characteristics were similar between groups. Among patients treated with PVAC, 93.1% of the pulmonary veins were isolated (620/666), similar to the 98.3% immediate success of the PbP group (697/709). Although the complication rate was similar in both groups (PVAC: 4.9% vs. PbP: 7.8%; P = NS), the risk of hemopericardium was lower with PVAC (0% vs. 4.6%; P = 0.013). Two patients treated with PVAC developed stroke (1.13% vs. 0%; P = NS). The duration of the procedure was lower among the patients treated with PVAC [136 (100-180) vs. 230 (188-270) min; P <0.001], with no difference in fluoroscopy time [24.4 (14.5-36.8) vs. 27.1 (17.0-45.0) min]. The success rate after 1st ablation at 36 months was 68%, with no differences between groups. The success rate after multiple ablations increased to 85.8%, with no differences between groups.

Conclusion

The multipolar PVAC catheter can represent an added value in AF ablation, making the procedure simpler and faster, ensuring similar efficacy to the conventional technique and with a lower risk of cardiac tamponade. The present trial suggests the need for clinically manifested stroke risk surveillance, which may be increased with this technique.

Abstract Figure.
P1469Micra pacemaker implant at septal site induces a smaller increase on qrs duration than traditional pacemaker: a single center experience
Authors: Zucchelli G , Parollo M , Barletta V , Di Cori A , Della Tommasina V , Mazzocchetti L , Viani S , Giannotti Santoro M , De Lucia R , Segreti L , Cellamaro T , Paperini L , Soldati E , Bongiorni M G
Published: June 2020

BACKGROUND

Leadless pacemakers have been introduced into the clinical practice as a breakthrough technology that could tackle most of the major sources of complication of traditional pacemakers (PM). The excellent safety profile and optimal electrical performance of Micra have been already largely described, nevertheless the impact on QRS duration has not been investigated so far. We aimed to compare changes in QRS duration after septal Micra implant in comparison to patients who received transvenous right ventricular leads in the same position.

METHODS

We enrolled all patients who underwent Micra implantation (group 1) at our Center from April 2017 to March 2019. A septal placement was attempted in all cases. Duration of spontaneous and paced QRS and their difference (delta QRS) were measured using a polygraph. To provide a comparison group, we analyzed the QRS duration in a matched group of patients (group 2) who received a traditional single chamber pacing system with a transvenously implanted lead at septal position in the same period. Confounding variables that were used to provide the control group were age, sex, left ventricle ejection fraction, and rhythm at implant. High pacing threshold was defined as ≥1.0 V at pulse duration of 0.24 ms.

RESULTS

Twenty-eight consecutive patients (mean age 78 ± 3 years; 71.43% males) who underwent successful Micra implant were enrolled. A septal position was achieved in all cases with a single device delivery in 17/28 patients (60.7%). Mean pacing threshold at implant was 0.56 ± 0.34V/0.24 ms with only 3/28 patients (10.7%) presenting a high pacing threshold. No significant differences in demographic, clinical characteristics and ventricular pacing site were observed between groups. QRS duration was slightly longer in group 1 compared to group 2 before implant (median 123 ms (IQR 104-146.5 ms) vs median 116 ms (IQR 90-125 ms); p = 0.09). Nevertheless, there was a significantly lower delta QRS after implant in Micra compared to the traditional pacing group (15.82 ± 31.77 ms vs 35.82 ± 22.13 ms, p = 0.008).

CONCLUSION

Right ventricular stimulation induces ventricular dyssynchrony, which is correlated with the amount of QRS enlargement after pacing. Micra implant, in a non-apical position, produces significantly smaller changes on the QRS duration in comparison with transvenous lead implanted at the same site, although larger studies are necessary to confirm these results.
P1134Cardiac pacemakers and transient electromagnetic interferences during radiotherapy courses: a multicentre, real-time, in-vitro evaluation
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

The effects of high dose oncologic radiotherapy (RT) on cardiac pacemakers (PMs), at even less than 6 MV power, are unpredictable, depending on multiple factors. Normal PM function may be impaired during direct exposure, due to electromagnetic interferences (EMIs). Potentially life-threatening malfunctions may occur, expecially in PM-dependent patients, and both manufacturers and guidelines discourage direct exposure.

Purpose

To evaluate transient EMI-related PM malfunctions during direct exposure to doses up to 10 Gy during radiotherapy course, 17 wireless-telemetry-enabled PMs with sufficient residual battery charge for the purpose of the study (at least 4 months to elective replacement indicator, E.R.I.) were evaluated in three different centres.

Methods

All PMs underwent baseline interrogation. Single chamber devices were programmed in the VVI/40 mode while dual or triple chamber devices were programmed in the DDD/40 mode. To avoid the "run-away" phenomenon during exposure rate-adaptive function was disabled. A centering computed tomography was performed to build the corresponding treatment plan and the PMs were blinded randomized to receive either 2, 5 or 10 Gy exposure by a 6 MV linear accelerator in a homemade water phantom (600 Um/min). The effective dose received by the PMs was randomly assessed by an in-vivo dosimetry. During RT course, the devices were observed in a real-time session using manufacturer specific equipment, and PM function (pacing and sensing, programmed parameters) was recorder by a video camera in the bunker throughout the entire radiation exposure.

Results

During RT course, 13 PMs (76.5%) recorded not clinically relevant minor transient  EMIs, and no atrial and/or ventricular oversensing nor base-rate-pacing inhibition were observed. Only 4 PMs (23.5%) reported neither transient malfunction nor minor EMIs, withstanding direct radiation exposure. Transient EMI-related malfunctions were observed regardless of either 2, 5 or 10 Gy exposure.

Conclusions

Minor, not clinically relevant EMI-related interferences were observed in most of the PMs during direct exposure. Nevertheless, to avoid potentially life-threatening PM malfunctions, magnet application on the PM pocket site or reprogramming are still suggested in PM-dependent (high risk) patients ongoing even low energy RT exposure.
P1419Persistent atrial fibrillation terminates during ablation more often using dispersion mapping than with fractionated electrogram mapping
Authors: Zaman J , Agarwal S
Published: June 2020

Introduction

Persistent AF termination rates have increased since the advent of AF driver mapping, with a recent meta-analysis (Baykaner Circ AE 2018) of over 3200 patients showing improved 12 month freedom from AF/AT.  However,  recent randomised clinical trials have cast doubt on the efficacy of complex fractionated atrial electrograms (CFAE) based mapping strategies. We

set out to study a consecutive single centre series pre-and post- use of spatio-temporal dispersion (STD) to identify termination rates between the two approaches.

Methods

We recruited consecutive patients over 18 months at a single high volume tertiary centre undergoing first redo ablation for persistent AF. Patients were all

mapped using Pentarray to mark areas of substrate using the spatio-temporal dispersion (STD) method (Seitz JACC 2017).

Ablation was performed by a single operator using catheters to standardise equipment and workflow, to enable true

comparison of mapping and ablation results in a consecutive series.

Results

In total 38 patients were studied at redo ablation for persistent AF (age 69, 87% male, LA diameter 4.5cm). Termination of persistent

AF to SR (30%) or AT (70%) was obtained in 30/38 (79%) of the group with STD based substrate ablation vs. 1/38 (3%) in patients mapped

with CFAE targeting using identical equipment and operator (p < 0.001). Procedure time was no different between STD and CFAE based

approaches (263 vs. 248 mins, p = ns). Figure shows STD patterns (red arrows) on Pentarray in a 67 year old man anterior to left inferior

pulmonary vein (A), where ablation terminated AF to sinus rhythm. At 12 month follow up, 30/38 (79%) patients were in sinus rhythm with no AF detected on ECG or continuous monitoring.

Conclusions

In this single centre series of persistent AF ablations, the use of STD mapping increased rates of termination compared to a fractionation based mapping strategy alone, without increasing overall procedure time. Clinical outcome data suggest this translates into better 12 month clinical outcomes, and motivate prospective randomised trials to definitively study this technique.

Abstract Figure.
P542Cardiac autonomic dysfunction and inflammatory response in heart failure - markers for cardiac resynchronization therapy response?
Authors: Oliveira S , Abreu A , Cunha P , Carmo M M , Valente B , Ricardo I , Delgado A S , Oliveira L , Pinto F , Oliveira M M
Published: June 2020

Funding Acknowledgements

FCP

Introduction

Cardiac sympathetic activation and inflammatory response are involved in chronic heart failure (HF) pathophysiology. The severity of autonomic dysfunction and inflammation might be responsible for different responses to HF treatment.

Aim

To evaluate the impact of cardiac autonomic dysfunction, and it´s association with systemic inflammation, on cardiac resynchronization therapy (CRT) response in severe HF patients.

Methods

Single centre, prospective, longitudinal study, including consecutive patients, referred to CRT. Demographic data, HF aetiology and NYHA class were evaluated. Left ventricular (LV) function data (LV ejection fraction - LVEF) by echocardiography, heart to mediastinum early ratio (HMRe) by 123I-MIBG cardiac scintigraphy, and plasmatic TNF-α levels (pg/mL) were determined, at baseline and 4 months after CRT implantation. CRT response was defined by an absolute increase of at least 5% in LVEF at 4 months evaluation after CRT. Patients were divided in 4 groups according to HMRe and TNF-α cut-points: Group I (TNF-α > 2.0 pg/ml + HMRe ≥ 1.6), Group II (TNF-α > 2.0 pg/ml + HMRe < 1.6), Group III (TNF-α ≤ 2.0 pg/ml + HMRe ≥ 1.6) and Group IV (TNF-α ≤ 2.0 pg/ml + HMRe < 1.6). Data was analyzed using descriptive statistics and groups were compared by Fisher"s exact test.

Results

A total of 95 patients were included (age 68.6 ± 10.2 years), 67.4% male and 32.6% female, 40% with diabetes mellitus, 30.5% with ischemic cardiomyopathy, 23.2% in NYHA III/IV, baseline LVEF - 26 ± 7%. At 4 months, LVEF was 40 ± 11%. In total, 73.7% were responders and 26.3% were non-responders to CRT. There were 28 patients (29.5%) with HMRe ≥ 1.6, with 25 responders (89.3%) and 48 patients (50.5%) with TNF-α ≤ 2.0 pg/ml, with 38 responders (79.2%). Group I had 16 patients (16.8%), with 81.2% responders; Group II had 31 patients (32.7%), with 61.3% responders; Group III had 12 patients (12.6%), with 100% responders, and Group IV had 36 patients (37.9%), with 72.2% responders. Conclusion: In patients with severe HF submitted to CRT, combining cardiac autonomic dysfunction and inflammation, associated to high rate of CRT non response. Contrarily, those with preserved cardiac autonomic function and no increased levels of inflammation identified most significantly CRT responders.

CRT response according to HMRe and TNFα HMRe ≥ 1.6 (n = 28) HMRe < 1.6 (n = 67) Responders NO Respondersn (%) Responders NO Respondersn (%) TNF α > 2 pg/mL (n = 47) G I: 13 (81.2%) 3 (18.8%) GII: 19 (61.3%) 12 (38.7%) * TNF α ≤ 2 pg/mL (n = 48) G III: 12 (100%) 0 (0%)* G IV: 26 (72.2%) 10 (27.8%)
P1398The modified left atrial anterior line: optimal ablation index target to detect a transmural lesion on cardiac magnetic resonance imaging
Authors: Ammar-Busch S , Mahnkopf C , Mitlacher M , Tose Costa Paiva B , Schwab Figueiredo C , Butz S , Brachmann J , Forkmann M
Published: June 2020

Background

The modified anterior line (MAL) has been described as an alternative to the mitral isthmus line. Despite better ablation results, achieving a bidirectional line block is sometimes challenging.  Ablation Index (AI) is a novel lesion quality marker that integrates contact force, time and power. This index has been evaluated for pulmonary vein isolation (PVI) but not for other left atrial (LA) lesions. We aimed to investigate the AI-values to determine a scar on cardiac magnetic resonance (CMR) imaging 3 months after MAL ablation.

Methods

Twelve consecutive patients who underwent a MAL ablation have been included. The indication for MAL was perimitral flutter (n = 3) or substrate ablation for diffuse anterior LA low-voltage area in persistent atrial fibrillation (AF) (n = 9). The MAL was divided into three segments: segment 1 (S1) from mitral annulus to height of lower begin of left atrial appendage (LAA) antrum; segment 2 (S2) height of lower begin of LAA antrum to end of upper LAA antrum; segment 3 (S3) from end of upper LAA antrum to left superior pulmonary vein. Ablation was performed using a contact force catheter, automated lesion tagging and Ablation Index. AI target was left to the operator’s choice. An inter-lesion distance of ≤ 6mm was recommended. The bidirectional block was systematically evaluated at the end of procedure. All patients underwent a CMR study at 3 months, regardless of symptoms, to identify myocardial lesions (scar).

Results

Bidirectional MAL block was achieved in all patients. The mean reached AI value was 443 ± 55. CMR imaging revealed scar in 25 of 36 (69%) segments. In total, the mean AI value for detecting a scar was 451 ± 51 and was higher in S1 compared to S2 and S3 (474 ± 36 vs. 451 ± 63 vs. 423 ± 46, respectively). The AI value in S1 was significantly higher compared to S3 (p = 0.02). The minimal AI value to detect a scar was 410 ± 183 in S1, 379 ± 109 in S2 and 369 ± 68 in S3.

Conclusion

Different AI targets are required for each segment of the MAL to show transmural lesions on CMR imaging 3 months post-ablation. Higher AI values are required for the lower segment of the line. Additional data are needed to demonstrate if considering these targets will be reflected in better long-term results.
P387Revealing channels of interatrial communication during atrial fibrillation
Authors: Pope M , Kuklik P , Briosa E Gala A , Mahmoudi MICHAEL , Paisey J O H N , Betts TIMOTHY
Published: June 2020

Introduction

Interatrial propagation has been widely studied in anatomical specimens and electrophysiological studies during sinus rhythm or pacing. However, pathways of conduction during atrial fibrillation (AF) are poorly characterised in vivo.

Purpose

We sought to develop a method of identifying the dominant channel of communication between atria during AF with a view to characterising the role of localised mechanisms in maintaining AF between both chambers.

Methods

10 patients undergoing simultaneous bi-atrial non-contact charge density mapping before and following pulmonary vein isolation (PVI) were analysed. Simultaneous 30s recordings during AF were obtained. Virtual electrograms from every vertex of the reconstructed left and right atrial (LA, RA) anatomies were exported and phase calculated using a method of sinusoidal recomposition and Hilbert transform. For each vertex, coherence between a sequence of activations between this point and every other point on the opposing chamber was calculated using mean phase coherence (MPC). The maximum of all MPC values was assigned to this local point to estimate the degree of coherence between activity at a given point and the entire opposing chamber. The regions with highest MPC value represent the channel of communication. Each activation of this zone is then evaluated and difference in local activation time between LA and RA determined (figure). Communication between atria is determined where a normal distribution of timing shift within this channel can be demonstrated (as opposed to a uniform histogram in the case of a lack of any correlation between electrograms). If seen to be preceding the opposite chamber for ≥60% of the recording then the chamber was deemed to be leading.

Results

A total of 18 maps were obtained (pre-PVI only in 2). A clear channel of interatrial propagation could be seen in 17 maps (MPC value 0.48 ± 0.16) with communication within this channel demonstrated in 13 of these (MPC 0.52 ± 0.16). In the RA the most common site was in the posterior inter-caval zone (in 13) and on the posterior septum of the LA (in 14). The LA was leading in 4 maps and the RA in 2 with balanced propagation in 7.

Conclusion

The method of average MPC identifies channels of inter-atrial communication during AF which appear to predominantly involve posterior interatrial connections. Further application of this technique to characterise interatrial propagation may help to define patient specific phenotypes of AF and guide targeted therapy.

Abstract Figure 1