Single Chamber Research Articles

A NUMERICAL STUDY ON COMBUSTION IN ARRAYS OF BIDIRECTIONAL SWIRLING JETS

A numerical study of combustion in bidirectional swirling jets arrays is performed for the first time. A choice of bidirectional flow for designing burner arrays is caused by their advanced properties in terms of combustion stability, long fuel residence time, pollutants emission, etc. The simplest array studied in the paper is of square shape (3 × 3) and consists of the central toroidal bidirectional chamber and 8 peripheral cylindrical chambers. Such a decision is made to improve the stability of combustion due to the advantages of the toroidal shape known from the previous studies. The main result for the square array is that the flame surface area increases significantly, and the fuel burning rate is 1.68 times more compared to a single bidirectional chamber. Additionally, the simulations show that the key factor in array combustion stability is related to the formation of central recirculation zones in each bidirectional jet. Based on these results, the multipoint gas turbine combustor is designed. Its primary combustion zone is formed using the multiplied 3 × 3 array of bidirectional jets over the annulus. Thus, the overall number of simple vortex chambers in the annular array is 90. A numerical simulation of the new multipoint combustor operation shows a very intense jets interaction in its first half and its efficiency is more than 99%. Moreover, the calculated emission properties at an overall pressure ratio OPR = 40 suit the modern environmental requirements: CO = 12 ppm, NO = 22 ppm.

Enhancing wave energy harvesting: Performance analysis of a dual chamber oscillating water column

This study investigates the hydrodynamic characteristics of a dual chamber oscillating water column (OWC) setup through a series of experiments, aiming to assess its potential for harvesting wave energy. The investigation involves varying frontwall drafts, power take-off (PTO) dampings, and incident wave conditions, while quantitatively evaluating the OWC system's performance using the capture width ratio (CWR) as the key metric. The findings indicate that the dual chamber configuration consistently exhibits enhanced performance for all combinations of orifice ratios, opening heights, and incident wave frequencies studied. As expected, increasing the opening height of the second chamber leads to improved performance of the OWC. Interestingly, the effect of varying applied PTO damping on improvement of CWR values is found to be relatively insensitive. The most significant improvements in CWR are observed for larger incident wave frequency values. For instance, for dimensionless wave frequency (Kh) values of 1.43 and 1.68, the CWR increases from 0.47 and 0.26 to 0.72 and 0.52, respectively, with the orifice ratio combination of τ1, 0.015, and τ2, 0.018. It is worth noting that the single chamber OWC operates most efficiently within the resonant frequency range of 0.94–1.23, while the dual chamber design extends this frequency range, enabling efficient wave energy capture over a wider spectrum of wave conditions. The dual chamber configuration offers considerable advantages for wave energy conversion applications by increasing the effective frequency bandwidth for optimal energy capture. The research findings suggest that this innovative design has the potential to significantly enhance the efficiency and adaptability of wave energy converters, contributing to the advancement of sustainable and renewable energy technologies.

Dual-chamber versus single chamber pacemakers, a systemic review and meta-analysis on sick sinus syndrome and atrioventricular block patients

AimsThe atrioventricular block (AVB) is a conduction system problem that results from the impairment in the transmission of an impulse from the atria to the ventricle, the disease has many etiologies. This article aimed to evaluate the efficacy and safety of dual and single-chamber pacemakers in patients with SSS and AVB. MethodsAn electronic search of PubMed (Medline), EMBASE, and Google Scholar was performed from 2000 till August 15th, 2022. Retrieved articles were exported to Endnote Reference Library Software, where duplicate studies were removed from the list, and only articles meeting the eligibility criteria of this study were selected. RevMan 5.4 and STATA 16 software were used for the analysis. The modified Cochrane Collaboration's risk of bias and New-castle Ottawa scale were used for quality assessment of RCTs and observational studies respectively. ResultsThis study is composed of 8953 patients with sick-sinus syndrome and atrioventricular block. A total of thirteen outcomes are included in this meta-analysis, out of which atrial fibrillation significantly favored dual chamber [OR = 1.29; 95 % CI = 1.05–1.59; P = 0.01 I2 = 29 %] and overall complications [OR = 0.48; 95 % CI = 0.29–0.77; p = 0.03 I2 = 0 %] and pneumothorax [OR = 0.31; 95 % CI = 0.10–0.93; p = 0.04, I2 = 0 %] were satisfied by single-chamber pacing. ConclusionThis study concluded that neither single-chamber nor dual-chamber pacemakers are superior to each other, but they are unique in their own ways as the results of this study manifest remarkable reduction in atrial fibrillation rates and pneumothorax using dual-chamber and single-chamber pacemakers respectively.

Improving outcomes in single chamber leadless pacemakers: strategies for minimizing vascular complications

BackgroundLeadless pacemaker therapy is associated with a significant reduction in lead-related complication rate compared to conventional transvenous single chamber pacemaker therapy. However, a significant complication rate of 1.2% was observed in vascular access due to the use of large delivery femoral sheath (27Fr). The aim of this study was to evaluate the effectiveness of real-time ultrasound guidance and Z suture technique in reducing total and major vascular complications in leadless pacemaker therapy.MethodIn this study, we performed a retrospective and prospective analysis of all adverse events associated with leadless pacemaker (Micra) implantation by two operators at a single tertiary center from December 2016 to December 2018. To mitigate the risk of vascular complications, all patients underwent real-time ultrasound-guided venipuncture for vascular access, as well as the application of a Z-suture technique for hemostasis at the end of the procedure. Data were collected on implant indications, implant procedure details, complications, and follow-up information.ResultsIn this study, 45 patients with an age range of 24 to 94 years (mean 76 ± 14 years) were recruited, with 21 (46.6%) being female. The pacing indications for the patients included atrial fibrillation (24, 53.3%), vascular (7, 15.5%), infection (9, 20%), cognitive/frailty (3, 6.6%), and occupational (2, 4.4%). The implant procedures were performed under general anesthesia in 6 (13.3%) of the cases, and under local anesthesia and sedation in 39 (86.6%) of the cases. A single deployment was achieved in 43 (95.5%) of the patients, while 2 deployments were required in 2 (4.4%) of the patients. Notably, no vascular or major complications were reported in our cohort of patients.ConclusionsThe results of this observational study indicate that incorporating real-time ultrasound guidance during venipuncture and the use of a Z-suture technique significantly reduce the occurrence of both total and major vascular complications associated with the implantation of leadless pacemaker. However, more robust and larger studies are required in order to confirm these results and implications for clinical practice.

Pacing mode survival in patients with single chamber atrial pacemaker for sinus node dysfunction

BackgroundSingle chamber atrial pacemaker should be sufficient for patients with sinus node dysfunction (SND) with normal atrioventricular (AV) conduction. However, most patients undergo dual chamber pacemaker implantation because of concern of new onset AV block. The annual incidence of new AV block has been reported from 0.6 to 4.4 % in various studies. ObjectivesOur aim is to assess mode survival in sinus node dysfunction with normal AV conduction patients implanted with AAIR. MethodsPatients who underwent single chamber atrial pacemaker implantation for SND with normal AV conduction between January 2014 and December 2021 were followed up for pacemaker device change, new onset AV block, bundle branch block, atrial fibrillation (AF), lead complications, reoperation and mortality rate. ResultsA total of 113 patients underwent single chamber atrial pacemaker implantation for SND during the study period. Mean age was 55.6 ± 12.7 years. During a mean follow up of 48.7 ± 24.9 months, none of the patients required pacemaker device change to VVIR/DDDR. Nine patients underwent reoperation, 5 for lead dislodgment, 1 for high threshold, 1 for pocket site erosion and 3 for pulse generator change. None developed AV block or AF with slow ventricular rate. Only 4 patients developed AF (3 paroxysmal,1 permanent). There were 3 deaths during follow up and none were sudden deaths. ConclusionSingle chamber atrial pacing is an acceptable mode of pacing in patients with SND in developing countries. Development of AV conduction abnormalities is rare in this relatively younger population.

APPLICATION OF CARBON-CARBON COMPOSITE MATERIALS FOR THE MANUFACTURE OF HIGH-TEMPERATURE HEATERS OF HEAT EXCHANGERS WITH AUTOMATIC TEMPERATURE CONTROL


 The article justifies the use of high-temperature heaters made of carbon-carbon composite material (CCCM) for the thermal unit of a silicon single crystal growth chamber. The conducted analysis confirms that the electrical properties of composite materials, specifically their specific resistance, allow for the creation of heating elements for high-temperature vacuum furnaces or furnaces operating in inert atmospheres at temperatures up to 2200°C.
 The use of heaters made from carbon-carbon composite material eliminates the main drawback of graphite heaters - uncontrolled energy dissipation during resistive heating due to the presence of transient electrical resistance at the junctions of graphite plates, and ensures a more uniform temperature field throughout the chamber volume. The capabilities in terms of the maximum permissible temperature of such a CCCM heater exceed the working temperature by more than two times, which also positively affects the service life.
 The modes of thermal processes occurring during crystal growth are determined by the technological process depending on the composition of the raw material and require high uniformity of heating in the working zone, high precision, and stability of the heater's temperature control. For precise temperature regulation, it is proposed to additionally measure the integral temperature in the chamber indirectly, which is based on measuring the electrical current passing through the heater, which is in thermodynamic equilibrium with the object. Thus, the heater is considered as a system susceptible to various thermal influences that determine the heat transfer process and the temperature change within the chamber and in the zone of the thermal unit's bricks.
 An improved structural diagram of a step-type extremal control system is proposed for automatic temperature control of a high-temperature heater using modern power electronics, sensors, microprocessors. To ensure speed and accuracy in temperature control, the pulse-phase control method implemented with modern specialized thermoregulator with PID-regulation was applied.
 Experimental tests conducted on the «Redmet-30» installation under factory conditions confirm the energy efficiency of using high-temperature heaters made of CCCM.

PP49 Cost Of Cardiac Implantable Electronic Device (CIED) Infections In Australia: A Private And Public Sector Payer Perspective

IntroductionIn Australia, approximately 200,000 patients have a cardiac implantable electronic device (CIED), and in an aging population that number is rising. CIED-related infections are also increasing, causing considerable morbidity and mortality, and substantial healthcare costs. Internationally, the rate of CIED infection ranges from 1.0 percent to 1.6 percent, while in Australia, the reported range is from less than 1 percent to 7.0 percent. The average hospital cost to treat an infection in the US ranges between USD48,000–USD83,000. To date, few publications have estimated the cost of CIED infections in Australia. Critical appraisal of these studies has highlighted issues in their methodology, making them unreliable sources for use in economic evaluations. The purpose of this study was to utilize Australian routinely collected health data to robustly model costs of CIED infections to reduce uncertainty for future health technology assessment (HTA).MethodsThe cost of treating a CIED infection was modeled for the public and private sector including cost of system removal and re-implantation procedures, hospital and intensive care unit (ICU) stay, and outpatient follow-up. Cost inputs were obtained from the Australian Prostheses List, Medicare Benefits Schedule, Australian Institute of Health and Welfare, and Private Hospital Data Bureau. Other inputs were obtained by surveying Australian clinicians, which were validated with published data. Phone interviews and online surveys were conducted with clinicians to elicit specific Australian practice pathways for patients with a CIED infection.ResultsThe majority of patients with a CIED have their device system removed (95-100%) and re-implanted (83%) once the infection has cleared. In the private sector, cost of infection ranged from AUD80,869 (USD54,384) for a single chamber pacemaker (PM), to AUD140,103 (USD94,248) for a dual chamber Implantable Cardioverter-defibrillator (ICD). Modeled costs of CIED infection were slightly lower in the public sector (AUD73,643-AUD88,446 (USD49,555 – USD59,516) for the same devices).ConclusionsThe cost of a CIED infections to the healthcare system is high and differs by device type. Utilizing local real-world data to estimate costs will improve accuracy of economic evaluations and reduce uncertainty for decision makers.

Single center retrospective clinical audit and comparison of outcome between epicardial and transvenous endocardial permanent pacemaker implantations in dogs.

The aim of this retrospective cohort study was to provide a single-center clinical audit of complications for single chamber permanent pacemaker implantation (PPI) techniques and determine if the clinical parameters, PPI technique or complications were associated with outcome. The electronic medical records were searched for dogs treated for bradyarrhythmia with PPI. Data related to presenting complaint, signalment of the dog, ECG diagnosis, echocardiographic findings, PPI technique, and programing of the pacemaker were recorded. Survival length (days) was recorded as the last veterinary visit; if the dog was dead the reason was documented. Cumulative survival of each pacemaker was examined by a Kaplan-Meier survival curve and the two techniques compared with a logrank test. Chi-square was used to determine the association between major complications and death. A total of 66 dogs with 52 transvenous and 30 epicardial PPIs were included. All epicardial pacemakers were implanted via transdiaphragmatic approach. A total of 31 life-threatening complications were reported. There were nine deaths related to major complications (13.6% of the study sample). The median follow-up period was 366 days, with a median survival of 255 days, and a significant difference in cumulative survival of each pacemaker (P = 0.01) between epicardial (93 days, range 0-1882 days) and transvenous (334 days, range 0-2745) PPIs but no significant difference in cumulative survival between the two techniques when only the first pacemaker was considered (p = 0.07). The presence of a major complications had a significant association with death due to pacemaker complications (P<0.001). The decision to perform epicardial PPI in failed transvenous PPI patients may have skewed the cumulative survival as was evident in the lack of significant difference in survival when only first PPI were examined. Major complication rates between the two techniques were similar and the authors consider both techniques equally reliable to manage symptomatic bradycardia in dogs.

Improved performance of land-fixed oscillating water column through dual chamber design

Improvements to the hydrodynamic efficiency of oscillating water columns (OWC) have the potential to influence commercial OWC adoption. The main goal of this study is to determine whether dual chamber OWCs with either a shared turbine or dual turbines can improve the hydrodynamic efficiency of the OWC through two-dimensional numerical simulations using computational fluid dynamics. In the numerical simulations, water depth is 0.8 m and the total length of the two chambers is 0.6 m. Numerical results show that when the non-dimensional turbine coefficient is 0.192, 1.432, and 3.070, a dual chamber dual turbine configuration can achieve between 7.6% to 26.8% greater hydrodynamic efficiency than both the single chamber single turbine and the dual chamber shared turbine configuration. Dual chamber, dual turbine configurations can increase hydrodynamic efficiency by operating over a broader range of wavelengths due to multiple resonant frequencies and are not affected by phase differences at shorter wavelengths.

Simultaneous biodegradation of Teflaro contained wastewater and electricity generation in an air–cathode microbial fuel cell

Despite the broad-spectrum antibacterial effect, 5th-generation cephalosporin fosamil (Teflaro) is highly resistant to traditional chemical and biological degradation. Here, biodegradation of Teflaro was achieved in a single chamber air–cathode microbial fuel cell (MFC). Using either Teflaro-acetate mixture or pristine Teflaro as the substrate, the MFCs outputted a maximal power density of 0.307 W/m2 with ∼86% degradation rates when inoculated with 100 mg/L Teflaro contained medical wastewater. Compared to a Teflaro-free MFC, the maximal output increased by 2.1 times (∼112 mV), which was attributed to abated transmembrane electrical impedance due to enhanced electron transfer by inhibiting the biosynthesis of peptidoglycan on cell walls. Dynamic microbial community analysis revealed that Klebsiella pneumoniae and Pseudomonas aeruginosa were the dominant species to generate stable electricity regardless of the altered community structure. This study first revealed that highly resistant antibiotics Teflaro can serve as a MFC substrate to simultaneously generate sustainable electricity and remediate medical wastewater.

Choice of cardiac implantable electronic device and age-stratified clinical outcome in patients with known heart failure prior to implant

Abstract Background Patients with heart failure (HF) and bradycardia may be eligible for different types of cardiac implantable devices, depending on presence of AV conduction disease, left ventricular ejection fraction, severity of heart failure symptoms, other comorbidities, and age. Once a pacing device is in place, there is a risk that ensuing heart failure progression or worsening of symptoms do not always prompt a device upgrade to resynchronization or conduction system pacing therapy, even if this should be warranted. We therefore aimed to compare prognosis in a national cohort of patients with prior HF diagnosis, who received a pacemaker or defibrillator with or without resynchronization therapy. Methods All patients with preexisting HF diagnosis who received a pacemaker with a right ventricular lead during the period 2005-2018 in Sweden were identified via the Pacemaker Registry. Data was crossmatched with the population registry and national disease registries. Primary outcome was 5-year mortality, and secondary was mode of death and hospitalization for heart failure. Cox regression and Kaplan Meier curves with log rank test were used for time dependent outcome analyses. Demography variables were compared with Chi2 test or Mann Whitney U test, as appropriate. Adjustment was done for history of atrial fibrillation, diabetes, hypertension, malignancy, age, gender, ischemic heart disease, renal disease, lung disease and cerebrovascular disease. Separate analyses were made for patients with complete AV block, based on the assumption of 100% ventricular pacing in this group, regardless of choice of implanted device. Results 37745 patients were included in the study (see figure 1). Demographic data was similar for the different device groups, except that patients with single chamber pacemaker were older, and all those with single chamber devices (pacemaker, ICD) were more likely to have a history of atrial fibrillation. All listed comorbidities, male sex and higher age were associated with lower 5-year survival in multivariable Cox regression analyses. Unadjusted 5-year mortality was 40% (highest for single chamber pacemakers (61%), and lowest for dual chamber ICDs (17%), p=0.001). When stratified by age group, and adjusted for relevant covariables, patients with single-chamber pacemakers still had higher mortality in all age decile groups (ranging from &amp;lt;60 to &amp;gt;90 years old, all p&amp;lt;0.001). Proportion of device upgrades to CRT was very low; 2.9% for dual- and 0.8% for single-chamber pacemakers. 17% of patients with traditional pacemakers died from HF, and 31% were hospitalized for HF. Conclusions Survival for patients with prior HF diagnosis who receive traditional pacemakers is poor, risk of HF hospitalization is high, whereas upgrades to CRT are scarce. This highlights the need for choosing correct device type at the primary implant, if ventricular pacing is anticipated.Flowchart of included patientsAge stratified survival per device group

Risk factors and prognostic implications for new-onset heart failure with ventricular pacing - a nationwide study

Abstract Background Studies have shown that the incidence of new-onset heart failure (HF) is higher for patients receiving pacemaker therapy with traditional right ventricular pacing, compared to age matched controls. Conduction system pacing may overcome this, but is more expensive and technically challenging. Objectives To investigate risk factors and implications for long-term prognosis of new-onset HF in patients after pacemaker-implant, with the aim of identifying patients at high risk already prior to device implant. Methods All patients without preexisting HF, who received a pacemaker with a right ventricular lead in Sweden during the period 2005-2020, were identified via the nationwide Pacemaker Registry. Data was crossmatched with the population registry and national disease registries. Outcome was new-onset HF within 5 years post-implant, HF hospitalization and all-cause mortality. Results In all, 65579 patients met the inclusion criteria (10351 single chamber ventricular and 55228 dual chamber pacemakers). 13792 (21.0%) patients were diagnosed with HF within five years post-implant. Of these, 6244 (45.3%) were hospitalized for HF (see Figure 1). Patients with heart failure were older (80.6 vs. 76.7 years, p&amp;lt;0.001), had a higher burden of comorbidities, and were more likely to die within five years compared to those without HF (41.2% vs. 19.7%, p&amp;lt;0.001). Independent risk factors with more than 25% increased odds ratio for developing heart failure within 5 years included increasing age, diabetes, atrial fibrillation, chronic lung- and kidney disease, ischemic heart disease, and AV block. A combined score using these variables was strongly associated with increased risk of both HF-hospitalization (OR 1.48 [1.46-1.51], p&amp;lt;0.0001) and 5-year mortality (OR 1.81[1.77-1.98], p&amp;lt;0.0001). There was a progressively increasing risk proportional to the summed score. Patients with at least five points on the score had &amp;gt;25% risk of new-onset heart failure within five years, and patients with at least seven points had &amp;gt;25% risk of new-onset heart failure within two years. In figure 2 we present a suggested score model, based on the results. Conclusions Pacemaker therapy with a lead in the right ventricle was associated with &amp;gt;20% risk of new-onset HF within five years. This in turn was associated with higher risk of death. Based on clinical risk factors, our proposed score can be used to identify patients at high risk for new-onset heart failure. These patients may be eligible for conduction system pacing or resynchronisation therapy. Randomized trials are needed to determine if a score-based pacing strategy (right ventricular or conduction system pacing) approach results in better clinical outcome, and if it is cost-effective.Included patients and risk of HF hosp.Decision algorithm based on results

First month global longtudinal strain for predicting early pacemaker-induced left ventricular dysfunction (PIVD) six month after pacemaker implantation

Abstract Background Pacemaker-induced ventricular dysfunction (PIVD) and pacemaker-induced cardiomyopathy (PICM) emerged as a complication following right ventricular permanent pacemaker (PPM) implantation, showing a great occurrence in the first year. Finding an early predictor of PIVD and PICM is crucial in order to alleviate mortality, morbidity, and increase health-care cost efficiency. Purposes to find new predictor by analyzing effect of first month GLS using 2D-speckle tracking echocardiography and reduction of left ventricular ejection fraction (LVEF), known as PIVD, in the first 6 month after PPM implantation. Methods A single center, prospective cohort study was conducted to all patients with normal LVEF, indicated for PPM implantation. Data of GLS was measured before and after one month of PPM implantation. Data of LVEF was measured before and six month after PPM implantation. The change of GLS in one month after PPM implantation was measured as delta GLS, and the change of LVEF in six month was measured as delta EF. Results Fifty-three patients from May 2018 until October 2020 was enrolled for this study based on inclusion and exclusion criteria. Patient’s baseline characteristics show 62±14 years of age, most of them had hypertension (54.7%) and had single chamber pacemaker implantation (81.1%). Study analysis reveals that ejection fraction (EF) reduce significantly after six months pacemaker implantation (66,5±5,6% become 60,7±10.7%; p= &amp;lt;0,00001). There were 6 patients (11.3 % ) suffering PICM. Correlation analysis between the change of GLS in the first month and the change of LVEF in the first six months after PPM implantation was statistically significant with moderate correlation (p&amp;lt;0.00001; r= -0.486). Linear regression analysis shows that every 1 point decrease of first month GLS, affecting 1.83 point decrease of sixth month LVEF (b= -0.1837, p=&amp;lt;0.00001). Conclusion There is significant moderate correlation between the change of GLS in the first month and early reduction of LVEF in the first 6 months after PPM implantation.The Scheme of Research Sampling Method

Abstract 17188: Electrocardiographic Algorithms for Localization Ventricular Ectopy From the Ventricular Outflow Tracts Demonstrate Poor Accuracy and Agreement

Background: Premature ventricular contractions (PVCs) and ventricular tachycardia (VT) commonly arise from the outflow tracts of the left and right ventricles and can be treated with catheter ablation when symptomatic or associated with cardiomyopathy. Accurate localization of these ectopic sources aids procedural planning. Several different electrocardiographic (ECG) algorithms have been published, but their relative performance has not been assessed. Objective: Compare the accuracy and agreement of three ECG algorithms for PVC localization. Methods: ECGs from patients who underwent catheter ablation for PVCs or VT originating the outflow tract region were analyzed using three published PVC localization algorithms. The predictions from these algorithms were then compared to the site of successful catheter ablation (right ventricular outflow tract [RVOT], left ventricular outflow tract [LVOT], or epicardium). The accuracy and agreement of the three algorithms were compared. Results: A total of 43 patients were evaluated and ectopy was suppressed via ablation from a single chamber in 37 (86%) of patients. VT/PVCs originated from the RVOT (N=10), LVOT (N=26), and epicardium (N=1). The three studied algorithms demonstrated accuracy rates of 46-70%. The algorithms disagreed on the predicted ectopy location for 19 (51%) patients. When all algorithms agreed (N=18), the prediction was accurate for only 11 patients (61%). Conclusion: Rules-based ECG algorithms demonstrate poor performance and use of different published algorithms frequently result in disparate results. More accurate and consistent methods incorporating individualized electroanatomic variation may improve accuracy and periprocedural management for PVC and VT ablation.

Abstract 18539: The Impact of Prophylactic Heparin on Pocket Hematoma Formation After Cardiac Implantable Electronic Device Implantation a Real-World Experience

Introduction: Intravenous heparin is strongly associated with pocket hematoma (PH) formation in patients undergoing cardiac implantable electronic device (CIED) implantation. However, there is no data on subcutaneous prophylactic heparin in this population Hypothesis: We hypothesized that the subcutaneous heparin may increase the odds of PH in patients undergoing CIED implantation using data from a large, nationally representative sample of the US population. Methods: The Premier Healthcare Database was analyzed from 2016-2019 to identify patients &gt;18 years old undergoing CIED implantation. Patients with PH were then identified by using ICD-10 CM codes. A multivariable logistic regression model was used to adjust for confounders Results: A total of 267,650 patients underwent CIED implantation between January 1, 2016, and December 31, 2019, of which 4,496 (1.68%) \developed PH. Single chamber pacemaker in 7.22%, dual-chamber pacemaker was implanted in 58.3% of patients, and CRT-P in 4.59%, ICD in 18.58%, CRT-D in 11.31%. Of the total cohort, 559 Patients received subcutaneous heparin within 3 days of the CIED implant procedure. Of these 559 patients, 91 (16%) patients were on subcutaneous heparin (pre-procedural: 19; post-procedural: 57) and developed PH. Subcutaneous heparin is associated with increased odds (OR :13.8,p&lt;0.01) of PH formation. Conclusions: This study suggests that subcutaneous heparin is a strong risk factor for the development of PH. This may independently drive up the rates of PH in the inpatient population. Further studies on the timing of subcutaneous heparin need to be conducted.

Abstract 12595: Vascular and Cardiac Ultrasound as the Primary Imaging Tool to Safely Deliver Pacing Leads While Implanting Single Chamber Cardiac Implantable Electronic Devices. RADICAI USE Investigators

Introduction: Conventional Cardiac implantable electronic devices (CIEDs) implantation requires fluoroscopy. Risks involved with implantation include pneumothorax, lead dislodgement, and perforation of the right ventricular wall. In addition, there are long-term risks of malignancy associated with prolonged and repeated use of radiation over the decades of operators’ employment and mechanical injuries related to heavy personal protection equipment. To reduce these risks, we aimed to study the utilization and safety of ultrasound (US) for the entire procedure to implant single-chamber devices. Methods: The RADICAI USE study (Reduction or Elimination of Radiation Use in Single Chamber Cardiac Devices using ultrasound) is a prospective, single-arm and multi-operator case series enrolled patients awaiting a single-chamber CIED. A fluoroscopic cut-off time of 20 seconds was used to define the success (Group A) or failure (Group B) of using the US for the entire implant duration. Patients were followed up at 1 week, 1 month and 1-year post-implant. Results: The study enrolled 63 patients, with 50 pacemakers and 13 ICDs, a mean age of 79.5 ± 13.8 years (95% CI = 76.1 - 82.9), and a mean weight of 74.1 ± 14.6 (95% CI = 70.5 - 77.7). Overall, 53 (84.1%) CIEDs were successfully implanted with a radiation time of less than 20 seconds (Group A). Fluoroscopic over 20 seconds was required due to poor echocardiographic windows, challenging access, or anatomy. No iatrogenic new or worsening of tricuspid regurgitation was noted. The mean procedure time including US setup time was 65.2 ± 20.2 (95% CI = 60.2 -70.2) minutes. Fluoroscopic time was significantly reduced in Group A compared to Group B (5.8 ± 4.5s vs 109.5 ± 92.9s, p = 0.004). Follow-up showed no device-related complications, with only two patients requiring lead revisions due to poor sensitivity, one unrelated to US use and another probably related. Conclusions: US-guided implantation of single-chamber CIEDs is feasible and safe, reducing the need for fluoroscopic guided implantation and subsequent risks of higher radiation exposure. Further studies are required to evaluate the cost-effectiveness and to explore fluoroscopic-free single-chamber CIED implantations using the US.

Abstract 16276: Complex Corynebacterium Case: Management of Recurrent Corynebacterium Bacteremia in a Patient With Cardiac Implanted Electronic Device and Left Ventricular Assist Device

Background Cardiac implantable electronic device (CIED) infections are morbid and costly. Atypical organisms are increasingly recognized as a cause of CIED infections. We present a case of recurrent Corynebacterium striatum bacteremia requiring CIED and left ventricular assist device (LVAD) extraction. Case Presentation A 54-year-old female dialysis patient with diabetes, ischemic cardiomyopathy, primary prevention single chamber transvenous defibrillator (ICD) 8 years prior, and destination LVAD presented with chronic C. striatum driveline site infection and relapsing and remitting bacteremia. Over the prior two years, she suffered from chronic driveline infections requiring wound care, driveline washouts, and antibiotics, although not seen by the electrophysiology (EP) team. After a fourth episode of bacteremia, she underwent ICD extraction and LVAD pump exchange, followed by 6 weeks of vancomycin and 3 months of rifampin. She then remained free of bacteremia for 19 months, though continued to demonstrate evidence of driveline infection despite pump exchange. Ultimately, C. striatum bacteremia recurred. Given unrelenting soft tissue infection and recurrent bacteremia, redo LVAD exchange was deferred and she was treated with lifelong suppressive antibiotics. Discussion Corynebacterium species have historically been considered skin flora, but more recently have been identified as pathogens, both as a cause of endocarditis, and a common organism in LVAD associated soft tissue infections. There are few reports of CIED infection. Source control is difficult in bacteremia patients with both CIED and LVAD. In this case, recurrent bacteremia could be attributed to recurrent driveline-soft tissue infection. However, the prolonged freedom from bacteremia off antibiotics after CIED extraction, despite ongoing soft tissue and driveline infection, argues that her transvenous ICD may have been seeded. This case highlights the growing spectrum of bacteria implicated in CIED-related infection, that early extraction may be a critical intervention regardless of infectious source, and importance of multidisciplinary discussions including heart failure, surgery, infectious disease, and EP to improve outcomes in this complex population.

Microbial electrolysis drives ammonium removal from saline wastewater through marine anammox bacteria

Currently, ammonium removal from saline wastewater still poses a challenge to conventional biological nitrogen removal process. Herein, the conversion of NH4+-N to N2 was successfully driven by marine anammox bacteria (MAB) in a single chamber microbial electrolytic cell (MEC) using NH4+-N as the sole substrate. Compared with no ammonium removal in the abiotic reactor with applied voltage (0–1.5 V), the maximum ammonium and total nitrogen removal rate (ARR and TNRR) of 55 and 50 g/m3•d were obtained at the voltage of 1.1 V, which were 78 % and 76 % higher than that of 0.5 V, respectively. At the voltage ≥ 1.1 V, the accumulation of NO2–-N and NO3–-N was observed in the MEC, and the nitrifying bacteria Nitrosmonas and Nitrospira were detected on the anode surface with the relative abundances of 0.84 % and 0.21 %, respectively. It was proved that the production of NO2–-N and NO3–-N was an electrochemical biological process by electroactive nitrifying bacteria. Candidatus Scalindua was the main functional genus for ammonium removal at anode biofilm with the relative abundance of 19.27 %. Therefore, ammonium was successfully removed by integrating anodic anammox and anodic nitrification. Applied voltage increased the microbial diversities at anode surface and promoted the formation of electrode biofilm. These findings indicated a promising saline wastewater treatment by employing salt-tolerant MAB for ammonium removal.

Differential Diagnosis of Cardiac Amyloidosis and Hypertrophic Cardiomyopathy

Diagnosis and differential diagnosis of cardiac amyloidosis and hypertrophic cardiomyopathy is difficult in some cases, which is confirmed by the presented clinical observation. The patient A., 67 years old, from the age of 59 for 7 years suffered from arterial hypertension with a maximum blood pressure of 170/100 mmHg, received hypotensive therapy. Myocardial infarction, a history of stroke denies. Since January 2018, at the age of 65, against the background of spontaneous stabilization of blood pressure figures, shortness of breath when climbing to the 2nd floor, lifting weights, suffocation at night, swelling of the shins, feet, in connection with which I turned to a doctor. When examined on an electrocardiogram, a low voltage of QRS complexes in the leads from the extremities was noted, there was no increase in the amplitude of the r wave in V1–3. Echocardiography revealed a thickening of the interventricular septum and the posterior wall of the left ventricle up to 1.9 cm without obstruction of the outlet of the left ventricle, restrictive type of diastolic dysfunction, dilation of the left and right atria, moderate pulmonary hypertension, moderate amount of fluid in the pericardial cavity. Magnetic resonance imaging of the heart revealed a pattern typical of cardiac amyloidosis: diffuse subendocardial contrast of the myocardium of both ventricles in the absence of local contractility disorders, increased myocardial thickness in all segments, hydropericardium. Biopsy of the skin and subcutaneous fat with Congo red staining and polarization microscopy revealed no amyloid deposits. No mutations in the transthyretin gene responsible for transthyretin amyloidosis (ATTR–amyloidosis) were detected during the genetic study. Sequencing of 10 genes encoding myocardial sarcomeric proteins in the MYBPC3 gene revealed a mutation c.3197C &gt;G (p.Pro1066Arg) in a heterozygous state, previously described in patients with hypertrophic cardiomyopathy of Slavic origin. Cascade family screening for the mutation was not carried out due to the fact that the patient did not know the father, the mother died at the age of 75 from heart failure, the only son died from an accident six months before the patient’s treatment. On 15.02.2019, the patient suffered a circulatory arrest with successful resuscitation measures. For the purpose of secondary prevention of sudden cardiac death, a single–chamber cardioverter-defibrillator was implanted on 22.02.2019. Despite the ongoing therapy, the patient died in March 2019. from progressive heart failure. Thus, a clinical case is presented where magnetic resonance imaging suspected amyloid cardiomyopathy, which did not receive morphological confirmation in biopsies of extra–cardiac localization. Hypertrophic cardiomyopathy caused by mutation c.3197C &gt;G (p.Pro1066Arg) in the MYBPC3 gene was confirmed on the basis of clinical and instrumental and molecular genetic methods. The pattern characteristic of cardiac amyloidosis described in this patient with instrumental examination methods may be due to a violation of autophagy processes previously described with a number of mutations in the MYBPC3 gene, which may lead to the accumulation of amyloid-like inclusions in cardiomyocytes. For differential diagnosis of cardiomyopathies in complex cases, endomyocardial biopsy may be required. The possibility of coexistence of genetically determined hypertrophic cardiomyopathy and amyloid heart disease is not excluded.

Effects of municipal waste compost on microbial biodiversity and energy production in terrestrial microbial fuel cells

Microbial Fuel Cells (MFCs) transform organic matter into electricity through microbial electrochemical reactions catalysed on anodic and cathodic half-cells. Terrestrial MFCs (TMFCs) are a bioelectrochemical system for bioelectricity production as well as soil remediation. In TMFCs, the soil is the ion-exchange electrolyte, whereas a biofilm on the anode oxidises organic matter through electroactive bacteria. Little is known of the overall microbial community composition in a TMFC, which impedes complete exploitation of the potential to generate energy in different soil types. In this context, an experiment was performed to reveal the prokaryotic community structure in single chamber TMFCs with soil in the presence and absence of a municipal waste compost (3% w/v). The microbial community was assessed on the anode and cathode and in bulk soil at the end of the experiment (54 days). Moreover, TMFC electrical performance (voltage and power) was also evaluated over the experimental period, varying the external resistance to improve performance. Compost stimulated soil microbial activity, in line with a general increase in voltage and power. Significant differences were observed in the microbial communities between initial soil conditions and TMFCs, and between the anode, cathode and bulk soil in the presence of the compost. Several electroactive genera (Bacillus, Fulvivirga, Burkholdeira and Geobacter) were found at the anode in the presence of compost. Overall, the use of municipal waste compost significantly increased the performance of the MFCs in terms of electrical power and voltage generated, not least thanks to the selective pressure towards electroactive bacteria on the anode.