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The paper describes an algorithm to differentiate leads from sea ice using the dual polarization synthetic aperture radar (SAR) data from the Sentinel-1 satellite in an extrawide swath mode. The algorithm uses the polarimetric features of the sea surface signal obtained in the SAR images: the ratio between co- and cross-polarization. A technique is proposed for classifying the SAR images to identify discontinuities (cracks, leads) in drifting sea ice using the ratio and difference of polarizations together with texture features and the neural network implementation. The method was tested using the satellite data obtained over the Arctic seas in the Russian Federation. [ABSTRACT FROM AUTHOR]

A deep brain stimulator (DBS) device is a surgically implanted system that delivers electrical impulses to specific targets in the brain to treat abnormal movement disorders. A DBS is like a cardiac pacemaker, but instead of sending electrical signals to the heart, it sends them to the brain instead. When DBS leads and extension wires are exposed in the biological environment, this can adversely affect impedance and battery life, resulting in poor clinical outcomes. A posthumously extracted DBS device was evaluated using visual inspection and optical microscopy as well as electrical and mechanical tests to quantify the damage leading to its impairment. The implantable pulse generator (IPG) leads, a component of the DBS, contained cracks, delamination, exfoliations, and breakage. Some aspects of in vivo damage were observed in localized areas discussed in this paper. The duration of the time in months that the DBS was in vivo was estimated based on multiple regression analyses of mechanical property testing from prior research of pacemaker extensions. The test results of three DBS extensions, when applied to the regressions, were used to estimate the in vivo duration in months. This estimation approach may provide insight into how long the leads can function effectively before experiencing mechanical failure. Measurements of the extension coils demonstrated distortion and stretching, demonstrating the changes that may occur in vivo. These changes can alter the impedance and potentially reduce the effectiveness of the clinical treatment provided by the DBS system. Ultimately, as both DBSs and pacemakers use the same insulation and lead materials, the focus of this paper is to develop a proof of concept demonstrating that the mechanical properties measured from pacemaker extensions and leads extracted posthumously of known duration, measured in months while in vivo, can be used to predict the duration of DBS leads of unknown lifespan. The goal is to explore the validity of the proposed model using multiple regression of mechanical properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Highlights on recent advancements of benzazoles as potential anti-TB agents. • Coverage of benzazoles with promising anti-TB activity with lower MICs than standard drugs. • Discussions on anti-tubercular mode of actions of benzazoles against MmpL3, FtsZ, HisG, etc. • Focus on favorable drug-like properties of benzazoles for the medicinal chemists working on drug discovery against TB. •.Detailed discussions on the SAR of benzazoles as anti-tubercular agents. Tuberculosis (TB) remains a global health challenge, claiming numerous lives each year, despite recent advancements in drug discovery and treatment strategies. Current TB treatment typically involves long-duration chemotherapy regimens that are often accompanied by adverse effects. The introduction of new anti-TB drugs, such as Bedaquiline, Delamanid, and Pretomanid, offers hope for more effective treatment, although challenges persist keeping the quest to find new anti-TB chemotypes an incessant exercise of medicinal chemists. Towards this initiative, the benzazoles continue to draw attention and have been recognised as new anti-TB scaffolds. Benzazole-containing compounds emerged as new chemotypes with potential to offer a versatile platform for new anti-TB drug design to generate new leads for further optimization. The elucidation of their chemical properties, biological effects, and potential mechanisms of action, would lead to identify innovative candidates for TB therapy. As medicinal chemists delve deeper into the SARs and mechanisms of action of benzazole derivatives, new opportunities for creating effective and safe anti-TB medications arise. This review highlights the potential impact of benzazole-based compounds on the search for new therapeutic agents against tuberculosis, emphasizing the importance of continued research and innovation in the field. [ABSTRACT FROM AUTHOR]

In winter 2013, a sea ice breakout in the Beaufort Sea produced extensive fracturing and contributed to record ice export. Rheinlænder et al. (2022, https://doi.org/10.1029/2022GL099024) simulated this event using the neXtSIM sea ice model, reproducing a realistic progression of lead opening and ice drift following the track of an anticyclone. Their simulations indicate strong winds and thin ice are key factors in breakouts. We discuss observational records giving additional insight into the mechanisms controlling breakout events, including the role of wind direction. Breakouts are common and have occurred under weaker winds than in 2013 and in thicker ice of previous decades. During 2013 and other events, patterns of lead opening during breakout followed changes in wind direction relative to the coast with anticyclone position. For skillful predictions of future breakouts, models must reproduce this behavior, and their performance should be assessed across a range of wind and ice conditions. Plain Language Summary: In winter, the Beaufort Sea is covered by a layer of sea ice that is usually frozen against the southern and eastern coastlines that bound the sea. When winds continuously blow from east to west away from these boundaries, the ice cover can tear apart and rapidly drift away from the coasts in what is called a breakout event. The prediction of such dynamic events is important for those who navigate the region. Rheinlænder et al. (2022, https://doi.org/10.1029/2022GL099024) recently used the neXtSIM sea ice model to simulate realistic ice cracking and drift during an exceptionally strong breakout that occurred in 2013. The authors highlighted strong winds and thin sea ice as key factors for breakout. We use observational records to provide additional insight into processes during Beaufort breakouts. Records of many similar events demonstrate that breakouts are common under weather patterns that produce east‐to‐west winds, even for weaker winds and thicker ice than in 2013. Across observed events, wind direction influences sea ice fracturing patterns and breakout timing. To ensure that model predictions of future sea ice breakouts are accurate, simulations should be compared against observations of multiple recorded events that span a range of wind and ice conditions. Key Points: Observational data provide context for a 2013 Beaufort Sea (BS) breakout simulated with the neXtSIM model by Rheinlænder et al. (2022, https://doi.org/10.1029/2022GL099024)While the 2013 event was exceptional, winter sea ice breakout is common under anticyclonic winds including in years with thicker ice packsWind direction relative to the coast influences the timing and location of lead opening during breakout in the BS [ABSTRACT FROM AUTHOR]

The aim of the present research paper was to evaluate the main electrocardiogram parameters in goat. The electrocardiograms were performed on a batch of 20 Carpathian goats, using the Dubois lead system. By analysing the results obtained, we concluded that, using the Dubois lead system, the best method of performing the electrocardiogram in goats is using lead II, the amplitude values being 0.117 mV for the P wave, 0.310 mV for the ventricular complex and 0.386 mV for the T wave, while lead I is not suitable for the EKG exam in this species, due to the extremely low waves’ amplitude, resulting in an almost obscure recording. Regarding the duration of the electrocardiographic waves, the values obtained were 0.048±0.016 seconds for the P wave, 0.046±0.014 seconds for the QRS complex and 0.088±0.016 seconds for the T wave. As for the segments and intervals, the durations obtained were 0.062±0.020 seconds for the P-R segment, 0.246±0.014 seconds for the Q-T interval, 0.384±0.037 seconds for the P-T interval and 0.096±0.020 seconds for the T-P segment. The heart rate, electrographically calculated, was 128.5 bpm ± 12.215. [ABSTRACT FROM AUTHOR]

Background: The standard configuration's set of twelve electrocardiogram (ECG) leads is optimal for the medical diagnosis of diverse cardiac conditions. However, it requires ten electrodes on the patient's limbs and chest, which is uncomfortable and cumbersome. Interlead conversion methods can reconstruct missing leads and enable more comfortable acquisitions, including in wearable devices, while still allowing for adequate diagnoses. Currently, methodologies for interlead ECG conversion either require multiple reference (input) leads and/or require input signals to be temporally aligned considering the ECG landmarks.Methods: Unlike the methods in the literature, this paper studies the possibility of converting ECG signals into all twelve standard configuration leads using signal segments from only one reference lead, without temporal alignment (blindly-segmented). The proposed methodology is based on a deep learning encoder-decoder U-Net architecture, which is compared with adaptations based on convolutional autoencoders and label refinement networks. Moreover, the method is explored for conversion with one single shared encoder or multiple individual encoders for each lead.Results: Despite the more challenging settings, the proposed methodology was able to attain state-of-the-art level performance in multiple target leads, and both lead I and lead II seem especially suitable to convert certain sets of leads. In cross-database tests, the methodology offered promising results despite acquisition setup differences. Furthermore, results show that the presence of medical conditions does not have a considerable effect on the method's performance.Conclusions: This study shows the feasibility of converting ECG signals using single-lead blindly-segmented inputs. Although the results are promising, further efforts should be devoted towards the improvement of the methodologies, especially the robustness to diverse acquisition setups, in order to be applicable to cardiac health monitoring in wearable devices and less obtrusive clinical scenarios. [ABSTRACT FROM AUTHOR]

Sea ice leads, or fractures account for a small proportion of the Arctic Ocean surface area, but play a critical role in the energy and moisture exchanges between the ocean and atmosphere. As the sea ice area and volume in the Arctic has declined over the past few decades, changes in sea ice leads have not been studied as extensively. A recently developed approach uses artificial intelligence (AI) and satellite thermal infrared window data to build a twenty-year archive of sea ice lead detects with Moderate Resolution Imaging Spectroradiometer (MODIS) and later, an archive from Visible Infrared Imaging Radiometer Suite (VIIRS). The results are now available and show significant improvement over previously published methods. The AI method results have higher detection rates and a high level detection agreement between MODIS and VIIRS. Analysis over the winter season from 2002–2003 through to the 2021–2022 archive reveals lead detections have a small decreasing trend in lead area that can be attributed to increasing cloud cover in the Arctic. This work reveals that leads are becoming increasingly difficult to detect rather than less likely to occur. Although the trend is small and on the same order of magnitude as the uncertainty, leads are likely increasing at a rate of 3700 km2 per year with a range of uncertainty of 3500 km2 after the impact of cloud cover changes are removed. [ABSTRACT FROM AUTHOR]

Knowledge of the wintertime sea-ice production in Arctic polynyas is an important requirement for estimations of the dense water formation, which drives vertical mixing in the upper ocean. Satellite-based techniques incorporating relatively high resolution thermal-infrared data from MODIS in combination with atmospheric reanalysis data have proven to be a strong tool to monitor large and regularly forming polynyas and to resolve narrow thin-ice areas (i.e., leads) along the shelf-breaks and across the entire Arctic Ocean. However, the selection of the atmospheric data sets has a large influence on derived polynya characteristics due to their impact on the calculation of the heat loss to the atmosphere, which is determined by the local thin-ice thickness. In order to overcome this methodical ambiguity, we present a MODIS-assisted temperature adjustment (MATA) algorithm that yields corrections of the 2 m air temperature and hence decreases differences between the atmospheric input data sets. The adjustment algorithm is based on atmospheric model simulations. We focus on the Laptev Sea region for detailed case studies on the developed algorithm and present time series of polynya characteristics in the winter season 2019/2020. It shows that the application of the empirically derived correction decreases the difference between different utilized atmospheric products significantly from 49% to 23%. Additional filter strategies are applied that aim at increasing the capability to include leads in the quasi-daily and persistence-filtered thin-ice thickness composites. More generally, the winter of 2019/2020 features high polynya activity in the eastern Arctic and less activity in the Canadian Arctic Archipelago, presumably as a result of the particularly strong polar vortex in early 2020. [ABSTRACT FROM AUTHOR]

The article develops the theoretical and methodological principles of messenger marketing, forms its scheme and proposes the main stages for use in the practice of business entities. It is noted that messenger marketing has become a trend in recent years and involves the use of messenger tools to better interact with the target audience to promote the company or its products and services. As a messenger tool, you can consider a wide selection of content that should be sent to users: videos, images, texts, animations, etc. In Ukraine, the most popular messengers are Viber, Facebook Messenger, Skype, Telegram, WhatsApp and others. A messenger marketing scheme has been developed, which includes processes in the sales department, processes in messengers and traffic channels. The processes in the sales departments of the companies are defined, which include the construction of the CRMsystem and the payment system, the site and the work of the sales managers. The main processes in messengers - funnels, chatbots and mailings are considered and given a brief description. The main stages for effective use of messenger marketing in practice are proposed, including the choice of messengers for communication with customers, the choice of a platform that will help automate communication, as well as collect data and segment and connect to this platform, integration of messengers with CRM-system. The main tasks of messenger marketing are defined: automation and optimization of managers' work, which makes it possible to minimize the response time to the application, qualification of potential customers (leads), optimization of advertising costs. The next step in solving this problem should be to reach a new level of communication with customers through messenger marketing. In the future, CRM-marketing is worth to be emphasized, when different channels and CRM-systems work, chatbots are created, which are actively beginning to integrate. [ABSTRACT FROM AUTHOR]

Pacemakers, implantable cardiac defibrillators, and cardiac resynchronization therapy devices are potentially life-saving treatments for a number of cardiac conditions, but are not without risk. Most concerning is the risk of a cardiac implantable electronic device (CIED) infection, which is associated with significant morbidity, increased hospitalizations, reduced survival, and increased healthcare costs. Recommended preventive strategies such as administration of intravenous antibiotics before implantation are well recognized. Uncertainties have remained about the role of various preventive, diagnostic, and treatment measures such as skin antiseptics, pocket antibiotic solutions, anti-bacterial envelopes, prolonged antibiotics post-implantation, and others. Guidance on whether to use novel device alternatives expected to be less prone to infections and novel oral anticoagulants is also limited, as are definitions on minimum quality requirements for centres and operators and volumes. Moreover, an international consensus document on management of CIED infections is lacking. The recognition of these issues, the dissemination of results from important randomized trials focusing on prevention of CIED infections, and observed divergences in managing device-related infections as found in an European Heart Rhythm Association worldwide survey, provided a strong incentive for a 2019 International State-of-the-art Consensus document on risk assessment, prevention, diagnosis, and treatment of CIED infections. [ABSTRACT FROM AUTHOR]

The aim of this research was to determine in which areas of the bovine body surface the electrodes should be placed to record T waves with stable polarity and morphology by using bipolar and unipolar leads to detect alterations in the conduction of the ventricular repolarization impulse. One hundred animals of both sexes from different age groups were used. Each T-wave form was numerically coded and its polarity was classified. Sixteen different forms of T waves were observed, presenting four types of polarity: positive, negative, biphasic +/- and biphasic -/+. In the bipolar shoulder lead IH, the T wave was largely negative or biphasic +/-; and it was positive or biphasic -/+ in the remaining bipolar leads. The T-wave was negative or in some cases biphasic +/- in the unipolar basal leads of the heart. Positive or biphasic polarity was always obtained in the apical leads -/+ and four to six different forms were recorded. It is concluded that, in the areas located towards the base or the apex of the heart, leads can be used originating electrocardiographic records with great stability in the polarity of the T wave and in which the quantity of different forms detected is very reduced, with great predominance of the pointed one, so that they become a very useful reference to diagnose the alterations in the conduction of the repolarization impulse through the cardiac ventricles. [ABSTRACT FROM AUTHOR]

Given its polar orbit, CryoSat-2 provides frequent, high-resolution SAR altimeter measurements of the Arctic region over changing terrain ( e.g. ice, water and sea ice). The purpose of this research is to improve SAR waveform retracking in the Arctic region by analysing different retrackers on their performance in varying (Arctic) conditions and combine the positive behaviours into one optimal retrackers system. Based on the accuracy and precision performance, four retrackers are evaluated in order to determine this retrackers system: the empirical primary peak centre of gravity, the primary peak threshold and the ESA retracker, as well as the physical SAMOSA3 retracker. Empirical retrackers determine the retracking point depending on the retrieved waveform statistics, while physical retrackers take the system characteristics, the geometry and the surface properties into account. Three sea surface types are considered in this research: ocean, sea ice, and ice leads. For the majority of the months, SAMOSA3 has the highest accuracy for ocean waveforms as its physical full-analytic approach provides a good fit for the predictable ocean waveforms. The primary peak retrackers have the best precision performance for irregular waveforms like sea ice and ice leads. The year-round retrackers system includes per month the most accurate retracker for ocean waveforms and the best precision retracker for sea ice and leads. To remove the bias caused by combining different retracking algorithms, four bias removal strategies are developed and evaluated on their accuracy and precision performance. The retrackers system with the primary peak centre of gravity as a basis retracker and a mean bias removal approach performed best, as it has a precision improvement of 47.1% with respect to retracking all waveform classes with the primary peak COG retracker solely. By applying the developed optimal retrackers system and using the bias removal strategy, the mean standard deviation of the altimeter measurements in the Kara Sea study area is reduced from 6.7 cm to 3.6 cm. [ABSTRACT FROM AUTHOR]

Abstract: Sea ice kilometer‐scale characteristics are not explicitly represented in weather and climate model systems. However, due to the large differences of the surface temperature between sea ice and ocean, sea ice‐free areas (leads, polynyas, etc.) can have a strong impact on the surface heat fluxes and, in turn, on atmospheric dynamics. In the present study we analyze the atmospheric response to changes in the sea ice characteristics in the marginal ice zone of the Fram Strait and Barents Sea. A kilometer‐scale convection permitting atmospheric modeling system is used. The model sensitivity experiment is idealized, since there is no complete information on sea ice on these scales available. Instead, we are merging information from the passive microwave satellite product of sea ice concentration with a sea ice lead product based on thermal infrared sensors. An important constraint is that the sea ice‐free areas are introduced locally, but on scales of 100 km the sea ice coverage is kept constant for both the experiments. The sensitivity of air‐sea fluxes, atmospheric temperature, and winds is analyzed between the model experiments. In general, the standard deviation of the changes in surface air temperature and winds is, on large scales, about 2 K and 2 m/s, respectively. Those values are in the same order as the mean 12‐hr forecast error of advanced weather forecast models in this region. [ABSTRACT FROM AUTHOR]

Water level from sea ice-covered oceans is particularly challenging to retrieve with satellite radar altimeters due to the different shapes assumed by the returned signal compared with the standard open ocean waveforms. Valid measurements are scarce in large areas of the Arctic and Antarctic Oceans, because sea level can only be estimated in the openings in the sea ice (leads and polynyas). Similar signal-related problems affect also measurements in coastal and inland waters. This study presents a fitting (also called retracking) strategy (ALES+) based on a subwaveform retracker that is able to adapt the fitting of the signal depending on the sea state and on the slope of its trailing edge. The algorithm modifies the existing Adaptive Leading Edge Subwaveform retracker originally designed for coastal waters, and is applied to Envisat and ERS-2 missions. The validation in a test area of the Arctic Ocean demonstrates that the presented strategy is more precise than the dedicated ocean and sea ice retrackers available in the mission products. It decreases the retracking open ocean noise by over 1 cm with respect to the standard ocean retracker and is more precise by over 1 cm with respect to the standard sea ice retracker used for fitting specular echoes. Compared to an existing open ocean altimetry dataset, the presented strategy increases the number of sea level retrievals in the sea ice-covered area and the correlation with a local tide gauge. Further tests against in-situ data show that also the quality of coastal retrievals increases compared to the standard ocean product in the last 6 km within the coast. ALES+ improves the sea level determination at high latitudes and is adapted to fit reflections from any water surface. If used in the open ocean and in the coastal zone, it improves the current official products based on ocean retrackers. First results in the inland waters show that the correlation between water heights from ALES+ and from in-situ measurement is always over 0.95. [ABSTRACT FROM AUTHOR]

This paper deals with the intrasystem electromagnetic interference (EMI) in a pacemaker equipped with a wireless power transfer (WPT) charging system. The WPT application to pacemakers is very new, and no results are yet published on possible EMI effects produced by the WPT coil currents in the pacemaker pacing leads. To this aim, an efficient and original co-simulation circuit/field method is proposed to predict the induced voltages on a pacing lead. In the numerical calculation, the pacemaker with WPT secondary coil and a pacing lead is implanted in a sophisticated human body model. The numerical results are validated by measurements showing a good agreement. The proposed approach would be a useful tool for pacemaker EMI compliance tests and safety assessment evaluations. [ABSTRACT FROM AUTHOR]

Background Echocardiographically detected patent foramen ovale (PFO) has been associated with stroke/transient ischemic attack (TIA) in patients with cardiac implantable electronic devices (CIEDs). We sought to evaluate the relationship between echocardiographic characteristics and risk of stroke/TIA and mortality in CIED patients with PFO. Methods In 6,086 device patients, PFO was detected in 319 patients. A baseline echocardiogram was present in 250 patients, with 186 having a follow-up echocardiogram. Results Of 250 patients with a baseline echocardiogram, 9.6% (n = 24) had a stroke/TIA during mean follow-up of 5.3 ± 3.1 years; and 42% (n = 105) died over 7.1 ± 3.7 years. Atrial septal aneurysm, prominent Eustachian valve, visible shunting across PFO, baseline or change in estimated right ventricular systolic pressure (RVSP)/tricuspid regurgitation (TR), or maximum RVSP were not associated with postimplant stroke/TIA (P > 0.05). An exploratory multivariate analysis using time-dependent Cox models showed increased hazard of death in patients with increase in TR ≥2 grades (hazard ratio [HR] 1.780, 95% confidence interval [CI] 1.447-2.189, P < 0.0001), or increase in RVSP by >10 mm Hg (HR 2.018, 95% CI 1.593-2.556, P < 0.0001), or maximum RVSP in follow-up (HR 1.432, 95% CI 1.351-1.516, P < 0.0001). A significant increase (P < 0.001) in TR was also noted during follow-up. Conclusions In patients with CIED and PFO, structural and hemodynamic echocardiographic markers did not predict future stroke/TIA. However, a significantly higher TR or RVSP was associated with higher mortality. [ABSTRACT FROM AUTHOR]

In this article, a comprehensive review on bioactive flavonoids that are abundant in medicinal and functional food (dietary) plants has been made, with special reference to antimalarial flavonoid molecules. Flavonoids have been found to exist in plants/plant medicines comprising numerous polyphenolic compounds with a wide structural diversity having pharmacological potential in diverse range of therapeutic areas. Flavonoids derived from certain dietary plants described herein have been investigated for their antimalarial effectiveness against malaria parasites, particularly Plasmodium falciparum. The biological target specificity of their antimalarial action is so interesting that they act at protein targets at molecular level other than the conventional antimalarial targets. This approach may be a basis of establishing plant flavonoids as future antimalarial leads for the development of new and potent antimalarial drug molecules. [ABSTRACT FROM AUTHOR]

The existence and detection of leads are critical to obtain a local Sea Surface Height (SSH) reference for computing total freeboard and sea ice thickness from NASA's IceBridge Airborne Topographic Mapper (ATM) elevations. However, the shaded areas of the Digital Mapping System (DMS) images and the biased ATM elevations impact the correct determination of leads and SSH. This study develops an automated approach to overcome the above challenges and to correctly determine SSHs by combining DMS images, ATM L1B's apparent reflectivity and statistical discrimination. Dynamic pixel intensity thresholds are established to classify leads under different solar illuminations. This automated approach is then validated by manual selection in detecting SSHs. The high agreement of SSHs from this automated approach with those from manual selection indicates the reliability and usefulness of this approach. Within a 45-km section of one ATM L1B file, SSH demonstrates a linear gradient, which is applied to derive SSHs where there are no leads. The resulted SSHs are then used to compute total freeboard and ice thickness. This automated approach is also tried to retrieve SSH and then compute the total freeboard on one entire IceBridge sea ice flight each in Arctic and Antarctica. [ABSTRACT FROM AUTHOR]

In this article, the concept and essence of lead generation, the main types of customer acquisition and methods of successful work on lead generation, directions using lead generation and billing system are considered. The actions taken into account when creating the cost of website promotion by actions are analyzed. Guarantees for the promotion of the site on the leaders revealed. [ABSTRACT FROM AUTHOR]

Our researches are aimed to determine the amplitude of the recorded electrocardiograph waves by means of three leads systems (two systems found in the scientific literature, and a leads system imagined by us), of a dairy cow. To this end, there were recorded electrocardiograms on group of 20 dairy cows and then the electrocardiograms were interpreted by calculating the amplitudes of the waves P and T and the total amplitude (summing the positive and negative for each branch in part) of the ventricular complex QRS, from the all three leads systems used. After interpreting the obtained results, we can conclude that neither of the leads system used in our study provides a complete electrocardiographic investigation. Thus, derivations Dubois may be recommended for recording ECG in D II (bipolar derivation II), D III (bipolar derivation III) and aVF (unipolar derivation, with electrode placed on the left hindlimb), while recording electrocardiogram in D I (bipolar derivation I), we recommend using limbs leads and leads system designed by us. Regarding recording of the electrocardiogram in aVR (unipolar derivation, with electrode placed on the right forelimb) and aVL (unipolar derivation, with electrode placed on the left forelimb) we appreciate that all three systems examined in our research can be successfully used. [ABSTRACT FROM AUTHOR]

The presence of sea-ice leads represents a key feature of the Arctic sea ice cover. Leads promote the flux of sensible and latent heat from the ocean to the cold winter atmosphere and are thereby crucial for air-sea-ice-ocean interactions. We here apply a binary segmentation procedure to identify leads from MODIS thermal infrared imagery on a daily time scale. The method separates identified leads into two uncertainty categories, with the high uncertainty being attributed to artifacts that arise from warm signatures of unrecognized clouds. Based on the obtained lead detections, we compute quasi-daily pan-Arctic lead maps for the months of January to April, 2003-2015. Our results highlight the marginal ice zone in the Fram Strait and Barents Sea as the primary region for lead activity. The spatial distribution of the average pan-Arctic lead frequencies reveals, moreover, distinct patterns of predominant fracture zones in the Beaufort Sea and along the shelf-breaks, mainly in the Siberian sector of the Arctic Ocean as well as the well-known polynya and fast-ice locations. Additionally, a substantial inter-annual variability of lead occurrences in the Arctic is indicated. [ABSTRACT FROM AUTHOR]

Data from an IceBridge Arctic campaign on April 20, 2010 with the Airborne Topographic Mapper (ATM) and the Land, Vegetation, and Ice Sensor (LVIS) in operation on the same airplane were used in this study. ATM and LVIS lidar waveforms were fitted with Gaussian curves to calculate pulsewidth, peak location, pulse amplitude, and signal baseline. For each waveform, the centroid, skewness, kurtosis, and pulse area were also calculated. Received waveform parameters, such as pulsewidth, pulse amplitude, pulse area, skewness, and kurtosis, show coherent response to variations of geophysical features along an ATM or LVIS profile. These parameters, combined with elevation, were used to identify leads in sea-ice freeboard calculation. The relationship between these parameters and sea-ice freeboard and surface features were studied by comparing the parameters with ATM and LVIS-derived freeboard and coincident Digital Mapping System images which have been used to classify sea-ice surface types such as leads, thin ice, gray ice, and thick ice. An elevation bias of more than 16 cm (peak-to-peak) as a function of laser scanner azimuth was found in the ATM data, and an empirical correction was applied; this correction will improve the ATM shot-to-shot freeboard significantly. The newly derived ATM freeboard was compared with the current IceBridge IDCSI2 freeboard product at National Snow and Ice Data Center (NSIDC) and the freeboard derived from LVIS data. Over the studied area, the mean freeboard is 0.540 $\pm$ 0.091 m for the IDCSI2 at NSIDC, 0.496 $\pm$ 0.062 m for the ATM after empirical elevation correction, and 0.509 $\pm$ 0.048 m for the LVIS. [ABSTRACT FROM PUBLISHER]

Detailed mapping of fast-ice deformation can be used to characterize the rheological behavior of fast ice and subsequently improve sea ice modeling. This study uses interferometric synthetic aperture radar to map fast-ice deformation with unprecedented spatial resolution (meter range) and sensitivity (cm-mm range). Two interferometric acquisitions, each with a temporal baseline of 24 h, were performed by the X-band SAR satellite constellation Cosmo-SkyMed over the northeast Bay of Bothnia in the middle of the 2012 ice season. The first interferogram shows deformation of the fast ice due to force from impinging drift ice, and the normal strain within the fast ice is measured. Complementary intensity correlation measurements reveal a slow movement of the drift ice toward the fast ice. The second interferogram exhibits a low fringe rate over the fast ice with fringes being aligned along the coastline. Deformation appears to be stronger around leads, skerries, and grounded ice ridges. It is also observed that the coherence images provide information that is complementary to the information in the backscatter images. [ABSTRACT FROM PUBLISHER]

Frost flowers are transient crystal structures that form on new and young sea ice surfaces. They have been implicated in a variety of biological, chemical, and physical processes and interactions with the atmosphere at the sea ice surface. We describe the atmospheric and radiative conditions and the physical and thermal properties of the sea ice and atmosphere that form, decay, and destroy frost flowers on young sea ice. Frost flower formation occurred during a high-pressure system that caused air temperatures to drop to -30°C, with relative humidity of 70% (an undersaturated atmosphere), and very calm wind conditions. The sea ice surface temperature at the time of frost flower initiation was 10° - 13°C warmer than the air temperature. Frost flowers grew on nodules raised above the mean surface height by 5 mm, which were 4° - 6°C colder than the bare, brine-wetted, highly saline sea ice surface that provided the necessary moisture. The cold nodules created potential water vapour supersaturation zones above them with respect to air over the brine skim. Frost flowers formed and grew overnight in the absence of shortwave radiation, while the net longwave radiation was negative and dominated the net all-wave radiation balance at the surface. The observed crystal habits of the frost flowers were long needles, betraying their origin from the vapour phase at temperatures between -20°C and -30°C. After a night of growth, frost flowers decayed in association with increased solar radiation, a net surface radiation balance of 0 W m-2, increased air and surface temperatures, increased wind speed, and decreased relative humidity. We hypothesize that these conditions increased vertical mixing, which eroded near-surface water vapour saturation and initiated sublimation. The frost flowers finally were rapidly destroyed by snowfall. [ABSTRACT FROM AUTHOR]

Schistosomiasis is a neglected parasitic tropical disease that claims around 200,000 human lives every year. Praziquantel (PZQ), the only drug recommended by the World Health Organization for the treatment and control of human schistosomiasis, is now facing the threat of drug resistance, indicating the urgent need for new effective compounds to treat this disease. Therefore, globally, there is renewed interest in natural products (NPs) as a starting point for drug discovery and development for schistosomiasis. Recent advances in genomics, proteomics, bioinformatics, and cheminformatics have brought about unprecedented opportunities for the rapid and more cost-effective discovery of new bioactive compounds against neglected tropical diseases. This review highlights the main contributions that NP drug discovery and development have made in the treatment of schistosomiasis and it discusses how integration with virtual screening (VS) strategies may contribute to accelerating the development of new schistosomidal leads, especially through the identification of unexplored, biologically active chemical scaffolds and structural optimization of NPs with previously established activity. [ABSTRACT FROM AUTHOR]

We infer the fractional coverage of sea ice leads (as concentration) in the Arctic from Advanced Microwave Scanning Radiometer for Earth Observing System (EOS) (AMSR-E) brightness temperatures. The lead concentration resolves leads of at least 3 km in width. We introduce a new algorithm based on the progressive probabilistic Hough transform to automatically infer lead positions and orientations from daily AMSR-E satellite observations. Because the progressive probabilistic Hough transform often detects an identical lead several times the algorithm clusters neighboring leads that belong to one lead position. A first comparison of automatically detected lead positions and orientations with manually detected lead positions and orientations reveals that 57% of the reference leads are correctly determined. Around 11% of automatically detected leads are located where no reference lead occurs. The automatically detected lead orientations are distributed slightly differently from the reference lead orientations. A second comparison of automatically detected leads in the Fram Strait to leads in a wide swath mode Advanced Synthetic Aperture Radar scene shows a good agreement. We provide an Arctic-wide time series of lead orientations for winters from 2002 to 2011. For example, while a lead orientation of 110° with respect to the Greenwich meridian prevails in the Fram Strait, lead orientations in the Beaufort Sea are more isotropically distributed. We find significant preferred lead orientations almost everywhere in the Arctic Ocean when averaged over the entire AMSR-E time series. [ABSTRACT FROM AUTHOR]

Current pressures on public health systems have led to increased emphasis on restructuring, which is seen as a potential solution to crises of accessibility, quality, and funding. Leadership is an important factor in the success or failure of these initiatives. Despite its importance, health leadership evades easy articulation, and its study requires a thoughtful methodological approach. We used a modified Delphi method in a Participatory Action Research (PAR) project on health leadership in Canada. Little has been written about the combination of Delphi method with PAR. We offer a rationale for the combination and describe its usefulness in researching the role of leadership in a restructuring initiative in "real time" with the participation of health system decision makers. Recommendations are provided to researchers wishing to use the Delphi method qualitatively (i.e., without statistical consensus) in a PAR framework while protecting the confidentiality of participants who work at different levels of authority. We propose a modification of Kaiser's (2009) post-interview confidentiality form to address power differentials between participants and to enhance confidentiality in the PAR process. [ABSTRACT FROM AUTHOR]

Abstract: Insulation wear in implanted cardiac leads may result in serious failure modes, including inappropriate or missing therapy. A novel test apparatus intended to simulate a range of loading conditions between cardiac lead components has been developed. Wear testing performed in an aqueous environment at loads and velocities anticipated to occur in-vivo shows that a material with decreased toughness exhibited increased wear rate. Order of magnitude variability within test groups was observed, suggesting that reliability projections should incorporate the statistical nature of the wear rate. Ranking of implantable material wear rates are possible using this methodology. [Copyright &y& Elsevier]

Ultrasound-Guided Lead Placement. Introduction: Ultrasound guidance is widely recommended to reduce the risk of complications during central venous catheter placement. However, ultrasound guidance is not commonly utilized for implanting leads for cardiac rhythm management devices. Methods and Results: We describe our technique of ultrasound-guided pacemaker implantation, including a novel pull-through technique that allows percutaneous guidewire insertion prior to the first incision. We review the literature and recent advances in ultrasound imaging technology that may facilitate the adoption of ultrasound guidance. Conclusions: Ultrasound guidance provides a safe and rapid technique for extrathoracic subclavian or axillary venous lead placement. (J Cardiovasc Electrophysiol, Vol. 24, pp. 370-374, March 2013) [ABSTRACT FROM AUTHOR]

Implanted cardiac devices, including pacemakers, defibrillators, and resynchronization devices, are known to develop thrombus on their intravascular leads. Patent foramen ovale (PFO) occurs in approximately one-quarter of the adult population. It is unclear whether paradoxical cardioembolism and clinically relevant stroke occur in patients with implanted cardiac leads and PFO. We present a case series of four patients with cardioembolic stroke, presumed to arise from intravascular cardiac leads and associated PFO that required device closure of the PFO. (PACE 2013; 36:50-54) [ABSTRACT FROM AUTHOR]

Abstract: Twenty-six 2-pyridone derivatives (8a–8z), which are structurally analogous to amrinone and milrinone two important cardiotonic drugs, are synthesized and characterized. The synthesis of 2-pyridone derivatives involves addition, followed by cyclization between Baylis–Hillman acetates (7a–7k) and enamino esters or nitriles (3a–3e). Thus synthesized pyridones were subjected to PDE3 inhibitory activity, 14 pyridones were found to be hits out of 26 pyridones synthesized and out of 14 hits, there are 5 pyridones found to be lead compounds having excellent PDE3 inhibitory activity. Further we have carried out computational analysis to understand protein/enzyme and 2-pyridone derivative interactions to identify amino acid residues involved in the vicinity of binding and compared with milrinone drug. [Copyright &y& Elsevier]

Impact of Recalls on ICD Utilization. Introduction: The study was designed to evaluate the feasibility and performance of right ventricular (RV) mid-septal versus apical implantable defibrillator (ICD) lead placement. Methods and Results: SEPTAL is a randomized, noninferiority trial, which randomly assigned patients to implantation of ICD leads in the RV mid-septum versus apex, with a primary objective of comparing the implant success rate of implant at each site, based on strict electrical predefined criteria. We also compared the (1) pacing lead characteristics, (2) rates of appropriate and inappropriate ICD therapies, and (3) all-cause mortality between the 2 sites at 1 year. The trial enrolled 215 patients (mean age = 59.7 ± 12.4 years, mean LVEF = 34.0 ± 14.2%, 84.2% men), of whom 148 (68.8%) presented with ischemic heart disease. The ICD indication was primary prevention in 117 patients (54.4%). The lead was successfully implanted in 96/107 patients (89.7%) assigned to the RV mid-septum, and in 99/108 (91.7%) assigned to the apex (ns). The 1-year rate of lead-related adverse events was similar in both groups. A total of 8 first inappropriate ICD therapies (7.9%) were delivered in the RV mid-septal group, versus 8 (7.8%) in the apical group (ns), while first appropriate therapies were delivered to 22 (21.4%) and 24 patients (23.8%), respectively (ns). All-cause mortality was 7.9% in the RV mid-septal versus 2.9% in the RV apical group (ns). Conclusion: This study confirmed the technical feasibility and noninferior performance of ICD leads implanted in the RV mid-septum versus the apex. (J Cardiovasc Electrophysiol, Vol. 23, pp. 853-860, August 2012) [ABSTRACT FROM AUTHOR]

Background: There has been concern over declining bipolar (BP) impedance (Z) in aging polyurethane (PU) cardiac pacing leads. Subsequently, a prospective study was conducted comparing BP Z, threshold (Th), and R-wave sensing amplitude of 55D PU-insulated (Model 4024, Medtronic, Inc., Minneapolis, MN, USA) and silicone-insulated (Model 5024) leads. Methods: This study was initiated by The Iowa Heart Center. Patients with Model 4024 (N = 162) or 5024 (N = 120) pacing leads with at least 6 years implant time were enrolled and followed for an additional 5 years. Results: There was a significant drop in the mean BP Z for the Model 4024 population, between enrollment (6 years) and the final endpoint (11 years), which was in contrast to the Model 5024 which did not see a significant drop in its mean BP Z for this same period. The trend difference seen in the means between the two models was statistically significant (P < 0.0001). In addition, a statistically significant relationship was found between dropping BP Z and rising Th (P < 0.0001). The analysis showed that if BP Z dropped below 200 ohms, the probability of having a >3X increase over baseline, in Th at 2.5 V, increases from approximately 3-7% to as high as 30%. Conclusions: A significant drop in BP Z observed in the PU-insulated Model 4024 lead was not present in the silicone-insulated Model 5024 lead. The statistically significant relationship between dropping BP Z and rising Th helps to understand how to better manage patients with aging leads. (PACE 2012; 35:51-57) [ABSTRACT FROM AUTHOR]

The biocompatibility of all metallic, polymeric, or ceramic materials used for functional electrical stimulation is governed by the inevitable inflammatory tissue response, but possibly also by immunological reactions to the bulk material or released constituents. Besides chemical, physical, and corrosion properties of the conductive electrode materials, increased surface area and roughness of the electrode can influence tissue contact and signal delivery, and can also affect electrode-tissue impedance due to increased connective tissue encapsulation. The polymeric materials used for electrode insulation and those for leads and stimulator packaging seem more or less compatible in an aggressive biological environment. For the long-term performance of electrodes and leads, the relative motion in the various implant bed situations also has to be considered. [ABSTRACT FROM AUTHOR]

Objectives: This study sought to examine the safety and efficacy of laser-assisted lead extraction and the indications, outcomes, and risk factors in a large series of consecutive patients. Background: The need for lead extraction has been increasing in direct relationship to the increased numbers of cardiovascular implantable electronic devices. Methods: Consecutive patients undergoing transvenous laser-assisted lead extraction at 13 centers were included. Results: Between January 2004 and December 2007, 1,449 consecutive patients underwent laser-assisted lead extraction of 2,405 leads (20 to 270 procedures/site). Median implantation duration was 82.1 months (0.4 to 356.8 months). Leads were completely removed 96.5% of the time, with a 97.7% clinical success rate whereby clinical goals associated with the indication for lead removal were achieved. Failure to achieve clinical success was associated with body mass index <25 kg/m2 and low extraction volume centers. Procedural failure was higher in leads implanted for >10 years and when performed in low volume centers. Major adverse events in 20 patients were directly related to the procedure (1.4%) including 4 deaths (0.28%). Major adverse effects were associated with patients with a body mass index <25 kg/m2. Overall all-cause in-hospital mortality was 1.86%; 4.3% when associated with endocarditis, 7.9% when associated with endocarditis and diabetes, and 12.4% when associated with endocarditis and creatinine ≥2.0. Indicators of all-cause in-hospital mortality were pocket infections, device-related endocarditis, diabetes, and creatinine ≥2.0. Conclusions: Lead extraction employing laser sheaths is highly successful with a low procedural complication rate. Total mortality is substantially increased with pocket infections or device-related endocarditis, particularly in the setting of diabetes, renal insufficiency, or body mass index <25 kg/m2. Centers with smaller case volumes tended to have a lower rate of successful extraction. [Copyright &y& Elsevier]

Introduction: Insulation defects are a leading cause of transvenous lead failure. The purpose of this study was to determine the effects of electrocautery on transvenous lead insulation materials. Methods: A preparation was done to simulate dissection of a transvenous lead from tissues. Radiofrequency energy was delivered using a standard cautery blade at outputs of 10, 20, and 30 W, for 3 and 6 seconds, using parallel and perpendicular blade orientations on leads with outermost insulations of silicone rubber, polyurethane, and silicone–polyurethane copolymer. Damage to each lead segment was classified after visual and microscopic analysis. Results: Significant insulation damage occurred to almost all polyurethane leads. Full insulation breaches were observed with 30 W regardless of application duration with a parallel direction and with all power outputs with a perpendicular direction. Thermal insulation damage to copolymer insulation was similar to that of the polyurethane leads. In contrast, there was no thermal damage to silicone leads, regardless of the power output and duration of power delivery. However, mechanical insulation damage was observed to all silicone leads when at least 20 W was applied in a direction perpendicular to the lead. Conclusions: Polyurethane (PU55D) and copolymer materials have low thermal stability and are highly susceptible to thermal damage during cautery. Implanting physicians should be aware of the lead insulation materials being used during implant procedures and their properties. The use of direct contact cautery on transvenous leads should be minimized to avoid damage to the lead, especially on leads with polyurethane or copolymer outer insulations. [ABSTRACT FROM AUTHOR]

Abstract: This article explains the principles of electrocardiography, and explains how it is used by Safety Pharmacology, with a focus on the requirement for multiple leads in Safety Pharmacology assessment. Electrocardiography as used in different disciplines (e.g., medicine, anesthesiology, physiology, and pharmacology/toxicology/safety pharmacology) has different requirements for the number of electrodes applied. Electrodes may be placed at an infinite number of points on the body, and voltages (electrocardiograms) may be registered between/among them. However in safety pharmacology there is little evidence that more than 1—or at most 3—lead(s) is (are) required to provide all of the information that might be present using an infinite number. This is based upon (1) the biophysics of the heart as a generator of electrical potential/voltage, (2) the fact that most properties of electrophysiology affected adversely by drugs are expressed as changes in durations, and (3) experience. A single, unipolar lead (V3) recorded from the left sternal border at the 5th intercostal space possesses minimal artifact and large, stable deflections. This lead allows for accurate measurement of heart rate and rhythm, durations of component deflections (e.g., PQ, QRS, QT), and J-point deviation. A greater number of leads seldom or never yield additional information that detects liabilities. Commonly voltages recorded between the right thoracic and left pelvic limbs (lead II) provides information similar to lead V3, and lead II is easier to apply, and produces voltages with less artifact and similar to those in lead V3. A lead measuring the voltage between the left and right thoracic limbs (lead I) along with lead II allows for estimating orientation of vectors in the frontal plane, but knowledge of these vectors seldom or never indicates liability of a test article. [Copyright &y& Elsevier]

Background: The potential advantages of using a 4Fr lumenless pacing lead (3830 SelectSecure™, Medtronic Inc, Minneapolis, MN, USA) in children are largely negated due to the large size of the delivery system. Here we describe an innovative, sheath guided, delivery technique using conventional 5F sheaths. Methods: Transvenous access was obtained via the left cephalic or axillary vein. A 5Fr introducer set with a 45° curved tip (CheckFlo® Performer® Introducer Set with the Children's Hospital Boston Modification, Cook Medical Inc, Bloomington, IN, USA) was placed over a wire into the right atrium (RA) or right ventricle (RV). The sheath was modified by cutting off the valved end and a SelectSecure™ lead was introduced through the sheath. Rotating the sheath provided steerability and allowed for precise placement of the lead. After successful lead placement, the sheath was removed with a universal sheath splitter. Results: We placed seven atrial and six ventricular leads in eight patients during nine separate cases with this method. Patient ages and weights ranged from 5 to 16 years and 16 to –59 kg respectively. Pacing thresholds were excellent at implant. Leads were placed successfully in all attempts. There were no procedural complications. One patient had leads placed twice; both lead systems were removed for suspected infection. Over short-term follow-up in five patients, lead position and characteristics have remained stable. Conclusion: Delivery of the SelectSecure™ lead in children can be successfully and precisely performed using a modified 5Fr sheath obviating the need for a large steerable delivery system. [ABSTRACT FROM AUTHOR]

Information about several papers discussed at a conference organized by the International Cardiac Pacing and Electrophysiology Society (ICPES) in December 2007 in Rome, Italy is presented. Topics included those on pacemakers and implantable cardioverters and on how to improve device performance monitoring. It featured several professors including C. P. Lau from Hong Kong, China and M. Santini.

Objectives: Implantation of an additional HV-P/S lead versus extraction of the defective HV-P/S lead and implantation of a new one is one possible therapeutic approach in cases of a defective high-voltage pace/sense lead (HV-P/S). No information is available on potential differences in clinical outcome in these different approaches. Methods: Between January 2000 and February 2006, 86 patients with HV-P/S lead defect received either an additional transvenous HV-P/S lead (n = 33, group 1) or the HV-P/S lead was replaced (n = 53, group 2). The duration of the initially implanted leads was significantly different in the two groups (7.4 ± 2.9; group 1 and 4.1 ± 3.4 years; group 2).The outcome of these two groups of patients was retrospectively analyzed. Results: Seventy-three patients [85%] survived until the end of follow-up of 29 ± 15 (group 1) and 33 ± 21 (group 2) months (P = ns), respectively. Thirteen patients died: six in group 1 and seven in group 2 (P = ns). Fourteen patients experienced perioperative complications (group 1: six; group 2: eight; P = ns). ICD system-related complications occurred in 22 patients (group 1: seven; group two: 15; P = ns). The event-free cumulative survival of patients with additional and replaced HV-P/S lead for postoperative events (including death) after 1, 2, and 3 years was 82%, 70%, 70%, and 86%, 81%, 66%, respectively (P = 0.93). Conclusions: Implantation of an additional HV-P/S lead or replacement of the HV-P/S lead in case of HV-P/S lead failure is statistically not different concerning mortality and morbidity. There are no predictors for further lead defects. Implantation of an additional HV-P/S lead should not be recommended in young patients or patients with greater likelihood of living many years. Predictors for death were an age over 70 years and renal insufficiency. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of the study was to assess the effects of electrodes and leads on electromagnetic field and specific absorption rate (SAR) distributions during simultaneous electroencephalography (EEG) and 7-T MRI. Two different approaches were evaluated and compared to the case without electrodes: (a) the use of different EEG lead resistivity and (b) the use of a radiofrequency (RF) resistor on the lead near the EEG electrode. These configurations are commonly used in research and clinical settings. Electromagnetic field and SAR distributions generated by the transmit RF coil were evaluated using finite difference time domain simulations on an anatomically accurate head model. The spatiotemporal changes of temperature were estimated with the heat equation. Temperature changes during turbo spin echo sequences were also measured using a custom-made phantom: the conductive head mannequin anthropomorphic (CHEMA). The results of this study showed that the SAR and temperature distributions in CHEMA (a) increased when using low resistive leads, with respect to the no-electrode case; (b) were affected by the resistivity of the EEG leads, with carbon fiber leads performing better than standard copper leads; and (c) were not affected by the use of an RF resistor between the EEG electrode and the lead. [Copyright &y& Elsevier]

Drug-like and lead-like hits derived from HTS campaigns provide good starting points for lead optimization. However, too strong emphasis on potency as hit-selection parameter might hamper the success of such projects. A detailed absorption, distribution, metabolism, excretion and toxicology (ADME–Tox) profiling is needed to help identify hits with a minimum number of (known) liabilities. This is particularly true for drug-like hits. Herein, we describe how to break down large numbers of screening hits and we provide a comprehensive overview of the strengths and weaknesses for each structural class. The overall profile (e.g. ligand efficiency, selectivity and ADME–Tox) is the distinctive feature that will define the priority for follow-up. [Copyright &y& Elsevier]

Introduction: Much clinical evidence has shown that right ventricular (RV) apical pacing is detrimental to left ventricular function. Preservation of the use of the His-Purkinje (H-P) system may be ideal in heart block that is restricted to the AV node, but may be of no benefit when H-P disease exists. Aim: To investigate the feasibility of direct His-bundle pacing (DHBP) using a new system consisting of a steerable catheter and a new 4.1 F screw-in lead. Method: Between May and December 2004, 26 patients (19 male, mean age: 77 ± 5 years) with a standard pacemaker (PM) indication and preserved His-bundle conduction were enrolled and DHBP was attempted. Results: DHBP was achieved in 24 patients (92%); two patients were paced in the His area, but the paced QRS morphology and duration were different from the native QRS. The mean time for lead positioning was 19 ± 17 minutes, the mean fluoroscopy time was 11 ± 8 minutes, and the total procedure time (skin-to-skin including positioning of a quadripolar diagnostic catheter for His recording) was 75 ± 18 minutes. In DHBP pacing, the acute pacing threshold was 2.3 ± 1.0 V at a pulse duration of 0.5 msec, and the sensed potentials were 2.9 ± 2.0 mV. At a 3-month follow-up examination, the same QRS duration and morphology recorded on implantation were observed in all patients. The pacing threshold was 2.8 ± 1.4 V, and sensed potentials were 2.5 ± 1.8 mV; the sensing configuration was changed from bipolar to unipolar in 6 patients to resolve undersensing issues. No major complications were observed. Conclusions: This feasibility study shows that DHBP can be accomplished with a new system consisting of a steerable catheter and an active fixation lead in 92% of the patients in whom it was attempted. [ABSTRACT FROM AUTHOR]

In order to quantitatively investigate the role of leads and sea-ice in air-mass modification, aircraft observations were conducted over the partially ice-covered Sea of Okhotsk. We investigated two cold-air outbreak events with different sea-ice concentrations. In both cases, the difference between the temperatures of surface air and the sea surface (Δ T) dropped rapidly with the accumulated fetch-width of leads up to about 35-40 km, and then decreased very slowly. The surface sensible heat flux originating from open water was about 300 W m−2 within a few kilometres from the coast and decreased with increasing accumulated fetch-width. The sensible heat flux was about 100 W m−2 on average. These results indicate that the downwind air-mass modification depends mainly on the total (accumulated) extent of open water. The total buoyancy flux $$\left(\overline {w'T \, '_v}\right)$$ calculated by the joint frequency distribution method correlated very well with ice concentration. Such a relationship was not clear in the case of the moisture flux $$(\overline {w'q'})$$. The ratio between rising thermals $$\left(\overline {w^+T^+_v}\right) $$ and cold downdrafts $$\left(\overline {w^-T^-_v}\right)$$ differed significantly between upwind and downwind regions; that is, the buoyancy flux was dominated by $$\overline {w^+T^+_v} $$ in the developing stage of the boundary layer, while $$\overline {w^-T^-_v} $$ also became important after the development of the boundary layer. [ABSTRACT FROM AUTHOR]

WOLLMANN, C.G., et al.: Incidence of Complications in Patients with Implantable Cardioverter/Defibrillator Who Receive Additional Transvenous Pace/Sense Leads. Background: Implantation of an additional pace/sense (P/S) lead is commonly used in patients with implantable cardioverter/defibrillators (ICDs) to overcome P/S defects of integrated defibrillation leads (HV-P/S leads). No information is available about the clinical outcome and the incidence of complications in these patients. Methods: Retrospective analysis was performed in 151 patients (125 male, age 54.9 ± 13.6 years, LVEF 48.1 ± 17.8%, CAD in 86 [57%], DCM in 24 [16%], ARVCM in 11 [7%]) who received an additional P/S lead between 1990 and 2002 (54 patients with abdominal and 97 patients with pectoral ICD system). Statistical analysis was done using Kaplan-Meier survival curves. Results: The average follow-up (FU) after implantation of the additional P/S lead was 43 ± 27 months. In total 117 patients [77.5%] remain implanted; 22 patients died due to cardiac-related reasons. After a FU of 23 ± 23 months, 43 patients [28.5%] experienced lead-related problems after implantation of the additional P/S lead: oversensing in 23 [53.5%], insulation defect in 3 [7.0%], fracture in 1 [2.3%], system infection in 4 [9.3%], and defect of the HV-P/S lead in 6 [14.0%] patients. The event-free cumulative survival of the additional P/S lead after 1, 2, and 5 years was 87.0%, 79.8%, and 59.4%, respectively (for pectoral leads: 89.6%, 82.0%, and 60.0%, respectively). Conclusions: Implantation of an additional P/S lead in case of failure of an HV-P/S lead is safe. However, it is associated with a substantial rate of complications during FU. Therefore, extraction of damaged defibrillation leads instead of implantation of P/S leads should be favored. (PACE 2005; 28:795–800) [ABSTRACT FROM AUTHOR]

GULA, L.J., et al.: Central Venous Occlusion Is Not an Obstacle to Device Upgrade with the Assistance of Laser Extraction . Objective: To assess the efficacy and safety of laser-assisted lead extraction for upgrade of existing pacemakers and defibrillators in patients with central venous obstruction. Background: Implantable cardiac defibrillators and biventricular pacing have become the accepted therapeutic measures for patients with congestive heart failure. Many patients who are candidates for device therapy, however, already have existing right ventricular leads and the presence of central venous obstruction. Upgrade of existing devices in these patients is a dilemma, which is increasingly encountered by device-implanting physicians. Laser-assisted extraction of existing leads can facilitate access for device upgrade and provide an alternative to lead abandonment and contralateral implant. Methods: We review our experience with laser-assisted lead extraction in patients, referred for upgrade of existing devices, who were found to have, or known to have, ipsilateral subclavian vein occlusion. Results: Over the past 3 years, 18 patients (13 men, 5 women; mean age 63.9 ± 16 years) with subclavian vein occlusion underwent successful laser-assisted lead extraction (total 29 leads) and upgrade of existing leads to defibrillators and/or biventricular systems. Mean implant duration prior to extraction was 70.8 ± 43.5 (11–192) months. Cannulation of the coronary sinus and placement of a transvenous left ventricular lead were achieved in all 13 patients in whom it was attempted. No complications occurred. Conclusions: Laser-assisted lead extraction is a safe and effective approach, allowing for ipsilateral device upgrade in patients with existing devices and central venous obstruction. (PACE 2005; 28:661–666) [ABSTRACT FROM AUTHOR]

RÜB, N., et al.: Addition of a Defibrillation Electrode in the Low Right Atrium to a Right Ventricular Lead Does Not Reduce Ventricular Defibrillation Thresholds. Transvenous unipolar active can defibrillation systems have proven to be effective in treating ventricular tachyarrhythmias. However, a further reduction of ventricular defibrillation thresholds (V-DFT) would increase the longevity, reduce the size of pulse generators, and help to avoid additional leads in patients with inacceptable high V-DFTs. In a finite difference computer model, the extension of the right ventricular (RV) defibrillation coil into the low right atrium led to a 40% reduction of unipolar V-DFT. To evaluate this finding, we conducted a prospective, randomized study in 11 patients receiving an ICD. Extension of the RV electrode was simulated by adding a second coil placed in the low right atrium with the same polarity. Using a binary search protocol, V-DFT was determined with and without the additional electrode in each patient. Total shock impedance was significantly lower in the two coil (low RA) configuration, compared to the single coil (RV) configuration. Corresponding values were 49.9 ± 6.7 Ohm and 61.1 ± 9.3 Ohm, respectively (P < 0.01, paired t-test). However, there was no reduction, but even a nonsignificant increase in V-DFTs. Mean V-DFT in the RV configuration was 12.0 ± 5.6 J and 16.3 ± 7.8 J in the low RA configuration (P = 0.09, paired t-test). Despite a reduction in total impedance, the addition of a defibrillation coil in the low right atrium does not reduce ventricular defibrillation thresholds. (PACE 2004; 27:346–351) [ABSTRACT FROM AUTHOR]